EFFECT OF DRIP LATERAL SPACING ON WATER PRODUCTIVITY AND ONION YIELD (ALLIUM CEPA L.) AT RARE, HARAMAYA UNIVERSITY, EAST HARARGHE ZONE, ETHIOPIA

Abstract

Drip irrigation or trickle irrigation is a type of micro-irrigation system that has the potential to save water and nutrients by allowing water to drip slowly to the roots of plants, either from above the soil surface or buried below the surface. Field experiment was conducted at Haramaya University to evaluate Effect of Drip lateral spacing on Water Productivity and Onion yield (Allium cepa L.) at rare, Haramaya University, East Hararghe Zone, Ethiopia the experiment was laid out in completely randomized block plot design. After the installation of drip irrigation system, the hydraulic characteristics of the drippers that were determined include emitter flow rate, emitter flow variation, and uniformity coefficient, coefficient of variation and emission uniformity. Water application uniformity test of irrigation system was determined for drip lateral spacing in every row and lateral spacing between two rows at the beginning and end of the experiment. Drip irrigation spacing (100cm, 50cm, 30cm, 25 and 20cm) the lateral spacing were arranged with four blocks. The highest seasonal water requirement of onion was 426.9 mm at 100% ETc under every drip irrigation spacing. The analysis of variance revealed that there was significant (p<0.05) difference in yield among treatments and the highest yield (37.26t/ha) was obtained from drip irrigation of lateral spacing with 20cm of ETc application and while the lowest (29.61 t/ha) was obtained from plots treated 100cm treatment. The highest (4.14kg/m3) and the lowest (1.54kg/m3) water productivity were recorded from the plots treated with drip irrigation at 100cm and drip irrigation at 20cm treatments, respectively. In terms of water productivity and natural resource scarcity, irrigating with drip irrigation system with 30cm spacing can be recommended for production of onion production.