Technical Abstract: The Great Plains is generally defined as North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, the Texas Panhandle, the southern part of Manitoba, Canada, and eastern regions of Colorado, Wyoming, and Montana. Throughout the Great Plains, agricultural production is limited by soil water and nutrient availability. Using and supplementing these resources to enhance production without damaging the environment is a major challenge. To meet this challenge, the GPFARM DSS was developed. GPFARM provides crop/livestock management support at the whole farm and ranch level with emphasis on water, nutrient, and pesticide management. In addition, GPFARM has strong links to economic and environmental analysis, site database generation, and site-specific management from which alternative farm and ranch agricultural management strategies can be developed and tested.