Spatial Distribution and Uniformity Evaluations for Chemigation with Center Pivots

Abstract

Traditional calculation of distribution uniformity as a basis for hydraulic design evaluation may not be appropriate for chemigation with center pivots. Recent development in site-specific crop management (SSCM) requires the spatial distribution of water and nutrient inputs to the fields. A two-dimensional interpolation algorithm has been developed to build these spatial distribution maps from a limited number of observations. A coefficient of uniformity is then calculated from the application depth distribution and compared with Heermann-Heins coefficient of uniformity, CUH, from both catch-can test data and computer simulation data. The results showed that the interpolated coefficient of uniformity, CUI, is comparable to Heermann-Heins CUH but more robust at larger catch-can spacing.