Water Supply: Yield Relationships Developed for Study of Water Management

• Published in: Journal of natural resources and life sciences education 2006, Vol.35 (1), p.161-173
• Main Authors: Stone, L.R, Schlegel, A.J, Khan, A.H, Klocke, N.L, Aiken, R.M
• Format: Article
• Language: English
• Subjects: Air temperature; Alfalfa; Conservation (Environment); crop yield; Crops; dry environmental conditions; Economics; Educational materials; Efficiency; environmental factors; Glycine max; grain yield; Helianthus annuus; Irrigation; Loam soils; Medicago sativa; Natural resources; Resource conservation; Semiarid lands; semiarid zones; Silt loam; silt loam soils; Software packages; Solar radiation; Sorghum; Sorghum bicolor; Soybeans; Spreadsheets; statistical models; Studies; Triticum aestivum; Water; Water management; water requirement; Water resources; Water supply; water use; Winter wheat; Zea mays
• ISSN: 1059-9053; 1539-1582
• DOI: 10.2134/jnrlse2006.0161

The USA's west-central Great Plains is a semiarid region with irrigation largely from the Ogallala aquifer, which has experienced extensive water-level declines. Farmers respond to reduced water supplies with alternative management, irrigation equipment, and crops; and, it is imperative the economics of these changes be studied. Profit and risk in water management depend on the crop-water relationships. Our objective was to describe the development of, and tabulate, yield-water supply relationships for six primary crops of the region: alfalfa (Medicago sativa L.), corn (Zea mays L.), grain sorghum [Sorghum bicolor (L.) Moench], soybean [Glycine max (L.) Merr.], sunflower (Helianthus annuus L.), and winter wheat (Triticum aestivum L.). Soils were deep silt loams that developed from loess. Input weather data were long-term, daily means of air temperature, solar radiation, and precipitation. Crop growth patterns were consistent with full-season cropping. Yields modeled with the Natural Resources Conservation Service (NRCS) net irrigation requirement (NIR) for 80% chance rainfall ranged from 92 to 97% of the maximum yields. This illustrated that if net irrigation exceeds the recommended NIR, there will be no appreciable yield increase. These calculated yield vs. water supply results will aid in studying water resource optimization and the associated economics.