OPTIMIZING WATER UTILIZATION FROM A WINDPUMP-DRIP IRRIGATION SYSTEM FOR HIGH-VALUE CROP PRODUCTION

Abstract

Although the windmill has been used for water pumping for many centuries, its development and application is limited due to high investment cost. Using windmill instead of diesel engine to drive a water pump reduces dependence on fossil fuel and mitigates greenhouse gas emissions. Thus, this study was conducted to optimize water use from a windpump coupled to a drip irrigation system. Performance of the windpump-drip irrigation system was also evaluated based on technical and economic feasibility. Water from the windmill combined with suction pump and piston pump was applied to vegetable crops in a 0.18-ha area through a drip irrigation system. Results showed that average daily discharge of the windpump was 9.2 m 3 /day (24 hours) at 1.6 m/s daily wind speed. It varied from 0.7 at 1.6 m/s to 22.1 m 3 /day at 2.7 m/s. Overall efficiency of the windmill-suction pump system varied from 23.1 to 6.1% corresponding to wind speed of 1.7 to 4.3 m/s, respectively. With total available water supply from the windpump and rainfall of 17.1 m 3 /day, optimum service area of the system would be 0.81 ha, 0.95 ha, 0.65 ha, and 0.32 ha for tomato, eggplant, onion, and rice crops, respectively. Economic analysis showed that with three tomato crops per year in 0.81 ha, annual net income would be PhP38,960. Financial rate of return was 19% with a payback period of 9 years. Thus, the investment for the windpump-drip irrigation system would be feasible only for high-value crops