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| Publication Title: | Soil management effects on organic C in isolated fractions of a Gray Luvisol |
| Authors: |
Alain F. Plante, Colorado State University Catherine E. Stewart, Colorado State University Richard T. Conant, Colorado State University Keith Paustian, Colorado State University Johan Six, Colorado State University |
| Publication Abstract: | Agricultural management affects soil organic matter, which is important for sustainable crop production and as a greenhouse gas sink. Our objective was to determine how tillage, residue management and N fertilization affect organic C in unprotected, and physically, chemically and biochemically protected soil C pools. Samples from Breton, Alberta were fractionated and analysed for organic C content. As in previous reports, N fertilization had a positive effect, tillage had a minimal effect, and straw management had no effect on whole-soil organic C. Tillage and straw management did not alter organic C concentrations in the isolated C pools, while N fertilization increased C concentrations in all pools. Compared with a woodlot soil, the cultivated plots had lower total organic C, and the C was redistributed among isolated pools. The free light fraction and coarse particulate organic matter responded positively to C inputs, suggesting that much of the accumulated organic C occurred in an unprotected pool. The easily dispersed silt-sized fraction was the mineral-associated pool most responsive to changes in C inputs, whereas the microaggregate-derived silt-sized fraction best preserved C upon cultivation. These findings suggest that the silt-sized fraction is important for the long-term stabilization of organic matter through both physical occlusion in microaggregates and chemical protection by mineral association. |
| Publication File: | 17_pub.php |
| Full Citation: | Plante, A., C. Stewart, R. Conant, K. Paustian, and J. Six. 2006. Soil management effects on organic C in isolated fractions of a Gray Luvisol. Canadian Journal of Soil Science 86:141-151. |