Abstract:
Improving water productivity for sustainable crop production and water savings represents a
major challenge for agricultural water management in water scarce areas. A field experiment
was conducted at Haramaya University experimental site during 2019/2020 irrigation season
to evaluate the response of onion yield and water productivity to deficit irrigation levels and
mulch techniques. The treatments include 100, 85, 70 and 55% of ETc applications. The
experimental design was a split plot in RCBD arrangement with three replications. Crop
water requirement was estimated using actual daily climatic temperature data. The analysis of
variance revealed that there was a highly significant (p<0.01) difference among growth
parameters, yield and yield parameters. The interaction effect of mulch and irrigation has also
shown a significant effect for bulb height and unmarketable bulb yield except for leaf number
per plant and a highly significant (p<0.01) effect for the rest parameters considered. The
maximum yield of 38.43 ton/ha was recorded from 100% ETc with plastic mulch whereas the
minimum yield of 16.36 ton/ha was recorded from 55% ETc with no mulch. The highest water
productivity (9.08 kg/m3) was obtained from the plots treated with 70% ETc application under
plastic mulch and shows no significant differences with 85% ETc application under plastic
mulch and 70% ETc application under straw mulch. The lowest water productivity (6.57
kg/m3) was recorded from 55% ETc application under no mulch treatments. Budget analysis
revealed that the most economically feasible combination for small-scale grower farmers with
lower cost of production and maximum net return was from the application of 70% ETc and
85% ETc treated with straw mulch. Therefore, in terms of marketable bulb yield and water
productivity, irrigating with 70% ETc and straw mulch would be recommended for production
of onion in the study area.
