Estimation of global irrigation distribution uniformity.

For most irrigation systems, the most practical method for determining the global distribution uniformity (i.e., that experienced by the entire crop) is to measure the uniformity resulting from several components and combine them statistically. In this paper, procedures and equations are presented for determining global distribution uniformity from several components. Distribution uniformity is defined in terms of extreme values in the distribution, representing some fraction of the field area (e.g., low quarter). The equations and procedures provided herein apply regardless of the size of the area under consideration (e.g., low quarter, low half, etc.), and whether the low or high values are of concern. Procedures and equations for estimating the accuracy of these estimates are also provided.