Dripper Discharge Design Bases For Line Source Drip Irrigation

Abstract: In the design of drip irrigation system, the choice of dripper discharge affects the irrigating water quality and the costs of drip irrigation engineer, while the soil moisture uniformity for line source drip irrigation affects crops water use directly, and it is the foundation to design drip irrigation system. Based on the technological requirements of drip irrigation and the factors influencing the dripper discharge, the importance of studying the design models for dripper discharge was indicated in this paper, as well as, the foundation of designing the dripper discharge for point drip irrigation and linear drip irrigation, especially the foundation of designing the dripper discharge meeting with the soil moisture uniformity for line source drip irrigation. In terms of the question of soil moisture uniformity for line source drip irrigation, experiments were conducted to study the effects of dripper discharge and irrigation water supply to soil moisture uniformity. The results indicated that irrigation water supply and dripper discharge had extreme effects on the moisture uniformity in soil along the drip irrigation pipe direction (the direction of moist zone) for line source drip irrigation, the soil moisture uniformity would be raised with the increase of irrigation quantity and dripper discharge. Irrigating water supply had more effects on the moisture uniformity than dripper discharge in soil along the vertical drip irrigation pipe direction and intersection of wetted front. It was proposed that the requirements should be satisfied for the models of designing dripper discharge when applied in engineering design. In the design of drip irrigation system, reasonable dripper discharge should be chosen and irrigation water should be supplied in order to make soil reach the designed moisture uniformity; the moisture uniformity of soil along the drip irrigation pipe should be controlled mainly. In the direction of vertical drip irrigation pipe and intersection of wetted front, the required soil moisture uniformity could be met through controlling irrigation water supply in certain width. Little interval of water dropper should be chosen for sand, but large interval of water dropper can be chosen for loam soil. The study in this paper has the directive significance for choosing dripper discharge and interval of water dropper, as well as, designing irrigation quantity for line source drip irrigation.