Computerized calculations may soon help ranchers in the central Great Plains determine which cattle or sheep stocking rate scenarios are sustainable. The Great Plains Framework for Agricultural Resource Management Range computer model is the possible key to success. GPFARM would allow ranchers to test various scenarios involving forage yields and the weight gains of beef cattle and calves and other livestock under various stocking and weather scenarios.
Soil scientists Gale Dunn and Laj Ahuja with USDA's Agricultural Research Service are testing the model in enough locations to get the model fully usable throughout the central Great Plains. GPFARM-Range is one of a few range models that can factor in the effects of climate change on stocking rates, predicting the response of forage plants to increased carbon dioxide and higher temperatures.
Most recent tests of the model were on sheep pastures in Miles City, Montana, and beef cattle pastures at Fort Supply, near Woodward, Oklahoma. The Oklahoma tests taught scientists to account for forage yield losses from soil compaction at higher stocking rates.