Development of water saving strategy for wheat crop by combining drip irrigation system with regulated deficit irrigation

Controlled field experiments on wheat crop were at Shiv Nadar Institution of Eminence, Greater Noida, India during 2021-22 crop season in sandy-loam soil type in humid sub-tropical climate zone. The aim was to determine water saving irrigation treatment and amount of water saving for wheat crop by combining drip irrigation with regulated deficit irrigation. The experimental setup consists four irrigation treatments with four replications of each irrigation treatment in which soil moisture values are regularly measured. Irrigation is supplied to the four treatments at different levels of soil moisture depletion, thus varying the timing and amount of irrigation. Drip irrigation system was used in two irrigation treatments while flood irrigation was used for remaining two treatments. The soil moisture depletion levels, referred here as maximum allowable deficit (MAD), for the three irrigation treatments were 25% MAD (drip), 50% MAD (drip) and 50% MAD (flood). In the fourth irrigation treatment (farmer’s field), irrigation is applied based on the recommendations of a local farmer, without considering the soil moisture measurements.
Grain yield (t/ha) and crop water productivity, i.e. grain yield per unit water applied (t/ha-mm) for the irrigation treatments are assessed. Highest value of grain yield was recorded for 50% MAD (drip), very closely followed by 25% MAD (drip). The crop water productivity value was highest for 50% MAD (drip) treatment and lowest for farmer’s field treatment. The crop productivity value of 50% (drip) treatment is found 98%, 35% and 28% higher than the farmer’s field, 50% MAD (flood), 25% MAD (drip) irrigation treatments, respectively. The results show vast potential of drip irrigation system combined with regulated deficit irrigation in water saving for wheat crop in sandy-loam soil.