Performance Evaluation of Center Pivot Irrigation Systems and Water Productivity in Some Farms of Semnan Province

By evaluating irrigation systems, their performance can be improved. The purpose of this study was to evaluate the center pivot irrigation system in some fields of Semnan province. Also, the amount of water consumption in the field was compared with the water requirement and the national water document. For this purpose, center pivot irrigation systems were studied in three fields. Average potential and actual application efficiency (PELQ and AELQ), distribution uniformity (DU), uniformity coefficient (CU) and evaporation and wind losses were 69.1, 67.2, 76.7, 82.1 and 7.6% respectively. The average of the above parameters was good. The operation of center pivot systems was easier than other sprinkler systems due to the mechanization of center pivot systems. Technical problems in one system reduced uniformity and efficiency. The volume of water consumption in field 3 was less than the irrigation requirement thus deficit irrigation was done. Irrigation water productivity in alfalfa and wheat fields was 0.92 and 0.79 kg/m3, respectively. Considering appropriate irrigation frequency and time, night irrigation to reduce evaporation and wind losses and paying more attention to educating farmers on proper operation of system were the important factors in increasing irrigation efficiency and water productivity.