Modeling the Net Ecosystem Carbon Balance and Net Ecosystem Exchange of Agroecosystems of the Mid-Continent Intensive Campaign Region during 2000-2008

The terrestrial ecosystem model EPIC (Environment Policy Integrated Climate) is used to simulate the Net Ecosystem Carbon Balance (NECB) and Net Ecosystem Exchange (NEE) in the Mid-Continent Intensive Campaign Region during 2000-2008. EPIC simulates NECB as the difference between C additions (surface and subsurface litter, organic amendments) and C losses (harvest, heterotrophic respiration, soil erosion, and leaching), and NEE as the difference between net primary productivity and heterotrophic respiration. We used the USDA Crop Data Layer to delineate croplands and pasturelands, NCEP Reanalysis data to construct weather files, the SSURGO database to build soil layer files, the NRI database to build management files, and the CTIC database to capture the evolution of tillage practices during the study period. Each site is simulated multiple times by varying input parameters in order to estimate output uncertainty. Simulations of NECB and NEE are aggregated to and reported at the county scale in order to be compared with C flux results obtained using atmospheric inversion methods.