Evaluating The Effects Of Deficit Irrigation And Mulching On Yield And Water Productivity Of Onion At Melkassa, Ethiopia

Abstract

Water Availability Is Becoming A Critical Issue In Ethiopia In Arid And Semiarid Areas Like The Rift Valley Areas Of The Country. Therefore, Enhancing The Water Productivity Of Irrigated Crops Through Water Management Is A Vital Option In Water-Scarce Areas. An Experiment Was Conducted At Melkassa Agricultural Research Center (Marc) Experimental Site In 2022/23 Under A Furrow Irrigation System To Evaluate The Effects Of Deficit Irrigation And Mulch Materials On The Yield And Water Productivity Of Onion. A Split Plot Combination Of Three Levels Of Deficit Irrigation (100% Etc, 80% Etc, And 60% Etc) Based On Etc And Two Mulching Materials White Plastic Mulch (Wpm) And Straw Mulch (Sm) With No Mulch As A Control Were Evaluated With Three Replications. Application Of Sm At The Rate Of 6 T/Ha, While 25-Micron Thickness Was Used For Wpm. Daily Eto, Etc, And Irrigation Scheduling Were Computed Using The Cropwat 8.0 Model Based On Climate, Soil, And Crop Data. The Results Of These Studies Showed That The Yield Of Onion And Water Productivity Was Significantly Affected By The Main Effects Of Deficit Irrigation And Mulching Materials. The Deficit Irrigation Results Showed That The Highest Marketable Yield (37.0 T/Ha) Of Onion Was Recorded Under A Plot Irrigated With 100% Etc With No Significant Difference From 80% Etc (34.9 T/Ha). Moreover, The Highest Water Productivity (10.4 Kg/M3) Was Obtained From Plots Irrigated With 60% Etc But It Has A Non-Significant Difference From 80% Etc (9.9 Kg/M3). Furthermore, Higher Yield And Yield Components Including Water Productivity Were Obtained From Straw Mulched Plots Than Plastic Mulched And No Mulch. The Maximum Marketable Yield Of 36.4 T/Ha And Water Productivity Of 10.6 Kg/M3Were Obtained From Straw Mulch. However, It Has A Non-Significant Difference From Plastic Mulched Treatment. The Partial Budget Analysis Revealed That Straw Mulched Treatment Was More Economically Feasible For Farmers Than Plastic Mulch For Onion Production In Melkassa Area. Therefore, The Present Study Suggests That, Under Limited Irrigation Water Conditions, Deficit Irrigation At 80% Etc Or Covering The Soil With Straw Mulch Application Could Be Used To Minimize Evaporation Loss And Maximize Water Productivity And Yield Of Onion At Melkassa And Similar Agroecology And Soil Types.