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Crop Residue Returns and Equilibrium Soil Organic Carbon in England and Wales
- Webb, J., Bellamy, P., Loveland, P. J., Goodlass, G.
- Soil Science Society of America journal 2003 v.67 no.3 pp. 928-936
- arable soils, clay, climate change, crop residues, crop yield, grains, issues and policy, pollution, simulation models, soil organic carbon, temperature, England, Wales
- Increased temperatures caused by climatic change may increase the turnover of soil organic matter (SOM) and hence reduce soil organic C (SOC). This effect may be exacerbated if crop yields decrease in consequence of policies that limit fertilizer-N applications to reduce N pollution from agriculture. Model simulations were made of changes in SOC over 140 yr under three fertilizer-N regimes to examine the effects of changes in fertilizer-N use on SOC in arable soils in England and Wales (E&W). The RothC model was used in preference to CENTURY as the input fertilizer-N could be changed in RothC and could not in CENTURY. Results indicate that decreasing annual fertilizer-N use to 50 or 100 kg ha less than is currently applied to cereals in E&W will have a negligible impact on SOC in arable soils over the next 140 yr. Soils with >180 g kg clay with 16 to 27 g kg SOC at the beginning of the model runs, were predicted to have about 21 to 23 g kg SOC after 140 yr, while soils with <180 g kg clay and about 12 g kg SOC would change little over 140 yr. Increases in temperature because of climate change were predicted to reduce SOC concentrations to about 18 to 20 and 11 g kg respectively.