This document describes the files used for the N deposition and herbivory Century runs discussed in Throop et al. (2004).
cent_insectherb.exe This version of Century 4 includes new grazing functions that simulate insect herbivory (as described in Throop et al. 2004). The functions differ from previously described grazing functions in the equations used for calculating flgrem (the fraction of live shoots removed by a grazing event).
Grzeff 7: flgrem = (0.2889 * exp(-0.0213 * C/N)); decreased CN positively affects flgrem, no effect on root:shoot (this is the positive consumption response of Throop et al.)
Grzeff 8: same as greff 7, but herbivory has a linear effect on root:shoot
Grzeff 9: flgrem = (0.0365 * exp(0.0224 * C/N)); decreased CN negatively affects flgrem, no effect on root:shoot (this is the negative consumption response of Throop et al.)
Grzeff 10: same as greff 9, but herbivory has a linear effect on root:shoot
Grzeff 11: flgrem = (0.2889*(EXP(-0.0213*C/N)))*((popslp*C/N)+popint); decreased CN positively affects flgrem and affects herbivore population size, no effect on root:shoot (this is the population response of Throop et al.)
Grzeff 12: same as grzeff 11, but herbivory has a linear effect on root:shoot
This version of Century produces an additional output file, graz.out, when a simulation is run. The output of this file can be used to check the intensity of grazing.
file100.exe
The FILE100 program can be used to modify the *.100 files. No changes have been made to the this file from the Century 4 version.
event100.exe
The FILE100 program can be used to create and modify schedule files. No changes have been made to the this file from the Century 4 version.
ndep1_gz11a.sch
This is an example of a schedule file used for the Throop et al (2004) simulations. This file schedules insect herbivory using the population response function with 10kg ha-1 yr-1 of N deposition.
crop.100
This file contains the "E2" crop parameterization that simulates Ambrosia artemisiifolia production as described in Throop et al. (2004).
fert.100
This file includes the N deposition simulation used by Throop et al (2004). There are 10 possible fertilization routines:
NDEP1 Simulates 10kg ha-1 yr-1 of N addition added as 12 equal monthly allotments.
NDEP2 Simulates 20kg ha-1 yr-1 of N addition added as 12 equal monthly allotments.
NDEP3 Simulates 30kg ha-1 yr-1 of N addition added as 12 equal monthly allotments.
NDEP4 Simulates 40kg ha-1 yr-1 of N addition added as 12 equal monthly allotments.
NDEP Simulates 50kg ha-1 yr-1 of N addition added as 12 equal monthly allotments.
NDEP6 Simulates 60kg ha-1 yr-1 of N addition added as 12 equal monthly allotments.
NDEP7 Simulates 70kg ha-1 yr-1 of N addition added as 12 equal monthly allotments.
NDEP8 Simulates 80kg ha-1 yr-1 of N addition added as 12 equal monthly allotments.
NDEP9 Simulates 90kg ha-1 yr-1 of N addition added as 12 equal monthly allotments.
NDP10 Simulates 100kg ha-1 yr-1 of N addition added as 12 equal monthly allotments.
graz.100
The modified version of Century requires a modified graz.100 file because there are several new variables used for the insect herbivory routines
The new variables are:
agcnmx - This is the maximum aboveground live CN ratio at which flgrem responds dynamically to changes in aglcn. If aglcn is above agcnmx, flgrem is static at 0.1. (In Throop et al. agcnmx = 50)
popslp - This is the slope of the equation describing the effect of changes in C:N on herbivore populations. (In Throop et al. popslp = -0.3211)
popint - This is the intercept of the equation describing the effect of changes in C:N on herbivore populations. (In Throop et al. popint = 17.069)
This graz.100 file contains four different grazing routines which correspond to the four different grazing functions used by Throop et al. (2004).
GZ1a Constant consumption response function (grzeff = 1)
GZ7a Positive consumption response function (grzeff = 7)
GZ9a Negative consumption response function (grzeff = 9)
GZ11a Population response function (grzeff = 11)
fix.100
The file contains the fixed parameters used in CENTURY.
c4grs.100
Site file for C4 grassland (Konza Prairie) used in Throop et al. simulations.
list100.exe
The LIST100 program can be used to extract the needed output from the binary file produced in the simulation run. No changes have been made to the this file from the Century 4 version.
This information was last updated on January 29, 2004.