Organization of agricultural resources in the lower Rio Grande Valley of Texas with limiting and non-limiting water supply

Among the problems relating to water and land use in the Rio Grande Valley of Texas are: (1) periodic water shortages, (2) in-efficient management of resources including water, and (3) non-optimum selections of crop enterprise combinations. These problems are not new, but their significance has increased recently due to the decrease in water supply and the increase in municipal and industrial demand for water. This study treated these problems by determining the optimal combination of water and other resources in agricultural crop production in 1970 in the Valley given the amount of water currently available and by projecting the 1980 optimal resource and enterprise combinations with an increased water supply. The potentially irrigable cropland in the Valley was estimated to be 1,250,000 acres out of which 750,000 irrigated acres are currently used in the production of cotton, grain sorghum, vegetables, citrus fruits and pasture. About 78 percent of the cropland was classified as loam soils and about 22 percent as clay soils. The Rio Grande constitutes the major source of water for irrigation since ground water is limited and of poor quality. The 1970 water supply actually available was estimated to be 19,236,000 acre-inches out of which 16,919,100 acre-inches were considered to be available for irrigation oat Falcon Reservoir. A linear programming model was used to determine optimal resource use and enterprise combinations subject to marketing, institutional, agronomic and resource restrictions. Input-output coefficients necessary for this model were developed for loam and clay soil groups for two time periods, 1970 and 1980.