Models to Evaluate Soil Organic Matter Storage and Dynamics

This chapter discusses the soil organic matter (SOM) models have been used as tools to improve our understanding about nutrient cycling and SOM dynamics, and how these models have been used as policy and management tools to evaluate the long-term implication of different management practices. One of the difficulties encountered in studies of SOM dynamics has been the lack of a physical or chemical methods to isolate directly the various organic matter pools suggested by various decomposition studies. Field and model results suggest that the major impact of tillage on SOM dynamics isincreased decay rates due to stirring of the soil and alterations of soil microclimate which impacts the decomposition rate of the SOM pools. The direct effect of climatic change on plant production is to increase production for most regions with the exception of the extreme continental steppe regions where production decreased dramatically.