Modeling Impact of Agricultural Practices on Soil C and N2O Emissions

Soil organic carbon (SOC) generally decreases with cultivation, and the carbon lost from soil transfers into atmospheric carbon dioxide (CO₂), a greenhouse gas. Meanwhile agricultural activities also enhance nitrous oxide (N₂O), another greenhouse gas, emissions from soils. Based on reviewing the literature, a process-oriented simulation model, denitrification and decomposition (DNDC), was recently developed for predicting effects of agricultural practices on carbon (C) and nitrogen (N) dynamics and N₂O evolution in soils. DNDC model is driven by climate scenarios. Impact of reduced tillage on CO₂ and N₂O emissions and SOC storage change was computed for conservation tillage (CT) and no-till (NT). Reducing tillage may decrease decomposition rate, and reduce CO₂ emission and the production of inorganic dissolved nitrogen in soil. Planting winter-cover crop increased the amount of residue produced and, hence, increased SOC input. The yield of winter-cover crop was related to soil fertility and climate.