Executing legitimate irrigation scheduling by deficit irrigation mechanism to maximize onion production

Abstract

Lack of irrigated water poses a threat in arid and semi-arid areas. Hybrid irrigation system has become an obligatory to save water and increase productivity. Deficit irrigation scheduling is a recent innovative approach of water-saving method. An experiment was conducted to estimate the irrigation interval and find an amicable solution by optimum deficit irrigation level at Arba Minch of southern Ethiopia using conventional furrow irrigation system. The treatments comprised 75%, 50% and 25% of irrigation requirement and four growth stages (initial, development, bulb formation, and late), which were considered in random complete block design with three replications. Refilling was commenced when 25% of Readily Available Water (RAW) depletion at the full irrigation was observed. The irrigation intervals at growth stages were 4, 6, 4, and 3 days, respectively, with an overall irrigation interval of 3 days. The net and gross irrigation of the crop were 311.80 mm and 445.42 mm, respectively. The highest crop phenology and yield were obtained by applying Irrigation Requirement (IR) of a maximum 100% and minimum at 25%. The maximum yield of 25.88 ton/ha was obtained from full irrigation which hardly affects the yield of 25.70 ton/ha obtained from 75%IR at late growth stages. Therefore, application of 100%IR at 3 days interval was assessed as economically productive. However, 50%IR at 3 days interval can be an option when there is a constraint of water supply. The findings will be useful for irrigation water management to maximize crop yields with limited water and unlimited land resources.