Hydraulic performance of drip system of irrigation as influenced by different operating pressures

Abstract

Drip irrigation is considered to be the best irrigation systems because of its high uniformity of water distribution. Irrigation non-uniformity is one of the reasons for reduced crop yields. The hydraulic performance is one of the factors that affect the overall uniformity of a micro-irrigation system. A field experiment was conducted at Department of Soil and Water Engineering, FAE, IGKV, Raipur to analyze the hydraulic performance of drip irrigation system including emitter discharge, coefficient of variation and emission uniformity. Drip irrigation discharge of 2.4 l h-1 inline emitter was measured in the field at 4 different operating pressures (0.7, 1.0, 1.2 and 1.5 kg cm-2) to ascertain the hydraulic performance. The experiment revealed that the average emitter discharge, emission uniformity (EUf) and uniformity coefficient (Uc) were maximum at 1.5 kg cm-2 operating pressure (2.3 l h-1, 96.39% and 96.99%, respectively) as compared to 1.2 kg cm-2 (2.1 lh-1, 96.33% and 95.66%, respectively), 1.0 kg cm-2 (1.94 l h-1, 95.25% and 93.83%, respectively) and 0.7 kg cm-2 (1.63 l h-1, 86.92% and 87.22%). Coefficient of manufacturer’s variation (Cv) and emitter flow variation (Qavg) were found minimum at 1.5 kg cm-2 operating pressure (0.03 and 8%, respectively) as compared to 1.2 kg cm-2 (0.04 and 13.16%), 1.0 kg cm-2 (0.06 and 19.44%) and 0.7 kg cm-2 (0.1 and 33.33%). Application efficiency and distribution efficiency were found maximum at 1.5 kg cm-2 operating pressure (95.96% and 97.34%, respectively) as compared to 1.2 kg cm-2 (94.43% and 96.46%), 1.0 kg cm-2 (89.59% and 94.90%) and 0.7 kg cm-2 (80.52% and 89.39%) for 2.4 l h-1 inline emitters. The system needs to be operated between 1.2 kg cm-2 to 1.5 kg cm-2 to get maximum efficiency.