Optimal Crop Choice and Water Allocation in the Texas High Plains

The Texas High Plains is one of the most important agricultural regions in the US. Major irrigated crops in this region include cotton, corn, and grain sorghum. This region depends heavily on the Ogallala Aquifer for its irrigation water supply. Subsequently, irrigation water use efficiency is a major concern in the region due to dwindling water supplies from the aquifer. Since commodity prices vary considerably and each commodity’s response to irrigation differs, simultaneously identifying the profit maximizing irrigation level for each crop and optimal land allocation to maximize farm profitability, particularly under limited water availability, is a complex task. This study used the cotton, corn, and grain sorghum production functions reported for the region and a range of price scenarios to maximize farm level profit by simultaneously optimizing irrigation level and crop choice using Excel Solver with the Generalized Reduced Gradient Non-linear Algorithm. The percentage of land allocated to each crop was estimated for low (12 inches), medium (18 inches), and high (24 inches) seasonal rainfall scenarios assuming an additional 15 acre-inches of water available from irrigation. The results provided optimal crop combinations at current prices and switching points for the crops in response to changing commodity prices.