Response Of Onion (Allium Cepa L.) To Deficit Irrigation Under Different Furrow Irrigation Methods

Abstract

Scarcity of water is a major constraint for development of agriculture in arid and semi-arid areas. Deficit irrigation and use of appropriate irrigation systems are considered as means to improve water use efficiency without significant yield loss. A field experiment was conducted with the objective of identifying the levels of deficit irrigation and different furrow irrigation methods that provide optimum onion yield and per unit of water under limited water condition at Alage Agricultural Technical and Vocational Education Training College. The experimental plots were designed as split plot in randomized arrangement with three replications having 12 treatments. The treatments included are three furrow irrigation methods as a sub-plot; namely, alternative furrow irrigation (AFI), fixed furrow irrigation (FFI) and convectional furrow irrigation (CFI) methods and four irrigation levels as a main plot of 90, 75 and 50% of the water requirement (ETc) and a control irrigation of 100% ETc depth. Crop water requirement was determined by using CRPWAT 8.0 and a discharge was measured by using Parshall flume. The collected data?��?s were analyzed by analysis of variance (ANOVA) using ?��?gen stat?��? statistical software. Furrow irrigation methods and deficit irrigation levels were significantly (P<0.05) affected onion growth, yield parameters and water productivity. The interaction of deficit irrigation level and furrow irrigation method also significantly (P<0.01) affected the bulb weight, dry weight of bulb, marketable bulb yield, total bulb yield, crop water use efficiency (CWUE) and irrigation water use efficiency (IWUE). The maximum and minimum total bulb yield of 33098 and 27275 kgha-1 were obtained from 100 and 50% ETc. The total bulb yield of onion was maximum at 34812 kgha-1 from the treatment irrigated with CFI method with 100% ETc depth, followed by the treatment irrigated with AFI method with 100% ETc depth that resulted in comparable total bulb yield of 33784 kgha-1. The minimum total bulb yield of 25922 kgha-1 was attained