Water Management of Alfalfa through Individual Harvest Production Functions

Abstract

Some research has indicated that seasonal estimates of alfalfa (Medicago sativa L.) water production functions are transferable between geographical areas while other research has Indicated that these functions are not transferable. Research testing whether or not alfalfa water production functions between harvests are statistically different has been limited. The objectives of this study were to: (i) develop a production function that includes irrigation water and crop evapotranspiration (ET) as variables; and (ii) estimate individual harvest water production functions and determine if they are statistically different. Yield data were derived from four different water application rates based on 50, 75, 100, and 125% of FAO modified pan evaporation. The production functions used both ET and irrigation water, in ratio form, in a quadratic equation. Results showed statistically significant differences between individual harvest functions. This means that when developing water allocation efficiency programs for alfalfa, individual harvest production functions should be used. Additionally, the results imply that individual harvest production functions are not transferable between geographic areas, at least to the extent that number of harvests are different.