FIELD ESTIMATION OF EMISSION, DISTRIBUTION AND STATISTICAL UNIFORMITIES FOR DRIP IRRIGATION SUBUNIT

Abstract

Maximization of crop yield depends on irrigation water distribution uniformity; therefore the effective use of water by modern irrigation systems, especially drip irrigation, had a great concern in both arid and semi-arid regions, where the water is with limited resources. Field estimation of emission, distribution and statistical uniformities for drip irrigation subunit is the main objective of this paper. For this purpose, a drip irrigation subunit for field evaluation was constructed. Manifold line was divided into four locations. Ten emitters at each location are considered to study the variations due to manufacture and due to differences in operating pressure. Three levels of lateral length were considered at each manifold location, which are 10, 20 and 30m. The greatest coefficient of variation (13.45%) was observed at third location with 30 m of lateral line length, while the lowest (0.66%) was at first location with 10 m of lateral line length with 10.19m H₂O of the operating pressure. Increasing operating pressure led to decrease both coefficient of manufacturing variation and average coefficient of variation for all locations of the manifold line. The changing of distribution uniformity (DU) along lateral line was approximately ranged from 83.47% to 98.75%, which can be classified as “good” to “excellent”. It was observed that, average distribution uniformity (DU_av) increased with the increase in lateral length. The effect of the operating pressure on average distribution uniformity (DU_av) was clear where, it decrease with higher pressure. So, these factors should be considered carefully when designing a drip irrigation system.