Response of Soybean [Glycine max (L.)Merrill] to Irrigation at Different Growth Stages

A field experiment was carried out in rainy seasons of 2009, 2010 and 2011 to study the effect of irrigation schedules on yield, water use efficiency and other traits in soybean. Seven irrigation schedules consisted of irrigations at seedling stage (15–20 days after sowing), flower initiation stage, seed filling stage (20 days after flower initiation) and four different combinations of these 3 stages. Irrigation at flower initiation + seed filling stages produced the highest seed yield (3221 kg/ha). Maximum average values for seed index (14.59 g) and harvest index (50.87%) were recorded in this treatment. This treatment also recorded maximum net returns (₹ 44028/ha) followed by irrigation at seedling + flower initiation + seed initiation stages (₹ 42046/ha) and flower initiation stage (₹ 41880/ha). Control (no irrigation) had maximum water use efficiency (84.85 kg/ha/cm) followed by irrigation at flower initiation stage (83.30 kg/ha/cm). Studies indicated that irrigation to the soybean crop at flower initiation and seed filling stages helps to obtain the optimum yield and earn maximum net returns.