Wind drift and evaporation losses of a mechanical lateral-move irrigation system: oscillating plate versus fixed spray plate sprinklers

Abstract

The mechanical lateral-move irrigation system has the capacity to achieve high irrigation efficiency when handled properly; however, during irrigation, wind drift and evaporation losses (WDEL) can occur that are caused by operational and meteorological factors. Thus, the objectives of this study were: to determine the WDEL of a mechanical lateral-move irrigation system fully equipped with oscillating plate sprinklers (I-Wob) under different meteorological conditions; to evaluate the predictive capacity of eight published WDEL models that were compared with field data of the full length mechanical lateral-move irrigation system; to develop a model for estimating the WDEL of a mechanical lateral-move irrigation system equipped with an oscillating plate; and to compare the WDEL and Christiansen Uniformity coefficient for fixed-spray plate (Superspray) and I-Wob under field conditions. The study was conducted using 65 in-field tests that were divided into two groups; the first group of 35 in-field tests used a full-length lateral-move irrigation system equipped with I-Wob sprinklers, and the second group consisted of 30 in-field tests that used only the span 2 (Superspray) and the span 4 I-Wob sprinklers. The WDEL for the full-length lateral-move systems ranged from 4.4 to 25.2%, with an average of 11.6%. A Pearson’s correlation test found that wind speed was significant at a 5% significance level. The proposed model performed better than the eight published models. A comparison of the I-Wob and Superspray sprinklers installed in the mechanical lateral-move irrigation systems indicated that I-WOB performed better and had higher Christiansen’s Uniformity coefficient values and lower wind drift and evaporation losses.