COMET-Tools were created as a function of USDA’s Quantifying Greenhouse Gas Fluxes in Agriculture (we call it the “Blue Book”) which defines all of the methods and models used in both COMET-Farm and Planner. COMET-Farm allows for a flexible, field specific conservation scenario analysis because users enter specific management details to their up to 20-year baseline. COMET-Planner (created later) implements a fixed baseline rendered through random cropland and grassland sample points from the MLRA’s around the country. Then, regionally specific crop rotations were constructed from USDA-NASS Cropland Data back until 2008, in addition to survey data for average fertilizer use, planting, and harvest dates. This is used to construct the fixed baseline in COMET-Planner for what are typical management practices in a given region. This significantly decreases the data entry load for users compared to COMET-Farm, but is not as field specific.
COMET-Farm allows for users to input specific management changes to their future scenario to compare against the baseline. Both COMET-Farm and COMET-Planner are run through the COMET-Farm analysis platform implementing the Daycent and Empirical Models necessary for the conservation scenario analysis. However, because COMET-Planner has a fixed baseline, the outputs reported in COMET-Planner only display the changes in emissions/carbon sequestration from the management changes where as COMET-Farm allows users to see the emission/reductions and carbon sequestration estimates from the baseline if they had continued their original management scenario.