ASSESSMENT OF EFFECTS OF VARIOUS PRESSURE LOSSES IN LATERAL PIPES ON THE FORAGE CROP YIELDS IN THE HAND MOVE SPRINKLER IRRIGATION SYSTEMS

摘要

In developing agriculture, the goal is high crop yield and in order to achieve this goal water losses should be reduced and irrigation efficiency should be increased. Higher friction losses in the laterals of sprinkler irrigation systems, would require higher driving pressure and will result to non-uniform water distribution, giving rise to more water losses. If laterals are designed with less allowable pressure variation, irrigation uniformity will be better, which will improve water application efficiency and enhance crop yield. In this study, sample fields with manually shifting sprinkler irrigation system were designed with 5 to 30% allowable variation of application pressure of sprinkler for irrigating alfalfa in Khuzestan. In each field, system’s uniformity coefficient, water application efficiency, and crop yield were obtained for different friction losses. Results showed that an increase friction losses from 5 to 30% reduced system’s uniformity efficiency by 4%, application efficiency by 5% and relative production of crops by 1%