Evaluation of gravity drip irrigation kit in a greenhouse

Abstract

The Research was carried out to evaluate the performance of a gravity drip irrigation kit in a greenhouse. The system consists of a 2m³ tank mounted 2m above ground, connected to a mainline which is also connected to two sub-mainlines. Each sub-main has six junctions and each junction has two laterals connected to it giving a total of 24 laterals in the system. Measurement of emitters discharges was carried out from six (6) laterals selected one from each of the six junctions. The pressure heads at the designated laterals were measured using a pitot tube from which the operating pressure was calculated. The result of the Research shows an average discharge of the emitter for the system of 857mLh^-1. The uniformity coefficient and emitter coefficient of variation for the whole system were found to be 94.87% and 0.07 respectively. The uniformity of the system is classified as Excellent while the emitter coefficient of variation CV, obtained from the study (0.07) for this type of emitter is classified as average. The value of the emitter coefficient (k) and emitter exponent(x) were found to be k=2.54 and x=0.5. The value of the emitter exponent (x=0.5) shows that the flow regime of the emitter is fully turbulent flow. The results of tests show that the emitter discharges were uniformly distributed over all operating pressures. The discharge also increases with operating pressure for all tested emitters.