Estimation of micro-irrigation water application uniformity based on sample emitter flow variation
JU Xueliang1,2, WU Pute1,2, ZHU Delan2, ZHANG Lin1,2
1.Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; 2.Institute of Water-saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China
Abstract:The field estimation of water application uniformity is the major way to assess the hydraulic design, operation and management and the equipment quality of the micro-irrigation system. The traditional emitter flow variation using the maximum, minimum and average emitter discharge was only used as the hydraulic design uniformity criterion, which could not be used to evaluate the field water application of micro-irrigation systems. The sample emitter flow variation was defined to evaluate the field water application uniformity. The relationships between the sample emitter flow variation and the other traditional indexes of water application uniformity were developed based on the assumption that the emitter flow of the field micro-irrigation systems obeys the normal distribution. The related formulations of sample errors were derived. The sample size and grouping number were also proposed. The criteria of sample emitter flow variation under different sample grouping number were proposed by comparison with those of the ASABE and GB. The estimation procedure of sample emitter flow variation was then proposed to assess the field water application uniformity. The application case indicated that the new method is easily adaptable and reliable for estimating the field water application uniformity.
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