Marginal Productivity of Irrigation Water as Applied to Selected Field Crops

In Nebraska the quantity of water received from precipitation has been a limiting factor in yields of crops. Irrigation water has been used extensively in certain areas of the State to supplement precipitation. The focus of this study is directed toward the problem of how to allocate a limited quantity of water on certain crops in order to obtain the highest total net return. The crops to be included in this study are corn, alfalfa, and grain sorghum. These three crops are important in Nebraska and receive most of the irrigation water in the State. Research personnel in both Agronomy and Agricultural Engineering at Nebraska and several other states were contacted. Through personal conferences and correspondence data which could be adapted for use in this study were obtained. Results of studies from North Platte, Scotts Bluff and Arapahoe, Nebraska, were used in the section on corn. The data used in the grain sorghum section are from Texas; while the alfalfa results are based on data from Kansas. A questionnaire was developed and administered through personal interview in order to determine the irrigation practices of farmers in regard to corn, grain sorghum and alfalfa production. Twenty farmers in precinct M of Seward County, Nebraska, were interviewed concerning their irrigation practices. This precinct in Seward County was selected because it had a high concentration of irrigators, and also the farmers in this area irrigate a variety of crops. Advisor: Loyd K. Fische