Project Number: 5402-61660-006-08
Project Type: Grant

Start Date: Sep 15, 2008
End Date: Jul 14, 2009

Objective:
Calibrate and validate the GPFARM/OMS-range model for herd management under drought conditions with experimental data from three range research stations in the Great Plains.

Approach:
In 2006 ARS entered into a partnership agreement with USDA-Risk Management Agency (RMA) to develop drought management decision support tools for ranchers in 7 western states. This objective matches the Unit¿s research project objective to deliver decision support tools to farmers and ranchers dealing with limited water conditions. To accomplish the mission of the partnership this approach will be followed: GPFARM/OMS-Range will be applied to field data from three ARS range research locations, Cheyenne, WY, Miles City, MT, and Woodward, OK. These locations provide information on three different range ecosystems: short-, mixed-, and tall-grass prairies. Data previously collected from these locations will need to be collated and prepared for use in GPFARM/OMS-Range. Using some of the field data from each location to calibrate the model and the rest of the data to validate the model, regionalized models will be created. The regional models will then be used to evaluate forage growth under different drought scenarios. Output from these simulations will be reduced to coefficients to be applied to monthly precipitation for prediction of forage production. Regression analysis will be used to evaluate drought affects on the different forage functional groups and determine carryover effect from year to year. This information will be used in a drought management decision support tool designed to help ranchers evaluate possible outcomes drought may have on their herd and herd numbers.