Irrigation Schedules for Wheat Crop and Water Saving

<p>Agricultural water takes more than 70% of the available water resources, globally and wheat is one of the most widely grown and irrigated crops in the world. Keeping the ongoing and predicted global water scarcity, water saving in agriculture is very critical for the food and water security nexus. Therefore, controlled field experiments on wheat have been carried out at Indian Institute of Technology, Roorkee, India for 2014-15 and 2016 seasons. The aim is to arrive at optimum irrigation schedules for wheat crop grown in sandy-loam soil which will result in water saving without affecting the grain yield considerably. The experimental setup includes four experimental field plots in which wheat crop is grown. Soil water content of the field plots are regularly monitored. Irrigation schedules of the four field plots are varied by irrigating at different soil moisture depletion (SMD) levels: 0-20% SMD (fully irrigated), 40% SMD, 50% SMD and 60% SMD, thus varying the timing and amount of irrigation. Irrigation at 50% SMD is observed to irrigation schedule with highest water productivity for the wheat crop in sandy-loam soil after comparing the grain yield and irrigation values for two cropping seasons. There was a decrease of 6.9% and 2.3% in grain yield of 50% SMD irrigation treatment when compared to the fully irrigated treatment. 50% SMD treatment has the highest water productivity of all the irrigation treatments with values of 17.34 kg/ha-mm and 14.1 kg/ha-mm for two crop seasons while values of water productivity for the fully irrigated treatment are 13.29 kg/ha-mm and 11.14 kg/ha-mm.&#160; 50% SMD treatment resulted in water saving of 26.4% and 25.2% of water saving for the two cropping seasons 2014-15 and 2016, respectively when compared to the fully irrigated treatment for per unit water usage. A substantial decline in grain yield of 60% SMD irrigation treatment points out that irrigation should be applied in the wheat crop at a maximum soil moisture deficit of 50%.</p>