Effect of Deficit Irrigation on Growth and Yield of Red Onion (Allium cepa) in Drip Irrigation System

Improving water use efficiency is a vital strategy for addressing future water scarcity.Irrigation is a wide-ranging practice using every drop of water for crop production through suitable practices.Since irrigation plays a key role in global water availability by impacting water productivity, a field experiment was conducted in DL 3 agro ecological region during the yala season of 2018 using drip and basin irrigation methods to evaluate the effect of deficit irrigation practices on growth, yield and water use efficiency of onion.Four treatments; water application through drip irrigation at 150%, 100% and 70% of crop water requirement and basin irrigation as control were designed.Water application at 100% of crop water requirement gave significantly higher onion yield as compared to 70% of crop water requirement and basin irrigation treatment.Also yield from 70% of water application and basin was not significantly different.The onion irrigated at 100% recorded 22.3% of increase in yield over basin method of irrigation.But, irrigation water use efficiency was found highest with drip irrigation at 70% of water application and lowest with basin irrigation.The amount of water saved at 150%, 100% and 70% under drip method was 13.8%, 31.12% and 50.8% respectively over basin method and this would be sufficient to irrigate additional area of onion crop earning better economic returns as compared to basin irrigation method.When consider the irrigation water use efficiency 70% of water application was the best irrigation practice compared to basin irrigation.Hence, the study suggests farmers in the dry region having limited amount of water for irrigation, should adopt drip method with combination of deficit irrigation rather than practice of basin irrigation methods.