Water productivity and yield of wheat as affected by irrigation systems and water deficit under New Valley conditions

Abstract

Improving the irrigation water productivity of wheat under water shortage and high evaporation such as New Valley conditions is crucial. Two field experiments were carried out during the two successive winter seasons of 2014/2015 and 2015/2016 on the Experimental Farm, Agricultural Research Station at El-Kharga, the New Valley Governorate. The experiment was laid out in strip plot design with four replications. Irrigation methods (flood, sprinkler and drip) were allocated horizontally; while, irrigation regimes (25, 50 and 75% soil moisture depletion, SMD) were arranged vertically.Results reveal that applying drip and sprinkler irrigation methods increased grain yield of wheat by 19.86-33.72% and 4.83-13.14% in both seasons, respectively as compared with flood irrigation method.The maximum mean values of grain yield (2825 and 2609 kg fed -1 ) were obtained under the 25% SMD regime in the both seasons.Seasonal ET a mean values were 1614 and 1706 m 3 fed -1 under flooding irrigation method; 1586 and 1676 m 3 fed -1 under sprinkler irrigation method; 1559 and 1653 m 3 fed -1 under drip irrigation method in the first and second seasons, respectively.The crop water productivity (CWP) mean values for grain and straw yields of wheat were 1.67 and 2.77 kg m -3 in the first season being 1.64 and 2.60 kg m -3 in the second season, respectively. The IWP followed the same trend; the values of irrigation water productivity (IWP) were 1.42 and 2.36 kg m -3 in the first season and 1.40 and 2.22 kg m -3 in the second season for grain and straw yields of wheat, respectively.Comparing with flood irrigation method, the gross return (grain + straw) per consumptive water in ET unit under drip irrigation was increased by 23.97 and 32.04%. Moreover, this revenue was enhanced to 81.42 and 94.06% for irrigation water unit in both seasons, respectively.It could be concluded that applying drip irrigation at 50% SMD improved yield and water productivity of wheat as well as saving irrigation water.