ABSTRACT
Wilson stated that the Great Plains and the Corn Belt regions of the Central United States have gone under extensive ecological disturbance by the conversion of native ecosystems to agricultural lands. This chapter presents the approach used to simulate the historical pattern of soil organic carbon (SOC). It discusses the assumptions that were made for historical agronomic and agricultural production practices that formed the basis of CENTURY model simulation runs. The basic premise was that adjusting CENTURY model parameters to accurately portray historical crop yield data, and using reasonable assumptions for historical tillage and management practices, would result in accurate estimates of carbon inputs into the soil environment. In agricultural systems, changes in soil carbon depend on soil texture, regional climate, and carbon inputs to the soil, which are determined by cropping practices, crop yields, and management, i.e., rotations, tillage, fertilizer applications, residue/harvest practices.
