A Review of Irrigation Water Management Research Achievements of JARC

Abstract

Crop production in Ethiopia is largely dominated by rain-fed agriculture, which is suffered by climate change, due to occurrence of erratic rain falls. Therefore, it should be supplemented with irrigation; unless it is difficult to supply food for extremely growing country’s food demands. To alleviate such problems, Jimma irrigation research departments conducted a number of experiments to improve crop productivity as well as water use efficiency with minimum yield penalty at the expense of water saving at different climatic condition of southwestern Ethiopia. Therefore, the objective of this review is to analyze best research findings and technologies that were checked at different locations. Among promising results, deficit irrigation, inducing moisture stress at different growth stages of crops, supplemental irrigation, integrated use of mulching with deficit irrigation, mineral fertilization (Phosphorous and Nitrogen) vis irrigation, and irrigation scheduling are the major one. Accordingly, optimum yield of maize was reported when it was irrigated at alternate furrow method, is preferably good when irrigation amount is not less than 75% ETc, which saved about 50% of water over conventional furrows 100% ETc. Then the saved water used to irrigate additional piece of land. The other irrigation strategy is skipping irrigation in less sensitive stage of crops, the report comes from Haru ( Gimbi area) indicated that skipping irrigation during initial and late season had minimum impacts on maize yields, with  50% water saving as compared to all stage irrigated maize. In addition to reducing the amount of water significantly, the cover crop could play significant role in reducing soil evaporation. For instance, the experiment conducted at Haru showed that alternate furrow mulched with plastic mulch provided highest potato yield over non-mulched. Most of time, the fertilizer recommendation made for rain fed agriculture does not work for irrigated agriculture. The full irrigation (100% ETc) combined with 46 kg/ha phosphorous in soybean provided highest yield. However, increasing the amount of phosphorous fertilizer beyond this level did not increase the yield even if the field receives enough moisture. Finally, the future research direction should focus on water saving together with optimized fertilization through liquid water, and integrated with water harvesting in areas with limited water source either physical or economical.

Keywords: Deficit Irrigation, Moisture Stress and Irrigation Scheduling

DOI: 10.7176/JRDM/78-01

Publication date:August 31^st 2021