Evaluation of Pressure Compensating Drip Emitters fitted in a Polyvinyl Chloride Pipe

Abstract

Evaluating the effect of pressure head on the water distribution uniformity in a polyvinyl chloride (PVC) drip irrigation system is important in irrigation water management and could serve as the basis for optimizing water use efficiency and improving crop productivity. This laboratory study was to evaluate pressure compensating (PC) drip emitters fitted in a PVC pipe. A 6.00 m length PVC pipe with five selected randomized emitter points on each lateral were considered for five (5) different operating pressure heads (OPH) (1.60, 1.40, 1.20, 1.00, and 0.80 m) at 10, 20, and 30 minutes dripping interval and was repeated three (3) times each. PC drip emitters used in this study had a design or manufacturing discharge rate of 10 L/h and a 3/4 mm emitter diameter at an emitter interval of 0.35 m for corn planting specification. Uniformity Coefficient (UC) values for all OPHs were above 90% and classified as excellent based on criteria for assessing drip irrigation system. Emission Uniformity (EU) values decreased as OPH was reduced. Low EU values showed that OPHs of 1.00 m and 0.80 m were highly unrecommendable for the adoption of PVC drip irrigation systems. Larger values for average emitter discharge (Qvar) were obtained as OPH was reduced. Larger Qvar values proves unacceptable drip emitter characteristics. Flow variations is essentially kept minimum as the OPH is increased. Except for the 1.60 m OPH, the coefficient of variation (CV) for all OPHs was unsatisfactory. As a result, the 1.60 m OPH is recommended over the other OPHs considering the lateral length in the study.