Evaluating Greenhouse Gas Emissions from Swine Production in Central Iowa Using Comet-FarmTM.

COMET-Farm^TM is an integrated web-based decision support tool developed in collaboration with and support from the NRCS and USDA to aid farmers, agricultural producers, natural resource professionals, land managers and conservationists in making land and livestock management decisions regarding greenhouse gas emissions and carbon sequestration. COMET-Farm^TM provides total farm, ranch and woodlot greenhouse gas accounting, including cropland, pasture, range, agroforestry, forestry, livestock and on-farm/ranch energy use modules.  The impact of greenhouse gas emissions from livestock management are well understood in the agricultural sector. Using COMET-Farm^TM, livestock producers can accurately assess current greenhouse gas emissions against emissions under various conservation scenarios to determine the relative greenhouse gas balances of each.  Methane from enteric fermentation as well as methane and nitrous oxide emissions from housing and manure management are estimated using the methods set forth in the USDA document, Quantifying Greenhouse Gas Fluxes in Agriculture and Forestry: Methods for Entity-Scale Inventory using detailed animal and feed characteristics. To showcase the tools capabilities, conservation scenarios are contrasted in real-world swine production systems in central Iowa, demonstrating how on-farm practices influence the greenhouse gas flux from livestock production systems.