Estimation of green water footprint of animal feed for beef cattle production in Southern Great Plains

The goal of our study is to safeguard and promote regional beef production while mitigating its environmental footprint. Conducting a Life Cycle Analysis (LCA) including green water footprint (GWF) is one of the objectives. This manuscript describes the estimation of GWF of animal feed crops including grasses of native range and introduced pasture, winter pasture and small grains typical to Southern Great Plains. The estimates are based on modeled evapotranspiration from Agricultural Policy Environmental Extender (APEX) model under Nutrient Tracking Tool (NTT) framework. NTT simulated crop growth, water balance, animal grazing, and manure management using 47 years of weather data from 1960. Our results aggregated by county indicate grasses in the native range and field crops used as winter pasture show smaller GWF than grasses in the introduced pasture and small grains. Animal stocking rate appears to be directly correlated with water requirement to produce a unit quantity of forage.