Effect of regulated deficit irrigation on yield and water use efficiency of grapes

Abstract

Thompson Seedless grafted on Dogridge was irrigated at variable rates of pan evaporation replenishment at different growth stages for consecutive five years (2012–13 to 2016–17) with the objective of developing the grower friendly irrigation schedule. The new schedule standardized by applying regulated deficit irrigation (RDI) to the vines at the rate of 60% evaporation replenishment (ER) at shoot growth and berry setting to harvest and at the rate of 20% ER at bud differentiation and development, bloom to shatter stage saved considerable amount of water (45.7%) without affecting the yield and quality of the grapes. In the standardized RDI schedule, 460 mm of irrigation water was applied to realize a Brix yield of 4t/ha with a WUE of 0.34 t/cm/ha when compared to standard irrigation control STD 80-T1 (irrigating at uniform rate of 80% ER at all the growth stages) where 848 mm irrigation water was applied to attain a brix yield of 3.5t/ha with a WUE of 0.18 t/cm/ha. The petiole nutrient content at bud differentiation was not significantly influenced by irrigation treatments. However, at full bloom stage significantly low petiole N content was recorded in SDI 40-T3(irrigating at 40% ER at all growth stages) and RDI-T6 irrigating at 40% ER and reducing to 20% ER at bud differentiation, cane maturity, fruit bud development and bloom to shatter stages) while low petiole P content was recorded only in RDI-T6.