Hydraulic Performance and Soil Moisture Distribution under central Pivot Irrigation System

Abstract

The Irrigation uniformity plays an important role in the performance of the sprinkler irrigation system and for good plant quality; however, sprinkler systems are typically gauged by the uniformity of water application above the crop canopy. The objectives of this study were to evaluate the hydraulic performance including: uniformity coefficients (CU %), distribution uniformity (DU %) and application efficiency (Ea %) and soil moisture distribution under center pivot. This study was conducted under central pivot irrigation systems (eight units) at the farms of Authority of Merowi Dam Area for Agricultural Development (AMDAD) in New Hamdab Scheme, Northern State, season 2016/17. Results showed that the volume of caught water ranged from 135.2 to 419.3 mm with an average of 5.05, 3.86 and 11.98 mm for central pivot 1, 5 and 8, respectively. However, the application efficiency (Ea %) of the central pivot irrigation system no. 1, 5 and 8 were 36.1, 27.6 and 85.6 %, respectively. The results showed that uniformity coefficients (CU%) of the center pivot irrigation system were 40.9% and 74.4% for center pivot no.1and 5, respectively which were generally below the recommended value while center pivot no. 8 (84.4 %) was in the range recommended. The water distribution uniformity (DU %) values were 57.4% and 77.5% for center pivot no.1and 5, respectively which were generally below the recommended value except center pivot no. 8 (84.3 %) was in the range recommended. The water distribution uniformity (DU %) values were 57.4% and 77.5% for center pivot no.1and 5, respectively which were generally below the recommended value except center pivot no. 8 (84.3 %). The results of soil moisture (MC%) were 3.47, 2.66 and 8.29% for center pivot no.1, 5 and 8 in depth 0-30cm, respectively they showed a clear variation between centers while the change didn’t exceed 1% in depth 30-60cm. Results of soil moisture uniformity (SCU %) and soil moisture distribution (SDU %) in depth 0-30cm were below the recommended value for all centers, however, the irrigation requirement was not satisfied and, hence, resulted in low yield. Generally, among the three systems, both 1 and 5 showed lower performance than 8. Hence, the test of performance for a center pivot irrigation system should be carried out each season.