The Effect of Deficit Irrigation on Yield And Water Productivity Of Onion (Red Bombay) Under Drip Irrigation And Mulching At Wolaita Sodo, Ethiopia.

Abstract Water-saving agricultural counter measures were required to deal with the current water scarcity. Therefore, the purpose of this research was to investigate how deficit watering affects onion yield and water productivity when drip irrigation and mulching were used. Factorial arrangement in a randomized complete block design with three replications was used to set up the experiment. The experiment was consisted six treatments combinations: Control and two deficit irrigation (100% crop evapotranspiration with and without mulch), two mulch treatments with and without mulch, resulting in a total of 18 plots. The first factor was three different water application levels as 100 %, 80 %, 70 % of crop evapotranspiration and the second factor was three water application levels of with mulch as wheat straw mulch at 4 tons/ha and the third factor was three water application without mulch. The average yield values demonstrated that, in comparison to 70% crop evapotranspiration treatments, 100% crop evapotranspiration and 80% crop evapotranspiration irrigation levels produced greater values of total and marketable yield. The results of the analysis of variance showed that the application of mulch to wheat straw and the absence of mulch treatment significantly affected yields as well. The effects of mulching and irrigation levels on the mean bulb and clove weight of onions were highly significant (P < 0.01). However, there was a noticeable variation in the water productivity values when varying the irrigation application amounts, and applying mulch made of wheat straw, compared to without mulching condition. Based on the research's findings, it may be possible to use 100% crop evapotranspiration to produce onion yields that were comparable to those of full irrigation, and it may be useful to utilize wheat straw mulch to conserve water and increase yield. Consequently, it is possible to draw the conclusion that 100% crop evapotranspiration with straw mulch could address the issue of water scarcity and guarantee the possibility of additional irrigation expansion and agro-ecology in the studied area. Applying 100% crop evapotranspiration with straw mulch irrigation water application level over the whole growing season under drip irrigation system was advised to obtain optimal onion bulb output in locations where water was not scarce.