Field-level Estimation of Full GHG Impacts for Cropland, Grassland and Agroforestry

The COMET-VR decision support system is a user-friendly web-based tool that provides estimates of net greenhouse gas emissions at the field scale, within the US. It was originally develop to support the voluntary reporting of emissions and emissions mitigation to the US 1605B system, by individual agricultural producers. A new version of the model adds horticultural (e.g. orchards, vineyards), specialty crops (e.g. rice, sugarcane, vegetables) and agroforestry practices (e.g. windbreaks, riparian woodlands), to the previous model representations of field crop, pasture, hay and CRP agroecosystems. In addition to estimates of soil carbon stock and in-field fossil C emission estimates, the new version includes woody biomass C storage estimates and soil nitrous oxide emissions. The tool includes statistically based estimates of uncertainty for soil C stock changes and N₂O emissions in annual crops, hay, pasture and rangeland systems. Examples of model application for a diverse suite of land conservation practices are presented.