APPROPRIATE DEPTHS OF APPLICATION FOR SCHEDULING CENTER PIVOT IRRIGATIONS

The center pivot irrigator is faced with a problem of determining the appropriate depth of water application to use for management purposes to minimize both yield loss and water quality degradation. The current study builds on the work of Peri, Hart, and Norum (1979), using the normal distribution of application depth and linear yield and economic functions to calculate the appropriate depth of application with known uniformity and user specified economic conditions. A method is also presented to determine the potential savings from improving the uniformity. The optimum applied depth for 60 pivots tested varies from less than 10% to almost twice the mean depth, depending on the system uniformity and the economic and environmental scenario.