DNDC: A process-based model of greenhouse gas fluxes from agricultural soils

The high temporal and spatial variability of agricultural nitrous oxide (N2O) emissions from soil makes their measurement at regional or national scales impractical. Accordingly, robust process-based models are needed. Several detailed biochemical process-based models of N-gas emissions have been developed in recent years to provide site-specific and regional scale estimates of N2O emissions. Among these DNDC (Denitrification–Decomposition) simulates carbon and nitrogen biogeochemical cycles occurring in agricultural systems. Originally developed as a tool to predict nitrous oxide (N2O) emissions from cropping systems, DNDC has since been expanded to include other ecosystems such as rice paddies, grazed pastures, forests, and wetlands, and the model accounts for land-use and land-management effects on N2O emissions. As a process-based model, DNDC is capable of predicting the soil fluxes of all three terrestrial greenhouse gases: N2O, carbon dioxide (CO2), and methane (CH4), as well as other important environmental and economic indicators such as crop production, ammonia (NH3) volatilisation and nitrate (NO3−) leaching. The DNDC model has been widely used internationally, including in the EU nitrogen biogeochemistry projects NOFRETETE and NitroEurope. This paper brings together the research undertaken on a wide range of land-use and land-management systems to improve and modify, test and verify, and apply the DNDC model to estimate soil–atmosphere exchange of N2O, CH4 and CO2 from these systems.