- Appendix 1. CENTURY Reprints
- Appendix 2. Definitions for CENTURY Parameters
- Appendix 2. Definitions for CENTURY Parameters
- Appendix 2.1. Crop parameters (crop.100)
- Appendix 2.2. Cultivation parameters (cult.100)
- Appendix 2.3. Fertilization parameters (fert.100)
- Appendix 2.4. Fire parameters (fire.100)
- Appendix 2.5. Fixed parameters (fix.100)
- Appendix 2.6. Grazing parameters (graz.100)
- Appendix 2.7. Harvest parameters (harv.100)
- Appendix 2.8. Irrigation parameters (irri.100)
- Appendix 2.9. Organic matter addition parameters (omad.100)
- Appendix 2.10. Tree parameters (tree.100)
- Appendix 2.11. Tree removal parameters (trem.100)
- Appendix 2.12. Site specific parameters (<site>.100)
- Appendix 2.13. Output variables
- Appendix 2.2. Cultivation parameters (cult.100)
- Appendix 3. Sample Weather File and Atmospheric C14 Label
File
- Appendix 3.1. Sample Weather File for Weld County,
Colorado
- Appendix 3.2. Sample Atmospheric C14 Label File
- Appendix 3.2. Sample Atmospheric C14 Label File
- Appendix 4. Flow Diagrams for the Subroutines and Model Output
Variables
- Figure 2-1
- Figure 3-1
- Figure 3-2
- Figure 3-3
- Figure 3-4
- Figure 3-5
- Figure 3-6
- Figure 3-7
- Figure 3-8a
- Figure 3-8b
- Figure 3-9
- Figure 3-10
- Figure 3-11
- Figure 3-12
- Figure 3-13
- Figure 3-14
- Figure 3-15
- Figure 3-16
- Figure 3-17
- Figure 3-18
- Figure 3-19
- Figure 3-20
- Figure 3-21
- Figure 3-22
- Figure 3-23
- Figure 3-24
- Figure 3-1
- Appendix 5. CENTURY Data Files
- Appendix 5.1. CROP.100 Parameter Values
- Appendix 5.2. CULT.100 Parameter Values
- Appendix 5.3. FERT.100 Parameter Values
- Appendix 5.4. FIRE.100 Parameter Values
- Appendix 5.5. FIX.100 Parameter Values
- Appendix 5.6. GRAZ.100 Parameter Values
- Appendix 5.7. HARV.100 Parameter Values
- Appendix 5.8. IRRI.100 Parameter Values
- Appendix 5.9. OMAD.100 Parameter Values
- Appendix 5.10. TREE.100 Parameter Values
- Appendix 5.11. TREM.100 Parameter Values
- Appendix 5.12. <SITE.100> Parameter Values
- Appendix 5.2. CULT.100 Parameter Values
- Appendix 6. Addendum
CENTURY Soil Orgainc Matter Model Environment
Report any problems with this document via email
century@nrel.colostate.edu
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CENTURY Agroecosystem Version 4.0 was especially developed to deal with a wide range of cropping system rotations and tillage practices for system analysis of the effects of management and global change on productivity and sustainability of agroecosystems. Version 4.0 integrates the effects of climate and soil driving variables and agricultural management to simulate carbon, nitrogen, and water dynamics in the soil-plant system. Simulation of complex agricultural management systems including crop rotations, tillage practices, fertilization, irrigation, grazing, and harvest methods is now possible in this enhanced release of the model.
The CENTURY model is a general FORTRAN model of the plant-soil ecosystem that has been used to represent carbon and nutrient dynamics for different types of ecosystems (grasslands, forest, crops, and savannas). A brief description of the model structure and scientific basis for the model is included in this manual. Aspects of the current version are discussed in Metherell (1992). A more detailed description of the earlier development of the CENTURY model is contained in Parton et al. (1987), Parton et al. (1988), and Sanford et al. (1991).
The model is available on either the PC or UNIX platforms. The PC version is designed to work with the VIEW run time output module of "TIME-ZERO™: the integrated modeling environment." which allows the user to run the model and then generate graphic output analysis. Also available is a stand-alone PC version which produces ASCII text files and does not provide any graphics capabilities. The UNIX version is also stand-alone (with no graphics) and can be run on Sun, Hewlett-Packard, and IBM platforms. These platforms are suggested for batch processing of large numbers of sites.
This document will describe how to use the CENTURY model and the two utility programs which assist the user in creating the input files needed for CENTURY. Section two describes the components of the CENTURY environment and gives the installation instructions. Section three gives a brief description of the scientific basis for the model, with reference to actual variable names where applicable. The fourth section explains the variable parameterization program, FILE100. The fifth section gives instructions on how to use EVENT100, the scheduling utility. Section six explains how to run the CENTURY model for each of the available versions. Section seven describes a specific CENTURY scenario. Finally, section eight lists in bibliographical form the literature cited in the manual.
Note that the CENTURY model output names for the state variables and flows are shown in the figures (output names are shown in standard type under the state names shown in bold). Some of the output variables are not available in PC CENTURY. The exact definitions of these output variables are found in the *.def data files and are available through the FILE100 program. When running the model it is quite useful to have copies of flow diagram figures since they indicate the names of the output variables for the different submodels.
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2. CENTURY ENVIRONMENT
2.1. Overview of the CENTURY Environment
The program "CENTURYM" is a Fortran representation of the CENTURY SOM model which was developed by Parton et al. (1987). It simulates C, N, P, and S dynamics through an annual cycle to centuries and millennia. A grassland/crop, forest or savanna system may be selected as a producer submodel with the flexibility of specifying potential primary production curves which represent the site-specific plant community. While running the simulation, the program writes files which interface with the runtime output module of TIME- ZERO™ (called VIEW in this document). The use of this runtime module allows you to specify which variables are to be plotted or printed. Alternatively, the stand-alone version on either the PC or UNIX platforms creates a binary file and an ASCII list of selected variables can be created using the LIST100 utility.
The CENTURY environment (Figure 2-1) consists of the CENTURY model, which uses the VIEW output program, and two utilities. The FILE100 program assists the user in creating and updating any of the twelve data files used by CENTURY. The EVENT100 program creates the scheduling file which contains the agricultural plants and events that are to occur during the simulation.
The CENTURY model obtains input values through twelve data files. Each file contains a certain subset of variables; for example, the cult.100 file contains the values related to cultivation. Within each file there may be multiple options in which the variables are defined for multiple variations of the event. For example, within the cult.100 file, there may be several cultivation options defined such as plowing or rod-weeder. For each option, the variables are defined to simulate that particular option. Each data input file is named with a ".100" extension to designate it as a CENTURY file. These files can be updated and new options created through the FILE100 program.
The timing variables and schedule of when events are to occur during the simulation is maintained in the schedule file, named with a ".sch" extension. This file can be created and updated through the EVENT100 program.
First, the CENTURY environment must be installed on the computer to be used (see Section 2.5). Then, follow these steps to work through each facet of the environment:
- 1.
- Use the FILE100 program to update values or
create new options in any of the .100 data files
(Section 4).
- 2.
- Use the EVENT100 program to establish the
simulation time and to schedule events to occur during the simulation
(Section 5).
- 3.
- Run the CENTURY model. Refer to Section 6 for
specific instructions based on the PC or UNIX platform to be used.
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The CENTURY Environment consists of these files:
century.bat batch file used to run CENTURY and VIEW
centurym.exe the CENTURY executable model
centurym.tab table file generated by TIME-ZERO™ to handle I/O
centurym.dat master list of all variables used in CENTURY, not to be
modified by the user
temp.sav file required by VIEW
centuryx.exe the stand-alone CENTURY executable model
fix.100 file with fixed parameters primarily relating to organic matter
decomposition and not normally adjusted between runs
<site>.100 site-specific parameters such as precipitation, soil texture, and
the initial conditions for soil organic matter;
the name of this file is provided by the user
crop.100 crop options file
cult.100 cultivation options file
fert.100 fertilization options file
fire.100 fire options file
graz.100 grazing options file
harv.100 harvest options file
irri.100 irrigation options file
omad.100 organic matter addition options file
tree.100 tree options file
trem.100 tree removal options file
*.def for each *.100 file, there is a corresponding ".def" file which
contains the definitions of each parameter needed for
each option; the format of these ASCII files should
not be modified by the user
sample.wth sample weather file
c14data sample 14C data file
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2.3. Units of Major Parameters
Time step: one month (1/12 year or .083333 year) Minimum time: year Soil Organic Matter: grams C, N, P, or S per meter square Plant Material: grams C, N, P, or S per meter square Mineral pools: grams N, P, or S per meter square Temperature: degrees Centigrade Precipitation: centimeters per month
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2.4. Hardware Requirements for PC Version
The CENTURY Model plus the VIEW module from TIME-ZERO™ requires an IBM-PC or compatible with at least 512K of RAM. A graphics adapter (CGA, EGA, VGA, or Hercules monographic) is recommended. The model files supplied on the diskettes require approximately 220 kilobytes of disk space. The VIEW files require 394 kilobytes of disk space. An output file (CENTURYM.PLT) with data saved monthly for 100 years or annually for 1200 years requires 1-2 Mb of disk space.
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2.5. Installation of PC Version
The package contains 2 diskettes. Disk 1 is labeled VIEW, and contains the VIEW
module from TIME-ZERO™. Disk 2, labeled CENTURY, contains the CENTURY
environment files.
The CENTURY model files may be installed in any directory you wish. The
CENTURY diskettes contain an installation program. To run the installation program,
1. Insert Disk 1 into an appropriate drive (For example, drive A).
2. Change directories to the drive you chose:
A:
3. At the A:\ prompt enter,
INSTALLC C:\path ... \CENTURY
where path is the directory path to the location where you want to install
the model.
4. Follow the directions as they appear on the screen.
The installation procedure will create all the necessary directories and copy all files to the
appropriate directory.
During the installation of VIEW, you will be required to select a printer for the
screen dump utility. When the menu of printers is shown, select a printer using the
cursor keys, then press the TAB key and select the port to which the printer is connected.
Press RETURN when you are done.
There are two ways to set up the directory path so that the VIEW module can be
found by the CENTURY.BAT program.
1. Update the PATH statement in the AUTOEXEC.BAT file to include the
VIEW directory. This has the advantage that the path does not need to be
temporarily updated every time CENTURY is run.
OR
2. Allow the CENTURY.BAT file to temporarily update the PATH. If this
method is chosen, the batch file will need some environment space. If you
get an "OUT OF ENVIRONMENT SPACE" error message while running
CENTURY, modify your CONFIG.SYS file to provide additional
environment space. A typical entry to expand the environment space would
be,
SHELL=COMMAND.COM /P /E:512
where 512 is the number of bytes to be reserved for the environment. There
should also be at least 20 file handles reserved by the CONFIG.SYS. To
reserve 20 file handles, put the statement,
FILES=20
in the CONFIG.SYS. Be sure to CHECK THE DOS MANUAL for
instructions. Some versions of DOS prior to 3.2 used paragraphs (16
bytes/paragraph) as the argument in SHELL. If you try to reserve too much
space, DOS will ignore your /E: argument.
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2.6. Version 4.0 Upgrade Information
Minor upgrades to version 4.0 will be available free of charge via anonymous
ftp. These versions will be numbered 4.x and a text file will be included to
describe the changes.
Ftp to "ftp.nrel.colostate.edu", using "anonymous" as the name and your full
login name (e-mail address) as the password.
Change to the pub/century4.0 directory by typing "cd pub/century4.0".
You can get a listing of the contents of the directory by typing "dir".
Retrieve files by using the "get filename" command.
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3. CENTURY MODEL DESCRIPTION
3.1. Introduction
The CENTURY model simulates the long-term dynamics of Carbon (C), Nitrogen (N), Phosphorus (P), and Sulfur (S) for different Plant-Soil Systems. The model can simulate the dynamics of grassland systems, agricultural crop systems, forest systems, and savanna systems. The grassland/crop and forest systems, have different plant production submodels which are linked to a common soil organic matter submodel. The savanna model uses the grassland/crop and forest subsystems and allows for the two subsystems to interact through shading effects and nitrogen competition. The soil organic matter submodel simulates the flow of C, N, P, and S through plant litter and the different inorganic and organic pools in the soil. The model runs using a monthly time step and the major input variables for the model include:
(1) monthly average maximum and minimum air temperature,
(2) monthly precipitation,
(3) lignin content of plant material,
(4) plant N, P, and S content,
(5) soil texture,
(6) atmospheric and soil N inputs, and
(7) initial soil C, N, P, and S levels.
The input variables are available for most natural and agricultural
ecosystems and can generally be estimated from existing literature. Most of
the parameters that control the flow of C in the system are in the
fix.100 file.
The user can choose to run the model considering only C and N dynamics
(NELEM=1) or C, N, and P (NELEM=2) or
C, N, P, and S (NELEM=3).
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3.2. Soil Organic Matter Submodel
The SOM submodel is based on multiple compartments for SOM and is similar to
other models of SOM dynamics (Jenkinson and Rayner,
1977; Jenkinson, 1990;
van Veen and Paul, 1981). The pools and flows of C
are illustrated in Figure 3-1. The model includes three
soil organic matter pools (active, slow and passive) with different potential
decomposition rates, above and belowground litter pools and a surface microbial
pool which is associated with decomposing surface litter.
Above and belowground plant residues and organic animal excreta are partitioned
into structural (STRUCC(*)) and metabolic
(METABC(*)) pools as a function of the lignin to N ratio
in the residue. With increases in the ratio, more of the residue is
partitioned to the structural pools which have much slower decay rates than the
metabolic pools. The structural pools contain all of the plant lignin
(STRLIG(*)).
The decomposition of both plant residues and SOM are assumed to be microbially
mediated with an associated loss of CO2 (RESP(*)) as a
result of microbial respiration. The loss of CO2 on decomposition of the
active pool increases with increasing soil sand content. Decomposition
products flow into a surface microbe pool (SOM1C(1)) or
one of three SOM pools, each characterized by different maximum decomposition
rates. The potential decomposition rate is reduced by multiplicative functions
(DEFAC) of soil moisture and soil temperature and may be
increased as an effect of cultivation (CLTEFF(*),
cult.100). Average monthly soil temperature near the
soil surface (STEMP) is the input for the temperature
function while the moisture function uses the ratio of stored soil water (0-30
cm depth, AVH2O(3)) plus current month's precipitation
(RAIN) to potential evapotranspiration
(PET). The decomposition rate of the structural material
(STRUCC(*)) is a function of the fraction of the
structural material that is lignin. The lignin fraction of the plant material
does not go through the surface microbe (SOM1C(1)) or
active pools (SOM1C(2)) but is assumed to go directly to
the slow C pool (SOM2C) as the structural plant material
decomposes.
The active pool (SOM1C(2)) represents soil microbes and
microbial products (total active pool is ~2 to 3 times the live microbial
biomass level) and has a turnover time of months to a few years depending on
the environment and sand content. The soil texture influences the turnover
rate of the active soil SOM (higher rates for sandy soils) and the efficiency
of stabilizing active SOM into slow SOM (higher stabilization rates for clay
soils). The surface microbial pool (SOM1C(1)) turnover
rate is independent of soil texture, and it transfers material directly into
the slow SOM pool (SOM2C). The slow pool includes
resistant plant material derived from the structural pool and soil-stabilized
microbial products derived from the active and surface microbe pools. It has a
turnover time of 20 to 50 years. The passive pool (SOM3C)
is very resistant to decomposition and includes physically and chemically
stabilized SOM and has a turnover time of 400 to 2000 years. The proportions
of the decomposition products which enter the passive pool from the slow and
active pools increase with increasing soil clay content.
A fraction of the products from the decomposition of the active pool is lost as
leached organic matter (STREAM(5)). Leaching of organic
matter is a function of the decay rate for active SOM, and the clay content of
the soil (less loss for clay soils) and only occurs if there is drainage of
water below the 30 cm soil depth (leaching loss increases with increasing water
flow up to a critical level - OMLECH(3),
fix.100).
Anaerobic conditions (high soil water content) cause decomposition to decrease.
The soil drainage factor (DRAIN,
<site>.100) allows a soil to have differing
degrees of wetness (e.g., DRAIN=1 for well drained sandy
soils and DRAIN=0 for a poorly drained clay soil).
A detailed description of the structure of an earlier version of the model and
the way in which model parameters were estimated is found in
Parton et al. (1987) (see
Appendix 1).
The model has N, P, and S pools analogous to all of the C pools. Each SOM pool
has an allowable range of C to element ratios based on the conceptual model of
McGill and Cole (1981). Reflecting the concept that
N is stabilized in direct association with C, C to N ratios are constrained
within narrow ranges, while the ester bonds of P and S allow C to P and C to S
ratios to vary widely. The ratios in the structural pool are fixed at high
values, while the ratio in the metabolic pool is allowed to float in concert
with the nutrient content of the plant residues. The actual ratios for
material entering each SOM pool are linear functions of the quantities of each
element in the labile inorganic mineral pools in the surface soil layers
(MINERL(1,*)). Low nutrient levels in the labile pools
result in high C to element ratios in the various SOM pools. The N, P, and S
flows between SOM pools are related to the C flows. The quantity of each
element flowing out of a particular pool equals the product of the C flow and
the element to C ratio of the pool. Mineralization or immobilization of N, P,
and S occurs as is necessary to maintain the ratios discussed above. Thus,
mineralization of N, P, and S occurs as C is lost in the form of CO2 and as C
flows from pools with low ratios, such as the active pool, to those with higher
ratios, such as the slow pool. Immobilization occurs when C flows from pools
with high ratios, such as the structural pool, to those with lower ratios, such
as the active pool. The decomposition rate is reduced if the quantity of any
element is insufficient to meet the immobilization demand.
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3.3. Water Budget, Leaching and Soil Temperature
The CENTURY model includes a simplified water budget
model which calculates monthly evaporation (EVAP) and
transpiration (TRAN) water loss, water content of the soil
layers (ASMOS(*)), snow water content
(SNOW), and saturated flow of water between soil layers
(Figure 3-2). If the average air temperature
(TAVE) is less than 0 C monthly precipitation
(RAIN) occurs as snow. Sublimation and evaporation of
water from the snow pack occurs at a rate equal to the potential
evapotranspiration rate (PET). Snow melt occurs if the
average air temperature is greater than 0 C and is a linear function of the
average air temperature.
The potential evapotranspiration rate
(PET) is calculated as a function of the average monthly
maximum (TMX2M(*)) and minimum
(TMN2M(*)) air temperature using the equations developed
by Linacre (1977) and may be modified by a user
specified multiplier (FWLOSS(4),
fix.100). Bare soil water loss is a function of
standing dead and litter biomass (lower for high biomass levels),
rainfall and PET. Interception water
loss is a function of aboveground biomass (increases with biomass level),
rainfall and PET. Potential
transpiration water loss (PTTR) is a function of the live
leaf biomass and PET. Interception and bare soil water
losses are calculated as fractions of the monthly precipitation and are
subtracted from the total monthly precipitation, with the remainder of the
water added to the soil.
Water is distributed to the different layers by adding the water to the top
layer (0-15 cm, ASMOS(1)) and then draining excess water
(water above field capacity) to the next layer. Transpiration water loss
(TRAN) occurs after the water was added to the soil. Water
loss occurs first as interception, followed by bare soil evaporation and
transpiration (the sum does not exceed the PET rate). The
maximum monthly evapotranspiration water loss rate is equal to
PET.
Depending on the value of SWFLAG
(<site>.100), the field capacity
(AFIEL(*), <site>.100) and
wilting point (AWILT(*),
<site>.100) for the different soil layers can
optionally be input from the <site>.100 file or
calculated as a function of the bulk density (BULKD,
<site>.100), soil texture
(SAND, SILT, CLAY,
<site>.100), and organic matter content
(SOMSC) using a choice of equations developed by
Gupta and Larson (1979) or
Rawls et al. (1982). The number of soil layers
(NLAYER, <site>.100) is an
input variable in the model. 15 cm increments were used for each layer up to
the 60 cm soil depth and 30 cm increments below the 60 cm depth
(LAYER = 4 has this structure: 0-15,15-30,30-45,45-60,
and NLAYER = 6 has this structure: 0-15,15-30,30-45,
45-60,60-90,90-120). Water leached below the last soil layer is not available
for evapotranspiration and is a measure of interflow, runoff or leaching losses
from the soil profile. Water going below the profile can be lost as storm flow
(STORMF, <site>.100 -
fraction lost as fast stream flow) or leached into the subsoil where it can
accumulate or move into the stream flow (STREAM(1)) at a
specified rate (BASEF,
<site>.100 - fraction per month of subsoil H2O
going into stream flow). The model can simulate watershed stream flow by
adjusting STORMF and BASEF.
Leaching of labile mineral N, (NO3 + NH4), P, and S pools occurs when there is
saturated water flow between soil layers. The fraction of the mineral pool
that flows from the upper layer to the lower layer is a function of the sand
content (increasing with increasing sand content -
FLEACH(1) and FLEACH(2),
fix.100) and the amount of water that flows between
layers (linear function up to a maximum value - MINLCH,
fix.100 cm per month).
FLEACH(3), FLEACH(4) and
FLEACH(5) (fix.100) control
inorganic N, P, and S leaching respectively. Monthly watershed losses of H2O
(STREAM(1)), inorganic N, P, and S
(STREAM(2), STREAM(3) and
STREAM(4)), and organic C, N, P, and S
(STREAM(5), STREAM(6),
STREAM(7), and STREAM(8)) are
simulated by the model.
Average monthly soil temperature near the soil surface
(STEMP) is calculated using equations developed by
Parton (1984). These equations calculate maximum
soil temperature as a function of the maximum air temperature and the canopy
biomass (lower for high biomass) while the minimum soil temperature is a
function of the minimum air temperature and canopy biomass (higher for higher
biomass). The actual soil temperature (STEMP) used for
decomposition and plant growth rate functions is the average of the minimum and
maximum soil temperatures.
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The N submodel (Figure 3-3) has the same structure as
the soil C model. The N flows follow the C flows (Figure
3-3, N flows between organic pools not shown can be seen in
Figure 3-1) and are equal to the product of the carbon
flow and the N:C ratio of the state variable that receives the carbon. The C:N
ratio of the structural pools (150) remains fixed while the N contents of the
metabolic pools vary as a function of the N content of the incoming plant
residue. The C:N ratio of newly formed surface microbial biomass is a function
of the N content of the material being decomposed (increases for low N
content). The C:N ratios of organic matter entering each of the three soil
pools vary as linear functions of the size of the mineral N pool. As mineral N
in the surface soil layer increases from 0 to 2 g N / m2, the C:N ratios
decrease from 15 to 3 for the active pool, from 20 to 12 for the slow pool and
from 10 to 7 for the passive pool. The C:N ratio for slow material formed from
surface microbial biomass is a function of C:N ratio of the surface microbe pool.
The N associated with carbon lost in respiration (30% to 80% of the carbon flow
is respired) is assumed to be mineralized. Given the C:N ratio of the state
variables and the microbial respiration loss for each flow, decomposition of
metabolic residue, active, slow, and passive pools generally result in net
mineralization of N, while decomposition of structural residue immobilizes
N.
The model uses simple equations to represent N inputs due to atmospheric
deposition and soil and plant N fixation. Atmospheric N inputs
(EPNFA(*), <site>.100) are a
linear function of annual precipitation (PRCANN). The
model has the option (NSNFIX) of calculating soil N
fixation rates as a function of the mineral N to labile P ratio (high fixation
with lower ratios) or as a linear function (EPNFS(*),
<site>.100) of annual precipitation. Symbiotic
plant N fixation (SNFXAC,
crop.100) is assumed to occur only when there is
insufficient mineral N to satisfy the plant N requirement, having taken into
account all possible growth reductions including P or S deficiency. Symbiotic
N fixation can occur up to a maximum level of g N fixed per g C fixed
(SNFXMX, crop.100) specified for
each crop type and is hence related to the plant growth rate. The model also
includes fertilizer N inputs and N inputs through organic matter additions (see
parameters in the fert.def and
omad.def files, Appendix 2).
The losses of N due to leaching of NO3 are related to soil texture and the
amount of water moving through the soil profile (see water
flow submodel description, Section 3.3). Losses
accumulate in the layer below the last soil layer
(MINERL (NLAYER+1,1)) or are lost in the stream
flow (STREAM(2)). Loss of organic N
(STREAM(6) occurs with the leaching of organic matter.
Gaseous losses of N compounds associated with mineralization /nitrification
(VOLGMA), denitrification (VOLEXA),
volatilization from maturing crops or senescing grassland
(VOLPLA) are calculated. Losses due to crop removal,
burning, transfer of N in animal excreta, and soil erosion are also accounted
for.
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The P submodel (Figure 3-4) has the same general
structure as the N submodel. The major difference is that there are five
mineral P pools (labile P (PLABIL), sorbed P, strongly
sorbed P (SECNDY(2)), parent P
(PARENT(2), and occluded P
(OCCLUD)). The phosphorus submodel
(Figure 3-4) has been revised to give a better
representation of phosphorus sorption. Because CENTURY uses a relatively long
timestep (¼ month for the soil nutrient submodel) and soil solution very
rapidly equilibriates with the labile fraction of adsorbed P
(Cole et al., 1977) it is not appropriate to use soil
solution P for the available nutrient pool. Instead, a labile P pool
(PLABIL) has been defined, equivalent to resin
extractable P, which is in equilibrium with a sorbed P pool
(Figure 3-5). The equilibrium between the labile and
sorbed P pools is recalculated after any P additions or removals from the soil.
The sum of labile P and sorbed P are represented by the state variable
MINERL(1,2). Plant uptake, immobilization and leaching
of P (if allowed) are controlled by the size of the labile P pool. The
fraction of labile P that is available for plant uptake varies from 0.4 to 0.8
as a function (FAVAIL(*)) of the mineral N pool size
(higher fractions for high mineral N levels). As more P is removed through
plant and soil microbial uptake, larger amounts become immobilized in organic
matter.
The equilibrium relationship between labile P and sorbed P is defined in terms
of two parameters, sorption affinity (PSLSRB,
<site>.100) and sorption maximum
(SORPMX, <site>.100). The
sorption affinity parameter controls the fraction of the labile plus sorbed
pools which is in the labile pool at low levels of P in these pools. The
sorption maximum is the maximum amount of P which can be in the sorbed P pool.
The sorption maximum controls the curvature of the relationship between labile
P and the sum of the labile and sorbed P pools.
The sorbed P is in dynamic equilibrium (PSECMN(2),
PMNSEC(2), fix.100) with a more
strongly sorbed P pool (SECNDY(2)) which may in turn
lose P (PSECOC, fix.100) to an
occluded P pool (OCCLUD). Phosphorus can enter the
cycling P pools by weathering of parent material P
(PARENT(2)), which is typically apatite. The rate of
weathering (PPARMN(2), fix.100)
can be a function of soil texture (TEXEPP(*),
fix.100) (higher for fine textured soils). The rate of
these P flows are all multiplied by the same moisture and temperature functions
(DEFAC) that are used for organic matter
decomposition.
The organic part of the P submodel operates in the same way that the N submodel
works; C:P ratios of organic fractions are fixed for the structural P pool
(500) and vary as a function of the labile P pool
(PLABIL) for the active (30-80), slow (90-200), and
passive (20-200) SOM pools. C:P ratios of newly formed surface microbes are
functions of the P content of the material decomposing, and the C:P ratio of
slow material formed from the surface microbes is a function of the C:P ratio
of surface microbes. The flows for the organic P pools are calculated in
exactly the same way as organic N flow.
Phosphorus losses from the system occur as result of leaching of labile P
(MINERL(NLAYER+1,2) - P losses accumulate in
the soil layer below the last layer) and organic P compounds
(STREAM(7)), soil erosion, crop removal, grazing, and
burning P losses. P additions come from P fertilizer and organic matter
additions (see parameters in the fert.def and
omad.def file).
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The structure of the sulfur submodel (Figure 3-6) is similar to the P submodel. The only major difference is that the S model does not include occluded or sorbed pools. The main source of S in most soils is the weathering of primary minerals. Secondary S is formed as a result of adsorption of S on clay minerals. Organisms in the soil and plant roots take up S from soil solution (MINERL(layer,3) and start the formation of organic S compounds. The organic component of the S model operates in the same way as the organic N and P submodels with the C:S ratio of the structural pool being fixed (500) while the C:S ratios for the active (20-80), slow (90-200) and passive (20-200) pools vary as a function of the labile S pool (MINERL(1,3)). C:S ratios for surface microbes are calculated in the same way as the C:N and C:P ratios. The C:S ratios for the organic components are specified in the file fix.100 (see Appendix 2). The organic S flows are calculated in the same manner as the organic N and P flows while the inorganic S flows are functions of specified rate parameters (PPARMN(3), PSECMN(3), PMNSEC(3), fix.100) and the moisture and temperature functions that are used for organic matter decomposition (DEFAC). The model allows for S fertilization, addition of organic S material (see parameters in the fert.def and omad.def files, Appendix 2), atmospheric deposition (SATMOS(*), <site>.100), S in irrigation water (SIRRI, <site>.100), and accounts for S losses due to crop removal, grazing, leaching of organic S compounds (STREAM(8)), erosion of SOM, and fire. The S submodel has not been as well tested as the N and P submodels. Parton et al. (1988), Metherell (1992), and Metherell et al. (1993a) describe interactions of S with C, N, and P. The S model could be set up to simulate K dynamics instead of S dynamics if K is a limiting factor in particular soils.
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3.7. Plant Production Submodels
The CENTURY model is set up to simulate the dynamics of
grasslands, agricultural crops,
forests, and savanna (tree-grass)
systems. The grassland/crop production model simulates
plant production for different herbaceous crops and plant communities (e.g.
warm or cool season grasslands, wheat and corn). Grassland/crop options are
selected from the crop.100 file. Existing crop options
may be altered to suit particular varieties or environments or new options
created using the FILE100 program. Harvest, grazing,
fire and cultivation can all directly effect aboveground biomass, while grazing
and fire may also impact root to shoot ratios and nutrient content. The
forest model simulates the growth of deciduous or
evergreen forests in juvenile and mature phases. Fire, large scale
disturbances (e.g. hurricanes), and tree harvest practices may impact forest
production. The savanna system is simulated as a
tree-grass system, essentially using the existing tree
and grassland/crop submodels with the two subsystems
interacting through shading effects and nitrogen competition.
Both plant production models assume that the monthly maximum plant production
is controlled by moisture and temperature and that maximum plant production
rates are decreased if there are insufficient nutrient supplies (the most
limiting nutrient constrains production). The fraction of the mineralized
pools that are available for plant growth is a function of the root biomass
with the fraction of nutrients available for uptake increasing exponentially as
live root biomass increases from 20 to 300 gm-2. Most forest or grassland/crop
systems are limited by nutrient availability and generally respond to the
addition of N and P. The savanna model modifies maximum
grass production by a shade modifier that is a function of tree leaf biomass
and canopy cover. Additional nutrient constraints on plant production due to
nutrient allocation between trees and grasses decrease maximum production rates
for the grasses.
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3.7.1. Grassland/Crop Submodel
The model can simulate a wide variety of crops and grasslands by altering a
number of crop specific parameters (see Appendix 2 for the
crop.100 parameters). CENTURY is not designed to be a
plant production model and some parameters may have to be calibrated for
specific environments.
The plant production model (Figure 3-7) has pools for
live shoots and roots, and standing dead plant material. Potential production
(g C / m2 / month) is a function of a genetic maximum defined for each crop
(PRDX(1), crop.100) and 0-1
scalars depending on soil temperature, moisture status, shading by dead
vegetation, and seedling growth.
The maximum potential production of a crop, unlimited by temperature, moisture
or nutrient stresses, is primarily determined by the level of
photosynthetically active radiation, the maximum net assimilation rate of
photosynthesis, the efficiency of conversion of carbohydrate into plant
constituents, and the maintenance respiration rate
(van Heemst, 1986). Thus, the parameter for
maximum potential production (PRDX(1)) has both genetic
and environmental components. However, in CENTURY, the seasonal distribution
of production is primarily controlled by the temperature response function
rather than the seasonal variation in photosynthetically active radiation, so
the maximum potential production parameter should reflect aboveground crop
production in optimal summer conditions. This parameter will frequently be
used to calibrate the predicted crop production for different environments,
species, and varieties. In the CENTURY model formulation the potential
production is based on aboveground production, therefore root-shoot allocation
must also be taken into account. The value used should be set according to
estimates of potential crop production. In general, C4 species have higher
potential growth rates than C3 species because of higher maximum net
assimilation rates (van Heemst, 1986). The range
of potential production from 200 to 580 kg DM / ha / day corresponds to 240 to
700 g C / m2 / month.
The growth of most plant species exhibits a response curve to root temperature
which is sigmoidal up to an optimum temperature, has a band of optimum
temperatures over which there is relatively little effect on growth, and a
rapid decline above the optimum (Cooper, 1973).
Plant growth rates will depend on the combined temperature response of
photosynthesis and respiration. For most temperate species the lower limit at
which the rate of development is perceptible is between zero and 5 C.
Development increases in rate up to an optimum of 20 to 25 C and then
declines to an upper limiting temperature between 30 and 35 C. For tropical
species the base, optimum and maximum temperatures are approximately 10 higher
(Monteith, 1981). In the CENTURY model the
temperature response curve can be parameterized for each crop using a
generalized Poisson density function (PPDF(1...4),
crop.100) as shown in Figure
3-8.
The moisture status effect reduces growth when
The slope of the linear relationship is dependent on the available soil water
holding capacity, which varies with soil texture (Figure
3-9). This effect of soil texture has been observed in field data
(Sala et al., 1988) and accounts for the "reverse
texture effect" (Noy-Meir, 1973), in which the
greater infiltration rate and hence lower bare soil evaporation rate in coarser
textured soils results in higher production in arid environments.
NLAYPG (<site>.100) is the
number of soil layers that control plant growth (e.g. 0-60 cm depth for
NLAYPG=4 and 0-45 cm depth for
NLAYPG=3) and can be less than or equal to the total
number of soil layers.
The shading effect on potential growth rate is a response surface dependent on
the amounts of live and dead vegetation. This function, which was originally
developed for the tall grass prairie, was found to be too restrictive for
no-till cropping systems. Therefore, the magnitude of the effect has been
greatly reduced for crops by increasing the value of BIOK5
(crop.100).
A scaling factor for crops growing from seedlings
(PLTMRF, FULCAN,
crop.100) reflects the partial interception of light
with less than a full canopy present (Figure 3-10).
This factor takes effect after a PLTM (planting month)
command in EVENT100, but not after a
FRST (first month of growth) command.
Root growth is proportional to potential shoot growth, but the allocation of
carbon to root growth can be made a function of time since planting
(FRTC(1...3)) (Figure 3-11) to
reflect the dominance of root growth in seedling cereal crops or the initial
dominance of shoot growth in root crops. To account for winter dormancy the
root - shoot ratio does not change in months when soil temperature is below 2
C (RTDTMP, crop.100). In an
alternative formulation (FRTC(1) = 0.0) developed for Great
Plains grasslands, the root-shoot ratio is controlled by annual precipitation
(Parton et al., 1987) as shown in
Figure 3-12.
The actual production is limited to that achievable with the currently
available nutrient supply with plant nutrient concentrations constrained
between upper and lower limits set separately for shoots and roots. Invoking
Liebig's Law of the Minimum, the most limiting nutrient
(ELIMIT) constrains production
(RELYLD). The limits of nutrient content for shoot
growth are a function of plant biomass in order to reflect the changing
nutrient content with plant age (Figure 3-13). The user
specifies the effect of live shoot biomass on maximum and minimum nutrient
content (BIOMAX, PRAMN(*,*),
PRAMX(*,*), crop.100). This
formulation does cause some anomalies when growth is limited by nutrients, as a
nutrient limited crop can have a higher nutrient concentration than an
unlimited crop of the same age with greater biomass. The limits on nutrient
content of roots are a function of annual precipitation
(PRBMN(*,*), PRBMX(*,*),
crop.100). CENTURY also incorporates a function to
restrict nutrient availability in relation to root biomass (RTIMP;
Figure 3-14). For legume crops the potential rate of
symbiotic nitrogen fixation is specified in terms of grams N fixed per gram C
fixed (SNFXMX, crop.100). It is
assumed that plant available soil N will be preferentially used by the crop.
All other potential limitations to growth, including P and S supply, are taken
into account before calculating symbiotic N2 fixation.
Fertilizer addition can be either fixed amounts (FERAMT,
fert.100) or calculated automatically according to the
crop requirements. The automatic option (AUFERT,
fert.100) can be set to maintain crop growth at a
particular fraction of potential production with the minimum nutrient
concentration or to maintain maximum production with plant nutrient
concentrations at a nominated level between the minimum and maximum for that
growth stage.
At harvest, grain is removed from the system and live shoots can either be
removed or transferred to standing dead and surface residue. For grain crops a
harvest index is calculated based on a genetic maximum
(HIMAX, crop.100) and moisture
stress (HIWSF, crop.100) in the
months corresponding to anthesis and grain fill
(HIMON(1,2), crop.100) as shown in
Figure 3-15. Moisture stress is calculated as the ratio
of actual to potential transpiration in these months. The fractions of
aboveground N, P, and S partitioned to the grain are crop-specific constants
(EFRGRN(*), crop.100) modified by
the square root of the moisture stress term, resulting in higher grain nutrient
concentrations when moisture stress reduces the harvest index. At harvest a
proportion of the aboveground nitrogen is lost to volatilization
(VLOSSP, crop.100). The crop
harvest routine also allows for the harvest of roots, hay crops or straw
removal after a grain crop (see harv.100; Appendix 2).
The crop may be killed at harvest, as for cereal grain crops, or a fraction of
roots and shoots may be unaffected by harvest operations and growth may
continue.
The crop model allows for the death of shoots and roots during the growing
season. Shoot and root death are functions of available soil water in the
whole profile and the plant root zone respectively (Figure
3-16). Both are multiplied by crop specific maximum death rates
(FSDETH(1), RDR,
crop.100). Shoot death rates may be further increased
(FSDETH(3)) due to shading if the live biomass is
greater than a critical level (FSDETH(4)). Root death
is only allowed to occur when roots are physiologically active, defined by soil
temperature being greater than 2 C (RTDTMP,
crop.100). In months nominated as senescence months
the shoot death rate is set to a fixed fraction of live biomass
(FSDETH(2)). Standing dead material is transferred to
surface litter at a crop specific relative fall rate
(FALLRT, crop.100).
Plant lignin contents (FLIGNI(*,*),
crop.100) are specified for shoots and roots, and may
be constants or a linear function of annual precipitation
(Parton et al., 1992). They should reflect the
lignin content of senescent plant material.
The effects of grazing and fire on plant production are represented in the
model by using data from Holland et al. (1992) and
Ojima et al. (1990). The major impact of fire is to
increase the root to shoot ratio (FRTSH,
fire.100), increase the C:N ratio of live shoots and
roots (FNUE(*), fire.100), remove
vegetation and return nutrients during the years when fire occurs
(Ojima et al. 1990). Grazing removes vegetation,
returns nutrients to the soil, alters the root to shoot ratio, and increases
the N content of live shoots and roots (Holland et al.
1992). The model has three options (GRZEFF = 0, 1,
2) for dealing with the impact of grazing on the system. For option 1
(GRZEFF=0) there are no direct impacts of grazing on
plant production except for the removal of vegetation and return of nutrients
by the animals. Option 2 (GRZEFF=1) is referred to as
the lightly grazed effect (Holland et al., 1992)
and includes a constant root:shoot ratio (not changing with grazing) and a
linear decrease in potential plant production with increasing grazing
intensity. Option 3 (GRZEFF=2) is referred to as the
heavy grazed (Holland et al., 1992) option and
includes a complex grazing optimization curve where aboveground plant
production is increased for moderate grazing and decreasing sharply for heavy
grazing levels (<40% removed per month). The root:shoot ratio is constant
for low to moderate grazing levels and decreases rapidly for heavy grazing
levels. In all three options the nutrient content of new shoot will increase
in relation to the residual biomass (PRAMN(*,*),
PRAMX(*,*), BIOMAX,
crop.100).
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The forest plant production model (Figure 3-17)
divides the tree into leaves, fine roots, fine branches, large wood, and coarse
roots with carbon and nutrients allocated to the different plant parts using a
fixed allocation scheme. Maximum monthly gross production is calculated as the
product of maximum gross production rate (PRDX(2),
tree.100), moisture, soil temperature and live
leaf-area-index terms. The effect of moisture and temperature on potential
productions are the same functions used for the monthly grassland model
(Figures 3-8 and 3-9), while the
effect of live leaf-area-index on production is shown in
Figure 3-18. Plant respiration is calculated as a
function of wood N content and temperature using an equation developed by
Ryan (1991) and subtracted from the gross production
rate in order to get the net potential production rate. The net potential
production rate is not allowed to exceed the tree specific maximum net
production rate (PRDX(3) times the other limiting
factors). The model assumes that only the sapwood part of the tree respires C
and the sapwood fraction of aboveground large wood biomass is calculated using
the relationship shown in Figure 3-19. The same sapwood
fraction is used for coarse woody roots (Ryan, 1991).
The leaf biomass is not allowed to exceed a maximum value that is a function of
the live wood biomass (Figure 3-20). This function
specifies the effect of tree allometry and structure on maximum leaf area and
is potentially different for different species. Some of the important forest
specific parameters include the maximum gross and net production rates
(PRDX(2), PRDX(3),
tree.100), the leaf area index to wood biomass
relationship parameters (MAXLAI,
KLAI, tree.100), the sapwood to
large wood C ratio parameter (SAPK,
tree.100), and the allocation of C into different plant
parts (FCFRAC(1-5,1-2),
tree.100).
The model has two carbon allocation patterns for young and mature forests and
can represent either deciduous forests or forests that grow continuously. With
a continuous growth or evergreen forest the death of the live leaves is
specified as a function of month (LEAFDR(1-12),
tree.100), while with a deciduous forest the leaf death
rate is very high at the senescence month. For deciduous forest the leaf
growth rate is also much higher during the first month of leaf growth. Dead
leaves and fine roots are transferred to the surface and root residue pools
and are then allocated into structural and metabolic pools. Dead fine branch,
large wood, and coarse root pools receive dead wood material from the live
fine branch, large wood, and coarse root pools respectively. Each dead wood
pool has a specific decay rate. The dead wood pools decay in the same way
that the structural residue pool decomposes with lignin going to the slow SOM
pool and the non-lignin fraction going to surface microbes or active SOM
pool (above- or belowground material). The decay rates of the dead wood pools
are also reduced by the temperature and moisture decomposition functions,
and include CO2 losses.
A forest removal event, which is defined in the trem.100
file, can simulate the impact of different forest harvest practices, fires, and
the effect of large scale disturbances such as hurricanes. For each
disturbance or harvest event, the fraction of each live plant part lost and the
fraction of material that is returned to the soil system is specified (see
trem.def Appendix 2). Death of fine and coarse roots
are also considered in the removal event along with the removal of dead wood.
Another feature is that the nutrient concentration of live leaves that go into
surface residue can be elevated above the dead leaf nutrient concentration
(e.g. simulating the effect of adding live leaves to surface residue as a
result of hurricane disturbance) by specifying the return nutrient fraction of
the leaves to be greater than one (RETF(1,*),
trem.100).
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The savanna model is a coupled tree-grass system and uses the
forest and grassland/crop submodels
already described. The fundamental difference in the savanna submodel is the
manner in which total system production is obtained. Total system production
is the sum of forest and grass production. Potential maximum production of
forest is computed in the manner described above.
Grassland/crop production is modified to include the effect of tree canopy
cover on grassland/crop production. A shade modifier is calculated as a
function of the canopy cover and leaf biomass (Figure
3-21) and is multiplied by the normal grassland/crop production equation
(see Grassland/Crop Submodel, Section
3.7.1). Increasing canopy cover and leaf biomass reduces the potential
grass production. Removal of grass or forest is accomplished independently
with the FIRE and TREM commands
in EVENT100, so that user can specify fire intensity
and frequency as desired. Fire removal parameters for grassland/crop
vegetation are specified in fire.100, while forest fire
parameters are specified in trem.100. In this manner,
a grass fire can occur at a higher intensity and/or frequency than fires
affecting forest combustion losses. In the present model, fire does not
influence tree distribution and establishment.
Nitrogen competition is the other major interaction between the forest and
grass systems. The interaction is controlled by the amount of tree basal area,
total nitrogen available, and site potential for plant production. The
fraction of N available for tree uptake is calculated as a function of tree
basal area (m2 ha-1) and available mineral N using the function shown in
Figure 3-22. The fraction of N uptake by grass is one
minus the forest fraction and if grass N uptake did not consume all of the N
allocated to it, this amount is added to the pool of N which is available to
the trees. Two important site-specific parameters for the savanna model are
the site potential parameter (SITPOT,
tree.100) and the basal area conversion factor
(BASFCT, tree.100) which
calculates tree basal area as a function of large wood C level.
SITPOT controls how fast trees can dominate grasslands
with lower numbers (1200 vs. 2400) leading to quicker dominance by trees.
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Fertilizer addition can be either fixed amounts
(FERAMT(*), fert.100) or
calculated automatically (AUFERT <> 0.0,
fert.100) according to the crop requirements. The
automatic option can be set to maintain crop growth at a particular fraction of
potential production with the minimum nutrient concentration (0.0 <
AUFERT <= 1.0) or to maintain maximum production with
plant nutrient concentrations at a nominated level between the minimum and
maximum for that growth stage (1.0 < AUFERT
<= 2.0).
Organic matter additions are specified in omad.100.
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Irrigation amounts can be either fixed amounts (IRRAMT, irri.100) or automatically set (AUIRRI, irri.100) according to the soil moisture status. Automatic irrigations are scheduled if the available water stored in the plant root zone falls below a nominated fraction of the available water holding capacity (FAWHC, irri.100). The amount of water applied by the automatic option allows for the addition of a nominated amount of water (IRRAUT, irri.100) or for irrigation up to field capacity or up to field capacity plus an allowance for potential evapotranspiration.
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Cultivation options allow for the transfer of defined fractions (CULTRA(*), cult.100) of shoots, roots, standing dead and surface litter into standing dead, surface and soil litter pools as is appropriate. Thus the model can simulate a variety of conventional cultivation methods, such as plowing or sweep tillage, thinning operations or herbicide application. Each cultivation option also has parameters (CLTEFF(*) cult.100) for the multiplicative effect of soil disturbance by cultivation on organic matter decomposition rates for the structural, active, slow and passive pools. The values for these parameters range from 1.0 to about 1.6 with the actual value dependant on the degree of soil stirring and disruption caused by each implement.
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The grazing options can be parameterized to remove defined fractions of aboveground live (FLGREM, graz.100) and standing dead (FDGREM, graz.100) plant material each month. The fractional returns of C (GFCRET, graz.100), N, P, and S (GRET(*), graz.100) are specified, having allowed for losses in animal carcasses and milk, transfer of dung and urine off the area being simulated, volatile losses of N from dung and urine patches, and leaching of N and S under urine patches. The proportion of N, P, and S returned in organic forms (FECF(*), graz.100) is also specified as is the lignin content of the feces (FECLIG, graz.100). As discussed above in Section 3.7.1, grazing can have variable effects on plant production (GRZEFF, graz.100).
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The effect of different intensities of fire in herbaceous vegetation can be parameterized by specifying the fractions of live shoots (FLFREM, fire.100), standing dead (FDFREM(1), fire.100) and surface litter (FDFREM(2), fire.100) removed by a fire along with the return of N, P, and S in inorganic forms. As discussed above in Section 3.7.1, fire can also affect plant growth.
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3.13. Labeled C Simulation (14C and 13C)
The CENTURY model can simulate labeling by either 14C or 13C.
C labeling is specified in the .sch schedule file,
created by EVENT100. The 14C simulations act as a
labeled tracer from atmospheric sources or added organic matter
(ASTLBL, omad.100). The
c14data file contains a record of atmospheric 14C
concentrations which are used by the model to label new plant material, which
then flows through the other organic matter pools. A sample
c14data data file is included on the CENTURY
diskette.
Simulations using the option for 13C give a constant label to plant material
based on the value of DEL13C in the crop.100 and
tree.100 files. This option will primarily be of use
to follow the change in stable isotope signal when there has been a switch from
C3 to C4 vegetation or vice-versa. Fractionation of the stable carbon isotopes
is included in the model as discussed below.
The 13C/12C ratio in soil organic matter remains close to the ratio in the
original vegetation, but fractionation during decomposition of the plant
residues and soil organic matter can produce significant changes in the ratio.
The magnitude and direction of the change in the ratio may vary with time
and the prevailing environmental conditions (Stout and
Rafter, 1978; Stout et al., 1981).
13C/12C ratios are expressed relative to a standard as delta 13C values, where
The standard is carbonate from Pee Dee belemnite limestone and units are per
mille (‰). Atmospheric CO2, plant material, and soil organic matter are
depleted in 13C relative to the standard and therefore have negative delta 13C
values. The more depleted in 13C a material is, the more negative the delta
13C value will be.
Stout et al. (1981) identified four points in the
biological carbon cycle where major fractionation of carbon isotopes occurs.
The first takes place during photosynthesis with plant tissue being depleted in
13C relative to atmospheric CO2. Of considerable interest is the difference in
delta 13C between plants with different photosynthesis pathways
(Bender, 1971; Smith and
Epstein, 1971). The C3 plants, with the Calvin pathway, have low delta 13C
values (-24 to -34‰), while the C4 plants, with the Hatch and Slack pathway,
have high delta 13C values (-6 to -19‰). This difference in stable carbon
isotope signature can be used as a tracer for in situ labelling of soil organic
matter when the dominant vegetation type has changed from C3 to C4 species or
vice-versa (Cerri et al., 1985;
Schwartz et al., 1986;
Balesdent et al., 1987;
Balesdent et al., 1988;
Martin et al., 1990;
Balesdent and Balabane, 1992). The CENTURY model
has been modified to partition carbon production by plants to the two isotope
pools on the basis of a delta 13C value nominated in
the crop.100 file for each grassland or crop type.
The second major biological fractionation occurs in the synthesis of the major
cell components (Stout et al., 1981). The data of
Benner et al. (1987) for a variety of vascular
plants showed that cellulose and hemicellulose were typically enriched in 13C
by 1 to 2 ‰ relative to whole plant material while lignin was depleted by 2 to
6‰. They observed a greater depletion of 13C in grass lignins than in wood
lignins, which they attributed to different amino acid precursors. In the
CENTURY model this fractionation in the partitioning of plant material (shoots
and roots from crops and grasses, and leaves and fine roots from trees) to the
structural and metabolic pools is accounted for as all of the plant lignin is
assumed to enter the structural pool. The 13C depletion of lignin relative to
the whole plant 13C signature can be altered (DLIGDF,
fix.100). Because all dead wood and large tree roots
enter dead wood pools, which are analogous to the structural pool, there was no
need to account for 13C fractionation in wood lignin.
The third major biological fractionation of carbon noted by
Stout et al. (1981) is associated with animal
consumption of plant material, with animal tissues being depleted in 13C
relative to the plant material on which they feed. This is not accounted for
this in the model because the important comparison for the CENTURY model is
between delta 13C levels in feces and plant material.
The fourth major biological fractionation of carbon takes place during
microbial metabolism (Stout et al., 1981).
Macko and Estep (1984) examined the isotopic
composition of an aerobic, heterotrophic bacteria growing on a variety of amino
acid substrates. With most of substrates the bacterial cells were enriched in
13C relative to the amino acid. They suggested that the CO2 respired during
the Krebs cycle would be isotopically depleted in 13C. However, in an
anaerobic environment methane evolved is very depleted in 13C relative to the
organic substrate, but the CO2 evolved is enriched (Games
and Hayes, 1976). The net effect on the residual organic matter would
depend on the relative size of the fluxes. Environmental effects on
fractionation are also reflected in different patterns of stable isotope
distribution in soil profiles (Stout and Rafter,
1978). In well-drained mineral soils delta 13C values increase slightly
with depth and soil age, which is consistent with respired CO2 being slightly
depleted in 13C. In organic soils where decomposition is inhibited the delta
13C values decrease with depth. This could be due to the loss of readily
decomposable plant fractions, such as sugars and proteins, with an accumulation
of lignin, lipids and waxes in the residual plant material, resulting in
depletion of 13C relative to the original plant material
(Stout et al., 1981). In other soils, with
intermediate levels of drainage and organic matter accumulation, there may be
no change in delta 13C values with depth indicating a balance between
fractionation due to respiration and accumulation of the depleted plant
fractions. All decomposition flows in the CENTURY model are assumed to be the
result of microbial activity and have an associated loss of CO2. Fractionation
of the carbon isotopes in the loss of CO2 is allowed for
(DRESP, fix.100). The coefficient
for isotope discrimination was calibrated to give a slight increase in the
delta 13C value for the total soil organic matter relative to the
vegetation.
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The model was also enhanced to include the effects of documented changes in
atmospheric CO2 and thus predict the effects on crop production. The direct
effects of an increase in atmospheric CO2 concentration on soil processes will
be insignificant because the CO2 concentration in the soil atmosphere is
already greatly elevated. However, the indirect effects on SOM mediated
through effects on plant processes could be substantial and must be accounted
for in simulations of the effect of global change on SOM
(Long, 1991). Net primary production, litter
quality, and transpiration are all likely to be affected. Increases in
atmospheric CO2 concentration have increased plant production of a wide variety
of species by an average of 33% (Kimball, 1983).
Generally, the plant dry matter response to increasing rates of CO2 can be
approximated with a logarithmic response function
(Gifford, 1979;
Goudriaan, 1992):
where NPPE and NPP0 refer to net primary production in enriched and control CO2
environments respectively. Beta is an empirical parameter which ranges between
0 and approximately 0.7.
The response to CO2 is not simply due to the removal of a single limiting
factor (Sinclair, 1992), but results from a
hierarchy of effects (Acock, 1990).
First, increasing CO2 has a direct effect on C availability by stimulating
photosynthesis and reducing photorespiration. There is a very important
difference between C3 species, such as wheat, and C4 species, such as corn, in
this response. At present day CO2 concentrations around 350 umol / mol, C4
plants have higher rates of photosynthesis than C3 species. However, net
photosynthesis in corn does not increase much beyond 400 umol CO2 / mol, while
wheat responds to CO2 levels up to 800 umol / mol (Akita
and Moss, 1973). The growth response to CO2 is usually lower in C4 species
than in C3 species (Wong, 1979;
Rogers et al., 1983;
Morrison and Gifford, 1984b;
Cure and Acock, 1986). With wheat, a growth response
to elevated CO2 is almost invariably obtained (Kimball,
1983; Cure and Acock, 1986). Corn sometimes shows
no response to CO2 (Hocking and Meyer, 1991b). In
a field study with elevated CO2 in open top chambers, in which corn growth was
increased by about 40%, there was no effect on net photosynthesis per unit leaf
area (Rogers et al., 1983). Summarizing a number of
experiments, Cure and Acock (1986) found average
biomass responses of 31, 9, and 9% for wheat, corn and sorghum respectively.
The main reason for responses to CO2 in C4 species is due to improved water use
efficiency as discussed below.
The second effect of increased CO2 concentrations is a decrease in stomatal
conductance (Moss et al., 1961;
Akita and Moss, 1973; Wong,
1979; Rogers et al., 1983;
Morrison and Gifford, 1984a) at high CO2
concentrations, which reduces the transpiration rate per unit leaf area.
Reduced transpiration will also increase the leaf temperature which can further
increase photosynthesis (Acock, 1990). The effect on
stomatal conductance and transpiration is observed in both C3 and C4 species.
Over a range of species Morrison and Gifford
(1984a) found that stomatal conductance was reduced by 36% while
transpiration was reduced by 21%, the difference being attributed to the higher
leaf temperatures. Similar average values of 34% and 23% for stomatal
conductance and transpiration respectively were found in the literature survey
of Cure and Acock (1986). Both an increase in
photosynthesis and a decrease in transpiration result in an increase in the
plant's water use efficiency.
The third major effect of increased CO2 is a decrease in the plant N
concentration in C3 species (Schmitt and Edwards,
1981; Hocking and Meyer, 1991b). Clearly with
a fixed nutrient supply, an increase in C assimilation is likely to result in
lower plant nutrient concentrations due to a dilution effect, but this is not
the only effect. Hocking and Meyer (1991a)
clearly demonstrated that the critical plant N concentration for 90% maximum
yield is decreased under elevated CO2. However, CO2 had little effect on the
relationship between relative yield and the external N concentration. A
practical implication of this is that similar fertilizer application rates will
still allow near maximum yields under a high CO2 environment, but that more
fertilizer may be required to maintain similar grain protein concentrations
(Hocking and Meyer, 1991b). Physiologically, an
increase in N use efficiency in C3 species with elevated CO2 has been related
to decreased concentrations of the enzyme ribulose 1,5-bisphosphate carboxylase
(Schmitt and Edwards, 1981) which catalyses the
initial carboxylation reaction in C3 species and accounts for a large
proportion of the leaf protein.
A fourth effect of increased CO2 on plant growth which affects SOM levels is an
increase in root growth. Most studies with elevated CO2 with grain crops in
which root growth has been measured show very little or no effect on the root
to shoot ratio (Cure and Acock, 1986).
The above effects can be taken into account in CENTURY model simulations of
global change effects by selecting the enriched CO2 option in
EVENT100. This option can be implemented with either
a constant CO2 concentration or with a linear ramp with annual increments
from an initial concentration to a final concentration; the parameters
CO2RMP, CO2PPM(1), and
CO2PPM(2) are found in the
fix.100 file. The various effects of CO2 described
above are controlled by functions of the CO2 concentration and crop or tree
specific parameters in crop.100 and
tree.100. Parameter values are set using reference
concentrations of 350 and 700 ppm CO2 for ambient and doubled CO2
respectively.
The impact on maximum potential monthly production is described by a
transformation of Equation 3 given above in order that
the relative production for doubled CO2 can be set for each crop (CO2IPR(*),
crop.100, tree.100). The
effect on potential transpiration rate also uses this equation with the
fraction to which the transpiration will be reduced with a doubling of
atmospheric CO2 set (CO2ITR(*), crop.100,
tree.100). (See Figure 3-24.)
The effect of elevated CO2 on carbon to element ratios is similarly modelled
with the effect of doubled CO2 on the minimum and maximum ratios for N, P, and
S, in the shoots of grasses and crops and in the leaves of trees set
(CO2ICE(*,*,*), crop.100,
tree.100). The effect of CO2 on the allocation of C
to roots is set by (CO2IRS(*), crop.100,
tree.100) which specifies the proportional increase
in the root to shoot ratio at doubled CO2. A linear relationship of this
effect with CO2 concentration is assumed.
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3.15. Soil Incubation (Microcosms)
The model can be set up to simulate litter bag decomposition and soil
incubations at constant temperature and soil moisture. The incubation
option will simulate the dynamics of soil organic matter and surface or buried
litter under constant soil temperature and soil water conditions. Changes
in carbon levels and nutrient mineralization can be simulated for laboratory
incubations using this option. The soil temperature
(MCTEMP, .sch schedule file) is the only abiotic input
parameter; it is specified in the schedule file. To simulate a litter bag
simulation you would specify the initial litter level
(CLITTR, <site>.100) and
C:N, C:P and C:S ratio of the litter (RCELIT,
<site>.100). The lignin content of the litter bag
(FLIGNI, crop.100) would be
specified for either above- or belowground material depending on the placement
of the bag. Incubation of the soil occurs in a similar manner by initializing
all of the soil variables. Some of the options include fertilization,
cultivations (mixing of the soil) and the addition of new labeled or unlabeled
plant material during the incubations. Plant growth does not occur during the incubation.
Microcosm simulation is specified in the .sch
schedule file, created by EVENT100.
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CENTURY uses monthly precipitation (PRECIP
<site>.100) and mean monthly minimum and maximum
temperatures (TMN2M, TMX2M,
<site>.100). For each block in the simulation,
EVENT100 allows the user to choose between four
options for weather data. The first option uses the mean
values for each month in every year of the block simulation. The second option
uses the mean monthly temperature values in every year and
stochastically generates precipitation from a skewed
distribution (Nicks, 1974). If skewness parameters
are unavailable, a truncated normal distribution is used but this will increase
the overall mean precipitation when the coefficient of variation for
precipitation is high. The third option reads the monthly values for
precipitation, minimum and maximum air temperature from the
start of a weather data file, while the fourth option will
continue reading from the same file without
rewinding.
If a monthly value is missing from an actual weather file, it should be set
equal to the value "-99.99" within the file. When reading in this missing
value flag, CENTURY will replace the flag as follows:
for a minimum or maximum temperature, the mean monthly value (TMN2M or
TMX2M) from the <site>.100 file will be used.
for a precipitation value, the skewed distribution value will be calculated if
possible (if PRCSKW is not zero). Otherwise, the monthly mean (PRECIP)
will be used.
FILE100 can automatically analyze a CENTURY model
weather file with monthly precipitation and temperatures and place the
parameters for climate statistics in a <site>.100
file.
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Because CENTURY uses a monthly timestep and incorporates both continuous events such as crop growth and decomposition, and discrete events such as fertilizer addition, cultivation and harvest, it is necessary to set a priority order for calls to the model's subroutines (Figure 3-23). This is also necessary because the combined effect of subroutines on the changes in pool sizes can be large relative to the amount present and negative overflows would otherwise be a problem. Furthermore, because of the importance of nutrient availability to immobilization in organic matter, and the limitation that immobilization can place on the rate of organic matter decomposition, the decomposition and soil nutrient routines have a timestep of one quarter of a month.
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Most of the internal parameters in CENTURY were determined by fitting the
model to long-term soil decomposition experiments (1 to 5 year) where different
types of plant material were added to soils with a number of soil textures
(Parton et al., 1987). Other more general databases
(Parton et al., 1988; Parton
et al., 1989) were used to parameterize the P and S submodels and flows for
the formation of passive SOM. Many of the parameters such as the plant
nutrient content and lignin content were determined using a linear equation
where the slope and intercept were the input parameters. Work in the Great
Plains suggested that lignin and N content changed as a linear function of
annual precipitation. To specify constant values for these parameters, set the
slope parameter (FLIGNI(2,*),
crop.100) equal to zero and set the intercept
(FLIGNI(1,*), crop.100) equal to
the desired value for the parameter.
The model includes a method for estimating steady state soil C and N levels in
grassland systems which was developed for the U.S. Great Plains. If
IVAUTO (<site>.100) is set
to 1, the model will estimate initial soil C and N levels for the different
soil fractions based on the mean annual temperature, annual precipitation and
soil texture of grassland (Burke et al., 1989).
IVAUTO = 2 uses the cultivated fields equations to
estimate these levels. The soil P and S levels are quite different depending
on soil parent material and need to be estimated with site-specific
data.
One of the most difficult parts of initializing the model is
estimating the C, N, P, and S levels for the different soil fractions.
However, substantial progress has been made recently in estimating the size of
the soil fractions. The active soil fraction includes the live soil microbes
and microbial products. This fraction can be estimated by using the microbial
fumigation technique (Jenkinson and Powlson,
1976; Jenkinson et al.,1976;
Jenkinson and Rayner 1977) to estimate the live
microbial biomass and then doubling the live microbial biomass to account for
the microbial products (active SOM = 2 to 3 times the live microbial biomass).
In most soils the active soil fraction is approximately 2 to 4% of the total
soil C. The slow SOM fraction is made up of lignin derived plant material and
stabilized microbial products. This fraction makes up approximately 55% of the
total SOM. Recent developments in SOM fractionation
(Elliott and Cambardella, 1992) suggest that 40% of
the total SOM in grasslands is lignin-derived plant material (referred to as
POM (partial organic matter) in the paper). Comparison of the size of the slow
pool from C simulations with measurements of SOM indicate that the slow pool is
approximately 1.6 times the amount of POM (Metherell
et al., 1993b).
Unfortunately there is not a good technique for estimating the size of the
stabilized microbial products pool; however, it is estimated that it is
approximately 10 to 20% of the soil. The passive SOM generally makes up 30 to
40% of the total SOM and will have a higher value for high clay content soils.
The best estimate of the N content of these fractions are that the slow
fraction has a C:N ratio of 15 to 20, the active SOM has a C:N ratio of 8 to
12, while the passive SOM has a C:N ratio of 7 to 10. Clay soils have lower
C:N ratios while silty soils have higher C:N ratios for the passive SOM. These
approximations seem to work well for a large number of different soils.
The C:P and C:S ratios are not as predictable and are functions of the initial
soil parent material and degree of soil weathering. The same general rules
apply for C:P and C:S ratios with the active SOM having relatively low ratios
(50-100), the slow SOM the highest C:P and C:S ratios (100-300), while the
passive C:P and C:S ratios are fairly low (40-120). These values are
appropriate for the relatively unweathered soils in the U.S. Great Plains.
More weathered tropical soils have much higher C:P and C:S ratios that can be
as high as 800. To use the P and S submodels, determine the organic P and S
levels and it would be preferable to run full P fractionation of the soil (see
citations in Hedley et al., 1982). The C:N ratio
and relative size approximations are incorporated into the model when the Burke
equations are used (IVAUTO=1,
<site>.100) to estimate initial SOM pools. For
cultivated soils it is generally assumed that the size of the slow pool is
lower because of cultivation (40 to 50% of the total SOM) while the size of the
passive pool is increased (45 to 50%).
The model has been parameterized to simulate soil organic matter dynamics in
the top 20 cm of the soil. The model does not simulate organic matter
in the deeper soil layers and increasing the soil depth parameter
(EDEPTH, fix.100) does not have
much impact on the model. EDEPTH is only used to
calculate C, N and P loss when erosion occurs. To simulate a deeper soil depth
(i.e., 0-30 or 0-40 cm depth) the soil organic matter pools must be initialized
appropriately. As a general rule deeper soil depths have older soil carbon
dates (Jenkinson et al., 1992) and lower
decomposition rates (lower temperature at deeper depths). Thus, it would be
assumed that the fraction of total SOM in the passive SOM would be greater.
The major change for initializing the model for deep soil depths is adjusting
the fraction of SOM in the different pools (more C in passive SOM). The
initial soil C levels should reflect the observed soil C levels over that depth
and the decomposition rates should be decreased for all of the SOM pools
(DEC3, DEC4, DEC5).
To increase the soil depth from 20 cm to 30 cm, the decomposition rates should
be decreased by 15%. The other adjustment would be to increase the rate of
formation of passive SOM; the recommended way is to increase the flow of C from
active and slow SOM to passive SOM (PS1S3 and
PS2S3, fix.100). For example,
increasing the coefficients in PS2S3 and
PS1S3 will increase the amount of passive SOM formed from
slow SOM and active SOM.
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4. PARAMETERIZATION THROUGH FILE100
4.1. Introduction
The FILE100 program is designed to help the user create new options or change
values in existing options in any of the .100 data files used with EVENT100 and
CENTURY. This utility also provides parameter definitions, units, and valid values or
ranges. The instructions given below apply to both the PC and UNIX versions.
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The program begins with a numbered list of the .100 files, and asks the user to
enter the number of the file he wishes to work with:
File Updating Utility
Enter the number of the file you wish to update:
0. quit
1. crop.100
2. cult.100
3. fert.100
4. fire.100
5. fix.100
6. graz.100
7. harv.100
8. irri.100
9. omad.100
10. tree.100
11. trem.100
12. <site>.100
13. weather statistics
Enter selection:
Within that .100 file, the user may take any of five actions, as shown by the next menu:
What action would you like to take:
0. Return to main menu
1. Review all options
2. Add a new option
3. Change an option
4. Delete an option
5. Compare options
Enter selection:
Reviewing a file will list the abbreviations and descriptions found in the file.
Adding an option will allow the user to choose an existing option to copy, and then allow
the user to enter a new abbreviation and new values for the new option. Changing an
option will allow the user to change the abbreviation or any of the values associated with
that option. Deleting an option will completely remove the option from the .100 file.
Comparing shows the differences between options in the .100 file. Each of these actions is
described in more detail in the following sections.
Entering a "q" or "quit" at any point will return the user to the next highest menu.
[Previous Topic] [Next Topic] [Table of Contents]
"Review all options" will print a list on the screen of the options found in that .100
file by listing each option's abbreviation and corresponding descriptions. After reviewing,
the user may choose any of the five actions, or return to the main menu to choose another
.100 file. Note that reviewing automatically causes the file to be re-formatted to the
specifications needed by the PC version of CENTURY.
[Previous Topic] [Next Topic] [Table of Contents]
The user may choose to add a new option to the file. After entering 1, for adding,
the program will display each option already existing in the file and ask if the user would
like to begin with that option:
Current option is W1 Wheat-type-one
Is this an option you wish to start with?
A response of "Y" or "y" will cause the program to copy this option to begin the
addition phase. If no option is responded to with a yes answer, the
program will return to
the previous menu of five actions. Once an affirmative response has been given, the user
will be asked for a new abbreviation and description:
Enter a new abbreviation:
The abbreviation must be unique to that file and no more than 5 characters; if a
duplicate is entered, the user will be asked to enter another abbreviation.
Enter a new description:
The description may not be longer than 65 characters.
Then, for each value in that option, the program will display the value which the
original option had for that parameter and ask the user for a new value:
Commands: D F H L Q <new value> <return>
Name: PRDX(1) Previous value: 300
Enter response:
The user may enter any of these possible responses, as shown on the Command
line:
see the definition of that parameter ............. enter D
find a specific parameter in that option ......... enter F
see a help message ............................... enter H
list the next 12 parameters ...................... enter L
quit, retaining the old values for
this and the remaining parameters
in this option .............................. enter Q
take the old value ............................... enter <return>
enter a new value ................................ enter a new value
The command and previous value lines will continue to be shown until the user
enters Q, to quit, or until the end of the option is reached.
[Previous Topic] [Next Topic] [Table of Contents]
The user may change values of parameters within an existing option. After
entering 2, for changing, the program will display each option which exists in the file and
ask if the user would like to change that option:
Current option is W1 Wheat-type-one
Is this an option you wish to change
A response of "Y" or "y" will cause the program to move on to the change phase. If
no option is responded to with a yes answer, the program will return to the previous
menu of five actions. Once an affirmative response has been given, the user will be asked
for a new abbreviation and description:
Enter a new abbreviation or a <return>
to use the existing abbreviation:
A new abbreviation must be unique to that file and no more than 5 characters; if a
duplicate is entered, the user will be asked to enter another abbreviation.
Enter a new description or a <return>
to use the existing description:
The description may not be longer than 65 characters.
Then, for each value in that option, the program will display the existing value
for that parameter and ask the user for a new value:
Commands: D F H L Q <new value> <return>
Name: PRDX(1) Previous value: 300
Enter response:
The user may enter any of these possible responses, as shown on the Command
line:
see the definition of that parameter ............. enter D
find a specific parameter in that option ......... enter F
see a help message ............................... enter H
list the next 12 parameters ...................... enter L
quit, retaining the old values for
this and the remaining parameters
in this option .............................. enter Q
take the old value ............................... enter <return>
enter a new value ................................ enter a new value
The command and previous value lines will continue to be shown until the user
enters Q, to quit, or until the end of the file is reached. Finally, the user is asked if
changes made should be saved:
Do you want to save the changes made?
If this is answered with "y" or "Y", the changed values will be saved. Otherwise,
the changes will be lost.
[Previous Topic] [Next Topic] [Table of Contents]
4.6. Changing the <site>.100 File
Making changes to the <site>.100 file is different in that the parameters in
this file are subdivided for easier review. After selecting <site>.100 from the main menu,
enter the name of the site file without the .100 extension. The user may name a new
<site>.100 file to save these changes to:
Enter a new site filename to save changes
to or a <return> to save to (original filename).100:
The program will then display the existing abbreviation and description and allows
the user to provide new ones:
Enter a new abbreviation or a <return>
to use the existing abbreviation:
Enter an abbreviation of no more than 5 characters.
Enter a new description or a <return>
to use the existing description:
The description may not be longer than 65 characters.
The next menu will show the subheadings within the file:
Which subheading do you want to work with?
0. Return to main menu
1. Climate parameters
2. Site and control parameters
3. External nutrient input parameters
4. Organic matter initial parameters
5. Forest organic matter initial parameters
6. Mineral initial parameters
7. Water initial parameters
Enter selection:
Entering a response of 1 through 7 will cause the first parameter shown to be from
that subheading. The program then continues as with the regular Change function.
For each value in that subheading, the program will display the value which the
original had for that parameter and ask the user for a new value:
Commands: D F H L Q <new value> <return>
Name: PRDX(1) Previous value: 300
Enter response:
The user may enter any of these possible responses, as shown on the Command
line:
see the definition of that parameter ............. enter D
find a specific parameter in that option ......... enter F
see a help message ............................... enter H
list the next 12 parameters ...................... enter L
quit, retaining the old values for
this and the remaining parameters
in this option .............................. enter Q
take the old value ............................... enter <return>
enter a new value ................................ enter a new value
The command and previous value lines will continue to be shown until the user
enters Q, to quit, or until the end of the subheading is reached.
After selecting choice 0, Return to the main menu, from the subheadings menu, the
user is asked if the changes made should be saved:
Do you want to save the changes made?
If this is answered with "y" or "Y", the changed values will be saved. Otherwise,
the changes will be lost.
[Previous Topic] [Next Topic] [Table of Contents]
The user may choose to delete one or more options from that .100 file. After
entering 4, for delete, each abbreviation and description of each option found is shown:
Current option is W1 Wheat-type-one
Is this an option you wish to delete?
If the user responds with a "Y" or "y", a double check is made to insure that no
error was made:
Are you sure you want to delete W1 Wheat-type-one?
If the answer is again "Y" or "y", the option is completely deleted from the .100 file
and is not recoverable.
[Previous Topic] [Next Topic] [Table of Contents]
The user may choose to compare options from that .100 file. After entering 5, for
compare, all abbreviations found in the file are shown:
W1 W2 W3
G1 G2 G3
G4 G5 SYBN
Current limit of options to compare is 5.
The user is then asked to enter all of the options, up to 5, that should be compared
at one time:
Enter an option to compare, <return> to quit:
After entering up to five options, the differences between the options are displayed.
For example, the differences between two wheat crops may be:
Difference: Abbrev Name Value
W2 HIMAX 0.35
W3 HIMAX 0.42
Difference: Abbrev Name Value
W2 EFRGRN(1) 0.65
W3 EFRGRN(1) 0.75
Note that format differences are not displayed. There is no difference, for
example, between "1.00" and "1".
After four differences are displayed on the screen, the user may continue to see
more differences, if they exist, or quit:
"Hit <return> to continue, Q to quit."
[Previous Topic] [Next Topic] [Table of Contents]
4.9. Generating Weather Statistics
If the user has access to actual weather data for a minimum ten year period, those
weather values may be used to generate precipitation means, standard deviations, and
skewness values, minimum temperature means and maximum temperature means.
These statistical values can then be used to drive the stochastic weather generator in
CENTURY. These statistical values are maintained in the <site>.100 file.
The name of the actual weather file must have a maximum of eight characters
with a ".wth" extension.
The format of the file is the standard format as required by CENTURY:
a four character name field ("prec", "tmin", or "tmax")
two spaces
a four character year field
12 number fields of the format 7.2
such that the length of each line is 64 characters. For example:
prec 1915 0.31 2.55 5.07 7.01 8.87 5.13 1.61 8.83 3.55 3.53 0.99 0.92
tmin 1915 -13.50 -8.33 -8.17 0.78 1.67 7.00 9.72 8.33 5.39 -0.28 -6.06 -8.78
tmax 1915 4.44 8.56 4.33 16.33 17.50 21.06 26.83 26.06 22.89 18.89 10.78 8.50
prec 1916 1.57 0.31 0.37 1.68 8.07 2.90 4.27 2.84 1.06 2.64 2.06 3.06
tmin 1916 -16.50 -9.50 -4.89 -2.28 1.56 6.28 10.56 9.89 3.33 -2.44 -9.28 -14.78
tmax 1916 -0.61 8.67 14.22 14.33 20.28 25.44 32.39 27.28 24.56 14.78 8.78 1.56
To generate the weather statistical values, choose "13" from the main menu,
"weather statistics". Then enter the name of the actual weather file without the ".wth"
extension:
Enter the name of the actual weather file:
FILE100 will generate the weather statistics and place the new monthly values
for PRECIP, PRCSTD, PRCSKW, TMN2M, TMX2M into the named <site>.100 file.
Missing values in the weather file, given as "-99.99", are ignored when statistics are
calculated.
FILE100 will then ask for the name of a <site>.100 file to write the values to:
Enter the site file name:
Enter the site file name without the .100 extension.
The user may name a new <site.100> file to save these changes to:
Enter a new site filename to save changes
to or a <return> to save to (original filename).100:
[Previous Topic] [Next Topic] [Table of Contents]
In the event that FILE100 should abort from the program at some point, the user should attempt to locate the "XXXX.100" backup file in the current directory. This file should contain the original version of the file that was being edited. If necessary, the user can copy this backup file into a file of the original file name.
[Previous Topic] [Next Topic] [Table of Contents]
5. SCHEDULING THROUGH EVENT100
5.1. Introduction
EVENT100 is the scheduling preprocessor for the CENTURY Soil Organic Matter
Model. This preprocessor allows the user to schedule management events and crop
growth controls at specific times during the simulation and produces an ASCII output file
which is read in by CENTURY. EVENT100 uses a grid-like display to allow the user to
move among months and years to schedule crop type, tree type, planting and harvest
months, first and last month of growth (for grassland or perennial crops), senescence
month, cultivation, fertilizer addition, irrigation, addition of organic matter (straw or
manure), grazing, fire, tree removal and erosion. The instructions given below apply to
both the PC and UNIX versions.
[Previous Topic] [Next Topic] [Table of Contents]
EVENT100 produces a scheduling file which drives events in CENTURY. It also
produces the general time information about the simulation, such as the starting time and
ending time. The scheduling of crop rotations and management events uses the principle
of repeating sequences within blocks of time. A block is a series of events which will
repeat themselves, in sequence, until the ending time of the block is reached. For
example, a series of historical farm practices might have been: breaking of the native sod
in 1920, a wheat-fallow rotation with plow cultivation and straw removal until 1950,
wheat-fallow with stubble-mulch management until 1980, followed by wheat-sorghum-
fallow. To model this series the model user would set up the following blocks in
EVENT100.
Block Years Management Repeating sequence
1 0 - 1919† Grass with grazing 1 year
2 1920 Cultivation to break the sod 1 year
3 1921 - 1950 Wheat-fallow, plow, straw removal 2 years
4 1951 - 1980 Wheat-fallow, stubble-mulch 2 years
5 1981 - 1992 Wheat-sorghum-fallow 3 years
† This period needs to be long enough to establish equilibrium conditions and may start
with a negative year.
Each block in the schedule file starts with a set of header lines showing:
the block number and an optional comment
the last year of simulation for the block
the number of years in the repeating sequence
the output starting year
the output month
the output interval
the weather choice for this block
The events scheduled for this block follow next. The last line of the block is the End of
Block Marker "-999 -999 X". The output starting year may be any year greater than or
equal to the starting year. The output month may be any month 1 through 12. The
output interval indicates how many times the state variables are written to the output
file. A value of 1 writes the output annually; 0.0833 (1/12) writes monthly output. As a
smaller value results in a larger output file size, the user may wish to specify different
interval values for each block.
For example, the simulation might run to equilibrium with grassland and check
peak standing crop and SOM in September from 1800 to 1899:
Start year: -4000
End year: 1899
Output starting year: 1800
Output month: 9
Output interval: 1
Then, the simulation might initiate an agricultural agent and examine seasonal trends
with monthly output:
Start year: 1900
End year: 1919
Output starting year: 1900
Output month: 1
Output interval: 0.0833
The weather choice may also be different in each block. The user should not only
consider the events but also the output file requirements and weather source changes
when determining what blocks a particular simulation will consist of.
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Where a default or old value is shown, the user may accept this value by merely
hitting the <return> key. Any other value should be explicitly entered by typing it in.
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To run the EVENT100 event scheduler, the user will need the EVENT100
executable program and the twelve .100 data files. EVENT100 uses these data files to
limit the user's entries to those that exist. Therefore, the user should set up any
necessary options of specific .100 file entries before beginning work in EVENT100 (see
Section 4).
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To use EVENT100, make sure that the executable program and the .100 data files
are in the same directory. To start the program, enter "event100". After showing the
program title, several initial questions need to be answered.
CENTURY Events Scheduler
Enter the name of the site-specific .100 file:
Enter the file name without the .100 extension. EVENT100 checks to see that
this file exists in the current directory and if so, that the file is not empty. If either of
these error conditions are met, the user may still go on. Note, however, that CENTURY
is no longer interactive in this respect and will not allow the name of the <site>.100 file to
be re-entered if the file does not exist or is not readable.
Enter the type of labeling to be done:
0. No labeling
1. 14C labeling
2. 13C labeling (stable isotope)
Default: 0. No labeling
Enter 0, 1 or 2. If a value of 1 is entered, the next question will be:
In what year will labeling begin?
Enter a value greater than or equal to the simulation starting year. If no labeling
is to occur, a zero will automatically be filled in for the year to begin labeling.
Enter Y if a microcosm is to be simulated:
Default: N
Enter a "y" or "Y" to indicate that a microcosm is to be simulated in CENTURY;
refer Section 3.15 on what a microcosm is and what events it may require. If a "y" or "Y"
is entered, a constant temperature must be entered:
Enter the constant microcosm temperature (>= 0):
Enter a temperature greater than or equal to 0.
Enter Y if a CO2 effect is to be simulated:
Default: N
Enter a "y" or "Y" to indicate that a CO2 effect is to be simulated; refer to Section
3.14 on how the CO2 effect is implemented. If a "y" or "Y" is entered, the initial and final
times for the effect to take place over must be entered:
Enter the initial time:
Enter the final time:
Enter the initial time, which must be greater than or equal to 0, and the final
time, which must be greater than the initial time.
Under what management was the site before the simulation began?
1. Cropping/Grassland
2. Forest
3. Cropping/Grassland and Forest
Default: Cropping/Grassland
Enter the system which is to be simulated in CENTURY.
If answers 1 or 3 are chosen:
In order for the cropping system to run correctly,
you must specify an initial crop that will be used
to initialize the lignin values.
Enter an initial crop:
Enter a crop choice; this crop will be used by CENTURY to initialize the lignin
content of standing dead, surface, and below ground litter pools before the actual
simulation begins. Hitting the return key will give a list of options from the crop.100 file
If answers 2 or 3 are chosen:
In order for the forest system to run correctly,
you must specify an initial tree that will be used
to initialize the lignin values.
Enter an initial tree:
Enter a tree choice; this tree will be used by CENTURY to initialize the lignin
content of the wood and litter pools before the actual simulation begins. Hitting the
return key will give a list of options from the tree.100 file
The next few questions deal with setting up the first block.
Adding first new block:
Enter the starting year of simulation for this block:
The entered value must be greater than 0.
Enter the last year of simulation for this block:
The entered value must be greater than or equal to the starting year. For
example, to run an eight year simulation from January 1920 to December 1927 inclusive,
the ending year will be 1927. The next block will begin in January 1928.
Enter the number of years in the repeating sequence:
Enter the number of years that will be set up in the block; refer to Section 5.2,
"The Concept of Blocks" for information on what a block entails or how many years will
need to be set up.
Enter the year to begin output:
Default: the block starting year
Enter a year greater than or equal to the starting year of the block or a <return>
to accept the default.
Enter the month to begin output (1-12):
Default: 1
Enter a month between 1 and 12 or a <return> to accept the default.
Enter the output interval:
Monthly = 0.0833
6 monthly = 0.5
Yearly = 1.0
Etc.
Default: 0.0833 - monthly
Enter a time increment or a <return> to accept the default.
Enter the weather choice:
M (mean values from the site.100 file)
S ( from the site.100 file, but stochastic precipitation)
F (from the beginning of an actual weather file)
C (continued from an actual weather file, without rewinding)
Default: S - Stochastic
The possible answers are:
M to use the mean precipitation and temperature values which were read in
from the site-specific .100 file.
S to use the stochastically generated precipitation and the mean temperature
values from the site-specific .100 file. If the precipitation skewness values
are not zero, the precipitation values will be selected from a skewed
distribution, otherwise, the precipitation values will be selected from a
normal distribution. Variables used are "precip" as means, "prcstd" as
standard deviations and "prcskw" as skewness values; these variables are in
the site-specific .100 file. With both distributions, precipitation for the
month will equal zero if a negative value is stochastically generated.
Especially in the case of the normal distribution, this will increase the mean
annual precipitation above the sum of the monthly "precip" values.
F to use precipitation and temperature data from a new weather data file; the
weather file name must be no more that 8 characters and end with a ".wth"
extension. The format of the weather file is:
a four character name field ("prec", "tmin", or "tmax")
two spaces
a four character year field
12 number fields of the format 7.2
such that the length of each line is 64 characters. For example:
prec 1915 0.31 2.55 5.07 7.01 8.87 5.13 1.61 8.83 3.55 3.53 0.99 0.92
tmin 1915 -13.50 -8.33 -8.17 0.78 1.67 7.00 9.72 8.33 5.39 -0.28 -6.06 -8.78
tmax 1915 4.44 8.56 4.33 16.33 17.50 21.06 26.83 26.06 22.89 18.89 10.78 8.50
prec 1916 1.57 0.31 0.37 1.68 8.07 2.90 4.27 2.84 1.06 2.64 2.06 3.06
tmin 1916 -16.50 -9.50 -4.89 -2.28 1.56 6.28 10.56 9.89 3.33 -2.44 -9.28 -14.78
tmax 1916 -0.61 8.67 14.22 14.33 20.28 25.44 32.39 27.28 24.56 14.78 8.78 1.56
C to continue using the current weather data file without rewinding
Note that these choices (M, S, F, C) are fixed and may not be changed by the user.
Enter the comment:
Enter any comment desired up to 50 characters.
Once these questions have been answered, the empty grid is displayed.
Block# 1 Year: 1 of 2 Start: 1920 End: 1950 Comment: W-F
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CROP
PLTM
HARV
FRST
LAST
SENM
FERT
CULT
OMAD
IRRI
GRAZ
EROD
FIRE
TREE
TREM
TFST
TLST
System commands: FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK
DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT
Current date: January of Year 1
User command:
The first line of the grid shows the current block, the current year out of the total
number of years to be set up in this block, the block starting and ending years, and the
block's comment. The possible event commands are listed along the left hand edge, under
the month line, and the system command are displayed along the bottom. The last line
displays the current month and year. EVENT100 then waits for a response from the
user. Any event command entered at this time would be scheduled in the current month
shown.
The general format for entering a command is "command <addtl>" where command
is any one of the four-letter commands and addtl is any additional information needed for
that command. In general, an event command is "undone" by entering "command X".
Text may be typed in either lower, upper, or mixed case; EVENT100 will convert all text
to upper case. Each event and system command is described in detail in the following
section.
When all events have been entered, use QUIT to save the scheduling to an output
file and exit EVENT100.
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5.6. Explanation of Event Commands
Each event command is described in the following format:
XXXX The command name and explanation.
Addtl: What additional information the command needs.
Mark: How to schedule the event as occurring in the current month.
Unmark: How to remove the scheduling of the event in the current month.
Output: What the .sch output file will show for this command.
CROP Designates which crop is in use.
Addtl: Acceptable abbreviations are from the crop.100 file.
Mark: CROP addtl
Unmark: CROP X
Output: The year, month and the word "CROP", followed on the next line by
the crop selected.
PLTM Marks a month in which the current crop is planted.
Addtl: This command has no additional; it is simply marked or unmarked.
Mark: PLTM
Unmark: PLTM
Output: The year, month and the word "PLTM".
HARV Designates which type of harvest to use; automatically schedules a LAST event.
Addtl: Acceptable abbreviations are from the harv.100 file.
Mark: HARV addtl
Unmark: HARV X
Output: The year, month, and the word "HARV", followed on the next line by
the harvest method selected.
FRST Marks the current month as the first month of growing for crops.
Addtl: This command has no additional; it is simply marked or unmarked.
Mark: FRST
Unmark: FRST
Output: The year, month, and the word "FRST".
LAST Marks the current month as the last month of growing for crops.
Addtl: This command has no additional; it is simply marked or unmarked.
Mark: LAST
Unmark: LAST
Output: The year, month, and the word "LAST".
SENM Marks the current month as the month of senescence for crops.
Addtl: This command has no additional; it is simply marked or unmarked.
Mark: SENM
Unmark: SENM
Output: The year, month, and the word "SENM".
FERT Schedules a fertilization event in the current month.
Addtl: The acceptable abbreviations come from the fert.100 file.
Mark: FERT addtl
Unmark: FERT X
Output: The year, month, and the word "FERT", followed on the next line by
the fertilization method selected.
CULT Schedules a cultivation event in the current month.
Addtl: The acceptable abbreviations come from the cult.100 file.
Mark: CULT addtl
Unmark: CULT X
Output: The year, month, and the word "CULT", followed on the next line by
the cultivation method selected.
OMAD Schedules an organic matter addition event in the current month.
Addtl: The acceptable abbreviations come from the omad.100 file.
Mark: OMAD addtl
Unmark: OMAD X
Output: The year, month, and the word "OMAD", followed on the next line by
the type of organic matter addition selected.
IRRI Schedules an irrigation event in the current month.
Addtl: The acceptable abbreviations come from the irri.100 file.
Mark: IRRI addtl
Unmark: IRRI X
Output: The year, month, and the word "IRRI", followed on the next line by the
irrigation method selected.
GRAZ Schedules a grazing event in the current month.
Addtl: The acceptable abbreviations come from the graz.100 file.
Mark: GRAZ addtl
Unmark: GRAZ X
Output: The year, month, and the word "GRAZ", followed on the next line by
the grazing type selected.
EROD Schedules an erosion event in the current month.
Addtl: The amount of soil loss (kg/m2/month).
Mark: EROD amount
Unmark: EROD 0
Output: The year, month, and the word "EROD", followed on the next line by
the amount.
FIRE Schedules a fire in the current month.
Addtl: The acceptable abbreviations come from the fire.100 file.
Mark: FIRE addtl
Unmark: FIRE X
Output: The year, month, and the word "FIRE", followed on the next line by
the type of fire selected.
TREE Selects a tree type.
Addtl: The acceptable abbreviations come from the tree.100 file.
Mark: TREE addtl
Unmark: TREE X
Output: The year, month, and the word "TREE" followed on the next line by
the type of tree selected.
TREM Schedules a tree removal event in the current month.
Addtl: The acceptable abbreviations come from the trem.100 file.
Mark: TREM addtl
Unmark: TREM X
Output: The year, month, and the word "TREM" followed on the next line by
the type of tree removal selected.
TFST Marks the current month as the first month of growth for forest.
Addtl: This command has no additional; it is simply marked or unmarked.
Mark: TFST
Unmark: TFST
Output: The year, month, and the word "TFST".
TLST Marks the current month as the last month of growth for forest.
Addtl: This command has no additional; it is simply marked or unmarked.
Mark: TLST
Unmark: TLST
Output: The year, month, and the word "TLST".
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5.7. Explanation of System Commands
Each system command is described in the following format:
XXXX The command name and explanation.
Addtl: What additional information the command needs.
Execute: How the command should be entered.
FILL Copies the last event command (and addtl, if applicable) to the number of months
specified.
Addtl: The number of months to fill into (1-11)
Execute: FILL number
NEXT Changes to the next month. If the current month is December, changes to
January of the next year. If the current year is the last year, changes to January
of the first year.
Addtl: None
Execute: NEXT
NXTA (NeXT Auto) Toggle switch command that, when on, automatically does a NEXT
command after each event command is entered. The default is off; a NEXT
command is not done automatically after each event command.
Addtl: None
Execute: NXTA
GOMT Changes to the given month in the current year.
Addtl: The month number (1-12) to change to
Execute: GOMT number
NXYR Changes to the next year. If in the last year of the block, changes to the first
year of the block.
Addtl: None
Execute: NXYR
GOYR Changes to the given year in the current block.
Addtl: A year number in the current block
Execute: GOYR number
CPYR Copies all events in the current year to the given year.
Addtl: A year number in the current block to copy to
Execute: CPYR number
NBLK Changes to the next block. If this block has not yet been set up, the user may set
up the block by answering the set of block questions concerning the last year of
simulation, the number of years in the repeating sequence, the data output
interval value, the month to start writing output, the weather choice and the
comment.
Addtl: None
Execute: NBLK
GBLK Changes to the given block number, if that block has already been set up. If the
block has not been set up, the user may set up the block by answering the set of
block questions concerning the last year of simulation, the number of years in the
repeating sequence, the data output interval value, the month to start writing
output, the weather choice and the comment.
Addtl: The block number to change to
Execute: GBLK number
ABLK Adds a new block by having the user answer the block questions concerning the
last year of simulation, the number of years in the repeating sequence, the data
output interval value, the month to start writing output, the weather choice and
the comment. The user may append a block to the end of the current set or add a
block previous to an existing one.
Addtl: None
Execute: ABLK
DBLK Deletes the current block and any grid values associated with the block.
Addtl: The user is asked to double-check that the block should be deleted
Execute: DBLK
CBLK Copies the current block to a new block position. The user is asked the block
questions concerning the last year of simulation, the number of years in the
repeating sequence, the data output interval value, the month to start writing
output, the weather choice and the comment.
Addtl: None
Execute: CBLK
TIME Allows the user to update values given in the interactive questions concerning
block header information. For each block set up, the block header information is
displayed and the user may update the responses:
*** Update Block Header Information ***
Block Start End Rept Out Out Out Wthr Wthr Comment
# Year Year # Year Mnth Intv Type Name Field
1 1900 1950 1 1900 1 0.083 S Grass
2 1951 1970 2 1951 1 0.083 F sidney.wth W/F
Enter desired action:
Block number to start with ABLK to add a new block
Q or <return> to quit DBLK to delete a block
CBLK to copy a block
If the user chooses to update any of the information shown, each field is
displayed with the old value and the user is allowed to enter a new value. When
Q or <return> is entered, all blocks are checked for time continuity and
consistency. Any errors found must be corrected before the user is allowed to
return to the events grid.
Addtl: None
Execute: TIME
PREV Print a preview listing of the scheduler output file to the screen.
Addtl: None
Execute: PREV
DRAW Draws the display grid on the screen.
Addtl: None
Execute: DRAW
DRWA (Draw Auto) Toggle switch command that, when on, automatically draws the
display grid after each event command is entered. Otherwise, the display grid is
only drawn on a DRAW command. The default is on; the display grid is drawn
after each event command.
Addtl: None
Execute: DRWA
HELP Displays a brief help message and, where applicable, the acceptable abbreviations
from the specific .100 file.
Addtl: An event or system command
Execute: HELP command
SAVE Saves the scheduling to the output file name the user supplies. If a previous
SAVE command has been executed, that file name will be displayed as a default;
the user may use that name or supply a new name. The name of the output file
will be <file>.sch, where <file>: is the name supplied by the user.
Addtl: EVENT100 will ask for an output file name
Execute: SAVE
QUIT Terminates the EVENT100 program.
Planting and harvest dates are tested for sequence correctness and
symmetry; first and last months of growth are likewise checked. In the event
that the user has a simulation in which there are unpaired plantings and
harvests or first and last months of growth, the user may continue on although
the condition is detected. If an error condition is detected in one of these cases,
the user is asked if the program should still terminate. The user may return to
the grid to correct the problems or continue on. Next, the user is asked for the
name of an output file.
If a previous SAVE command has been executed, that file name will be
displayed as a default; the user may use that name or supply a new name. Also,
the user may quit without saving to any file by simply hitting the return key. If
an output file is produced, it will be of the name <file>.sch, where <file> is the
name supplied by the user. Finally, the EVENT100 program ends.
Addtl: EVENT100 will ask for an output file name
Execute: QUIT
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5.8. The -i Option: Reading from a Previous Schedule File
EVENT100 includes the option of reading from a previously generated scheduler
file through the -i option. The schedule file must exist in the current directory and be of
the name <file>.sch. Start EVENT100 by entering "event100 -i file"; note that the .sch
extension is not included. EVENT100 will then read in the scheduler file named. The
starting questions concerning site file name, type of labeling, year to begin labeling,
microcosm flag, the CO2 effect flag, initial crop and initial tree are displayed showing the
original value from the schedule file; the user may update any response to these
questions. A TIME command will automatically be executed to allow the user to update
any block header information from the previous file. Finally, the display grid is shown,
with the previous events filled in. Any changes may be made and any event or system
commands may be entered. Upon entering a SAVE or QUIT command, the name of the
schedule file given with the -i is used as the default.
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5.9. Example EVENT100 Sessions
The first scenario to be scheduled is from a Sidney, Nebraska site
in which these events occurred:
0-1919 grassland with grazing (1 year repeating sequence)
1920 breaking of the sod and planting wheat, examining output
from 1900 to 1919 in September (1 year repeating sequence)
1921-1930 fallow-wheat rotation (2 year repeating sequence) with
stochastic weather
1931-1940 fallow-wheat rotation (2 year repeating sequence) with actual
weather from a data file
For the purpose of this example, the user may assume that the <site>.100 file has
been created and is named "sidney.100" and that the weather file "sidney.wth" also exists.
Begin event100 and answer the initial questions:
prompt% event100
CENTURY Events Scheduler
Enter the name of the site-specific .100 file:
sidney
Enter the type of labeling to be done:
0. No labeling
1. 14C labeling
2. 13C labeling (stable isotope)
Default: 0. No labeling
0
Enter Y if a microcosm is to be simulated:
Default: N
n
Enter Y if a CO2 effect is to be simulated:
Default: N
n
Under what management was the site before
the simulation begins?
1. Cropping/Grassland
2. Forest
3. Cropping/Grassland and Forest
Default: 1
1
In order for the cropping system to run correctly,
you must specify an initial crop that will be used
to initialize the lignin values.
Enter an initial crop:
G3
Adding first new block:
Enter the starting year of simulation for this block:
0
Enter the last year of simulation for this block:
1919
Enter the number of years in the repeating sequence:
1
Enter the year to begin output:
Old value: 0
1900
Enter the month to begin output (1-12):
Default: 1
9
Enter the output interval:
Monthly = 0.0833
6 monthly = 0.5
Yearly = 1.0
Etc.
Default: 0.0833 - monthly
1.0
Enter the weather choice:
M (mean values from the site.100 file)
S (from the site.100 file, but stochastic
precipitation)
F (from the beginning of an actual weather file)
C (continued from an actual weather file,
without rewinding)
Default: S - Stochastic
S
Enter the comment:
Initial Grass
/* At this point, the scheduling grid is displayed, and the user
may begin to schedule the events of the grassland. Note that the grid
can be redrawn after each command, but for this example, only selected
grids will be displayed. */
Block# 1 Year: 1 of 1 Start: 0 End: 1919 Comment: Initial
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CROP
PLTM
HARV
FRST
LAST
SENM
FERT
CULT
OMAD
IRRI
GRAZ
EROD
FIRE
TREE
TREM
TFST
TLST
System commands: FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK
DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT
Current date: January of Year 1
User command: drwa /* Turn OFF drawing the grid after each command */
Current date: January of Year 1
User command: crop g3 /* Designate the first crop to be the grass "G3" */
Current date: January of Year 1
User command: graz w /* Grazing of winter standing dead */
Current date: January of Year 1
User command: fill 3 /* Copy grazing to next 3 months */
Current date: January of Year 1
User command: gomt 4 /* Change to April */
Current date: April of Year 1
User command: frst /* Designate grass to begin growing */
Current date: April of Year 1
User command: gomt 5 /* Change to May */
Current date: May of Year 1
User command: graz g /* Grazing of growing grass */
Current date: May of Year 1
User command: fill 4 /* Copy grazing to June, July, August and September */
Current date: May of Year 1
User command: gomt 10 /* Change to October */
Current date: October of Year 1
User command: last /* Designate grass to stop growing */
Current date: October of Year 1
User command: next /* Change to November */
Current date: November of Year 1
User command: senm /* Designate grass to senesce */
Current date: November of Year 1
User command: draw /* Draw the grid */
Block# 1 Year: 1 of 1 Start: 0 End: 1919 Comment: Initial
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CROP G3
PLTM
HARV
FRST X
LAST X
SENM X
FERT
CULT
OMAD
IRRI
GRAZ W W W G G G G G
EROD
FIRE
TREE
TREM
TFST
TLST
System commands: FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK
DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT
Current date: January of Year 1
User command: ablk /* Add next block, the sod breaking */
Add a new block before what existing block?
Current blocks: 1 to 1
(Default: adds new block to end)
<return> /* New block should be added to the end */
Enter the starting year of simulation for this block:
Old value: 1920
1920
Enter the last year of simulation for this block:
1920 /* Block is only 1 year in length */
Enter the number of years in the repeating sequence:
1
Enter the year to begin output:
Old value: 1920
1920
Enter the month to begin output (1-12):
Default: 1
1
Enter the output interval:
Monthly = 0.0833
6 monthly = 0.5
Yearly = 1.0
Etc.
Default: 0.0833 - monthly
0.0833
Enter the weather choice:
M (mean values from the site.100 file)
S (from the site.100 file, but stochastic
precipitation)
F (from the beginning of an actual weather file)
C (continued from an actual weather file,
without rewinding)
Default: S - Stochastic
S
Enter the comment:
Breaking the sod to plant wheat
Current date: November of Year 1
User command: gblk 2 /* Change to the new block in order to add events */
Changing to block #2
Current date: January of Year 1
User command: draw /* See that the grid header now refers to Block 2 */
Block# 2 Year: 1 of 1 Start: 1920 End: 1920 Comment: Breakin
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CROP
PLTM
HARV
FRST
LAST
SENM
FERT
CULT
OMAD
IRRI
GRAZ
EROD
FIRE
TREE
TREM
TFST
TLST
System commands: FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK
DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT
Current date: January of Year 1
User command: gomt 4 /* Change to April */
Current date: April of Year 1
User command: nxta /* After entering each command, automatically change to the
next month */
Current date: April of Year 1
User command: cult p /* Cultivate with a plow and change to May */
Current date: May of Year 1
User command: cult c /* Cultivate with a cultivator and change to June */
Current date: June of Year 1
User command: cult c /* Cultivate with a cultivator and change to July */
Current date: July of Year 1
User command: cult c /* Cultivate with a cultivator and change to August */
Current date: August of Year 1
User command: cult r /* Cultivate with a rodweeder and change to September */
Current date: September of Year 1
User command: cult r /* Cultivate with a rodweeder and change to October */
Current date: October of Year 1
User command: nxta /* Turn off automatic switching to next month */
Current date: October of Year 1
User command: crop w1 /* Designate wheat type W1 as new crop */
Current date: October of Year 1
User command: pltm /* Designate the wheat to begin growing */
Current date: October of Year 1
User command: cult d /* Cultivate with a drill */
Current date: October of Year 1
User command: draw /* View the grid as it now appears */
Block# 2 Year: 1 of 1 Start: 1920 End: 1920 Comment: Breakin
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CROP W1
PLTM X
HARV
FRST
LAST
SENM
FERT
CULT P C C C R R D
OMAD
IRRI
GRAZ
EROD
FIRE
TREE
TREM
TFST
TLST
System commands: FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK
DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT
Current date: January of Year 1
User command: save /* Save the work done so far to file "sidney.sch" */
Name of file to save grid to:
sidney
Saving...
The scheduling has been saved to the file: sidney.sch
Current date: October of Year 1
User command: ablk /* Add next block, the wheat-fallow rotation. Note that since
wheat has been planted in 1920, this rotation really needs to be
fallow-wheat, with harvesting in the first year of the
rotation and planting in the second year. */
Add a new block before what existing block?
Current blocks: 1 to 2
(Default: adds new block to end)
<return> /* New block should be added to the end */
Enter the starting year of simulation for this block:
Old value: 1921
1921
Enter the last year of simulation for this block:
1940
Enter the number of years in the repeating sequence:
2
Enter the year to begin output:
Old value: 1921
1921
Enter the month to begin output (1-12):
Default: 1
1
Enter the output interval:
Monthly = 0.0833
6 monthly = 0.5
Yearly = 1.0
Etc.
Default: 0.0833 - monthly
0.0833
Enter the weather choice:
M (mean values from the site.100 file)
S (from the site.100 file, but stochastic
precipitation)
F (from the beginning of an actual weather file)
C (continued from an actual weather file,
without rewinding)
Default: S - Stochastic
S
Enter the comment:
Fallow-wheat
Current date: October of Year 1
User command: gblk 3 /* Change to the new block in order to add events */
Changing to block #3
Current date: January of Year 1
User command: draw /* See that the grid header now refers to Block 3 */
Block# 3 Year: 1 of 2 Start: 1921 End: 1940 Comment: Fallow-
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CROP
PLTM
HARV
FRST
LAST
SENM
FERT
CULT
OMAD
IRRI
GRAZ
EROD
FIRE
TREE
TREM
TFST
TLST
System commands: FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK
DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT
Current date: January of Year 1
User command: crop w1 /* Designate that the current crop is wheat type w1 (this could
be omitted as "w1" will be the default carried forward from the
previous block) */
Current date: January of Year 1
User command: gomt 7 /* Change to July */
Current date: July of Year 1
User command: harv g /* Designate a harvesting of grain; this automatically
designates a LAST month of growing */
Current date: July of Year 1
User command: draw /* See the first year of the rotation */
Block# 3 Year: 1 of 2 Start: 1921 End: 1940 Comment: Fallow-
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CROP W1
PLTM
HARV G
FRST
LAST X
SENM
FERT
CULT
OMAD
IRRI
GRAZ
EROD
FIRE
TREE
TREM
TFST
TLST
System commands: FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK
DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT
Current date: January of Year 1
User command: goyr 2 /* Change to the second year of the rotation */
Current date: July of Year 2
User command: gomt 4 /* Change to April */
Current date: April of Year 2
User command: nxta /* After entering each command, automatically change to the
next month */
Current date: April of Year 2
User command: cult p /* Cultivate with a plow and change to May */
Current date: May of Year 2
User command: cult c /* Cultivate with a cultivator and change to June */
Current date: June of Year 2
User command: cult c /* Cultivate with a cultivator and change to July */
Current date: July of Year 2
User command: cult c /* Cultivate with a cultivator and change to August */
Current date: August of Year 2
User command: cult r /* Cultivate with a rodweeder and change to September */
Current date: September of Year 2
User command: cult r /* Cultivate with a rodweeder and change to October */
Current date: October of Year 2
User command: nxta /* Turn off automatic switching to next month */
Current date: October of Year 2
User command: pltm /* Designate the wheat to begin growing */
Current date: October of Year 2
User command: fert n45 /* Add some nitrogen fertilizer */
Current date: October of Year 2
User command: cult d /* Cultivate with a drill */
Current date: October of Year 2
User command: draw /* See the second year of the rotation */
Block# 3 Year: 2 of 2 Start: 1921 End: 1940 Comment: Fallow-
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CROP
PLTM X
HARV
FRST
LAST
SENM
FERT N45
CULT P C C C R R D
OMAD
IRRI
GRAZ
EROD
FIRE
TREE
TREM
TFST
TLST
System commands: FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK
DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT
Current date: January of Year 1
User command: save /* Save the work done thus far */
Previous file name: sidney.sch
Do you want to save to this file? (Default: Y)
Y /* Save to the same file */
Saving...
The scheduling has been saved to the file: sidney.sch
Current date: October of Year 2
User command: time /* Block 3 has stochastic weather for the entire time but
actual weather files have been created for 1931-1940, so Block
3 needs to be broken into 2 blocks; issue the "time" command
to do some re-arranging */
*** Update Block Header Information ***
Block Start End Rept Out Out Out Wthr Wthr Comment
# Year Year # Year Mnth Intv Type Name Field
1 0 1919 1 0 1 0.083 S Initial Gra
2 1920 1920 1 1920 1 0.083 S Breaking th
3 1921 1940 2 1921 1 0.083 S Fallow-whea
Enter desired action:
Block number to start with ABLK to add a new block
Q or <return> to quit DBLK to delete a block
CBLK to copy a block
cblk /* Copy Block 3 to the end; this will become Block 4, running
from 1931-1940 */
Enter block number to copy:
3
Copy current block before what existing block?
Current blocks: 1 to 3
(Default: copies new block to end)
<return> /* New block should be added to the end */
Enter the starting year of simulation for this block:
Old value: 1941
1931 /* New block begins in 1931 */
Enter the last year of simulation for this block:
1940 /* New block ends in 1940 */
Enter the number of years in the repeating sequence:
Old value: 2
2
Enter the year to begin output:
Old value: 1931
1931
Enter the month to begin output (1-12):
Default: 1
1
Enter the output interval:
Monthly = 0.0833
6 monthly = 0.5
Yearly = 1.0
Etc.
Default: 0.0833 - monthly
0.0833
Enter the weather choice:
M (mean values from the site.100 file)
S (from the site.100 file, but stochastic
precipitation)
F (from the beginning of an actual weather file)
C (continued from an actual weather file,
without rewinding)
Default: S - Stochastic
F /* Use F, to get the weather from the actual weather file */
Enter the name of the weather file:
sidney /* The name of the actual weather file is "sidney.wth" */
Enter the comment:
Fallow-wheat, with actual weather
*** Update Block Header Information ***
Block Start End Rept Out Out Out Wthr Wthr Comment
# Year Year # Year Mnth Intv Type Name Field
1 0 1919 1 0 1 0.083 S Initial Gra
2 1920 1920 1 1920 1 0.083 S Breaking th
3 1921 1940 2 1921 1 0.083 S Fallow-whea
4 1931 1940 2 1931 1 0.083 F sidney Fallow-whea
Enter desired action:
Block number to start with ABLK to add a new block
Q or <return> to quit DBLK to delete a block
CBLK to copy a block
3 /* Now fix the ending time of Block 3 */
Enter the starting year of simulation for this block:
Old value: 1921
1921
Enter the last year of simulation for this block:
Old value: 1940
1930 /* Block 3 should end in 1930 */
Enter the number of years in the repeating sequence:
Old value: 2
2
Enter the year to begin output:
Old value: 1921
1921
Enter the month to begin output (1-12):
Old value: 1
1
Enter the output interval:
Monthly = 0.0833
6 monthly = 0.5
Yearly = 1.0
Etc.
Old value: 0.083000
0.0833
Enter the weather choice:
M (mean values from the site.100 file)
S (from the site.100 file, but stochastic
precipitation)
F (from the beginning of an actual weather file)
C (continued from an actual weather file,
without rewinding)
Old value: S
S
Enter the comment:
Old value: Fallow-wheat
Fallow-wheat
*** Update Block Header Information ***
Block Start End Rept Out Out Out Wthr Wthr Comment
# Year Year # Year Mnth Intv Type Name Field
1 0 1919 1 0 1 0.083 S Initial Gra
2 1920 1920 1 1920 1 0.083 S Breaking th
3 1921 1930 2 1921 1 0.083 S Fallow-whea
4 1931 1940 2 1931 1 0.083 F sidney Fallow-whea
Enter desired action:
Block number to start with ABLK to add a new block
Q or <return> to quit DBLK to delete a block
CBLK to copy a block
<return> /* Ready to return to the grid */
Enter block number to return to:
(Default: block #1)
4 /* See that Block 4 is a copy of Block 3 */
Block# 4 Year: 1 of 2 Start: 1931 End: 1940 Comment: Fallow-
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CROP W1
PLTM
HARV G
FRST
LAST X
SENM
FERT
CULT
OMAD
IRRI
GRAZ
EROD
FIRE
TREE
TREM
TFST
TLST
System commands: FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK
DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT
Current date: January of Year 1
User command: nxyr /* Check that the second year is correct */
Block# 4 Year: 2 of 2 Start: 1931 End: 1940 Comment: Fallow-
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CROP
PLTM X
HARV
FRST
LAST
SENM
FERT N45
CULT P C C C R R D
OMAD
IRRI
GRAZ
EROD
FIRE
TREE
TREM
TFST
TLST
System commands: FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK
DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT
Current date: January of Year 2
User command: quit /* All events are scheduled, so exit from event100 */
Previous file name: sidney.sch
Do you want to save to this file? (Default: Y)
Y /* Save to same file */
Saving...
The scheduling has been saved to the file: sidney.sch
prompt%
/* To re-load event100 with the sidney.sch schedule file: */
prompt% event100 -i sidney
CENTURY Events Scheduler
Reading from old file sidney.sch...
Enter the name of the site-specific .100 file:
Old value: sidney.100
sidney.100 /* The designated <site>.100 file may be changed. */
Enter the type of labeling to be done:
0. No labeling
1. 14C labeling
2. 13C labeling (stable isotope)
Old value: 0
0 /* The type of labeling may be changed. */
Enter Y if a microcosm is to be simulated:
Default: N
N /* The microcosm designation may be changed. */
Enter Y if a CO2 effect is to be simulated:
Default: N
N /* The CO2 designation may be changed */
Under what management was the site before
the simulation begins?
1. Cropping/Grassland
2. Forest
3. Cropping/Grassland and Forest
Old value: 1
1 /* The previous management may be changed. */
In order for the cropping system to run correctly,
you must specify an initial crop that will be used
to initialize the lignin values.
Enter an initial crop:
Old value: G3
G3 /* The initial grass/crop may be changed. */
*** Update Block Header Information ***
Block Start End Rept Out Out Out Wthr Wthr Comment
# Year Year # Year Mnth Intv Type Name Field
1 0 1919 1 0 1 0.083 S Initial Gra
2 1920 1920 1 1920 1 0.083 S Breaking th
3 1921 1930 2 1921 1 0.083 S Wheat-fallo
4 1931 1940 2 1931 1 0.083 F sidney Wheat-f
Enter desired action:
Block number to start with ABLK to add a new block
Q or <return> to quit DBLK to delete a block
CBLK to copy a block
/* After the initial questions have been updated as necessary, the "time"
command is automatically issued; EVENT100 now operates as though the user
had issued this command. When any alterations have been made, the "quit"
command will exit from EVENT100. */
[Previous Topic] [Next Topic] [Table of Contents]
6. EXECUTING CENTURY SIMULATIONS
6.1. Executing the PC VIEW Version
Run the CENTURY model by typing "century" to use the century.bat batch
program. The name of the schedule file will then be requested:
Enter the name of the schedule file:
Enter the schedule file name, without the ".sch" extension.
The model will run, with the progressive time displayed. Note that the time is
updated in the output interval of that block. Thus, a block with an output interval of 100
years may appear to have stopped running, whereas the displayed time of a block with a
monthly output interval will update quickly.
When the progressive time reaches the simulation end time, the VIEW module is
automatically launched for the printing or plotting of output variables. Refer to the user's
manual provided with VIEW for an explanation of the capabilities of this module.
To stop the run prematurely, type "Control-C" and answer the question
Terminate batch job? (y/n):
with a "y".
[Previous Topic] [Next Topic] [Table of Contents]
6.2. Executing the PC Stand-Alone Version
To run CENTURY, type "centuryx" and answer the questions to provide the name
of the .sch schedule file and the name of the .bin binary file to save to. For example, on
the installation disk is a historic.sch schedule file. To run this schedule file and save the
output to testrun.bin, type "centuryx" to start the model:
CENTURY SOIL ORGANIC MATTER MODEL
Are you extending from a previous run? (Y/y/N/n)
Type "n".
Enter schedule file name:
Type "historic" to indicate the historic.sch file.
Enter name for binary output file:
Type "testrun" to indicate the testrun.bin file is the name of the file to be created.
The program will show the Model is running... message and will return to the
DOS prompt after completion. Typing "dir" will show that testrun.bin has been created.
[Previous Topic] [Next Topic] [Table of Contents]
6.3. Executing the UNIX Stand-Alone Version
To run CENTURY, use command-line arguments as follows:
century -s <schedule.file> -n <binary.output.file>
For example, on the installation disk is a historic.sch schedule file. To run this schedule
file and save the output to testrun.bin, type "century -s historic -n testrun". The program
will show the Model is running... message and will return to the UNIX prompt after
completion. Typing "ls" will show that testrun.bin has been created.
[Previous Topic] [Next Topic] [Table of Contents]
6.4. Using LIST100 with Stand-Alone Versions
To generate ASCII output from a binary file created by either the PC or UNIX
stand-alone versions of CENTURY, use the LIST100 utility. Enter "list100" to start the
utility and answer each question as directed. For example, to create an ASCII text file
called yields.lis of variables from the testrun.bin file, type "list100":
List100
Binary to Ascii Utility
Enter name of binary input file (no .bin):
Type "testrun" to indicate the testrun.bin file.
Enter name of ASCII output file (no .lis):
Type "yields" to indicate that the name of the new output file is to be yields.lis.
Enter starting time, <return> for time file begins:
Type <return> or a year.
Enter ending time, <return> for time file ends:
Type <return> or a year.
Enter variables, one per line, <return> to quit:
Type "crmvst" <return> cgrain <return> <return>" to indicate that these two variables, in
addition to the time, should be written to the ASCII file.
Execution success.
Typing "dir" or "ls" will show that the yields.lis file has been created. The testrun.bin file
still exists, and LIST100 may be used again to create another ASCII text file from the
CENTURY binary output.
[Previous Topic] [Next Topic] [Table of Contents]
7. WELD COUNTY, COLORADO HISTORICAL SCENARIO
Included on the installation disks is a sample schedule file, historic.sch. This file
is provided to give the user an idea of the process involved in mapping an actual historical
chain of events into a CENTURY simulation. This sample schedule file simulates the
historic cropping events of Weld County, Colorado. Following is a detailed description of
the events which occurred in this scenario. Capital letters in parentheses at the end of
the line indicate the actual option selected from the respective .100 file. To modify this
schedule file, use the EVENT100 utility and load in the schedule file by typing:
event100 -i historic
Block: 1
Time: 1900-1910
Management: Continuous grass
Crop Variety: Mixed 50% warm 50% cool grass (G3)
Life Cycle: Begins growing in April, ends growing in October, senesces in October
Cultivation: None
Fertilizer: None
Grazing: Winter grazing of standing dead in January, February, March, April
(W)
Summer grazing in May, June, July, August, September, October (G)
Winter grazing of standing dead in November, December (W)
Harvest: None
Weather: Mean annual minimum and maximum temperatures
Stochastic precipitation
Block: 2
Time: 1911-1916
Management: Wheat-fallow in alternate years with poor weed control (i.e. weed
growth) during fallow months, plowing cultivation and pre-combine
harvest
Crop Variety: Low-yield variety wheat (W)
Generic weed (E)
Life Cycle: Planted in October of fallow year, harvested in following June
Weed growth from July of harvest year to following March
Cultivation: Plowing to break winter growth in April of fallow year (P)
Cultivator in May, June, July of fallow year (C)
Rodweed in August, September of fallow year (R)
Drilling (to account for soil disturbance at planting) in October (D)
Fertilizer: None
Grazing: None
Harvest: Grain with 50% straw removal (GS)
Weather: Mean annual minimum and maximum temperatures
Stochastic precipitation
Block: 3
Time: 1917-1936
Management: Wheat-fallow in alternate years with poor weed control (i.e. weed
growth) during fallow months, plowing cultivation and pre-combine
harvest
Crop Variety: Low-yield variety wheat (W)
Generic weed (E)
Life Cycle: Planted in October of fallow year, harvested in following June
Weed growth from July of harvest year to following March
Cultivation: Plowing to break winter growth in April of fallow year (P)
Cultivator in May, June, July of fallow year (C)
Rodweed in August, September of fallow year (R)
Drilling (to account for soil disturbance at planting) in October (D)
Fertilizer: None
Grazing: None
Harvest: Grain with 50% straw removal (GS)
Weather: Actual historical minimum and maximum temperature and precipitation
data supplied in file "coweld.wth"
Block: 4
Time: 1937-1946
Management: Wheat-fallow in alternate years with poor weed control (i.e. weed
growth) during fallow months, plowing cultivation and combine
harvest (no straw removal)
Crop Variety: Low-yield variety wheat (W)
Generic weed (E)
Life Cycle: Planted in October of fallow year, harvested in following June
Weed growth from July of harvest year to following March
Cultivation: Plowing to break winter growth in April of fallow year (P)
Cultivator in May, June, July of fallow year (C)
Rodweed in August, September of fallow year (R)
Drilling (to account for soil disturbance at planting) in October (D)
Fertilizer: None
Grazing: None
Harvest: Grain (G)
Weather: Continued use of actual weather data
Block: 5
Time: 1947-1960
Management: Wheat-fallow in alternate years with poor weed control (i.e. weed
growth) during fallow months, disk cultivation and combine harvest
(no straw removal)
Crop Variety: Medium-yield variety wheat (W2)
Generic weed (E)
Life Cycle: Planted in October of fallow year, harvested in following June
Weed growth from July of harvest year to following March
Cultivation: Cultivator in April, May, June, July of fallow year (C)
Rodweed in August, September of fallow year (R)
Drilling (to account for soil disturbance at planting) in October (D)
Fertilizer: Automatic fertilizer to maintain production at 80% relative yield with
minimum nutrient concentrations from November to May during
wheat growth (A80)
Grazing: None
Harvest: Grain (G)
Weather: Continued use of actual weather data
Block: 6
Time: 1961-1991
Management: Wheat-fallow in alternate years with poor weed control (i.e. weed
growth) during fallow months, stubble-mulch cultivation and combine
harvest (no straw removal)
Crop Variety: High-yield variety wheat (W3)
Generic weed (E)
Life Cycle: Planted in October of fallow year, harvested in following June
Weed growth from July of harvest year to following March
Cultivation: Sweep in April, May, June, July of fallow year (S)
Rodweed in August, September of fallow year (R)
Drilling (to account for soil disturbance at planting) in October (D)
Fertilizer: Automatic fertilizer to maintain production at maximum yield and
minimum nutrient concentrations from November to May during
wheat growth (A)
Grazing: None
Harvest: Grain (G)
Weather: Continued use of actual weather data
[Previous Topic] [Next Topic] [Table of Contents]
Parton, W.J. 1984. Predicting soil temperatures in a shortgrass steppe. Soil Sci. 138:93-101.
Ryan, M.G. 1991. Effects of climate change on plant respiration. Ecol. Appl. 1:157-167.
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Baron, J., D.S. Ojima, E.A. Holland, and W.J. Parton. 1994. Analysis of
nitrogen saturation potential in Rocky Mountain tundra and forest: implications
for aquatic systems. Biogeochemistry 27:61-82. 698
Bradley, R.I., and T.R. Mayr. Modelling soil organic matter change in English
and Welsh soils using the CENTURY model. (In prep)
Bromberg, J.G., R. McKeown, L. Knapp, T.G.F. Kittel, D.S. Ojima, and D.S.
Schimel. 1996. Integrating GIS and the CENTURY model to manage and analyze
data. Pages 429-431 in GIS and Environmental Modeling: Progress and
Research Issues.
Burke, I.C., D.S. Schimel, C.M. Yonker, W.J. Parton, L.A. Joyce, and W.K.
Lauenroth. 1990. Regional modeling of grassland biogeochemistry using GIS.
Landscape Ecology 4:45-54. 573
Burke, I.C., T.G.F. Kittel, W.K. Lauenroth, P. Snook, C.M. Yonker, and W.J.
Parton. 1991. Regional analysis of the Central Great Plains: sensitivity to
climate variability. Bioscience 41:685-692. 628
Burke, I.C., W.K. Lauenroth, W.J. Parton, and C.V. Cole. 1994. Interactions
of landuse and ecosystem structure and function: a case study in the Central
Great Plains. Pages 79-95 in G.E. Likens and P.M. Groffman, editors.
Integrated regional models: interactions between humans and their environment.
Chapman and Hall, New York, New York, USA.
Carter, M.R., W.J. Parton, I.C. Rowland, J.E. Schultz, and G.R. Steed. 1993.
Simulation of soil organic carbon and nitrogen changes in cereal and pasture
systems of Southern Australia. Australian Journal of Soil Research
31:481-491. 662
Cole, C.V., I.C. Burke, W.J. Parton, D.S. Schimel, D.S. Ojima, and J.W.B.
Stewart. 1988. Analysis of historical changes in soil fertility and organic
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Challenges in dryland agriculture - a global perspective. Proceedings of the
International Conference on Dryland Farming, Amarillo/Bushland, Texas,
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Cole, C.V., J.W.B. Stewart, D.S. Ojima, W.J. Parton and D.S. Schimel. 1989.
Modelling land use effects of soil organic matter dynamics in the North
American Great Plains. Pages 89-98 in M. Clarholm and L. Bergström,
editors. Ecology of arable land. Kluwer Academic Publishers, Amsterdam,
Netherlands. 554
Cole, C.V., K. Paustian, E.T. Elliott, A.K. Metherell, D.S. Ojima, and W.J.
Parton. 1993. Analysis of agroecosystem carbon pools. Water, Air, and Soil
Pollution 70:357-371. 660
Crist, T.O., and J.A. Williams. Simulation of topographic and daily
variation in colony activity of Pogonomyrmex Occidentalis
(Hymenoptera: Formicidae) using a soil temperature model. Environmental
Entomology (submitted).
Gijsman, A.J., G. Hoogenboom, W.J. Parton, and P.C. Kerridge. Modifying
DSSAT for low-input agricultural systems, using a SOM module from CENTURY.
Agronomy Journal (submitted).
Gijsman, A.J., A. Oberson, H. Tiessen, and D.K. Friesen. 1996. Limited
applicability of the CENTURY model to highly weathered tropical soils.
Agronomy Journal 88:894-903.
Gilmanov, T.G., W.J. Parton, and D.S. Ojima. 1997. Testing the CENTURY
ecosystem level model on data sets from eight grassland sites in the former
USSR representing wide climatic/soil gradient. Ecological Modelling
96:191-210.
Hall, D.O., D.S. Ojima, W.J. Parton, and J.M.O. Scurlock. 1995. Response of
temperate and tropical grasslands to CO2 and climate change. Journal of
Biogeography 22:537-547.
Hall, D.O., J.M.O. Scurlock, D.S. Ojima, and W.J. Parton. Grasslands and the
global carbon cycle: modelling the effects of climate change. In The
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Modelling, Snowmass, CO, September 1993. OIES (in press).
Hartman, M.D., J.S. Baron, D.S. Ojima, and W. Parton. 1997. The effects of
land use and temperature change on ecosystem processes in the South Platte
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Vol. 78.
Holland, E.A., W.J. Parton, J.K. Detling, and D.L. Coppock. 1992.
Physiological responses of plant populations to herbivory and their
consequences for ecosystem nutrient flow. American Naturalist
140:685-706. 647
Howard, P.J.A., P.J. Loveland, R.I. Bradley, F.T. Dry, D.M. Howard, and D.C.
Howard. 1995. The carbon content of soil and its geographical distribution
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Note. The highlighted numbers represent the code number of that paper located at the Natural Resource Ecology Lab, Colorado State University.
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APPENDIX 2 DEFINITIONS OF CENTURY PARAMETERS
Appendix 2.1. Crop parameters (crop.100)
The crop.100 file will contain these parameters for each option:
Crop options file "crop.100" will contain these values:
prdx(1) potential aboveground monthly production for crops (gC/m2)
ppdf(1) optimum temperature for production for parameterization of a Poisson Density
Function curve to simulate temperature effect on growth
ppdf(2) maximum temperature for production for parameterization of a Poisson
Density Function curve to simulate temperature effect on growth
ppdf(3) left curve shape for parameterization of a Poisson Density Function curve to
simulate temperature effect on growth
ppdf(4) right curve shape for parameterization of a Poisson Density Function curve to
simulate temperature effect on growth
bioflg flag indicating whether production should be reduced by physical obstruction
= 0 production should not be reduced = 1 production should be reduced
biok5 level of aboveground standing dead + 10% strucc(1) C at which production is
reduced to half maximum due to physical obstruction by dead material (g/m2)
pltmrf planting month reduction factor to limit seedling growth; set to 1.0 for grass
fulcan value of aglivc at full canopy cover, above which potential production is not
reduced
frtc(1) initial fraction of C allocated to roots; for Great Plains equation based on
precipitation, set to 0
frtc(2) final fraction of C allocated to roots
frtc(3) time after planting (months with soil temperature greater than rtdtmp) at
which the final value is reached
biomax biomass level (g biomass/m2) above which the minimum and maximum C/E
ratios of new shoot increments equal pramn(*,2) and pramx(*,2) respectively
pramn(3,1) minimum C/E ratio with zero biomass
(1,1) = N (2,1) = P (3,1) = S
pramn(3,2) minimum C/E ratio with biomass greater than or equal to biomax
(1,2) = N (2,2) = P (3,2) = S
pramx(3,1) maximum C/E ratio with zero biomass
(1,1) = N (2,1) = P (3,1) = S
pramx(3,2) maximum C/E ratio with biomass greater than or equal to biomax
(1,2) = N (2,2) = P (3,2) = S
prbmn(3,2) parameters for computing minimum C/N ratio for belowground matter as a
linear function of annual precipitation
(1,1) = N, intercept (2,1) = P, intercept (3,1) = S, intercept
(1,2) = N, slope (2,2) = P, slope (3,2) = S, slope
prbmx(3,2) parameters for computing maximum C/N ratio for belowground matter as a
linear function of annual precipitation
(1,1) = N, intercept (2,1) = P, intercept (3,1) = S, intercept
(1,2) = N, slope (2,2) = P, slope (3,2) = S, slope
fligni(1,1) intercept for equation to predict lignin content fraction based on annual
rainfall for aboveground material
fligni(2,1) slope for equation to predict lignin content fraction based on annual rainfall for
aboveground material. For crops, set to 0.
fligni(1,2) intercept for equation to predict lignin content fraction based on annual
rainfall for belowground material
fligni(2,2) slope for equation to predict lignin content fraction based on annual rainfall for
belowground material. For crops, set to 0.
himax harvest index maximum (fraction of aboveground live C in grain)
hiwsf harvest index water stress factor
= 0 no effect of water stress
= 1 no grain yield with maximum water stress
himon(1) number of months prior to harvest in which to begin accumulating water stress
effect on harvest index
himon(2) number of months prior to harvest in which to stop accumulating water stress
effect on harvest index
efrgrn(3) fraction of the aboveground E which goes to grain
(1) = N (2) = P (3) = S
vlossp fraction of aboveground plant N which is volatilized (occurs only at harvest)
fsdeth(1) maximum shoot death rate at very dry soil conditions (fraction/month); for
getting the monthly shoot death rate, this fraction is multiplied times a
reduction factor depending on the soil water status
fsdeth(2) fraction of shoots which die during senescence month; must be greater than or
equal to 0.4
fsdeth(3) additional fraction of shoots which die when aboveground live C is greater than
fsdeth(4)
fsdeth(4) the level of aboveground C above which shading occurs and shoot senescence
increases
fallrt fall rate (fraction of standing dead which falls each month)
rdr maximum root death rate at very dry soil conditions (fraction/month); for
getting the monthly root death rate, this fraction is multiplied times a
reduction factor depending on the soil water status
rtdtmp physiological shutdown temperature for root death and change in shoot/root
ratio
crprtf(3) fraction of E retranslocated from grass/crop leaves at death
(1) = N (2) = P (3) = S
snfxmx(1) symbiotic N fixation maximum for grass/crop (Gn fixed/Gc new growth)
del13c delta 13C value for stable isotope labeling
co2ipr(1) in a grass/crop system, the effect on plant production ratio of doubling the
atmospheric CO2 concentration from 350 ppm to 700 ppm
co2itr(1) in a grass/crop system, the effect on transpiration rate of doubling the
atmospheric CO2 concentration from 350 ppm to 700 ppm
co2ice(1,2,3) in a grass/crop system, the effect on C/E ratios of doubling the atmospheric
CO2 concentration from 350 ppm to 700 ppm
(1,1,1) = minimum C/N (1,2,1) = maximum C/N
(1,1,2) = minimum C/P (1,2,2) = maximum C/P
(1,1,3) = minimum C/S (1,2,3) = maximum C/S
co2irs(1) in a grass/crop system, the effect on root-shoot ratio of doubling the
atmospheric CO2 concentration from 350 ppm to 700 ppm
[Previous Topic] [Next Topic] [Table of Contents]
Appendix 2.2. Cultivation parameters (cult.100)
The cult.100 file will contain these parameters for each option:
cultra(1) fraction of aboveground live transferred to standing dead
cultra(2) fraction of aboveground live transferred to surface litter
cultra(3) fraction of aboveground live transferred to the top soil layer
cultra(4) fraction of standing dead transferred to surface litter
cultra(5) fraction of standing dead transferred to top soil layer
cultra(6) fraction of surface litter transferred to top soil layer
cultra(7) fraction of roots transferred to top soil layer
clteff(1) cultivation factor for som1 decomposition; functions as a multiplier for
increased decomposition in the month of cultivation
clteff(2) cultivation factor for som2 decomposition; functions as a multiplier for
increased decomposition in the month of cultivation
clteff(3) cultivation factor for som3 decomposition; functions as a multiplier for
increased decomposition in the month of cultivation
clteff(4) cultivation factor for soil structural material decomposition; functions as a
multiplier for increased decomposition in the month of cultivation
[Previous Topic] [Next Topic] [Table of Contents]
Appendix 2.3. Fertilization parameters (fert.100)
The fert.100 file will contain these parameters for each option:
feramt(3) amount of E to be added (gE/m2)
(1) = N (2) = P (3) = S
aufert key for automatic fertilization
aufert = 0: no automatic fertilization
aufert < 1.0: automatic fertilizer may be applied to remove some nutrient
stress without increasing nutrient concentration above the
minimum level; the value of aufert is the fraction of potential C
production (temperature and moisture limited) which will be
maintained
aufert > 1.0: automatic fertilizer may be applied to remove nutrient stress
and increase nutrient concentrations above the minimum level;
a value of aufert between 1.0 and 2.0 determines the extent to
which nutrient concentration is maintained between the
minimum and maximum levels
aufert = 2.0: automatic fertilizer may be applied to remove nutrient stress
and increase nutrient concentrations to the maximum level
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Appendix 2.4. Fire parameters (fire.100)
The fire.100 file will contain these parameters for each option:
flfrem fraction of live shoots removed by a fire event
fdfrem(1) fraction of standing dead plant material removed by a fire event
fdfrem(2) fraction of surface litter removed by a fire event
fret(3) fraction of E in the burned aboveground material removed by a fire event
(1) = N (2) = P (3) = S
frtsh additive effect of burning on root/shoot ratio
fnue(1) effect of fire on increase in maximum C/N ratio of shoots
fnue(2) effect of fire on increase in maximum C/N ratio of roots
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Appendix 2.5. Fixed parameters (fix.100)
There can be only one option within this file.
adep(10) depth of soil layer X, where X = 1-10 (only nlayer+1 values used) (cm)
agppa intercept parameter in the equation estimating potential aboveground biomass
production for calculation of root/shoot ratio (used only if frtc(1) = 0) (g/m2/y)
agppb slope parameter in the equation estimating potential aboveground biomass
production for calculation of root/shoot ratio (used only if frtc(1) = 0)
(g/m2/y/cm) NOTE - agppb is multiplied by annual precipitation (cm)
aneref(1) ratio of rain/potential evapotranspiration below which there is no negative
impact of soil anaerobic conditions on decomposition
aneref(2) ratio of rain/potential evapotranspiration below which there is maximum
negative impact of soil anaerobic conditions on decomposition
aneref(3) minimum value of the impact of soil anaerobic conditions on decomposition;
functions as a multiplier for the maximum decomposition rate
animpt slope term used to vary the impact of soil anaerobic conditions on
decomposition flows to the passive soil organic matter pool
awtl(10) weighing factor for transpiration loss for layer X, where X = 1-10 (only
nlayer+1 values used); indicates which fraction of the available water can be
extracted by the roots
bgppa intercept parameter in the equation estimating potential belowground biomass
production for calculation of root/shoot ratio (used only if frtc(1) = 0) (g/m2/y)
bgppb slope parameter in the equation estimating potential belowground biomass
production for calculation of root/shoot ratio (used only if frtc(1) = 0) (g/m2/y)
NOTE - bgppb is multiplied by annual precipitation (cm)
co2ppm(1) initial parts per million for CO2 effect
co2ppm(2) final parts per million for CO2 effect
co2rmp flag indicating whether CO2 effect should be:
= 0 step function
= 1 ramp function
damr(1,3) fraction of surface E absorbed by residue
(1,1) = N (1,2) = P (1,3) = S
damr(2,3) fraction of soil E absorbed by residue
(2,1) = N (2,2) = P (2,3) = S
damrmn(3,3) minimum C/E ratio allowed in residue after direct absorption
(1) = N (2) = P (3) = S
dec1(1) maximum surface structural decomposition rate
dec1(2) maximum soil structural decomposition rate
dec2(1) maximum surface metabolic decomposition rate
dec2(2) maximum soil metabolic decomposition rate
dec3(1) maximum decomposition rate of surface organic matter with active turnover
dec3(2) maximum decomposition rate of soil organic matter with active turnover
dec4 maximum decomposition rate of soil organic matter with slow turnover
dec5 maximum decomposition rate of soil organic matter with intermediate turnover
deck5 available soil water content at which shoot and root death rates are half
maximum (cm)
dligdf difference in delta 13C for lignin compared to whole plant delta 13C
dresp discrimination factor for 13C during decomposition of organic matter due to
microbial respiration
edepth depth of the single soil layer where C, N, P, and S dynamics are calculated
(only affects C, N, P, S loss by erosion)
elitst effect of litter on soil temperature relative to live and standing dead biomass
enrich the enrichment factor for SOM losses
favail(1) fraction of N available per month to plants
favail(3) fraction of S available per month to plants
favail(4) minimum fraction of P available per month to plants
favail(5) maximum fraction of P available per month to plants
favail(6) mineral N in surface layer corresponding to maximum fraction of P available
(gN/m2)
fleach(1) intercept value for a normal month to compute the fraction of mineral N, P,
and S which will leach to the next layer when there is a saturated water flow;
normal leaching is a function of sand content
fleach(2) slope value for a normal month to compute the fraction of mineral N, P, and
S which will leach to the next layer when there is a saturated water flow;
normal leaching is a function of sand content
fleach(3) leaching fraction multiplier for N to compute the fraction of mineral N which
leaches to the next layer when there is a saturated water flow; normal leaching
is a function of sand content
fleach(4) leaching fraction multiplier for P to compute the fraction of mineral P which
leaches to the next layer when there is a saturated water flow; normal leaching
is a function of sand content
fleach(5) leaching fraction multiplier for S to compute the fraction of mineral S which
leaches to the next layer when there is a saturated water flow; normal leaching
is a function of sand content
fwloss(1) scaling factor for interception and evaporation of precipitation by live and
standing dead biomass
fwloss(2) scaling factor for bare soil evaporation of precipitation (h2olos)
fwloss(3) scaling factor for transpiration water loss (h2olos)
fwloss(4) scaling factor for potential evapotranspiration (pevap)
fxmca intercept for effect of biomass on non-symbiotic soil N fixation; used only when
nsnfix = 1
fxmcb slope control for effect of biomass on non-symbiotic soil N fixation; used only
when nsnfix = 1
fxmxs maximum monthly non-symbiotic soil N-fixation rate (reduced by effect of N:P
ratio, used when nsnfix = 1)
fxnpb N/P control for N-fixation based on availability of top soil layer (used when
nsnfix = 1)
gremb grazing effect multiplier for grzeff types 4, 5, 6
idef flag for method of computing water effect on decomposition
= 1 option using the relative water content of soil (0-15 cm)
= 2 ratio option (rainfall/potential evaporation rate)
lhzf(1) lower horizon factor for active pool; = fraction of active pool (SOM1CI(2,*)) used
in computation of lower horizon pool sizes for soil erosion routines
lhzf(2) lower horizon factor for slow pool; = fraction of slow pool (SOM2CI(*) used in
computation of lower horizon pool sizes for soil erosion routines
lhzf(3) lower horizon factor for passive pool; = fraction of passive pool (SOM3CI(*)
used in computation of lower horizon pool sizes for soil erosion routines
minlch critical water flow for leaching of minerals (cm of h2o leached below 30 cm soil
depth)
nsnfix equals 1 if non-symbiotic N fixation should be based on N:P ratio in mineral
pool, otherwise non-symbiotic N fixation is based on annual precipitation
ntspm number of time steps per month for the decomposition submodel
omlech(1) intercept for the effect of sand on leaching of organic compounds
omlech(2) slope for the effect of sand on leaching of organic compounds
omlech(3) the amount of water (cm) that needs to flow out of water layer 2 to produce
leaching of organics
p1co2a(1) intercept parameter which controls flow from surface organic matter with fast
turnover to CO2 (fraction of C lost to CO2 when there is no sand in the soil)
p1co2a(2) intercept parameter which controls flow from soil organic matter with fast
turnover to CO2 (fraction of C lost to CO2 when there is no sand in the soil)
p1co2b(1) slope parameter which controls flow from surface organic matter with fast
turnover to CO2 (slope is multiplied by the fraction sand content of the soil)
p1co2b(2) slope parameter which controls flow from soil organic matter with fast
turnover to CO2 (slope is multiplied by the fraction sand content of the soil)
p2co2 controls flow from soil organic matter with intermediate turnover to CO2
(fraction of C lost as CO2 during decomposition)
p3co2 controls flow from soil organic matter with slow turnover rate to CO2 (fraction
of C lost as CO2 during decomposition)
pabres amount of residue which will give maximum direct absorption of N (Gc/m2)
pcemic(1,3) maximum C/E ratio for surface microbial pool
(1,1) = N (1,2) = P (1,3) = S
pcemic(2,3) minimum C/E ratio for surface microbial pool
(2,1) = N (2,2) = P (2,3) = S
pcemic(3,3) minimum E content of decomposing aboveground material above which the C/E
ratio of the surface microbes equals pcemic(2,*)
(3,1) = N (3,2) = P (3,3) = S
peftxa intercept parameter for regression equation to compute the effect of soil texture
on the microbe decomposition rate (the effect of texture when there is no sand
in the soil)
peftxb slope parameter for regression equation to compute the effect of soil texture on
microbe decomposition rate; the slope is multiplied by the sand content fraction
phesp(1) minimum pH for determining the effect of pH on the solubility of secondary P
(flow of secondary P to mineral P) (for texesp(2) = m * (pH input) + b, m and
b calculated using these phesp values)
phesp(2) value of texesp(2), the solubility of secondary P, corresponding to minimum pH
(/yr)
phesp(3) maximum pH for determining effect on solubility of secondary P (flow of
secondary P to mineral P) (for texesp(2) = m * (pH input) + b, m and b
calculated using these phesp values)
phesp(4) value of texesp(2), the solubility of secondary P, corresponding to maximum pH
(/yr)
pligst(1) effect of lignin on surface structural or fine branch and large wood
decomposition
pligst(2) effect of lignin on soil structural or coarse root decomposition
pmco2(2) controls flow from metabolic to CO2 (fraction of C lost as CO2 during
decomposition)
(1) = surface (2) = soil
pmnsec(3) slope for E; controls the flow from mineral to secondary N (/yr)
(1) = N (2) = P (3) = S
pmntmp effect of biomass on minimum surface temperature
pmxbio maximum dead biomass (standing dead + 10% litter) level for soil temperature
calculation and for calculation of the potential negative effect on plant growth
of physical obstruction by standing dead and surface litter
pmxtmp effect of biomass on maximum surface temperature
pparmn(3) controls the flow from parent material to mineral compartment (fraction of
parent material that flows to mineral E)
(1) = N (2) = P (3) = S
pprpts(1) the minimum ratio of available water to PET which would completely limit
production assuming WC = 0
pprpts(2) the effect of WC on the intercept
pprpts(3) the lowest ratio of available water to PET at which there is no restriction on
production
ps1co2(2) controls amount of CO2 loss when structural decomposes to som1, subscripted
for surface and soil layer
(1) = surface (2) = soil
ps1s3(1) intercept for effect of clay on the control for the flow from soil organic matter
with fast turnover to som with slow turnover (fraction of C from som1c to
som3c)
ps1s3(2) slope for the effect of clay on the control for the flow from soil organic matter
with fast turnover to som with slow turnover (fraction of C from som1c to
som3c)
ps2s3(1) slope value which controls flow from soil organic matter with intermediate
turnover to soil organic matter with slow turnover (fraction of C from som2c to
som3c)
ps2s3(2) intercept value which controls flow from soil organic matter with intermediate
turnover to soil organic matter with slow turnover (fraction of C from som2c
to som3c)
psecmn(3) controls the flow from secondary to mineral E
(1) = N (2) = P (3) = S
psecoc controls the flow from secondary to occluded P
rad1p(1,3) intercept used to calculate addition term for C/E ratio of slow SOM formed
from surface active pool
(1,1) = N (1,2) = P (1,3) = S
rad1p(2,3) slope used to calculate addition term for C/E ratio of slow SOM formed from
surface active pool
(2,1) = N (2,2) = P (2,3) = S
rad1p(3,3) minimum allowable C/E used to calculate addition term for C/E ratio of slow
SOM formed from surface active pool
(3,1) = N (3,2) = P (3,3) = S
rcestr(3) C/E ratio for structural material
(1) = N (2) = P (3) = S
rictrl root impact control term used by rtimp; used for calculating the impact of root
biomass on nutrient availability
riint root impact intercept used by rtimp; used for calculating the impact of root
biomass on nutrient availability
rsplig fraction of lignin flow (in structural decomposition) lost as CO2
seed random number generator seed value
spl(1) intercept parameter for metabolic (vs. structural) split
spl(2) slope parameter for metabolic split (fraction metabolic is a function of lignin
to N ratio)
strmax(1) maximum amount of structural material in surface layer that will decompose
(gC/m2)
strmax(2) maximum amount of structural material belowground that will decompose
(gC/m2)
texepp(1) texture effect on parent P mineralization:
= 1 include the effect of texture using the remaining texepp values with the
arctangent function
= 0 use pparmn(2) in the weathering equation
texepp(2) x location of inflection point used in determining texture effect on parent P
mineralization
texepp(3) y location of inflection point used in determining texture effect on parent P
mineralization
texepp(4) step size (distance from the maximum point to the minimum point) used in
determining texture effect on parent P mineralization
texepp(5) slope of the line at the inflection point used in determining texture effect on
parent P mineralization
texesp(1) texture effect on secondary P flow to mineral P
= 1 include the effect of pH and sand content using the equation specified by
texesp(2) (a function of pH and phesp(1-4)) and texesp(3)
= 0 to use psecmn(2) in the weathering equation
texesp(3) slope value used in determining effect of sand content on secondary P flow to
mineral P
tmax maximum temperature for decomposition (deg. C)
tmelt(1) minimum temperature above which at least some snow will melt
tmelt(2) ratio between degrees above the minimum and cm of snow that will melt
topt optimum temperature for decomposition (deg. C)
tshl shape parameter to left of the optimum temperature (for decomposition)
tshr shape parameter to right of the optimum temperature
varat1(1,3) maximum C/E ratio for material entering som1
(1,1) = N (1,2) = P (1,3) = S
varat1(2,3) minimum C/E ratio for material entering som1
(2,1) = N (2,2) = P (2,3) = S
varat1(3,3) amount of E present when minimum ratio applies
(3,1) = N (3,2) = P (3,3) = S
varat2(1,3) maximum C/E ratio for material entering som2
(1,1) = N (1,2) = P (1,3) = S
varat2(2,3) minimum C/E ratio for material entering som2
(2,1) = N (2,2) = P (2,3) = S
varat2(3,3) amount of E present when minimum ratio applies
(3,1) = N (3,2) = P (3,3) = S
varat3(1,3) maximum C/E ratio for material entering som3
(1,1) = N (1,2) = P (1,3) = S
varat3(2,3) minimum C/E ratio for material entering som3
(2,1) = N (2,2) = P (2,3) = S
varat3(3,3) amount of E present when minimum ratio applies
(3,1) = N (3,2) = P (3,3) = S
vlosse fraction per month of excess N (i.e. N left in the soil after nutrient uptake by
the plant) which is volatilized
vlossg fraction per month of gross mineralization which is volatilized
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Appendix 2.6. Grazing parameters (graz.100)
The graz.100 file will contain these parameters for each option:
flgrem fraction of live shoots removed by a grazing event
fdgrem fraction of standing dead removed by a grazing event
gfcret fraction of consumed C which is excreted in faeces and urine
gret(3) fraction of consumed E which is excreted in faeces and urine (should take into
account E losses due to leaching or volatilization from the manure)
(1) = N (2) = P (3) = S
grzeff effect of grazing on production
= 0 no direct effect
= 1 moderate effect (linear decrease in production)
= 2 intensively grazed production effect (quadratic effect on production)
fecf(3) fraction of excreted E which goes into faeces (rest goes into urine)
(1) = N (2) = P (3) = S
feclig lignin content of feces
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Appendix 2.7. Harvest parameters (harv.100)
The harv.100 file will contain these parameters for each option:
aglrem fraction of aboveground live which will not be affected by harvest operations
bglrem fraction of belowground live which will not be affected by harvest operations
flghrv flag indicating if grain is to be harvested
= 0 if grain is not to be harvested
= 1 if the grain is to be harvested
rmvstr fraction of the aboveground residue that will be removed
remwsd fraction of the remaining residue that will be left standing
hibg fraction of roots that will be harvested
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Appendix 2.8. Irrigation parameters (irri.100)
The irri.100 file will contain these parameters for each option:
auirri controls application of automatic irrigation
= 0 automatic irrigation is off
= 1 irrigate to field capacity
= 2 irrigate with a specified amount of water applied
= 3 irrigate to field capacity plus PET
fawhc fraction of available water holding capacity below which automatic irrigation
will be used when auirri = 1 or 2
irraut amount of water to apply automatically when auirri = 2 (cm)
irramt amount of water to apply regardless of soil water status (cm)
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Appendix 2.9. Organic matter addition parameters (omad.100)
The omad.100 file will contain these parameters for each option:
astgc grams of C added with the addition of organic matter (g/m2)
astlbl fraction of added C which is labeled, when C is added as a result of the
addition of organic matter
astlig lignin fraction content of organic matter
astrec(3) C/E ratio of added organic matter
(1) = N (2) = P (3) = S
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Appendix 2.10. Tree parameters (tree.100)
The tree.100 file will contain these parameters for each option:
decid = 0 if forest is evergreen
= 1 if forest is deciduous
prdx(2) maximum gross forest production (g biomass/m2/month)
prdx(3) maximum net forest production (g C/m2/month)
ppdf(1) optimum temperature for production for parameterization of a Poisson Density
Function curve to simulate temperature effect on growth
ppdf(2) maximum temperature for production for parameterization of a Poisson
Density Function curve to simulate temperature effect on growth
ppdf(3) left curve shape for parameterization of a Poisson Density Function curve to
simulate temperature effect on growth
ppdf(4) right curve shape for parameterization of a Poisson Density Function curve to
simulate temperature effect on growth
cerfor(1,5,3) minimum C/E ratio for forest compartments
(1,1,1) = N, leaf (1,1,2) = P, leaf (1,1,3) = S, leaf
(1,2,1) = N, fine root (1,2,2) = P, fine root (1,2,3) = S, fine root
(1,3,1) = N, fine branch (1,3,2) = P, fine branch (1,3,3) = S, fine branch
(1,4,1) = N, large wood (1,4,2) = P, large wood (1,4,3) = S, large wood
(1,5,1) = N, coarse root (1,5,2) = P, coarse root (1,5,3) = S, coarse root
cerfor(2,5,3) maximum C/E ratio for forest compartments
(2,1,1) = N, leaf (2,1,2) = P, leaf (2,1,3) = S, leaf
(2,2,1) = N, fine root (2,2,2) = P, fine root (2,2,3) = S, fine root
(2,3,1) = N, fine branch (2,3,2) = P, fine branch (2,3,3) = S, fine branch
(2,4,1) = N, large wood (2,4,2) = P, large wood (2,4,3) = S, large wood
(2,5,1) = N, coarse root (2,5,2) = P, coarse root (2,5,3) = S, coarse root
cerfor(3,5,3) initial C/E ratio for forest compartments
(3,1,1) = N, leaf (3,1,2) = P, leaf (3,1,3) = S, leaf
(3,2,1) = N, fine root (3,2,2) = P, fine root (3,2,3) = S, fine root
(3,3,1) = N, fine branch (3,3,2) = P, fine branch (3,3,3) = S, fine branch
(3,4,1) = N, large wood (3,4,2) = P, large wood (3,4,3) = S, large wood
(3,5,1) = N, coarse root (3,5,2) = P, coarse root (3,5,3) = S, coarse root
decw1 maximum decomposition rate constant for wood1 (dead fine branch) per year
before temperature and moisture effects applied
decw2 maximum decomposition rate constant for wood2 (dead large wood) per year
before temperature and moisture effects applied
decw3 maximum decomposition rate constant for wood3 (dead coarse root) per year
before temperature and moisture effects applied
fcfrac(5,1) C allocation fraction of new production for juvenile forest (time < swold)
(1,1) = leaves
(2,1) = fine roots
(3,1) = fine branches
(4,1) = large wood
(5,1) = coarse roots
fcfrac(5,2) C allocation fraction of new production for mature forest (time >= swold)
(1,2) = leaves
(2,2) = fine roots
(3,2) = fine branches
(4,2) = large wood
(5,2) = coarse roots
leafdr(12) monthly death rate fractions for leaves for each month 1-12
btolai biomass to leaf area index (LAI) conversion factor for trees
klai large wood mass (g C/m2) at which half of theoretical maximum leaf area
(maxlai) is achieved
laitop parameter determining the relationship between LAI and forest production:
LAI effect = 1 - exp(laitop * LAI)
maxlai theoretical maximum leaf area index achieved in a mature forest
maxldr multiplier for effect of N availability on leaf death rates (evergreen forest only);
ratio between death rate at unlimited vs. severely limited N status
forrtf(3) fraction of E retranslocated from green forest leaves before litterfall
(1) = N (2) = P (3) = S
sapk controls the ratio of sapwood to total stem wood, expressed as gC/m2; it is
equal to both the large wood mass (rlwodc) at which half of large wood is
sapwood, and the theoretical maximum sapwood mass achieved in a mature
forest
swold year at which to switch from juvenile to mature forest C allocation fractions for
production
wdlig(5) lignin fraction for forest system components
(1) = leaves
(2) = fine roots
(3) = fine branches
(4) = large wood
(5) = coarse roots
wooddr(5) monthly death rate fractions for forest components
(1) = leaves (array placeholder only, use LEAFDR)
(2) = fine roots
(3) = fine branches
(4) = large wood
(5) = coarse roots
snfxmx(2) symbiotic N fixation maximum for forest (gN fixed/gC net production)
del13c delta 13C value for stable isotope labeling
co2ipr(2) in a forest system, the effect on plant production (ratio) of doubling the
atmospheric CO2 concentration from 350 ppm to 700 ppm
co2itr(2) in a forest system, the effect on transpiration rate (ratio) of doubling the
atmospheric CO2 concentration from 350 ppm to 700 ppm
co2ice(2,2,3) in a forest system, the effect on C/E ratios of doubling the atmospheric CO2
concentration from 350 ppm to 700 ppm
(2,1,1) = minimum C/N (2,2,1) = maximum C/N
(2,1,2) = minimum C/P (2,2,2) = maximum C/P
(2,1,3) = minimum C/S (2,2,3) = maximum C/S
co2irs(2) in a forest system, the effect on root-shoot ratio of doubling the atmospheric
CO2 concentration from 350 ppm to 700 ppm
basfc2 (savanna only) relates tree basal area to grass N fraction; higher value gives
more N to trees; if not running savanna, set to 1.0
basfct (savanna only) ratio between basal area and wood biomass (cm2/g); it is equal
to (form factor * wood density * tree height); if not running savanna, set to 1.0
sitpot (savanna only) relates grass N fraction to N availability; a higher value give
more N to grass
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Appendix 2.11. Tree removal parameters (trem.100)
The trem.100 file will contain these parameters for each option:
evntyp event type flag
= 0 for cutting, windstorm, or other non-fire
= 1 for fire
remf(5) fractions of material component removed from pools
(1) = live leaves
(2) = live fine branches
(3) = live large wood
(2) = dead fine branches
(5) = dead large wood
fd(2) fractions of live root components that die
(1) = fine root
(2) = coarse root
retf(1,4) fraction of E in killed live leaves that is returned to the system (ash or litter)
(1,1) = C (1,2) = N (1,3) = P (1,4) = S
retf(2,4) fraction of E in killed fine branches that is returned to the system (ash or dead
fine branches)
(2,1) = C (2,2) = N (2,3) = P (2,4) = S
retf(3,4) fraction of E in killed large wood that is returned to the system (ash or dead
large wood)
(3,1) = C (3,2) = N (3,3) = P (3,4) = S
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Appendix 2.12. Site specific parameters (<site>.100)
There can be only one option within this file. This file is named by the user to some
"filename".100.
*** Climate parameters
precip(12) precipitation for January through December (cm/month)
prcstd(12) standard deviations for January through December precipitation value
(cm/month)
prcskw(12) skewness value for January through December precipitation
tmn2m(12) minimum temperature at 2 meters for January through December (deg C)
tmx2m(12) maximum temperature at 2 meters for January through December (deg C)
*** Site and control parameters
ivauto use Burke's equations to initialize soil C pools
= 0 the user has supplied the initial values
= 1 initialize using the grass soil parameters
= 2 initialize using the crop soil parameters
nelem number of elements (besides C) to be simulated
= 1 simulate N
= 2 simulate N and P
= 3 simulate N, P, and S
sitlat latitude of model site (deg) (for reference only)
sitlng longitude of model site (deg) (for reference only)
sand fraction of sand in soil
silt fraction of silt in soil
clay fraction of clay in soil
bulkd bulk density of soil used to compute soil loss by erosion, wilting point, and field
capacity (kg/liter)
nlayer number of soil layers in water model (maximum of 9); used only to calculate
the amount of water available for survival of the plant
nlaypg number of soil layers in the top level of the water model; determines avh2o(1),
used for plant growth and root death
drain the fraction of excess water lost by drainage; indicates whether a soil is
sensitive for anaerobiosis (drain=0) or not (drain=1)
basef the fraction of the soil water content of layer NLAYER + 1 which is lost via
base flow
stormf the fraction of flow from NLAYER to NLAYER + 1 which goes into storm flow
swflag flag indicating the source of the values for awilt and afiel, either from actual
data from the site.100 file or from equations from Gupta and Larson (1979) or
Rawls et al. (1982).
swflag = 0 use actual data from the site.100 file
swflag = 1 use G & L for both awilt (-15 bar) and afiel (-0.33 bar)
swflag = 2 use G & L for both awilt (-15 bar) and afiel (-0.10 bar)
swflag = 3 use Rawls for both awilt (-15 bar) and afiel (-0.33 bar)
swflag = 4 use Rawls for both awilt (-15 bar) and afiel (-0.10 bar)
swflag = 5 use Rawls for afiel (-0.33 bar) with actual data for awilt
swflag = 6 use Rawls for afiel (-0.10 bar) with actual data for awilt
awilt(10) the wilting point of soil layer X, where X = 1-10 (fraction); used only if swflag
= 0, 5, or 6
afiel(10) the field capacity of soil layer X, where X = 1-10 (fraction); used only if swflag
= 0
ph soil pH used to calculate the solubility of secondary P within the boundaries
specified by phesp(1) and phesp(3)
pslsrb slope term which controls the fraction of mineral P that is labile
sorpmx maximum P sorption potential for a soil
*** External nutrient input parameters
epnfa(2) values for determining the effect of annual precipitation on atmospheric N
fixation (wet and dry deposition) (g/m2/y)
(1) = intercept (2) = slope
epnfs(2) values for determining the effect of annual precipitation on non-symbiotic soil
N fixation; not used if nsnfix = 1 (g/m2/y)
(1) = intercept (2) = slope
satmos(2) values for atmospheric S inputs as a linear function of annual precipitation (g
S /m2/yr/cm precip)
(1) = intercept (2) = slope
sirri S concentration in irrigation water (mg S / l)
*** Organic matter initial parameters
som1ci(1,1) initial value for unlabeled C in surface organic matter with fast turnover; used
only if ivauto = 0 (gC/m2)
som1ci(1,2) initial value for labeled C in surface organic matter with fast turnover; used
only if ivauto = 0 (gC/m2)
som1ci(2,1) initial value for unlabeled C in soil organic matter with fast turnover; used
only if ivauto = 0 (gC/m2)
som1ci(2,2) initial value for labeled C in soil organic matter with fast turnover; used only
if ivauto = 0 (gC/m2)
som2ci(1) initial value for unlabeled C in soil organic matter with intermediate turnover;
used only if ivauto = 0 (gC/m2)
som2ci(2) initial value for labeled C in soil organic matter with intermediate turnover;
used only if ivauto = 0 (gC/m2)
som3ci(1) initial value for unlabeled C in soil organic matter with slow turnover; used
only if ivauto = 0 (gC/m2)
som3ci(2) initial value for labeled C in soil organic matter with slow turnover; used only
if ivauto = 0 (gC/m2)
rces1(1,3) initial C/E ratio in surface organic matter with fast turnover (active som)
(1,1) = N (1,2) = P (1,3) = S
rces1(2,3) initial C/E ratio in soil organic matter with fast turnover (active som)
(2,1) = N (2,2) = P (2,3) = S
rces2(3) initial C/E ratio in soil organic matter with intermediate turnover (slow SOM)
(1) = N (2) = P (3) = S
rces3(3) initial C/E ratio in soil organic matter with slow turnover (passive SOM)
(1) = N (2) = P (3) = S
clittr(2,2) initial value for plant residue; used only if ivauto = 0 (g/m2)
(1,1) = surface, unlabeled (2,1) = soil, unlabeled
(1,2) = surface, labeled (2,2) = soil, labeled
rcelit(1,3) initial C/E ratio for surface litter
(1,1) = N (1,2) = P (1,3) = S
rcelit(2,3) initial C/E ratio for soil litter
(2,1) = N (2,2) = P (2,3) = S
aglcis(2) initial value for aboveground live C isotope; used only if ivauto = 0 or 2
(gC/m2)
(1) = unlabeled (2) = labeled
aglive(3) aboveground E initial value (gE/m2); used only if ivauto = 0 or 2
(1) = N (2) = P (3) = S
bglcis(2) initial value for belowground live C; used only if ivauto = 0 or 2 (gC/m2)
(1) = unlabeled (2) = labeled
bglive(3) initial value for belowground live E; used only if ivauto = 0 or 2 (gE/m2)
(1) = N (2) = P (3) = S
stdcis(2) initial value for standing dead C; used only if ivauto = 0 (gC/m2)
(1) = unlabeled (2) = labeled
stdede(3) initial value for E in standing dead; used only if ivauto = 0 (gE/m2)
(1) = N (2) = P (3) = S
*** Forest organic matter initial parameters
rlvcis(2) initial value for C in forest system leaf component (gC/m2)
(1) = unlabeled (2) = labeled
rleave(3) initial value for E in a forest system leaf component (gE/m2)
(1) = N (2) = P (3) = S
fbrcis(2) initial value for C in forest system fine branch component (gC/m2)
(1) = unlabeled (2) = labeled
fbrche(3) initial value for E in a forest system fine branch component (gE/m2)
(1) = N (2) = P (3) = S
rlwcis(2) initial value for C in forest system large wood component (gC/m2)
(1) = unlabeled (2) = labeled
rlwode(3) initial value for E in a forest system large wood component (gE/m2)
(1) = N (2) = P (3) = S
frtcis(2) initial value for C in forest system fine root component (gC/m2)
(1) = unlabeled (2) = labeled
froote(3) initial value for E in a forest system fine root component (gE/m2)
(1) = N (2) = P (3) = S
crtcis(2) initial value for C in forest system coarse root component (gC/m2)
(1) = unlabeled (2) = labeled
croote(3) initial value for E in a forest system coarse root component (gE/m2)
(1) = N (2) = P (3) = S
wd1cis(2) initial C values for forest system dead fine branch material (wood1) (g/m2)
(1) = unlabeled (2) = labeled
wd2cis(2) initial C values for forest system dead large wood material (wood2) (g/m2)
(1) = unlabeled (2) = labeled
wd3cis(2) initial C values for forest system dead coarse root material (wood3) (g/m2)
(1) = unlabeled (2) = labeled
w1lig initial lignin content of dead fine branches (fraction of lignin in wood1)
w2lig initial lignin content of dead large wood (fraction of lignin in wood2)
w3lig initial lignin content of dead coarse roots (fraction of lignin in wood3)
*** Mineral initial parameters
minerl(10,1) initial value for mineral N for layer X, X = 1-10 (gN/m2)
minerl(10,2) initial value for mineral P for layer X, X = 1-10 (gP/m2)
minerl(10,3) initial value for mineral S for layer X, X = 1-10 (gS/m2)
parent(3) initial E value for parent material (gE/m2)
(1) = N (2) = P (3) = S
secndy(3) initial E value for secondary E (gE/m2)
(1) = N (2) = P (3) = S
occlud initial value for occluded P (gP/m2)
*** Water initial parameters
rwcf(10) initial relative water content for layer X, X = 1-10
snlq liquid water in the snow pack (cm of H2O)
snow snow pack water content (cm of H2O)
[Previous Topic] [Next Topic] [Table of Contents]
Appendix 2.13. Output variables
The output definitions for both UNIX and PC versions are:
accrst accumulator of C in straw removed for grass/crop (g/m2)
acrcis(2) growing season accumulator for C production by isotope in forest system coarse
root component (g/m2/y)
(1) = unlabeled (2) = labeled
adefac average annual value of defac, the decomposition factor which combines the
effects of temperature and moisture
afbcis(2) growing season accumulator for C production by isotope in forest system fine
branch component (g/m2/y)
(1) = unlabeled (2) = labeled
afrcis(2) growing season accumulator for C production by isotope in forest system fine
root component (g/m2/y)
(1) = unlabeled (2) = labeled
agcacc growing season accumulator for aboveground C production (g/m2/y)
agcisa(2) growing season accumulator for aboveground C production for grass/crop (g/m2)
(1) = unlabeled (2) = labeled
aglcis(2) aboveground C by isotope for grass/crop (g/m2)
(1) = unlabeled (2) = labeled
aglcn aboveground live C/N ratio, = -999 if either component = 0 for grass/crop
aglivc C in aboveground live for grass/crop (g/m2)
aglive(3) E in aboveground live for grass/crop (g/m2)
(1) = N (2) = P (3) = S
alvcis(2) growing season accumulator for C production in forest system leaf component
(g/m2/y)
(1) = unlabeled (2) = labeled
alwcis(2) growing season accumulator for labeled C production in forest system large
wood component (g/m2/y)
(1) = unlabeled (2) = labeled
aminrl(3) mineral E in layer 1 before uptake by plants
(1) = N (2) = P (3) = S
amt1c2 annual accumulator for surface CO2 loss due to microbial respiration during
litter decomposition
amt2c2 annual accumulator for soil CO2 loss due to microbial respiration during litter
decomposition
anerb the effect of soil anaerobic conditions on decomposition; used as a multiplier on
all belowground decomposition flows
as11c2 annual accumulator for CO2 loss due to microbial respiration during soil
organic matter decomposition of surface som1 to som2
as21c2 annual accumulator for CO2 loss due to microbial respiration during soil
organic matter decomposition of soil som1 to som2 and som3
as2c2 annual accumulator for CO2 loss due to microbial respiration during soil
organic matter decomposition of som2 to soil som1 and som3
as3c2 annual accumulator for CO2 loss due to microbial respiration during soil
organic matter decomposition of som3 to soil som1
asmos(10) soil water content of layer X, where X = 1-10 (cm)
asmos(nlayer + 1) soil water content in deep storage layer (cm)
ast1c2 annual accumulator for CO2 loss due to microbial respiration during litter
decomposition of surface structural into som1 and som2
ast2c2 annual accumulator for CO2 loss due to microbial respiration during litter
decomposition of soil structural into som1 and som2
avh2o(1) water available to grass/crop/tree for growth in soil profile (sum of layers 1
through nlaypg) (cm h2o)
avh2o(2) water available to grass/crop/tree for survival in soil profile (sum of all layers
in profile, 1 through nlayer) (cm h2o)
avh2o(3) water in the first 2 soil layers (cm h2o)
bgcacc growing season accumulator for belowground C production for grass/crop (g/m2)
bgcisa(2) growing season accumulator for belowground C production for grass/crop (g/m2)
(1) = unlabeled (2) = labeled
bglcis(2) belowground live C for grass/crop (g/m2)
(1) = unlabeled (2) = labeled
bglcn belowground live C/N ratio; = -999 if either component = 0 for grass/crop
bglivc C in belowground live for grass/crop (g/m2)
bglive(3) E in belowground live for grass/crop (g/m2)
(1) = N (2) = P (3) = S
cgracc accumulator for grain and tuber production for grass/crop (g/m2)
cgrain economic yield of C in grain + tubers for grass/crop (g/m2)
cinput annual C inputs
cisgra(2) C in grain (g/m2) for grass/crop
(1) = unlabeled (2) = labeled
clittr(2,2) residue (g/m2)
(1,1) = surface, unlabeled (2,1) = soil, unlabeled
(1,2) = surface, labeled (2,2) = soil, labeled
cltfac(1) effect of cultivation on decomposition for som1; = clteff(1) if cultivation occurs
in the current month; = 1 otherwise
cltfac(2) effect of cultivation on decomposition for som2; = clteff(2) if cultivation occurs
in the current month; = 1 otherwise
cltfac(3) effect of cultivation on decomposition for som3; = clteff(3) if cultivation occurs
in the current month; = 1 otherwise
cltfac(4) effect of cultivation on decomposition for structural; = clteff(4) if cultivation
occurs in the current month; = 1 otherwise
co2cce(1,1,1) the calculated effect on C/E ratios of doubling the atmospheric CO2
concentration from 350 ppm to 700 ppm
(1,1,1) = grass/crop minimum C/N (2,1,1) = forest minimum C/N
(1,1,2) = grass/crop minimum C/P (2,1,2) = forest minimum C/P
(1,1,3) = grass/crop minimum C/S (2,1,3) = forest minimum C/S
(1,2,1) = grass/crop maximum C/N (2,2,1) = forest maximum C/N
(1,2,2) = grass/crop maximum C/P (2,2,2) = forest maximum C/P
(1,2,3) = grass/crop maximum C/S (2,2,3) = forest maximum C/S
co2cpr(2) the calculated effect on production of doubling the atmospheric CO2
concentration from 350 ppm to 700 ppm
(1) = grass/crop (2) = forest
co2crs(2) in a forest system, the calculated effect on root-shoot ratio of doubling the
atmospheric CO2 concentration from 350 ppm to 700 ppm
(1) = grass/crop (2) = forest
co2ctr(2) in a forest system, the calculated effect on transpiration rate of doubling the
atmospheric CO2 concentration from 350 ppm to 700 ppm
(1) = grass/crop (2) = forest
cproda annual accumulator of C production in grass/crop + forest = net primary
production (g/m2/year)
cprodc total monthly C production for grass/crop (g/m2/month)
cprodf total monthly C production for forest (g/m2/month)
creta annual accumulator of C returned to system during grazing/fire for grass/crop
(g/m2/year)
crmvst amount of C removed through straw during harvest for grass/crop
(g/m2/month)
crootc C in forest system coarse root component (g/m2)
croote(3) E in forest system coarse root component (g/m2)
(1) = N (2) = P (3) = S
crpstg(3) retranslocation E storage pool for grass/crop (g/m2)
(1) = N (2) = P (3) = S
crpval a numerical representation of the current crop, used for sorting output by crop;
created by a system of assigning values to characters as in A=1,B=2,etc. and
1=0.1, 2=0.2, etc. and adding the values together (example: AB2 = 3.2)
crtacc growing season accumulator for C production in forest system coarse root
component (g/m2/y)
crtcis(2) C in forest system coarse root component (g/m2)
(1) = unlabeled (2) = labeled
csrsnk(2) C source/sink (g/m2)
(1) = unlabeled (2) = labeled
dblit delta 13C value for belowground litter for stable isotope labeling
defac decomposition factor based on temperature and moisture
dmetc(2) delta 13C value for metabolic C in for stable isotope labeling
(1) = surface (2) = soil
dslit delta 13C value for surface litter for stable isotope labeling
dsom1c(1) delta 13C value for som1c(1) for stable isotope labeling
dsom1c(2) delta 13C value for som1c(2) for stable isotope labeling
dsom2c delta 13C value for som2c for stable isotope labeling
dsom3c delta 13C value for som3c for stable isotope labeling
dsomsc delta 13C value for soil organic matter for stable isotope labeling
dsomtc delta 13C value for total soil C for stable isotope labeling
dstruc(2) delta 13C value for belowground structural C for stable isotope labeling
(1) = surface (2) = soil
egracc(3) accumulator of E in grain + tuber production for grass/crop (g/m2)
(1) = N (2) = P (3) = S
egrain(3) economic yield of E in grain + tubers for grass/crop (g/m2)
(1) = N (2) = P (3) = S
elimit indicator of the limiting element
= 1 if N is the limiting element
= 2 if P is the limiting element
= 3 if S is the limiting element
eprodc(3) actual monthly E uptake for grass/crop (g/m2/month)
(1) = N (2) = P (3) = S
eprodf(3) actual monthly E uptake in forest system (g/m2/month)
(1) = N (2) = P (3) = S
ereta(3) annual accumulator of E returned to system during grazing/fire for grass/crop
(g/m2/year)
(1) = N (2) = P (3) = S
ermvst(3) amount of E removed as straw during harvest for grass/crop (g/m2/month)
(1) = N (2) = P (3) = S
esrsnk(3) E source/sink (g/m2)
(1) = N (2) = P (3) = S
eupacc(3) growing season accumulator for E uptake by grass, crop or tree(g/m2)
(1) = N (2) = P (3) = S
eupaga(3) aboveground growing season accumulator for E uptake by plants for grass/crop
(g/m2)
(1) = N (2) = P (3) = S
eupbga(3) belowground growing season accumulator for E uptake by plants for grass/crop
(g/m2)
(1) = N (2) = P (3) = S
eupprt(5,3) growing season accumulator for E uptake by forest component (g/m2)
(1,1) = N leaf (1,2) = P leaf (1,3) = S leaf
(2,1) = N fine root (2,2) = P fine root (2,3) = S fine root
(3,1) = N fine branch (3,2) = P fine branch (3,3) = S fine branch
(4,1) = N large wood (4,2) = P large wood (4,3) = S large wood
(5,1) = N coarse root (5,2) = P coarse root (5,3) = S coarse root
evap monthly evaporation (cm)
fbracc growing season accumulator for C production in forest system fine branch
component (g/m2/y)
fbrchc C in forest system fine branch component (g/m2)
fbrche(3) E in forest system fine branch component (g/m2)
(1) = N (2) = P (3) = S
fbrcis(2) C in forest system fine branch component (g/m2)
(1) = unlabeled (2) = labeled
fcacc growing season accumulator for C production in forest system (g/m2/y)
fertot(3) accumulator for E fertilizer
(1) = N (2) = P (3) = S
forstg(3) retranslocation E storage pool for forest
(1) = N (2) = P (3) = S
frootc C in forest system fine root component (g/m2)
froote(3) E in forest system fine root component (g/m2)
(1) = N (2) = P (3) = S
frstc sum of C in forest system live components (g/m2)
(rleavc + frootc + fbrchc + rlwodc + crootc)
frste(3) sum of E in forest system live components (g/m2)
(rleave(E) + froote(E) + fbrche(E) + rlwode(E) + croote(E))
(1) = N (2) = P (3) = S
frtacc growing season accumulator for C production in forest system fine root
component (g/m2)
frtcis(2) C in forest system fine root component (g/m2)
(1) = unlabeled (2) = labeled
fsysc total C in forest system i.e. sum of soil organic matter, trees, dead wood, forest
litter
fsyse(3) total E in forest system i.e. sum of soil organic matter, trees, dead wood, forest
litter
(1) = N (2) = P (3) = S
gromin(3) gross mineralization of E
(1) = N (2) = P (3) = S
harmth = 0 in non-harvest months
= 1 in a harvest month
hi harvest index (cgrain / aglivc at harvest) for grass/crop
irract actual amount of irrigation (cm h2o/month)
irrtot accumulator for irrigation (cm h2o)
lhzcac accumulator for C inputs to 0-20 cm layer from the lower horizon pools
associated with soil erosion (g/m2)
lhzeac(3) accumulator for E inputs to 0-20 cm layer from the lower horizon pools
associated with soil erosion (g/m2)
(1) = N (2) = P (3) = S
metabc(2) metabolic C in litter (g/m2)
(1) = surface (2) = soil
metabe(2,3) metabolic E in belowground litter (g/m2)
(1,1) = N surface (1,2) = P surface (1,3) = S surface
(2,1) = N soil (2,2) = P soil (2,3) = S soil
metcis(2,2) metabolic litter C (g/m2)
(1,1) = surface unlabeled (1,2) = surface labeled
(2,1) = soil unlabeled (2,2) = soil labeled
metmnr(2,3) net mineralization for E for metabolic litter
(1,1) = N surface (1,2) = P surface (1,3) = S surface
(2,1) = N soil (2,2) = P soil (2,3) = S soil
minerl(10,1) mineral N content for layer X, where X = 1-10 (g/m2)
minerl(10,2) mineral P content for layer X, where X = 1-10 (g/m2)
minerl(1,3) mineral S content for layer X, where X = 1-10 (g/m2)
minerl(nlayer+1,1) deep storage layer for N leached
minerl(nlayer+1,2) deep storage layer for P leached
minerl(nlayer+1,3) deep storage layer for S leached
mt1c2(2) accumulator for surface CO2 loss due to microbial respiration during litter
decomposition
(1) = unlabeled (2) = labeled
mt2c2(2) accumulator for soil CO2 loss due to respiration
(1) = unlabeled (2) = labeled
nfix amount of symbiotic N fixation (g/m2/month)
nfixac accumulator for amount of symbiotic N fixation (g/m2/month)
occlud occluded P (g/m2)
parent(3) parent material E (g/m2)
(1) = N (2) = P (3) = S
pet monthly potential evapotranspiration (cm)
petann annual potential evapotranspiration (cm)
plabil accumulator of labile phosphate in all layers
prcann annual precipitation (cm)
prcfal fallow period precipitation; the amount of rain which falls during the months
after harvest until the month before the next planting (cm)
ptagc growing season accumulator for potential aboveground C production for
grass/crop (g/m2/y)
ptbgc growing season accumulator for potential belowground C production for
grass/crop (g/m2/y)
pttr potential transpiration water loss for the month
rain monthly precipitation (cm)
relyld relative yield for grass, crop, or tree production
resp(2) annual CO2 respiration from decomposition (g/m2)
(1) = unlabeled (2) = labeled
rleavc C in forest system leaf component (g/m2)
rleave(3) E in forest system leaf component (g/m2)
(1) = N (2) = P (3) = S
rlvacc growing season accumulator for C production in forest
rlvcis(2) C in forest system leaf component (g/m2)
(1) = unlabeled (2) = labeled
rlwacc growing season accumulator for C production in forest system large wood
component (g/m2/y)
rlwcis(2) C in forest system large wood component (g/m2)
(1) = unlabeled (2) = labeled
rlwodc C in forest system large wood component (g/m2)
rlwode(3) E in forest system large wood component (g/m2)
(1) = N (2) = P (3) = S
rnpml1 mineral N/P ratio used to control soil N-fixation using a regression equation
based on Kansas data
rwcf(10) relative water content for layer X, where X = 1-10
s11c2(2) accumulator for CO2 loss due to microbial respiration during soil organic
matter decomposition of surface som1 to som2
(1) = unlabeled (2) = labeled
s1mnr(2,3) net mineralization for E
(1,1) = N surface (1,2) = P surface (1,3) = S surface
(2,1) = N som1e(2,1) (2,2) = P som1e(2,2) (2,3) = S som1e(2,3)
s21c2(2) accumulator for CO2 loss due to microbial respiration during soil organic
matter decomposition of soil som1 to som2 and som3
(1) = unlabeled (2) = labeled
s2c2(2) accumulator for CO2 loss due to microbial respiration during soil organic
matter decomposition of som2 to soil som1 and som3
(1) = unlabeled (2) = labeled
s2mnr(3) net mineralization for E for slow pool som2e(E)
(1) = N (2) = P (3) = S
s3c2(2) accumulator for CO2 loss due to microbial respiration during soil organic
matter decomposition of som3 to soil som1
(1) = unlabeled (2) = labeled
s3mnr(3) net mineralization for E for passive pool som3e(E)
(1) = N (2) = P (3) = S
satmac accumulator for atmospheric S deposition (g/m2)
sclosa accumulated C lost from soil organic matter by erosion (total C for entire
simulation) (g/m2)
scloss total C loss from soil organic matter by erosion for current month (g/m2)
sdrema annual accumulator of C removed from standing dead during grazing/fire for
grass/crop (g/m2)
sdrmae(3) annual accumulator of E removed from standing dead during grazing/fire for
grass/crop (g/m2)
(1) = N (2) = P (3) = S
sdrmai(2) annual accumulator of C removed from standing dead during grazing/fire for
grass/crop (g/m2)
(1) = unlabeled (2) = labeled
secndy(1) secondary N (g/m2)
secndy(2) slowly sorbed P (g/m2)
secndy(3) secondary S (g/m2)
shrema annual accumulator of C removed from shoots during grazing/fire for grass/crop
(g/m2)
shrmae(3) annual accumulator of E removed from shoots during grazing/fire for grass/crop
(g/m2)
(1) = N (2) = P (3) = S
shrmai(2) annual accumulator of C removed from shoots during grazing/fire for grass/crop
(g/m2)
(1) = unlabeled (2) = labeled
sirrac accumulator for irrigation S inputs (g S / m2)
snfxac(2) annual accumulator for symbiotic N fixation
(1) = grass/crop (2) = forest
snlq liquid water in snowpack (cm)
snow snowpack water content (cm H2O)
soilnm(3) annual accumulator for net mineralization of E in soil compartments (soil
organic matter + belowground litter + dead coarse roots) (g/m2)
(1) = N (2) = P (3) = S
som1c(2) C in active soil organic matter (g/m2)
(1) = surface (2) = soil
som1ci(2,2) C in active soil organic matter with fast turnover rate g/m2)
(1,1) = surface unlabeled (1,2) = surface labeled
(2,1) = soil unlabeled (2,2) = soil labeled
som1e(2,3) E in active soil organic matter (g/m2)
(1,1) = N surface (1,2) = P surface (1,3) = S surface
(1,1) = N soil (1,2) = P soil (1,3) = S soil
som2c C in slow pool soil organic matter (g/m2)
som2ci(2) C in slow pool soil organic matter (g/m2)
(1) = unlabeled (2) = labeled
som2e(3) E in slow pool soil organic matter (g/m2)
(1) = N (2) = P (3) = S
som3c C in passive soil organic matter (g/m2)
som3ci(2) C in passive soil organic matter (g/m2)
(1) = unlabeled (2) = labeled
som3e(3) E in passive soil organic matter (g/m2)
(1) = N (2) = P (3) = S
somsc sum of labeled and unlabeled C from som1c, som2c, and som3c (g/m2)
somsci(2) sum of C in som1c, som2c, som3c
(1) = unlabeled (2) = labeled
somse(3) sum of E in som1e, som2e, and som3e (g/m2)
(1) = N (2) = P (3) = S
somtc total soil C including belowground structural and metabolic (g/m2)
somtci(2) total C in soil including belowground structural + metabolic
(1) = unlabeled (2) = labeled
somte(3) total E in soil organic matter including belowground structural + metabolic
(1) = N (2) = P (3) = S
st1c2(2) accumulator for CO2 loss due to microbial respiration during litter
decomposition of surface structural into som1 and som2
(1) = unlabeled (2) = labeled
st2c2(2) accumulator for CO2 loss due to microbial respiration during litter
decomposition of soil structural into som1 and som2
(1) = unlabeled (2) = labeled
stdcis(2) C in standing dead for grass/crop (g/m2)
(1) = unlabeled (2) = labeled
stdedc C in standing dead material for grass/crop (g/m2)
stdede(3) E in standing dead for grass/crop (g/m2)
(1) = N (2) = P (3) = S
stemp average soil temperature (deg C)
strcis(2,2) litter structural C (g/m2)
(1,1) = surface unlabeled (1,2) = surface unlabeled
(2,1) = soil unlabeled (2,2) = soil unlabeled
stream(1) cm H2O of stream flow (base flow + storm flow)
stream(2) N from mineral leaching of stream flow (base flow + storm flow) (g/m2)
stream(3) P from mineral leaching of stream flow (base flow + storm flow) (g/m2)
stream(4) S from mineral leaching of stream flow (base flow + storm flow) (g/m2)
stream(5) C from organic leaching of stream flow (base flow + storm flow) (g/m2)
stream(6) N from organic leaching of stream flow (base flow + storm flow) (g/m2)
stream(7) P from organic leaching of stream flow (base flow + storm flow) (g/m2)
stream(8) S from organic leaching of stream flow (base flow + storm flow) (g/m2)
strlig(2) lignin content of structural residue
(1) = surface (2) = soil
strmnr(2,3) net mineralization for E for structural litter
(1,1) = N surface (1,2) = P surface (1,3) = S surface
(2,1) = N soil (2,2) = P soil (2,3) = S soil
strucc(2) litter structural C (g/m2)
(1) = surface (2) = soil
struce(2,3) litter structural E (g/m2)
(1,1) = N surface (1,2) = P surface (1,3) = S surface
(2,1) = N soil (2,2) = P soil (2,3) = S soil
sumnrs(3) annual accumulator for net mineralization of E from all compartments except
structural and wood (g/m2/y)
(1) = N (2) = P (3) = S
sumrsp monthly maintenance respiration in the forest system (g/m2)
tave average air temperature (deg C)
tcerat(3) total C/E ratio in soil organic matter including belowground structural +
metabolic
(1) = N (2) = P (3) = S
tcnpro total C/N ratio for grass, crop, or tree production
tcrem total C removed during forest removal events (g/m2)
terem(3) total E removed during forest removal events (g/m2)
(1) = N (2) = P (3) = S
tminrl(3) total mineral E summed across layers (g/m2)
(1) = N (2) = P (3) = S
tnetmn(3) annual accumulator of net mineralization for E from all compartments (g/m2/y)
(1) = N (2) = P (3) = S
tomres(2) total C in soil, belowground, and aboveground litter
(1) = unlabeled (2) = labeled
totalc total C including source/sink
totale(3) total E including source/sink
(1) = N (2) = P (3) = S
totc minimum annual total non-living C, where total is:
som1c(SOIL) + som1c(SRFC) + som2c + som3c + strucc(SOIL) + strucc(SRFC)
+ metabc(SOIL) + metabc(SRFC)
tran monthly transpiration (cm)
volex volatilization loss as a function of mineral N remaining after uptake by grass,
crop, or tree (g/m2)
volexa accumulator for N volatilization as a function of N remaining after uptake by
grass, crop, or tree (total N for entire simulation) (g/m2)
volgm volatilization loss of N as a function of gross mineralization
volgma accumulator for N volatilized as a function of gross mineralization (g/m2) (total
N for entire simulation)
volpl volatilization of N from plants during harvest for grass/crop
volpla accumulator for N volatilized from plant at harvest for grass/crop (total N for
entire simulation) (g/m2)
w1lig lignin content of dead fine branches of forest system (fraction lignin in wood1)
w1mnr(3) E mineralized from the wood1 (dead fine branch) component of a forest system
(g/m2)
(1) = N (2) = P (3) = S
w2lig lignin content of dead large wood of forest system (fraction lignin in wood2)
w2mnr(3) E mineralized from the wood2 (dead large wood) component of a forest system
(g/m2)
(1) = N (2) = P (3) = S
w3lig lignin content of dead coarse roots of forest system (fraction lignin in wood3)
w3mnr(3) E mineralized from the wood3 (dead coarse root) component of a forest system
(g/m2)
(1) = N (2) = P (3) = S
wd1cis(2) C in forest system wood1 (dead fine branch) material (g/m2)
(1) = unlabeled (2) = labeled
wd2cis(2) C in forest system wood2 (dead large wood) material (g/m2)
(1) = unlabeled (2) = labeled
wd3cis(2) C in forest system wood3 (dead coarse root) material (g/m2)
(1) = unlabeled (2) = labeled
wdfx annual atmospheric and non-symbiotic soil N fixation based on annual
precipitation (wet and dry deposition) (g/m2)
wdfxa annual N fixation in atmosphere (wet and dry deposition) (g/m2)
wdfxaa annual accumulator for atmospheric N inputs (g/m2/y)
wdfxas annual accumulator for soil N-fixation inputs (g/m2/y)
wdfxma monthly N fixation in atmosphere (g/m2)
wdfxms monthly non-symbiotic soil N fixation (g/m2)
wdfxs annual non-symbiotic soil N fixation based on precipitation rather than soil
N/P ratio (g/m2)
wood1c C in wood1 (dead fine branch) component of forest system (g/m2)
wood1e(3) E in wood1 (dead fine branch) component of forest system (g/m2)
(1) = N (2) = P (3) = S
wood2c C in wood2 (dead large wood) component of forest system (g/m2)
wood2e(3) E in wood2 (dead large wood) component of forest system (g/m2)
(1) = N (2) = P (3) = S
wood3c C in wood3 (dead coarse roots) component of forest system (g/m2)
wood3e(3) E in wood3 (dead coarse roots) component of forest system (g/m2)
(1) = N (2) = P (3) = S
woodc sum of C in wood components of forest system (g/m2)
woode(3) sum of E in wood components of forest system (g/m2)
(1) = N (2) = P (3) = S
Note:
Crop and forest production growing season accumulators are reset to zero in the planting
month or the first month of growth.
Annual accumulators for precipitation, evaporation, respiration, and mineralization are reset
at the end of the calendar year.
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APPENDIX 3 SAMPLE WEATHER FILE AND ATMOSPHERIC C14 LABEL FILE
Appendix 3.1. Sample Weather File for Weld County, Colorado
prec 1917 0.41 0.88 2.96 3.47 8.78 0.82 3.92 5.07 1.78 0.27 0.41 3.94 tmin 1917 -13.83 -9.94 -9.61 -2.72 0.94 5.56 10.50 7.56 5.06 -3.06 -3.67 -9.94 tmax 1917 4.06 6.22 6.89 13.06 14.67 25.39 31.17 26.78 26.00 18.39 14.61 6.44 prec 1918 3.19 1.72 0.10 6.84 2.98 5.47 7.89 2.47 3.29 0.47 0.12 1.84 tmin 1918 -16.06 -11.33 -4.72 -4.06 2.00 10.06 10.67 9.94 4.00 1.11 -9.11 -10.11 tmax 1918 -0.50 6.72 14.78 10.33 21.33 29.83 29.06 29.50 21.50 18.44 7.78 4.28 prec 1919 0.31 1.33 1.12 2.76 0.72 2.25 8.68 0.65 6.01 1.25 3.58 2.35 tmin 1919 -10.28 -12.17 -5.83 -0.72 1.78 6.72 12.17 9.83 7.06 -3.56 -11.06 -13.89 tmax 1919 8.06 4.50 10.22 15.33 21.72 28.61 30.33 30.39 24.89 13.50 5.78 2.33 prec 1920 0.61 0.39 1.33 5.80 1.53 8.56 3.31 3.72 1.80 1.12 0.99 0.29 tmin 1920 -8.67 -7.78 -8.06 -6.11 2.67 7.33 10.50 8.89 5.67 -2.06 -7.89 -9.56 tmax 1920 6.67 6.11 10.22 8.67 19.22 25.28 29.22 27.00 24.89 20.06 8.61 5.06 prec 1921 1.84 3.96 1.43 2.82 4.84 6.82 3.00 6.07 0.92 0.65 0.99 1.55 tmin 1921 -10.00 -8.11 -5.00 -4.06 4.67 9.78 10.72 10.56 6.28 0.95 -6.67 -10.39 tmax 1921 5.44 6.06 13.67 13.83 20.33 25.67 29.33 29.61 27.56 18.45 11.56 5.78 prec 1922 0.43 0.31 0.37 2.59 3.98 2.35 8.03 1.31 0.14 0.04 3.41 0.51 tmin 1922 -17.83 -14.78 -6.29 -2.72 3.61 8.17 10.56 12.11 5.72 0.11 -6.33 -9.28 tmax 1922 1.11 4.06 9.34 15.27 21.33 28.78 30.11 31.28 28.22 21.22 5.89 3.06 prec 1923 0.20 0.82 1.57 0.41 3.76 6.39 2.86 3.66 2.51 3.80 1.02 0.20 tmin 1923 -7.56 -13.00 -7.94 -2.89 4.11 8.94 12.06 10.89 4.94 -0.39 -5.39 -12.06 tmax 1923 8.00 4.44 6.39 15.06 19.44 24.28 29.44 27.67 23.94 12.94 12.39 6.72 prec 1924 0.20 2.04 1.94 1.29 1.53 0.41 1.65 3.41 5.13 3.02 1.02 1.08 tmin 1924 -14.22 -7.61 -9.72 -2.28 -0.56 5.72 10.06 9.17 4.61 0.78 -5.67 -14.72 tmax 1924 4.50 8.28 1.67 16.22 18.67 26.39 30.06 31.78 23.00 18.83 13.11 1.22 prec 1925 0.08 1.03 0.31 2.04 2.39 4.80 7.17 4.47 1.55 2.66 1.53 0.98 tmin 1925 -12.33 -7.50 -5.78 -0.11 4.72 8.94 12.33 9.94 7.61 -2.39 -5.94 -9.78 tmax 1925 -1.33 9.17 13.22 18.44 21.67 26.33 29.83 27.33 24.89 11.72 8.56 4.50 prec 1926 0.41 0.51 0.37 1.45 4.04 5.39 10.89 1.78 2.00 0.18 0.63 1.33 tmin 1926 -10.50 -4.89 -6.78 -1.33 4.28 8.61 11.17 8.94 4.11 -0.72 -5.17 -11.83 tmax 1926 2.28 7.78 9.00 14.83 21.67 26.33 28.89 30.72 22.78 19.50 10.62 3.11 prec 1927 0.69 0.43 1.33 1.63 0.51 3.49 2.82 3.19 2.98 0.86 0.33 0.78 tmin 1927 -9.17 -7.44 -6.33 -1.33 4.11 8.39 11.00 10.33 7.06 2.56 -2.28 -13.39 tmax 1927 7.00 7.50 7.11 14.67 22.44 24.28 29.17 25.89 24.44 20.61 13.22 2.28 prec 1928 0.20 0.10 0.27 0.06 6.29 3.49 5.23 0.61 0.37 3.08 0.82 0.00 tmin 1928 -7.89 -9.06 -4.94 -3.17 5.50 6.72 12.00 11.89 6.63 0.95 -3.61 -9.78 tmax 1928 7.28 7.33 11.11 15.39 21.33 20.83 29.44 30.56 25.04 18.45 9.11 3.22 prec 1929 0.10 0.76 0.31 7.40 1.70 2.10 5.11 4.43 4.15 0.57 1.21 0.00 tmin 1929 -12.11 -14.56 -3.83 -0.50 3.50 8.28 12.22 12.89 5.89 1.50 -9.56 -6.67 tmax 1929 1.56 -0.28 9.22 14.22 20.22 27.61 30.84 29.83 20.72 17.94 2.28 6.89 prec 1930 0.33 0.94 1.74 4.84 8.29 0.65 2.82 13.28 3.74 2.96 1.43 0.90 tmin 1930 -17.83 -4.28 -6.94 3.11 3.33 8.67 13.61 12.83 6.72 0.72 -2.39 -9.67 tmax 1930 -5.11 8.72 7.89 19.11 17.22 27.61 31.17 28.50 24.61 16.94 13.56 4.22 prec 1931 0.00 0.74 1.29 0.82 5.03 1.98 2.88 1.63 1.51 2.86 0.61 0.80 tmin 1931 -7.50 -6.22 -6.39 -0.72 3.33 11.50 13.06 11.94 9.56 2.22 -7.00 -7.83 tmax 1931 7.61 8.61 8.50 15.67 20.11 29.72 32.94 30.83 28.17 19.56 9.50 7.11 prec 1932 0.69 1.31 1.59 1.23 2.49 4.66 6.46 5.72 3.08 1.44 0.00 0.47 tmin 1932 -11.72 -6.72 -9.72 -0.28 5.50 9.00 13.72 12.33 6.17 -0.67 -3.22 -14.00 tmax 1932 2.11 7.61 5.22 16.78 21.11 26.61 33.17 30.67 24.94 14.33 9.89 -1.44 prec 1933 0.10 0.29 0.10 1.43 6.66 2.86 3.72 7.19 3.62 0.00 0.00 0.78 tmin 1933 -9.06 -13.83 -4.89 -2.56 3.39 11.28 13.94 11.50 8.78 1.50 -3.33 -5.39 tmax 1933 4.94 1.61 10.50 13.00 18.22 31.17 32.61 28.78 26.56 21.89 13.44 9.50 prec 1934 0.00 1.23 0.27 0.61 0.57 5.70 4.41 3.64 1.14 0.00 0.99 0.90 tmin 1934 -6.28 -6.89 -4.06 0.06 7.33 9.56 14.00 12.83 6.63 3.11 -2.39 -8.06 tmax 1934 9.67 8.17 12.94 17.22 26.78 29.22 34.17 30.89 25.04 23.72 13.78 9.17 prec 1935 0.69 0.08 1.41 2.06 10.32 1.29 1.53 1.53 4.45 0.31 0.82 0.90 tmin 1935 -8.56 -7.61 -5.44 -2.00 2.67 8.78 13.72 12.94 7.28 0.28 -5.61 -7.94 tmax 1935 10.78 9.61 13.33 14.22 16.00 26.67 33.50 31.56 24.67 17.78 7.94 5.72 prec 1936 0.37 0.67 0.08 1.33 6.01 2.78 4.15 1.51 2.51 0.31 0.10 0.51 tmin 1936 -10.00 -16.44 -4.89 -0.50 3.97 11.61 14.44 13.22 7.50 0.83 -5.06 -7.94 tmax 1936 3.78 0.78 10.33 12.22 20.56 30.17 34.61 31.89 25.56 16.33 10.94 7.83 prec 1937 0.63 1.02 1.12 0.04 4.31 4.02 4.13 0.18 1.76 0.82 0.69 2.82 tmin 1937 -18.44 -9.15 -7.00 -1.44 4.72 8.83 12.83 13.61 9.28 0.95 -5.17 -9.61 tmax 1937 -3.78 6.21 7.39 15.94 22.17 25.78 32.22 33.78 27.50 18.45 10.62 4.06 prec 1938 0.27 0.61 0.86 2.47 5.07 1.06 4.13 6.05 11.22 0.31 1.23 0.20 tmin 1938 -8.56 -7.94 -2.56 -0.56 4.28 9.50 12.78 13.72 9.00 3.50 -6.22 -9.22 tmax 1938 4.83 7.39 11.22 16.28 18.67 27.44 31.11 31.83 24.83 21.06 8.67 4.94 prec 1939 0.35 0.76 2.41 1.04 0.61 0.86 1.10 2.53 0.55 0.20 0.99 0.29 tmin 1939 -6.50 -13.50 -4.50 0.06 5.61 8.28 13.83 11.00 8.94 2.44 -3.67 -5.06 tmax 1939 5.28 1.72 10.17 16.56 24.50 28.17 34.33 30.78 27.61 20.22 13.72 10.22 prec 1940 1.94 1.86 1.02 1.78 6.60 2.03 6.86 2.29 11.43 0.51 0.76 0.25 tmin 1940 -12.83 -6.61 -2.39 -0.61 5.17 10.61 13.89 11.78 10.67 4.44 -5.17 -6.78 tmax 1940 -1.94 4.50 12.44 16.89 23.00 30.39 32.72 30.33 25.06 21.89 10.62 6.50 prec 1941 0.51 0.25 2.39 6.52 1.96 9.23 1.55 4.90 3.15 0.72 0.99 0.29 tmin 1941 -7.50 -6.72 -5.33 -0.06 6.39 8.78 12.67 12.28 5.56 1.17 -3.78 -7.72 tmax 1941 7.56 7.78 6.22 13.22 22.83 24.94 30.50 29.11 23.83 16.06 13.33 7.00 prec 1942 1.21 1.68 0.74 5.62 5.25 4.64 4.76 3.62 0.86 6.58 1.27 0.90 tmin 1942 -11.11 -12.22 -5.56 1.50 2.83 9.61 12.61 11.83 6.61 2.50 -4.56 -6.11 tmax 1942 3.22 0.78 9.11 17.61 19.06 23.11 30.78 29.50 24.11 17.50 12.61 6.33 prec 1943 0.00 1.61 1.52 7.11 4.32 13.72 9.65 6.86 3.30 2.03 0.51 0.25 tmin 1943 -8.72 -4.39 -6.72 3.56 3.78 9.56 13.11 13.94 6.22 1.61 -3.61 -7.22 tmax 1943 5.89 9.94 6.78 19.11 17.44 24.44 31.61 31.50 25.28 19.56 12.17 7.39 prec 1944 0.51 0.51 2.79 5.59 2.29 1.78 5.33 1.02 0.76 0.00 1.63 0.69 tmin 1944 -11.28 -7.61 -6.89 -2.06 4.00 8.50 11.11 11.67 6.00 1.50 -4.22 -10.17 tmax 1944 6.22 5.72 6.22 11.33 21.78 26.22 29.00 31.22 26.44 20.28 10.00 4.44 prec 1945 1.52 0.25 0.76 4.06 2.54 7.37 2.03 6.35 1.78 1.52 0.51 0.00 tmin 1945 -8.39 -7.83 -5.83 -4.17 2.56 6.28 11.17 11.44 4.39 0.94 -4.67 -9.89 tmax 1945 5.50 5.33 11.33 10.33 20.50 21.11 29.61 29.28 23.11 19.17 12.33 4.44 prec 1946 0.00 0.25 1.78 0.25 6.10 2.03 5.33 6.86 0.51 5.59 1.02 0.00 tmin 1946 -10.00 -9.56 -4.61 1.22 2.72 9.39 12.83 11.72 6.22 0.28 -5.83 -5.83 tmax 1946 7.28 8.44 13.56 20.11 16.83 27.44 31.44 29.17 25.39 15.22 6.44 9.11 prec 1947 0.35 1.31 2.00 1.02 4.83 10.16 7.87 2.54 2.29 4.06 0.76 0.25 tmin 1947 -9.28 -10.83 -6.67 -0.94 3.61 7.44 11.78 12.83 8.11 3.00 -7.94 -7.83 tmax 1947 5.17 4.72 8.00 14.67 19.56 23.22 30.28 31.22 28.56 20.22 5.94 6.78 prec 1948 0.51 0.51 0.76 0.76 1.27 5.08 3.56 4.06 0.51 0.76 0.51 1.27 tmin 1948 -9.78 -11.61 -8.61 -0.61 3.89 9.11 10.94 10.28 7.94 0.67 -4.17 -6.44 tmax 1948 3.56 3.33 6.89 18.44 22.39 25.44 30.83 30.78 28.33 19.11 8.56 4.44 prec 1949 3.05 0.00 2.03 2.03 9.14 9.40 3.30 2.79 0.51 1.78 0.25 0.00 tmin 1949 -20.55 -10.83 -6.29 -1.19 6.22 10.22 12.72 11.40 6.63 0.39 -0.11 -10.06 tmax 1949 4.49 4.72 9.34 15.27 19.56 24.67 30.61 29.84 25.04 18.45 17.17 6.33 prec 1950 0.81 0.36 0.43 2.36 4.47 2.95 9.09 1.75 6.15 0.58 0.99 0.00 tmin 1950 -12.94 -7.76 -7.96 -2.52 2.72 7.85 10.68 8.69 6.89 2.72 -6.20 -7.97 tmax 1950 6.68 10.20 9.96 14.80 19.16 26.22 26.99 28.78 22.02 22.20 10.19 9.89 prec 1951 0.74 0.61 0.48 2.29 7.92 4.22 3.20 6.02 1.57 4.83 0.61 0.51 tmin 1951 -13.17 -8.99 -9.62 -3.24 4.37 6.50 12.04 11.94 4.93 0.47 -6.46 -11.68 tmax 1951 3.10 8.06 8.82 11.24 19.62 22.33 30.36 28.53 23.93 15.13 11.57 3.03 prec 1952 0.00 0.13 2.82 2.26 7.42 7.37 3.40 10.24 0.69 0.20 0.66 0.10 tmin 1952 -12.46 -9.69 -10.00 -2.19 3.76 11.89 11.83 12.56 7.76 -0.81 -9.41 -10.32 tmax 1952 5.54 7.43 6.04 15.44 19.91 30.74 31.16 30.04 29.06 21.54 7.39 7.49 prec 1953 0.10 0.53 1.35 2.90 4.17 4.70 5.82 8.25 0.66 0.53 0.97 0.15 tmin 1953 -6.27 -9.80 -5.39 -3.11 4.12 10.57 13.55 12.46 6.15 1.18 -2.35 -7.58 tmax 1953 11.72 8.15 14.71 12.98 18.32 28.52 30.65 29.84 27.19 21.04 14.50 7.47 prec 1954 0.20 0.00 1.65 0.30 1.52 1.93 1.32 2.92 0.94 0.10 0.81 0.48 tmin 1954 -10.09 -4.58 -8.49 0.50 3.48 9.93 15.82 12.37 10.02 2.65 -4.52 -7.62 tmax 1954 7.03 15.93 8.78 19.54 20.30 28.13 34.55 30.84 29.06 20.95 14.31 8.76 prec 1955 1.14 0.99 0.97 1.85 3.71 6.40 1.60 7.44 5.11 0.41 2.64 0.51 tmin 1955 -11.02 -14.78 -7.01 -0.13 4.64 7.44 13.67 13.84 4.83 1.72 -8.33 -9.10 tmax 1955 3.85 2.12 10.34 18.22 21.38 21.74 31.95 29.64 22.87 21.47 7.00 6.36 prec 1956 0.91 0.15 0.76 2.13 3.96 4.52 3.76 5.87 0.05 0.00 1.09 1.14 tmin 1956 -7.94 -11.99 -5.11 -2.48 5.45 8.37 10.77 10.75 6.93 0.39 -6.91 -7.33 tmax 1956 8.10 2.97 12.51 14.98 21.79 28.93 28.39 28.26 28.61 21.40 9.69 8.82 prec 1957 0.66 0.00 1.09 4.93 14.83 4.67 3.48 5.49 1.63 3.63 1.07 0.00 tmin 1957 -14.59 -4.80 -6.42 -4.15 3.87 7.00 13.21 13.15 5.48 1.88 -6.89 -6.11 tmax 1957 2.74 13.77 10.52 11.00 17.10 23.96 30.57 29.10 24.44 16.11 7.24 12.51 prec 1958 0.00 1.24 3.07 2.79 7.77 3.63 8.89 0.56 1.24 0.63 0.41 2.84 tmin 1958 -10.82 -7.14 -7.37 -1.26 6.95 11.28 10.66 11.11 7.35 0.65 -6.48 -7.81 tmax 1958 8.92 9.09 6.25 13.22 22.67 27.57 25.99 29.35 26.13 20.05 12.80 7.04 prec 1959 0.86 0.76 2.29 3.99 5.66 5.99 2.87 0.91 2.64 4.62 0.05 0.00 tmin 1959 -11.25 -10.06 -7.10 -3.22 5.00 11.33 11.34 12.20 7.07 -2.83 -10.09 -7.40 tmax 1959 6.22 5.04 8.96 13.81 19.34 29.28 30.29 29.87 23.81 14.57 9.93 10.59 prec 1960 0.48 0.51 0.61 1.52 2.77 3.35 1.98 0.74 1.60 3.07 0.51 0.38 tmin 1960 -13.28 -12.95 -8.03 -0.48 3.28 8.43 10.82 9.12 7.76 1.08 -6.26 -8.94 tmax 1960 4.09 1.11 10.00 17.11 21.61 26.22 29.53 29.10 25.72 18.37 11.43 8.21 prec 1961 0.46 0.36 4.72 0.79 8.23 10.57 5.28 1.83 6.65 0.36 1.02 0.10 tmin 1961 -10.45 -7.74 -4.18 -1.78 5.07 10.78 11.56 11.38 3.67 1.02 -7.04 -11.68 tmax 1961 10.47 10.63 10.14 14.63 19.41 26.13 27.56 27.67 18.78 17.35 9.59 4.37 prec 1962 1.98 1.19 0.48 0.36 7.29 9.47 11.94 1.80 1.07 3.00 1.12 0.20 tmin 1962 -16.18 -8.65 -7.20 -1.06 4.78 9.81 11.36 9.46 5.61 1.40 -4.33 -9.35 tmax 1962 1.77 6.21 8.91 16.41 21.09 24.39 27.15 27.97 23.44 19.18 12.04 8.30 prec 1963 0.61 0.08 1.14 0.84 3.81 7.57 3.71 8.69 4.55 1.93 0.00 0.91 tmin 1963 -17.90 -7.54 -8.23 -2.41 4.73 9.69 14.27 13.24 9.35 4.19 -6.06 -11.90 tmax 1963 0.20 9.64 8.71 15.41 22.78 25.70 31.45 26.34 25.04 21.67 12.54 4.52 prec 1964 0.08 0.10 0.91 2.72 1.65 1.85 1.09 0.99 0.91 0.00 0.10 0.33 tmin 1964 -11.67 -13.72 -11.45 -2.57 2.20 8.13 13.42 10.52 5.56 -0.93 -7.28 -11.08 tmax 1964 5.16 2.41 5.34 12.44 19.25 23.72 31.79 27.60 23.94 18.42 8.80 4.44 prec 1965 0.86 0.51 1.19 2.59 4.04 12.55 8.26 1.02 5.82 0.00 0.00 0.30 tmin 1965 -8.80 -10.79 -11.61 0.80 4.39 8.24 12.28 10.65 3.83 2.22 -4.26 -9.32 tmax 1965 7.42 5.40 4.62 15.89 19.21 20.87 26.95 26.43 16.56 19.93 12.13 7.71 prec 1966 1.17 0.94 0.00 2.31 0.18 5.66 2.69 8.53 6.10 0.61 0.81 0.20 tmin 1966 -14.23 -13.59 -6.34 -4.35 2.15 9.35 14.87 10.56 7.07 -2.44 -6.04 -11.27 tmax 1966 4.23 3.63 12.24 12.09 21.00 24.67 30.97 25.77 21.98 16.22 9.24 4.50 prec 1967 1.88 0.97 1.40 5.64 12.62 16.56 10.54 2.92 3.20 0.71 0.97 1.40 tmin 1967 -10.88 -10.06 -5.39 -0.83 3.75 8.33 12.01 10.61 5.57 -1.58 -8.15 -14.43 tmax 1967 5.91 7.14 11.25 15.67 16.86 20.57 26.31 27.38 21.85 18.14 10.33 1.40 prec 1968 0.05 0.53 0.91 2.64 9.27 5.77 4.11 4.32 1.02 2.44 1.73 0.53 tmin 1968 -11.97 -9.37 -5.68 -4.15 1.72 10.02 11.13 8.12 4.17 -0.45 -8.78 -12.96 tmax 1968 5.57 6.51 11.83 12.43 17.04 26.63 27.06 24.44 23.52 18.08 7.41 3.96 prec 1969 0.31 0.66 0.61 3.99 5.75 11.88 4.44 3.54 3.12 7.14 0.25 0.00 tmin 1969 -10.58 -8.64 -10.00 -0.07 5.29 6.53 12.03 12.26 8.57 -2.32 -6.53 -9.19 tmax 1969 7.58 8.11 6.13 17.17 20.58 19.30 28.61 30.23 25.63 9.74 10.20 6.10 prec 1970 0.13 0.51 2.95 3.40 2.13 2.90 4.06 1.15 3.57 1.95 0.46 0.44 tmin 1970 -10.58 -10.64 -10.58 -5.33 2.55 6.87 11.90 12.42 4.73 -1.45 -4.73 -9.42 tmax 1970 6.35 9.96 4.42 10.93 21.00 24.87 30.81 31.48 23.73 13.39 9.47 5.97 prec 1971 1.14 0.88 2.19 7.09 9.12 0.97 1.14 1.27 5.89 1.08 0.28 0.08 tmin 1971 -9.94 -10.89 -8.81 -1.63 2.00 8.40 10.94 10.52 3.47 -0.68 -7.10 -11.19 tmax 1971 4.94 4.61 8.16 15.33 18.55 28.57 29.81 31.16 21.00 16.90 11.00 5.77 prec 1972 0.73 0.00 0.60 1.29 3.12 11.08 1.59 6.88 2.58 1.28 0.25 0.00 tmin 1972 -12.71 -8.83 -3.10 0.30 4.23 10.90 11.10 12.19 7.27 1.90 -6.17 -12.06 tmax 1972 4.61 11.10 14.94 16.63 20.77 26.70 29.03 28.13 23.50 17.03 5.87 1.32 prec 1973 0.00 0.00 0.00 2.34 0.48 2.92 11.83 0.84 5.90 0.06 0.00 0.00 tmin 1973 -9.42 -8.36 -3.52 -2.10 3.87 9.87 12.97 12.84 7.13 2.97 -3.97 -6.68 tmax 1973 4.26 8.43 8.55 12.67 20.68 28.07 28.29 30.74 23.30 20.84 8.17 6.74 prec 1974 1.05 0.00 2.08 0.30 1.84 6.50 5.29 2.61 1.32 2.59 0.30 0.00 tmin 1974 -11.26 -6.25 -2.97 0.40 6.10 10.63 14.16 10.61 5.47 3.29 -3.90 -9.58 tmax 1974 3.26 10.29 14.48 17.07 25.16 28.00 31.74 29.42 25.27 20.10 11.33 7.13 prec 1975 0.41 0.51 0.35 3.93 8.16 3.39 6.66 1.96 2.47 0.33 1.11 0.66 tmin 1975 -8.81 -9.79 -4.35 -1.33 4.10 9.33 13.58 12.55 6.67 1.68 -5.13 -4.87 tmax 1975 6.74 7.71 10.74 14.60 19.35 26.00 30.97 31.26 25.13 20.81 11.33 8.48 prec 1976 0.66 0.28 0.00 4.14 3.64 2.19 3.91 3.20 3.37 0.03 1.17 0.00 tmin 1976 -8.71 -4.28 -5.61 1.63 5.48 9.63 14.81 12.35 8.87 0.45 -5.03 -7.61 tmax 1976 6.71 11.52 11.71 17.60 21.77 28.60 32.71 29.45 25.13 18.42 11.47 11.10 prec 1977 0.14 0.00 0.83 3.93 6.66 2.56 5.24 1.76 0.77 0.16 0.62 0.33 tmin 1977 -12.00 -5.14 -5.77 2.43 8.10 13.63 15.68 13.68 9.80 2.90 -3.37 -6.19 tmax 1977 6.32 11.89 12.81 18.33 23.77 31.20 32.32 29.74 29.40 21.77 12.13 8.48 prec 1978 0.65 0.61 0.95 1.27 11.64 3.25 1.10 5.04 0.25 2.85 0.79 0.51 tmin 1978 -10.70 -7.61 -1.84 1.97 6.19 11.23 14.52 12.84 8.60 3.10 -3.83 -10.84 tmax 1978 2.87 3.96 14.68 18.66 20.77 28.67 33.87 30.81 28.83 21.52 10.17 3.16 prec 1979 0.00 0.00 1.25 1.20 11.01 7.60 3.53 13.84 3.13 0.86 2.10 0.00 tmin 1979 -13.42 -6.82 -1.17 2.23 6.26 10.33 12.71 13.06 9.47 4.17 -5.71 -5.60 tmax 1979 -1.26 8.61 12.27 18.60 19.97 26.30 29.74 29.61 28.57 22.50 9.71 9.90 prec 1980 1.27 4.05 3.84 1.53 4.55 2.21 7.80 1.60 1.68 0.84 0.84 0.05 tmin 1980 -11.52 -6.59 -3.81 0.76 6.29 10.90 15.48 12.73 8.97 1.84 -2.93 -3.39 tmax 1980 2.37 6.55 9.45 16.76 20.84 31.70 33.35 32.13 29.07 20.81 13.72 13.65 prec 1981 0.63 0.38 3.04 3.30 9.03 2.58 5.62 6.72 2.53 2.11 0.00 1.09 tmin 1981 -6.37 -7.71 -1.71 3.79 6.97 12.17 15.10 13.45 10.34 2.83 -1.59 -6.53 tmax 1981 11.97 12.00 12.90 21.69 20.42 29.67 32.26 30.23 28.10 18.57 15.48 8.97 prec 1982 0.44 0.13 1.09 0.81 5.88 11.72 14.00 3.35 6.88 2.01 1.37 0.23 tmin 1982 -9.59 -7.67 -2.93 -1.41 6.16 9.97 14.23 15.39 9.79 2.48 -5.14 -6.47 tmax 1982 6.66 9.56 13.03 18.76 22.03 25.21 31.60 31.86 24.97 18.21 10.46 7.83 prec 1983 0.00 0.03 5.17 6.98 7.28 7.38 4.08 4.50 0.93 0.85 2.00 0.86 tmin 1983 -5.06 -4.82 -2.06 -0.90 5.17 10.45 14.32 16.21 8.00 3.37 -3.79 -13.25 tmax 1983 10.23 11.71 10.68 12.72 20.03 24.66 32.07 33.07 30.07 22.20 11.18 -2.04 prec 1984 0.81 0.99 3.17 5.13 2.57 5.46 7.50 4.70 3.53 6.47 0.00 0.38 tmin 1984 -9.24 -5.14 -3.47 -0.78 6.94 10.59 14.79 14.97 7.41 0.93 -3.20 -8.67 tmax 1984 5.76 10.04 11.80 12.78 24.52 27.86 32.79 31.55 25.97 15.86 13.20 8.19 prec 1985 1.65 0.11 0.33 4.34 2.89 1.96 10.39 9.70 3.12 2.31 2.80 1.22 tmin 1985 -11.00 -10.00 -4.00 2.00 8.00 10.00 15.00 13.00 7.00 1.00 -9.0 -10.00 tmax 1985 5.00 5.00 15.00 20.00 23.00 28.00 30.00 31.00 22.00 18.00 5.00 3.00 prec 1986 0.08 0.70 1.15 3.58 3.33 3.68 3.35 2.63 2.93 2.15 2.22 0.69 tmin 1986 -4.00 -5.00 0.00 3.00 6.00 12.00 14.00 13.00 9.00 3.00 -3.00 -8.00 tmax 1986 10.00 9.00 17.00 17.00 21.00 29.00 32.00 31.00 23.00 17.00 10.00 7.00 prec 1987 0.31 1.82 1.62 0.88 5.71 7.27 2.38 6.71 2.72 1.28 2.26 0.74 tmin 1987 -8.00 -5.00 -4.00 2.00 9.00 12.00 14.00 13.00 8.00 1.00 -2.00 -8.00 tmax 1987 7.00 9.00 9.00 20.00 22.00 29.00 32.00 29.00 26.00 20.00 12.00 5.00 prec 1988 0.65 1.30 2.26 4.23 5.45 4.14 5.04 5.23 2.64 0.61 0.42 1.53 tmin 1988 -12.00 -7.00 -4.00 1.00 7.00 14.00 14.00 14.00 9.00 3.00 -3.00 -8.00 tmax 1988 2.00 6.00 10.00 17.00 23.00 30.00 32.00 31.00 26.00 21.00 12.00 7.00 prec 1989 0.69 1.89 0.79 1.97 4.31 7.19 4.32 2.69 4.53 0.85 0.05 0.77 tmin 1989 -8.00 -12.00 -2.00 2.00 7.00 11.00 15.00 14.00 9.00 3.00 -3.00 -10.00
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Appendix 3.2. Sample Atmospheric C14 Label File
1950 1.0 1994 1.30 1951 1.0 1995 1.30 1952 1.0 1996 1.30 1953 1.0 1997 1.30 1954 1.0 1998 1.30 1955 1.0 1999 1.30 1956 1.06 2000 1.30 1957 1.11 1958 1.19 1959 1.32 1960 1.29 1961 1.23 1962 1.41 1963 1.95 1964 1.99 1965 1.79 1966 1.74 1967 1.65 1968 1.60 1969 1.54 1970 1.54 1971 1.53 1972 1.50 1973 1.46 1974 1.42 1975 1.40 1976 1.40 1977 1.36 1978 1.32 1979 1.31 1980 1.30 1981 1.30 1982 1.30 1983 1.30 1984 1.30 1985 1.30 1986 1.30 1987 1.30 1988 1.30 1989 1.30 1990 1.30 1991 1.30 1992 1.30 1993 1.30
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Figure 2-1: The Century model environment showing the relationship between programs and the file structure.
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Figure 3-1: The pools and flows of carbon in the CENTURY model. The diagram shows the major factors which control the flows.
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Figure 3-2: Flow diagram for the water submodel. The structure represents a model set up to operate with NLAYER set to 5.
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Figure 3-3: The pools and flows of nitrogen in the CENTURY model. The diagram shows the major factors which control the flows.
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Figure 3-4: The pools and flows of phosphorus in the CENTURY model. The diagram shows the major factors which control the flows.
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Figure 3-5: The equilibrium between labile and sorbed P pools, showing the effect of changing the sorption affinity or the sorption maximum.
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Figure 3-6: The pools and flows of sulphur in the CENTURY model. The diagram shows the major factors which control the flows.
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Figure 3-7: Flow diagram for the grassland/crop submodel.
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Figure 3-8A: The impact of soil temperature on potential plant growth of different communities of C3 and C4 plants.
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Figure 3-8B: The impact of soil temperature on potential plant growth of different crops.
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Figure 3-9: The impact of moisture availability, expressed as the ratio of monthly precipitations plus stored water plus irrigation to PET rate, on potential plant growth. The effect of soil texture on this relationship is also shown.
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Figure 3-10: The effect of plant growth on the scaling factor for seedling growth.
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Figure 3-11: The effect of time since planting on the allocation of carbon to roots.
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Figure 3-12: The effect of annual precipitation on the allocation of carbon to roots for Great Plains grasslands used when FRTC(1) = 0.
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Figure 3-13: The effect of plant biomass on the C/N ratio in new increments of plant growth (as parameterized for wheat).
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Figure 3-14: The effect of root biomass on nutrient availability.
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Figure 3-15: The effect of soil moisture status and available water holding capacity (AWHC) on shoot and root death.
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Figure 3-16: The effect of moisture stress on harvest index.
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Figure 3-17: Flow diagram for the forest production submodel.
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Figure 3-18: The effect of forest live leaf index (LAI) on potential plant production (Waring and Schlesinger 1982).
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Figure 3-19: The effect of live large wood C on the sapwood to large live wood C ratio. The function can be modified in CENTURY with SAPK in the tree.100 file.
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Figure 3-20: The effect of live large wood C on the maximum ratio of live leaf C to large wood C. This equation is a species-specific one that can be modified with MAXLAI and KLAI which are in the tree.100 file.
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Figure 3-21: The effect of tree cover and live leaf biomass on the shade modifier for grassland/crop growth.
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Figure 3-22: The fraction of N available for tree growth as a function of available N and tree basal area.
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Figure 3-23: The sequencing of events and processes in the CENTURY model.
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Figure 3-24: Example of CO2 effects on production and transpiration.
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APPENDIX 5 ACTUAL PARAMETER VALUES
Appendix 5.1. CROP.100 Parameter Values
Parameter G5 G4 G3 G2 G1 GCP TG PRDX(1) 300.0 270.0 300.0 300.0 240.0 350.0 270.0 PPDF(1) 27.0 18.0 22.0 30.0 15.0 22.0 22.0 PPDF(2) 45.0 35.0 38.0 45.0 32.0 35.0 35.0 PPDF(3) 1.0 1.2 0.3 1.0 1.0 0.8 0.8 PPDF(4) 3.0 3.0 5.0 2.5 3.5 3.5 3.5 BIOFLG 1.0 1.0 1.0 1.0 1.0 1.0 1.0 BIOK5 60.0 60.0 60.0 60.0 60.0 200.0 60.0 PLTMRF 1.0 1.0 1.0 1.0 1.0 0.5 0.5 FULCAN 100.0 100.0 100.0 100.0 100.0 150.0 150.0 FRTC(1) 0.0 0.0 0.0 0.0 0.0 0.5 0.5 FRTC(2) 0.0 0.0 0.0 0.0 0.0 0.5 0.5 FRTC(3) 0.0 0.0 0.0 0.0 0.0 1.0 1.0 BIOMAX 400.0 400.0 400.0 400.0 400.0 400.0 400.0 PRAMN(1,1) 30.0 30.0 30.0 30.0 30.0 8.5 30.0 PRAMN(2,1) 390.0 390.0 390.0 390.0 390.0 100.0 133.0 PRAMN(3,1) 340.0 340.0 340.0 340.0 340.0 125.0 133.0 PRAMN(1,2) 90.0 90.0 90.0 90.0 90.0 8.5 90.0 PRAMN(2,2) 390.0 390.0 390.0 390.0 390.0 100.0 160.0 PRAMN(3,2) 340.0 340.0 340.0 340.0 340.0 125.0 160.0 PRAMX(1,1) 35.0 35.0 35.0 35.0 35.0 11.0 35.0 PRAMX(2,1) 440.0 440.0 440.0 440.0 440.0 133.0 200.0 PRAMX(3,1) 440.0 440.0 440.0 440.0 440.0 160.0 200.0 PRAMX(1,2) 95.0 95.0 95.0 95.0 95.0 11.0 95.0 PRAMX(2,2) 440.0 440.0 440.0 440.0 440.0 133.0 260.0 PRAMX(3,2) 440.0 440.0 440.0 440.0 440.0 160.0 260.0 PRBMN(1,1) 50.0 50.0 50.0 50.0 50.0 17.0 50.0 PRBMN(2,1) 390.0 390.0 390.0 390.0 390.0 100.0 390.0 PRBMN(3,1) 340.0 340.0 340.0 340.0 340.0 125.0 340.0 PRBMN(1,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PRBMN(2,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PRBMN(3,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PRBMX(1,1) 55.0 55.0 55.0 55.0 55.0 22.0 55.0 PRBMX(2,1) 420.0 420.0 420.0 420.0 420.0 133.0 420.0 PRBMX(3,1) 420.0 420.0 420.0 420.0 420.0 160.0 420.0 PRBMX(1,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PRBMX(2,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PRBMX(3,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 FLIGNI(1,1) 0.02 0.02 0.02 0.02 0.02 0.04 0.02 FLIGNI(2,1) 0.0012 0.0012 0.0012 0.0012 0.0012 0.0 0.0012 FLIGNI(1,2) 0.26 0.26 0.26 0.26 0.26 0.12 0.26 FLIGNI(2,2) -0.0015 -0.0015 -0.0015 -0.0015 -0.0015 0.0 -0.0015 HIMAX 0.0 0.0 0.0 0.0 0.0 0.0 0.0 HIWSF 0.0 0.0 0.0 0.0 0.0 0.0 0.0 HIMON(1) 2.0 2.0 2.0 2.0 2.0 2.0 2.0 HIMON(2) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 EFRGRN(1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 EFRGRN(2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 EFRGRN(3) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 VLOSSP 0.15 0.15 0.15 0.15 0.15 0.02 0.04 FSDETH(1) 0.2 0.2 0.2 0.2 0.2 0.3 0.2 FSDETH(2) 0.95 0.95 0.95 0.95 0.95 0.4 0.6 FSDETH(3) 0.2 0.2 0.2 0.2 0.2 0.1 0.2 FSDETH(4) 150.0 150.0 150.0 150.0 150.0 500.0 150.0 FALLRT 0.15 0.15 0.15 0.15 0.15 0.5 0.15 RDR 0.05 0.05 0.05 0.05 0.05 0.6 0.2 RTDTMP 2.0 2.0 2.0 2.0 2.0 2.0 2.0 CRPRTF(1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CRPRTF(2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CRPRTF(3) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SNFXMX(1) 0.0 0.0 0.0 0.0 0.0 0.0375 0.0 DEL13C -18.0 -24.0 -21.0 -15.0 -27.0 -27.0 -27.0 CO2IPR(1) 0.0 0.0 0.5 0.0 0.0 0.0 0.0 CO2ITR(1) 0.0 0.0 0.77 0.0 0.0 0.0 0.0 CO2ICE(1,1,1) 0.0 0.0 1.0 0.0 0.0 0.0 0.0 CO2ICE(1,1,2) 0.0 0.0 1.0 0.0 0.0 0.0 0.0 CO2ICE(1,1,3) 0.0 0.0 1.0 0.0 0.0 0.0 0.0 CO2ICE(1,2,1) 0.0 0.0 1.15 0.0 0.0 0.0 0.0 CO2ICE(1,2,2) 0.0 0.0 1.0 0.0 0.0 0.0 0.0 CO2ICE(1,2,3) 0.0 0.0 1.0 0.0 0.0 0.0 0.0 CO2IRS(1) 0.0 0.0 1.0 0.0 0.0 0.0 0.0 Parameter W1 W2 W3 PRDX(1) 300.0 300.0 300.0 PPDF(1) 18.0 18.0 18.0 PPDF(2) 35.0 35.0 35.0 PPDF(3) 0.7 0.7 0.7 PPDF(4) 5.0 5.0 5.0 BIOFLG 0.0 0.0 0.0 BIOK5 1800.0 1800.0 1800.0 PLTMRF 0.4 0.4 0.4 FULCAN 150.0 150.0 150.0 FRTC(1) 0.6 0.6 0.6 FRTC(2) 0.1 0.1 0.1 FRTC(3) 3.0 3.0 3.0 BIOMAX 600.0 600.0 600.0 PRAMN(1,1) 12.0 12.0 12.0 PRAMN(2,1) 100.0 100.0 100.0 PRAMN(3,1) 100.0 100.0 100.0 PRAMN(1,2) 57.0 57.0 57.0 PRAMN(2,2) 160.0 160.0 160.0 PRAMN(3,2) 200.0 200.0 200.0 PRAMX(1,1) 25.0 25.0 25.0 PRAMX(2,1) 200.0 200.0 200.0 PRAMX(3,1) 230.0 230.0 230.0 PRAMX(1,2) 125.0 125.0 125.0 PRAMX(2,2) 260.0 260.0 260.0 PRAMX(3,2) 270.0 270.0 270.0 PRBMN(1,1) 45.0 45.0 45.0 PRBMN(2,1) 390.0 390.0 390.0 PRBMN(3,1) 340.0 340.0 340.0 PRBMN(1,2) 0.0 0.0 0.0 PRBMN(2,2) 0.0 0.0 0.0 PRBMN(3,2) 0.0 0.0 0.0 PRBMX(1,1) 60.0 60.0 60.0 PRBMX(2,1) 420.0 420.0 420.0 PRBMX(3,1) 420.0 420.0 420.0 PRBMX(1,2) 0.0 0.0 0.0 PRBMX(2,2) 0.0 0.0 0.0 PRBMX(3,2) 0.0 0.0 0.0 FLIGNI(1,1) 0.15 0.15 0.15 FLIGNI(2,1) 0.0 0.0 0.0 FLIGNI(1,2) 0.06 0.06 0.06 FLIGNI(2,2) 0.0 0.0 0.0 HIMAX 0.3 0.35 0.42 HIWSF 0.5 0.5 0.5 HIMON(1) 1.0 1.0 1.0 HIMON(2) 0.0 0.0 0.0 EFRGRN(1) 0.6 0.65 0.75 EFRGRN(2) 0.6 0.6 0.6 EFRGRN(3) 0.6 0.6 0.6 VLOSSP 0.04 0.04 0.04 FSDETH(1) 0.0 0.0 0.0 FSDETH(2) 0.0 0.0 0.0 FSDETH(3) 0.0 0.0 0.0 FSDETH(4) 200.0 200.0 200.0 FALLRT 0.12 0.12 0.12 RDR 0.05 0.05 0.05 RTDTMP 2.0 2.0 2.0 CRPRTF(1) 0.0 0.0 0.0 CRPRTF(2) 0.0 0.0 0.0 CRPRTF(3) 0.0 0.0 0.0 SNFXMX(1) 0.0 0.0 0.0 DEL13C -27.0 -27.0 -27.0 CO2IPR(1) 0.0 0.0 1.0 CO2ITR(1) 0.0 0.0 0.77 CO2ICE(1,1,1) 0.0 0.0 1.0 CO2ICE(1,1,2) 0.0 0.0 1.0 CO2ICE(1,1,3) 0.0 0.0 1.0 CO2ICE(1,2,1) 0.0 0.0 1.3 CO2ICE(1,2,2) 0.0 0.0 1.0 CO2ICE(1,2,3) 0.0 0.0 1.0 CO2IRS(1) 0.0 0.0 1.0 Parameter C-HI C6 C5 C4 C3 C2 C1 C PRDX(1) 650.0 620.0 600.0 550.0 400.0 300.0 250.0 360.0 PPDF(1) 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 PPDF(2) 45.0 45.0 45.0 45.0 45.0 45.0 45.0 45.0 PPDF(3) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 PPDF(4) 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 BIOFLG 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 BIOK5 1800.0 1800.0 1800.0 1800.0 1800.0 1800.0 1800.0 1800.0 PLTMRF 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 FULCAN 150.0 150.0 150.0 150.0 150.0 150.0 150.0 150.0 FRTC(1) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 FRTC(2) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 FRTC(3) 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 BIOMAX 700.0 700.0 700.0 700.0 700.0 700.0 280.0 650.0 PRAMN(1,1) 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 PRAMN(2,1) 150.0 150.0 150.0 150.0 150.0 150.0 150.0 150.0 PRAMN(3,1) 190.0 190.0 190.0 190.0 190.0 190.0 190.0 190.0 PRAMN(1,2) 62.5 62.5 62.5 62.5 62.5 62.5 62.5 62.5 PRAMN(2,2) 150.0 150.0 150.0 150.0 150.0 150.0 150.0 150.0 PRAMN(3,2) 150.0 150.0 150.0 150.0 150.0 150.0 150.0 150.0 PRAMX(1,1) 20.0 20.0 20.0 20.0 20.0 20.0 20.0 16.0 PRAMX(2,1) 230.0 230.0 230.0 230.0 230.0 230.0 230.0 230.0 PRAMX(3,1) 230.0 230.0 230.0 230.0 230.0 230.0 230.0 230.0 PRAMX(1,2) 125.0 125.0 125.0 125.0 125.0 125.0 125.0 95.0 PRAMX(2,2) 230.0 230.0 230.0 230.0 230.0 230.0 230.0 230.0 PRAMX(3,2) 230.0 230.0 230.0 230.0 230.0 230.0 230.0 230.0 PRBMN(1,1) 45.0 45.0 45.0 45.0 45.0 45.0 45.0 45.0 PRBMN(2,1) 390.0 390.0 390.0 390.0 390.0 390.0 390.0 390.0 PRBMN(3,1) 340.0 340.0 340.0 340.0 340.0 340.0 340.0 340.0 PRBMN(1,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PRBMN(2,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PRBMN(3,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PRBMX(1,1) 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 PRBMX(2,1) 420.0 420.0 420.0 420.0 420.0 420.0 420.0 420.0 PRBMX(3,1) 420.0 420.0 420.0 420.0 420.0 420.0 420.0 420.0 PRBMX(1,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PRBMX(2,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PRBMX(3,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 FLIGNI(1,1) 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 FLIGNI(2,1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 FLIGNI(1,2) 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 FLIGNI(2,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 HIMAX 0.5 0.5 0.45 0.45 0.4 0.35 0.35 0.0 HIWSF 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.5 HIMON(1) 2.0 2.0 2.0 2.0 2.0 2.0 3.0 3.0 HIMON(2) 1.0 1.0 1.0 1.0 1.0 1.0 2.0 2.0 EFRGRN(1) 0.75 0.75 0.75 0.75 0.75 0.75 0.5 0.7 EFRGRN(2) 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 EFRGRN(3) 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 VLOSSP 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 FSDETH(1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 FSDETH(2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 FSDETH(3) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 FSDETH(4) 500.0 500.0 500.0 500.0 500.0 500.0 500.0 500.0 FALLRT 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 RDR 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 RTDTMP 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 CRPRTF(1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CRPRTF(2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CRPRTF(3) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SNFXMX(1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 DEL13C -15.0 -15.0 -15.0 -15.0 -15.0 -15.0 -15.0 -15.0 CO2IPR(1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 CO2ITR(1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CO2ICE(1,1,1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.77 CO2ICE(1,1,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 CO2ICE(1,1,3) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 CO2ICE(1,2,1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 CO2ICE(1,2,2) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 CO2ICE(1,2,3) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 CO2IRS(1) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 Parameter E M SYBN PRDX(1) 300.0 500.0 300.0 PPDF(1) 27.0 30.0 27.0 PPDF(2) 45.0 45.0 40.0 PPDF(3) 1.0 1.0 1.0 PPDF(4) 3.0 2.5 2.5 BIOFLG 0.0 0.0 0.0 BIOK5 1800.0 1800.0 1800.0 PLTMRF 0.2 0.5 0.5 FULCAN 100.0 150.0 150.0 FRTC(1) 0.3 0.5 0.5 FRTC(2) 0.3 0.0 0.1 FRTC(3) 1.0 1.0 3.0 BIOMAX 400.0 500.0 800.0 PRAMN(1,1) 30.0 10.0 7.55 PRAMN(2,1) 390.0 150.0 150.0 PRAMN(3,1) 340.0 190.0 190.0 PRAMN(1,2) 90.0 72.5 30.0 PRAMN(2,2) 390.0 150.0 150.0 PRAMN(3,2) 340.0 190.0 190.0 PRAMX(1,1) 35.0 20.0 10.0 PRAMX(2,1) 440.0 230.0 230.0 PRAMX(3,1) 440.0 230.0 230.0 PRAMX(1,2) 95.0 95.0 40.0 PRAMX(2,2) 440.0 230.0 230.0 PRAMX(3,2) 440.0 230.0 230.0 PRBMN(1,1) 50.0 45.0 24.0 PRBMN(2,1) 390.0 390.0 390.0 PRBMN(3,1) 340.0 340.0 340.0 PRBMN(1,2) 0.0 0.0 0.0 PRBMN(2,2) 0.0 0.0 0.0 PRBMN(3,2) 0.0 0.0 0.0 PRBMX(1,1) 55.0 60.0 28.0 PRBMX(2,1) 420.0 420.0 420.0 PRBMX(3,1) 420.0 420.0 420.0 PRBMX(1,2) 0.0 0.0 0.0 PRBMX(2,2) 0.0 0.0 0.0 PRBMX(3,2) 0.0 0.0 0.0 FLIGNI(1,1) 0.05 0.12 0.12 FLIGNI(2,1) 0.0 0.0 0.0 FLIGNI(1,2) 0.06 0.06 0.06 FLIGNI(2,2) 0.1 0.0 0.0 HIMAX 0.0 0.45 0.31 HIWSF 0.0 0.0 0.0 HIMON(1) 2.0 2.0 2.0 HIMON(2) 1.0 1.0 1.0 EFRGRN(1) 0.0 0.7 0.67 EFRGRN(2) 0.0 0.6 0.6 EFRGRN(3) 0.0 0.6 0.6 VLOSSP 0.15 0.04 0.04 FSDETH(1) 0.2 0.0 0.0 FSDETH(2) 0.95 0.0 0.0 FSDETH(3) 0.2 0.0 0.0 FSDETH(4) 150.0 500.0 500.0 FALLRT 0.18 0.12 0.1 RDR 0.05 0.05 0.05 RTDTMP 2.0 2.0 2.0 CRPRTF(1) 0.0 0.0 0.0 CRPRTF(2) 0.0 0.0 0.0 CRPRTF(3) 0.0 0.0 0.0 SNFXMX(1) 0.0 0.0 0.0375 DEL13C -18.0 -15.0 -27.0 CO2IPR(1) 0.0 0.0 0.0 CO2ITR(1) 0.0 0.0 0.0 CO2ICE(1,1,1) 0.0 0.0 0.0 CO2ICE(1,1,2) 0.0 0.0 0.0 CO2ICE(1,1,3) 0.0 0.0 0.0 CO2ICE(1,2,1) 0.0 0.0 0.0 CO2ICE(1,2,2) 0.0 0.0 0.0 CO2ICE(1,2,3) 0.0 0.0 0.0 CO2IRS(1) 0.0 0.0 0.0
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Appendix 5.2. CULT.100 Parameter Values
Parameters P S C ROW R D N H CULTRA(1) 0.0 0.7 0.0 0.0 0.4 0.05 0.05 1.0 CULTRA(2) 0.1 0.25 0.5 0.0 0.4 0.05 0.05 0.0 CULTRA(3) 0.9 0.05 0.5 0.0 0.2 0.1 0.0 0.0 CULTRA(4) 0.1 0.1 0.5 0.0 0.2 0.05 0.05 0.0 CULTRA(5) 0.9 0.1 0.5 0.0 0.2 0.15 0.05 0.0 CULTRA(6) 0.9 0.1 0.5 0.5 0.2 0.2 0.05 0.0 CULTRA(7) 1.0 1.0 1.0 0.0 1.0 0.2 0.1 1.0 CLTEFF(1) 1.6 1.3 1.6 1.3 1.3 1.1 1.0 1.0 CLTEFF(2) 1.6 1.3 1.6 1.3 1.3 1.1 1.0 1.0 CLTEFF(3) 1.6 1.3 1.6 1.3 1.3 1.1 1.0 1.0 CLTEFF(4) 1.6 1.3 1.6 1.3 1.3 1.1 1.0 1.0
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Appendix 5.3. FERT.100 Parameter Values
Parameters A A90 A80 A75 FERAMT(1) 0 0 0 0 FERAMT(2) 0 0 0 0 FERAMT(3) 0 0 0 0 AUFERT 1.0 0.9 0.8 0.75 Parameters N5 N45 N3 N1 FERAMT(1) 5.0 4.5 3.0 1.0 FERAMT(2) 0 0 0 0 FERAMT(3) 0 0 0 0 AUFERT 0 0 0 0 Parameters PS1 PS2 PS3 PS4 PS5 FERAMT(1) 0 0 0 0 0 FERAMT(2) 1.125 2.25 1.75 3.5 5.25 FERAMT(3) 1.375 2.75 2.07 4.14 6.21 AUFERT 0 0 0 0 0 Parameters MAX MED FERAMT(1) 0 0 FERAMT(2) 0 0 FERAMT(3) 0 0 AUFERT 2.0 1.5
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Appendix 5.4. FIRE.100 Parameter Values
Parameters C M H FLFREM 0.6 0.7 0.8 FDFREM(1) 0.6 0.7 0.8 FDFREM(2) 0.2 0.3 0.4 FRET(1) 0.3 0.2 0.1 FRET(2) 1.0 1.0 1.0 FRET(3) 1.0 1.0 1.0 FRTSH 0.2 0.2 0.2 FNUE(1) 10.0 10.0 10.0 FNUE(2) 30.0 30.0 30.0
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Appendix 5.5. FIX.100 Parameter Values
Parameters ONLY ONE OPTION AVAILABLEADEP(1) 15 DRESP 0.999 PEFTXB 0.75 ADEP(2) 15 EDEPTH 0.2 PHESP(1) 5 ADEP(3) 15 ELITST 0.4 PHESP(2) 0.0008 ADEP(4) 15 ENRICH 2 PHESP(3) 7.6 ADEP(5) 30 FAVAIL(1) 0.9 PHESP(4) 0.015 ADEP(6) 30 FAVAIL(3) 0.5 PLIGST(1) 3 ADEP(7) 30 FAVAIL(4) 0.4 PLIGST(2) 3 ADEP(8) 30 FAVAIL(5) 0.8 PMCO2(1) 0.55 ADEP(9) 0 FAVAIL(6) 2 PMCO2(2) 0.55 ADEP(10) 0 FLEACH(1) 0.2 PMNSEC(1) 0 AGPPA -40 FLEACH(2) 0.7 PMNSEC(2) 2 AGPPB 7.7 FLEACH(3) 1 PMNSEC(3) 0 ANEREF(1) 1.5 FLEACH(4) 0 PMNTMP 0.004 ANEREF(2) 3 FLEACH(5) 0.1 PMXBIO 600 ANEREF(3) 0.4 FWLOSS(1) 0.8 PMXTMP -0.0035 ANIMPT 2 FWLOSS(2) 0.8 PPARMN(1) 0 AWTL(1) 0.8 FWLOSS(3) 0.65 PPARMN(2) 0.0001 AWTL(2) 0.6 FWLOSS(4) 0.75 PPARMN(3) 0.0005 AWTL(3) 0.4 FXMCA -0.125 PPRPTS(1) 0 AWTL(4) 0.3 FXMCB 0.005 PPRPTS(2) 1 AWTL(5) 0.2 FXMXS 0.35 PPRPTS(3) 0.8 AWTL(6) 0.2 FXNPB 7 PS1CO2(1) 0.45 AWTL(7) 0.2 GREMB 0 PS1CO2(2) 0.55 AWTL(8) 0.2 IDEF 2 PS1S3(1) 0.003 AWTL(9) 0 LHZF(1) 0.2 PS1S3(2) 0.032 AWTL(10) 0 LHZF(2) 0.4 PS2S3(1) 0.003 BGPPA 100 LHZF(3) 0.8 PS2S3(2) 0.009 BGPPB 7 MINLCH 18 PSECMN(1) 0 CO2PPM(1) 350 NSNFIX 0 PSECMN(2) 0.0022 CO2PPM(2) 700 NTSPM 4 PSECMN(3) 0.2 CO2RMP 1 OMLECH(1) 0.01 PSECOC 1E-06 DAMR(1,1) 0 OMLECH(2) 0.04 RAD1P(1,1) -8 DAMR(1,2) 0 OMLECH(3) 18 RAD1P(2,1) 3 DAMR(1,3) 0 P1CO2A(1) 0.6 RAD1P(3,1) 5 DAMR(2,1) 0 P1CO2A(2) 0.17 RAD1P(1,2) -200 DAMR(2,2) 0 P1CO2B(1) 0 RAD1P(2,2) 5 DAMR(2,3) 0 P1CO2B(2) 0.68 RAD1P(3,2) 100 DAMRMN(1) 15 P2CO2 0.55 RAD1P(1,3) -200 DAMRMN(2) 150 P3CO2 0.55 RAD1P(2,3) 5 DAMRMN(3) 150 PABRES 100 RAD1P(3,3) 100 DEC1(1) 3.9 PCEMIC(1,1) 20 RCESTR(1) 150 DEC1(2) 4.9 PCEMIC(1,2) 180 RCESTR(2) 500 DEC2(1) 14.8 PCEMIC(1,3) 150 RCESTR(3) 500 DEC2(2) 18.5 PCEMIC(2,1) 10 RICTRL 0.015 DEC3(1) 6 PCEMIC(2,2) 80 RIINT 0.8 DEC3(2) 7.3 PCEMIC(2,3) 50 RSPLIG 0.3 DEC4 0.0066 PCEMIC(3,1) 0.02 SEED -1 DEC5 0.2 PCEMIC(3,2) 0.0015 SPL(1) 0.99 DECK5 5 PCEMIC(3,3) 0.0015 SPL(2) 0.018 DLIGDF -4 PEFTXA 0.25 STRMAX(1) 500 STRMAX(2) 1000 TEXEPP(1) 1 TEXEPP(2) 0.7 TEXEPP(3) 0.0001 TEXEPP(4) 0.00016 TEXEPP(5) 2 TEXESP(1) 1 TEXESP(3) 0.004 TMAX 45 TMELT(1) 0 TMELT(2) 4 TOPT 35 TSHL 2.63 TSHR 0.2 VARAT1(1,1) 14 VARAT1(2,1) 3 VARAT1(3,1) 2 VARAT1(1,2) 100 VARAT1(2,2) 30 VARAT1(3,2) 2 VARAT1(1,3) 80 VARAT1(2,3) 20 VARAT1(3,3) 3 VARAT2(1,1) 18 VARAT2(2,1) 12 VARAT2(3,1) 2 VARAT2(1,2) 200 VARAT2(2,2) 90 VARAT2(3,2) 2 VARAT2(1,3) 200 VARAT2(2,3) 90 VARAT2(3,3) 3 VARAT3(1,1) 8 VARAT3(2,1) 6 VARAT3(3,1) 2 VARAT3(1,2) 200 VARAT3(2,2) 20 VARAT3(3,2) 2 VARAT3(1,3) 200 VARAT3(2,3) 20 VARAT3(3,3) 3 VLOSSE 0.05 VLOSSG 0.03
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Appendix 5.6. GRAZ.100 Parameter Values
Parameters GM G GCS W GL GH P FLGREM 0.1 0.25 0.9 0.15 0.1 0.3 0.6 FDGREM 0.01 0.02 0.9 0.07 0.05 0.15 0.05 GFCRET 0.3 0.3 0.25 0.3 0.3 0.3 0.2 GRET(1) 0.8 0.8 0.7 0.8 0.8 0.8 0.66 GRET(2) 0.95 0.95 0.95 0.95 0.95 0.95 0.95 GRET(3) 0.95 0.95 0.95 0.95 0.95 0.95 0.9 GRZEFF 1.0 1.0 0.0 1.0 0.0 2.0 0.0 FECF(1) 0.5 0.5 0.6 0.5 0.5 0.5 0.32 FECF(2) 0.9 0.9 0.9 0.9 0.9 0.9 0.8 FECF(3) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 FECLIG 0.25 0.25 0.25 0.25 0.25 0.25 0.25
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Appendix 5.7. HARV.100 Parameter Values
Parameters GS G R H T AGLREM 0.0 0.0 0.0 0.2 0.7 BGLREM 0.0 0.0 0.0 0.9 0.7 FLGHRV 1.0 1.0 0.0 0.0 0.0 RMVSTR 0.5 0.0 0.0 0.75 1.0 REMWSD 0.5 0.5 0.0 0.0 0.0 HIBG 0.0 0.0 0.9 0.0 1.0
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Appendix 5.8. IRRI.100 Parameter Values
Parameters A50 A25 A15 A75 A95 AF F5 FLOOD AUIRRI 1.0 1.0 1.0 1.0 1.0 2.0 0.0 0.0 FAWHC 0.75 0.25 0.15 0.75 0.95 0.25 0.0 0.0 IRRAUT 0.0 0.0 0.0 0.0 0.0 10.0 0.0 0.0 IRRAMT 0.0 0.0 0.0 0.0 0.0 0.0 5.0 15.0
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Appendix 5.9. OMAD.100 Parameter Values
Parameters M W ASTGC 100.0 100.0 ASTLBL 0.0 0.0 ASTLIG 0.25 0.15 ASTREC(1) 30.0 80.0 ASTREC(2) 300.0 300.0 ASTREC(3) 300.0 300.0
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Appendix 5.10. TREE.100 Parameter Values
Parameters HRDW CONIF CONOR PRTP HRDWD6 BFGN DECID 1.0 1.0 0.0 0.0 1.0 0.0 PRDX(2) 800.0 1500.0 800.0 800.0 300.0 680.0 PRDX(3) 300.0 400.0 300.0 300.0 3000.0 460.0 PPDF(1) 30.0 0.0 27.0 30.0 22.0 15.0 PPDF(2) 45.0 0.0 45.0 45.0 42.0 32.0 PPDF(3) 1.0 0.0 1.0 1.0 0.3 1.0 PPDF(4) 2.5 0.0 3.0 2.5 7.0 3.5 CERFOR(1,1,1) 39.3 60.0 47.0 40.0 48.0 99.0 CERFOR(1,1,2) 300.0 300.0 300.0 2122.0 745.0 300.0 CERFOR(1,1,3) 300.0 300.0 300.0 0.0 500.0 300.0 CERFOR(1,2,1) 46.9 55.0 81.0 76.0 34.0 100.0 CERFOR(1,2,2) 250.0 250.0 250.0 765.0 652.0 250.0 CERFOR(1,2,3) 250.0 250.0 250.0 0.0 500.0 250.0 CERFOR(1,3,1) 130.0 192.0 168.0 84.0 53.0 790.0 CERFOR(1,3,2) 1100.0 1100.0 1100.0 1366.0 589.0 1100.0 CERFOR(1,3,3) 1100.0 1100.0 1100.0 0.0 1000.0 1100.0 CERFOR(1,4,1) 557.0 261.0 892.0 155.0 405.0 1036.0 CERFOR(1,4,2) 4000.0 4000.0 4000.0 2260.0 2500.0 4000.0 CERFOR(1,4,3) 4000.0 4000.0 4000.0 0.0 1000.0 4000.0 CERFOR(1,5,1) 450.0 740.0 556.0 155.0 120.0 840.0 CERFOR(1,5,2) 4000.0 4000.0 4000.0 2478.0 1409.0 4000.0 CERFOR(1,5,3) 4000.0 4000.0 4000.0 0.0 1000.0 4000.0 CERFOR(2,1,1) 39.3 60.0 47.0 40.0 48.0 99.0 CERFOR(2,1,2) 300.0 300.0 300.0 2122.0 745.0 300.0 CERFOR(2,1,3) 300.0 300.0 300.0 0.0 500.0 300.0 CERFOR(2,2,1) 46.9 55.0 81.0 76.0 34.0 100.0 CERFOR(2,2,2) 250.0 250.0 250.0 765.0 652.0 250.0 CERFOR(2,2,3) 250.0 250.0 250.0 0.0 500.0 250.0 CERFOR(2,3,1) 130.0 192.0 168.0 84.0 53.0 790.0 CERFOR(2,3,2) 1100.0 1100.0 1100.0 1366.0 589.0 1100.0 CERFOR(2,3,3) 1100.0 1100.0 1100.0 0.0 1000.0 1100.0 CERFOR(2,4,1) 557.0 261.0 892.0 155.0 405.0 1036.0 CERFOR(2,4,2) 4000.0 4000.0 4000.0 2260.0 2500.0 4000.0 CERFOR(2,4,3) 4000.0 4000.0 4000.0 0.0 1000.0 4000.0 CERFOR(2,5,1) 450.0 740.0 556.0 155.0 120.0 840.0 CERFOR(2,5,2) 4000.0 4000.0 4000.0 2478.0 1409.0 4000.0 CERFOR(2,5,3) 4000.0 4000.0 4000.0 0.0 1000.0 4000.0 CERFOR(3,1,1) 39.3 60.0 47.0 40.0 48.0 99.0 CERFOR(3,1,2) 300.0 300.0 300.0 2122.0 745.0 300.0 CERFOR(3,1,3) 300.0 300.0 300.0 0.0 500.0 300.0 CERFOR(3,2,1) 46.9 55.0 81.0 76.0 34.0 100.0 CERFOR(3,2,2) 250.0 250.0 250.0 765.0 652.0 250.0 CERFOR(3,2,3) 250.0 250.0 250.0 0.0 500.0 250.0 CERFOR(3,3,1) 130.0 192.0 168.0 84.0 53.0 790.0 CERFOR(3,3,2) 1100.0 1100.0 1100.0 1366.0 589.0 1100.0 CERFOR(3,3,3) 1100.0 1100.0 1100.0 0.0 1000.0 1100.0 CERFOR(3,4,1) 557.0 261.0 892.0 155.0 405.0 1036.0 CERFOR(3,4,2) 4000.0 4000.0 4000.0 2260.0 2500.0 4000.0 CERFOR(3,4,3) 4000.0 4000.0 4000.0 0.0 1000.0 4000.0 CERFOR(3,5,1) 450.0 740.0 556.0 155.0 120.0 840.0 CERFOR(3,5,2) 4000.0 4000.0 4000.0 2478.0 1409.0 4000.0 CERFOR(3,5,3) 4000.0 4000.0 4000.0 0.0 1000.0 4000.0 DECW1 0.2 0.3 0.3 0.5 2.0 0.3 DECW2 0.0 0.0 0.0 0.1 0.6 0.0 DECW3 0.1 0.0 0.0 0.1 0.5 0.0 FCFRAC(1,1) 0.3 0.2 0.3 0.2 0.3 0.3 FCFRAC(2,1) 0.3 0.6 0.3 0.3 0.3 0.3 FCFRAC(3,1) 0.0 0.1 0.0 0.2 0.3 0.0 FCFRAC(4,1) 0.3 0.2 0.4 0.3 0.1 0.4 FCFRAC(5,1) 0.1 0.1 0.1 0.2 0.1 0.1 FCFRAC(1,2) 0.3 0.2 0.3 0.3 0.2 0.2 FCFRAC(2,2) 0.3 0.3 0.3 0.4 0.4 0.1 FCFRAC(3,2) 0.0 0.1 0.0 0.2 0.1 0.2 FCFRAC(4,2) 0.3 0.4 0.4 0.1 0.3 0.5 FCFRAC(5,2) 0.1 0.1 0.1 0.1 0.1 0.1 LEAFDR(1) 0.0 0.0 0.0 0.0 0.0 0.0 LEAFDR(2) 0.0 0.0 0.0 0.0 0.0 0.0 LEAFDR(3) 0.0 0.0 0.0 0.0 0.0 0.0 LEAFDR(4) 0.0 0.0 0.0 0.0 0.0 0.0 LEAFDR(5) 0.0 0.0 0.0 0.0 0.0 0.0 LEAFDR(6) 0.0 0.0 0.0 0.0 0.0 0.0 LEAFDR(7) 0.0 0.0 0.0 0.0 0.0 0.0 LEAFDR(8) 0.0 0.0 0.0 0.0 0.0 0.0 LEAFDR(9) 0.1 0.0 0.0 0.0 0.0 0.0 LEAFDR(10) 0.8 0.0 0.0 0.0 0.0 0.0 LEAFDR(11) 0.0 0.0 0.0 0.0 0.0 0.0 LEAFDR(12) 0.0 0.0 0.0 0.0 0.0 0.0 BTOLAI 0.008232 0.008232 0.008232 0.008232 0.008232 0.008232 KLAI 1000.0 20000.0 20000.0 1000.0 1000.0 700.0 LAITOP -0.5 -0.5 -0.5 -0.5 -0.5 -0.5 MAXLAI 4.0 20.0 20.0 4.0 4.0 4.0 MAXLDR 0.0 0.0 0.0 0.0 0.0 0.0 FORRTF(1) 0.5 0.5 0.5 0.5 0.5 0.5 FORRTF(2) 0.0 0.0 0.0 0.0 0.0 0.0 FORRTF(3) 0.0 0.0 0.0 0.0 0.0 0.0 SAPK 1500.0 5000.0 5000.0 1500.0 1500.0 1500.0 SWOLD 6.0 6.0 6.0 0.0 10.0 0.0 WDLIG(1) 0.2 0.2 0.2 0.2 0.2 0.2 WDLIG(2) 0.3 0.2 0.2 0.2 0.3 0.2 WDLIG(3) 0.3 0.3 0.4 0.3 0.3 0.4 WDLIG(4) 0.2 0.4 0.4 0.4 0.3 0.4 WDLIG(5) 0.2 0.4 0.4 0.4 0.3 0.4 WOODDR(1) 0.0 0.0 0.0 0.0 0.0 0.0 WOODDR(2) 0.1 0.1 0.1 0.1 0.0 0.1 WOODDR(3) 0.0 0.0 0.0 0.0 0.0 0.0 WOODDR(4) 0.0 0.0 0.0 0.0 0.0 0.0 WOODDR(5) 0.0 0.0 0.0 0.0 0.0 0.0 SNFXMX(2) 0.0 0.0 0.0 0.0 0.0 0.0 DEL13C 0.0 0.0 0.0 0.0 0.0 0.0 CO2IPR(2) 0.0 0.0 0.0 0.0 0.0 0.0 CO2ITR(2) 0.0 0.0 0.0 0.0 0.0 0.0 CO2ICE(2,1,1) 0.0 0.0 0.0 0.0 0.0 0.0 CO2ICE(2,1,2) 0.0 0.0 0.0 0.0 0.0 0.0 CO2ICE(2,1,3) 0.0 0.0 0.0 0.0 0.0 0.0 CO2ICE(2,2,1) 0.0 0.0 0.0 0.0 0.0 0.0 CO2ICE(2,2,2) 0.0 0.0 0.0 0.0 0.0 0.0 CO2ICE(2,2,3) 0.0 0.0 0.0 0.0 0.0 0.0 CO2IRS(2) 0.0 0.0 0.0 0.0 0.0 0.0 BASFC2 1.0 1.0 1.0 1.0 1.0 1.0 BASFCT 40.0 400.0 400.0 400.0 400.0 400.0 SITPOT 4800.0 2400.0 4800.0 2400.0 2400.0 2400.0
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Appendix 5.11. TREM.100 Parameter Values
Parameters SAMP EVNTYP 0.0 REMF(1) 0.2 REMF(2) 0.1 REMF(3) 0.1 REMF(4) 0.6 REMF(5) 0.2 FD(1) 0.0 FD(2) 0.0 RETF(1,1) 0.8 RETF(1,2) 0.8 RETF(1,3) 0.8 RETF(1,4) 0.0 RETF(2,1) 0.8 RETF(2,2) 0.8 RETF(2,3) 0.8 RETF(2,4) 0.0 RETF(3,1) 0.8 RETF(3,2) 0.8 RETF(3,3) 0.8 RETF(3,4) 0.0
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Appendix 5.12. <SITE.100> Parameter Values
Parameters Only one option allowed Climate values TMX2M(3) 10.60 EPNFS(1) -0.92 PRECIP(1) 1.00 TMX2M(4) 16.20 EPNFS(2) 0.03 PRECIP(2) 0.85 TMX2M(5) 21.60 SATMOS(1) 0.00 PRECIP(3) 2.00 TMX2M(6) 27.50 SATMOS(2) 0.00 PRECIP(4) 3.05 TMX2M(7) 31.40 SIRRI 0.00 PRECIP(5) 5.95 TMX2M(8) 30.30 Organic matter values PRECIP(6) 4.45 TMX2M(9) 25.70 SOM1CI(1,1) 56.00 PRECIP(7) 3.20 TMX2M(10) 19.10 SOM1CI(1,2) 0.00 PRECIP(8) 2.95 TMX2M(11) 10.60 SOM1CI(2,1) 60.00 PRECIP(9) 3.00 TMX2M(12) 5.90 SOM1CI(2,2) 15.00 PRECIP(10) 1.90 Site and control SOM2CI(1) 3700.00 PRECIP(11) 1.20 IVAUTO 1.00 SOM2CI(2) 0.00 PRECIP(12) 0.80 NELEM 1.00 SOM3CI(1) 2150.00 PRCSTD(1) 0.68 SITLAT 39.52 SOM3CI(2) 0.00 PRCSTD(2) 0.78 SITLNG 104.60 RCES1(1,1) 10.00 PRCSTD(3) 1.77 SAND 0.20 RCES1(1,2) 50.00 PRCSTD(4) 2.73 SILT 0.30 RCES1(1,3) 50.00 PRCSTD(5) 4.98 CLAY 0.50 RCES1(2,1) 10.00 PRCSTD(6) 4.17 BULKD 1.20 RCES1(2,2) 50.00 PRCSTD(7) 2.57 NLAYER 5.00 RCES1(2,3) 50.00 PRCSTD(8) 2.58 NLAYPG 5.00 RCES2(1) 17.00 PRCSTD(9) 2.91 DRAIN 0.50 RCES2(2) 117.00 PRCSTD(10) 1.99 BASEF 0.30 RCES2(3) 117.00 PRCSTD(11) 1.07 STORMF 0.60 RCES3(1) 7.00 PRCSTD(12) 0.97 SWFLAG 1.00 RCES3(2) 62.00 PRCSKW(1) 0.00 AWILT(1) 0.20 RCES3(3) 62.00 PRCSKW(2) 0.00 AWILT(2) 0.20 CLITTR(1,1) 100.00 PRCSKW(3) 0.00 AWILT(3) 0.20 CLITTR(1,2) 0.00 PRCSKW(4) 0.00 AWILT(4) 0.20 CLITTR(2,1) 100.00 PRCSKW(5) 0.00 AWILT(5) 0.20 CLITTR(2,2) 0.00 PRCSKW(6) 0.00 AWILT(6) 0.20 RCELIT(1,1) 66.00 PRCSKW(7) 0.00 AWILT(7) 0.20 RCELIT(1,2) 300.00 PRCSKW(8) 0.00 AWILT(8) 0.20 RCELIT(1,3) 300.00 PRCSKW(9) 0.00 AWILT(9) 0.20 RCELIT(2,1) 66.00 PRCSKW(10) 0.00 AWILT(10) 0.20 RCELIT(2,2) 300.00 PRCSKW(11) 0.00 AFIEL(1) 0.30 RCELIT(2,3) 300.00 PRCSKW(12) 0.00 AFIEL(2) 0.30 AGLCIS(1) 0.00 TMN2M(1) -11.00 AFIEL(3) 0.30 AGLCIS(2) 0.00 TMN2M(2) -8.40 AFIEL(4) 0.30 AGLIVE(1) 0.00 TMN2M(3) -4.90 AFIEL(5) 0.30 AGLIVE(2) 0.00 TMN2M(4) -0.20 AFIEL(6) 0.30 AGLIVE(3) 0.00 TMN2M(5) 5.10 AFIEL(7) 0.30 BGLCIS(1) 0.00 TMN2M(6) 9.90 AFIEL(8) 0.30 BGLCIS(2) 0.00 TMN2M(7) 13.50 AFIEL(9) 0.30 BGLIVE(1) 3.60 TMN2M(8) 12.30 AFIEL(10) 0.30 BGLIVE(2) 0.45 TMN2M(9) 7.00 PH 6.80 BGLIVE(3) 0.45 TMN2M(10) 0.80 PSLSRB 1.00 STDCIS(1) 50.00 TMN2M(11) -5.30 SORPMX 100.00 STDCIS(2) 0.00 TMN2M(12) -9.50 External nutrients STDEDE(1) 0.80 TMX2M(1) 4.70 EPNFA(1) 0.21 STDEDE(2) 0.20 TMX2M(2) 7.50 EPNFA(2) 0.00 STDEDE(3) 0.20 Forest organic matter MINERL(6,2) 0.00 RLVCIS(1) 0.00 MINERL(7,2) 0.00 RLVCIS(2) 0.00 MINERL(8,2) 0.00 RLEAVE(1) 0.00 MINERL(9,2) 0.00 RLEAVE(2) 0.00 MINERL(10,2) 0.00 RLEAVE(3) 0.00 MINERL(1,3) 0.50 FBRCIS(1) 0.00 MINERL(2,3) 0.00 FBRCIS(2) 0.00 MINERL(3,3) 0.00 FBRCHE(1) 0.00 MINERL(4,3) 0.00 FBRCHE(2) 0.00 MINERL(5,3) 0.00 FBRCHE(3) 0.00 MINERL(6,3) 0.00 RLWCIS(1) 0.00 MINERL(7,3) 0.00 RLWCIS(2) 0.00 MINERL(8,3) 0.00 RLWODE(1) 0.00 MINERL(9,3) 0.00 RLWODE(2) 0.00 MINERL(10,3) 0.00 RLWODE(3) 0.00 PARENT(1) 0.00 FRTCIS(1) 0.00 PARENT(2) 50.00 FRTCIS(2) 0.00 PARENT(3) 50.00 FROOTE(1) 0.00 SECNDY(1) 0.00 FROOTE(2) 0.00 SECNDY(2) 15.00 FROOTE(3) 0.00 SECNDY(3) 2.00 CRTCIS(1) 0.00 OCCLUD 0.00 CRTCIS(2) 0.00 Water initial values CROOTE(1) 0.00 RWCF(1) 0.00 CROOTE(2) 0.00 RWCF(2) 0.00 CROOTE(3) 0.00 RWCF(3) 0.00 WD1CIS(1) 0.00 RWCF(4) 0.00 WD1CIS(2) 0.00 RWCF(5) 0.00 WD2CIS(1) 0.00 RWCF(6) 0.00 WD2CIS(2) 0.00 RWCF(7) 0.00 WD3CIS(1) 0.00 RWCF(8) 0.00 WD3CIS(2) 0.00 RWCF(9) 0.00 W1LIG 0.30 RWCF(10) 0.00 W2LIG 0.30 SNLQ 0.00 W3LIG 0.30 SNOW 0.00 Mineral initial values MINERL(1,1) 0.25 MINERL(2,1) 0.00 MINERL(3,1) 0.00 MINERL(4,1) 0.00 MINERL(5,1) 0.00 MINERL(6,1) 0.00 MINERL(7,1) 0.00 MINERL(8,1) 0.00 MINERL(9,1) 0.00 MINERL(10,1) 0.00 MINERL(1,2) 0.50 MINERL(2,2) 0.00 MINERL(3,2) 0.00 MINERL(4,2) 0.00 MINERL(5,2) 0.00
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A Message from the CENTURY Crew
Dear CENTURY user,
Thank you for your interest in the CENTURY model. Since the publication the
century version 4.0 manual, there have been some substantial changes to the
model. This letter describes the changes to the model, and corrects some
errors in the manual. The version of the model available to you is not linked
to the Time-Zero output module described in the manual. This is known as the
stand-alone version of the model. Now, the PC and UNIX stand-alone versions
of the model are identical in function, so the directions for
"Executing the UNIX Stand-Alone Version
(section 6.3, page 6-2) should be followed for the version
you have. Because this is the stand-alone version of the model, you will
need List100 (our binary-to-ASCII translation utility)
in addition to the CENTURY, File100, and
Event100 executables. It will be necessary to use
the model in combination with a spreadsheet, graphics, or statistical package
because this version does not include the output module.
CENTURY and its component programs may be obtained via ftp:
ftp ftp.nrel.colostate.edu
Login : anonymous
password : <your email address>
cd CENT/CENTURY4.0/SRC (for UNIX source code)
cd CENT/CENTURY4.0/CENTX (for PC executable)
****remember to use a binary transfer for executable files and an ASCII transfer for everything else****
Multiple fix.100 files: The model now uses biome-
specific fix.100 files. These files differ primarily
in the FWLOSS(x) parameters that adjust the relative
impact of a PET equation originally developed for the
Tropics (further described on page 3-4, 2nd
paragraph under heading 3.3). Select the appropriate fix file for your
site from the list below, and copy it to "fix.100" before running your
simulation. (When simulating a savanna, use the fix file that corresponds to
the grass component of your system)
arcfix.100: arctic tundra
dryffix.100: dry forest
ffix.100: forest
trpfix.100: tropical
borfix.100: boreal forest
drygfix.100: dry grassland
gfix.100: mesic/subhumid grassland
Page 3-4, 1st paragraph under heading 3.3: The final
sentence should read
"Snow melt occurs if the average air temperature is greater than
TMELT(1) and is a linear function of the average air
temperature.
Section 3.7.3, page 3-32: Savanna submodel - many
CENTURY users have asked for clarification of the variable
SITPOT. It was originally conceived as a measure of the
aboveground herbaceous layer production in kg ha-1 yr-1 in the absence of
trees (SITPOT = 2400 * monthly N availability [in gN m-2
yr-1])
Page 3-43, 2nd paragraph, 3rd line from the bottom: "POM
(partial organic matter)" should read "POM (particulate organic
matter)".
Page 8-1: In the Burke et al. reference, "context"
should be "content".
Appendix 2.1:
prdx(1): g biomass/m²/month
bioflg: is a continuous measure ranging from 0 to 1
crprtf(x): this nutrient is transferred to a "vegetation
storage pool"
Appendix 2.3:
feramt(x): amount of E to be added (g E / m²) in
scheduled month
Appendix 2.4:
ffcret is no longer included in the file, so this parameter will need to be
removed from your existing fire.100 files
fret(x) should say: fraction of E in the burned
aboveground material returned to the soil following a fire event
Appendix 2.5:
tmax through tshr have been changed.
The new list is: teff(1), teff(2), teff(3), tmelt(1), tmelt(2). The
tmelt(x) parameters retain their previous definitions,
while the teff(x) parameters are defined by:
tcalc = teff(1) + teff(2) * exp (teff(3) * stemp)
teff(1) = intercept
teff(2) = slope
teff(3) = exponent (Q10)
tcalc is the temperature component of defac
tmax, topt, tshr
are no longer used
So, be sure to download the new biome-specific fix.100
files from our ftp site.
dec1(1) through dec5 = decomposition
rate. The fraction of the pool that turns over each year.
Appendix 2.10:
decid: 0 = evergreen
1 = temperature-deciduous
2 = drought-deciduous
btolai is a biome-specific parameter. Values we use
locally are:
arctic tundra 0.008
boreal forest 0.004
maritime coniferous forest 0.004
temperate coniferous forest 0.004
coniferous/deciduous mix forest 0.007
warm temperate deciduous forest 0.01
tropical evergreen forest 0.01
arid savanna/shrubland 0.007
temperate coniferous savanna 0.004
tropical savanna 0.006
temperate deciduous savanna 0.01
temperate mixed savanna 0.007
grassland 0.008
wooddr(1) controls the proportion of leaves that drop
when decid = 1 or 2.
This is especially useful for drought-deciduous systems where only a portion
of the leaves drop. Also useful when you are attempting to simulate a
deciduous/coniferous mixed system.
Appendix 2.11:
remf(x): dead fine branches should be remf(4)
Appendix 2.12:
sitlat is used in the pet
calculation, so it is not just for reference
Appendix 2.13:
relyld has been removed as an output option
rlvacc should say: "growing season accumulator for C
production in forest leaf compartment"
woodc: sum of C in dead components of forest system
(g/m²)
If you are interested in previous applications of the model, check the list of
abstracts and journal articles using CENTURY here on our web page. If you have
any CENTURY-related questions email us <century@nrel.colostate.edu>.
This is checked regularly, and answers are generally provided within a week.
If you do not have access to email or are unable to use ftp, please feel free
to contact Robin Kelly by telephone (970.491.2343) or fax ([attn: R. Kelly]
970.491.1965). Technical support for the CENTURY model is provided on a time-
available basis, and this limited support is available only to users who have
thoroughly read the CENTURY version 4.0 manual.
Because all CENTURY results (favorable or not) help us to improve the model,
we would appreciate a copy of any reports, abstracts, or manuscripts resulting
from the use of CENTURY. When possible, the inclusion of "CENTURY model" in
the list of key words or phrases improves our ability to track the use of the
model. CENTURY is protected by a United States copyright to Colorado State
University (1993), all rights reserved. We ask that you do not provide copies
of the model, source code, or manual to colleagues unless you contact us
directly about doing so. Any such copies should be accompanied by this
letter.
On behalf of the entire CENTURY group, thank you again for your interest in
the model.
Bill Parton
Dennis Ojima
Dave Schimel
Robin Kelly
Becky McKeown
Melannie Hartman
Bill Pulliam
Cindy Keough
Becky Techau
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