keywords: Drip irrigation, mulch, soil moisture deficit, water use efficiency
A field experiment was conducted in 2016 dry season at the Department of Agricultural and Bio-resources Engineering irrigation experimental field, Samaru to determine the yield and water use efficiency of cowpea under deficit irrigation and mulching. The treatment consisted of three levels of irrigation water application depth of 50, 75 and 100% replacement of soil moisture deficit and three types of mulch materials ((Black polythene mulch (BPM), Rice straw mulch (RSM) and no-mulch (NM)) combined in Randomized Complete Block Design and replicated three times, irrigation water was applied to each plot using drip laterals. The soil moisture was monitor throughout the season with a theta probes. Results obtained from the research showed that highest seed yield of 1499.8 kg/ha was obtained when the cowpea crop was irrigated at 75% soil moisture deficit with black polyethylene mulch (I75BPM). The lowest yield of 800.4 kg/ha was obtained when irrigation was done at 50% SMD and no mulch (I50NM). The highest seasonal water use was obtained at I100NM with 242 mm and the least is at I50BPM with 120 mm. The highest irrigation water applied is at I100NM with 283.15 mm and the least is at I50BPM with 133 mm. The highest crop water use efficiency and irrigation water use efficiency is at I75BPM with 10.37 and 9.28 kg/ha-mm, respectively. It can be concluded from the results of the present study that for achieving maximum grain yield and optimum water productivity, cowpea crop can be drip irrigated at 75% SMD with black polythene mulch.