Interactive Effect of Irrigation at Critical Growth Stages and Phosphorus on Growth, Yield and Root Nodulation of Summer Blackgram

The field experiment was conducted at College Agronomy Farm, Anand Agricultural University, Anand, Gujarat. Treatment combinations comprised of three levels of irrigation scheduling based on critical growth stages viz., I, (irrigation at branching and at flowering), I-2 (irrigation at branching, at flowering and at pod formation) and I-2 (irrigation at branching, at flowering, at pod formation and at grain filling stage) in main plot and three levels of phosphorus viz., P-0 (0 kg P2O5 ha(-1)), P-1 (20 kg P2O5 ha(-1)) and P-2 (40 kg P2O5 ha(-1)) in sub plot were tested in split plot design with four replications using blackgram cv. Gujarat Urd 1. Growth and yield attributes of black gram were significantly affected due to irrigation scheduling based on critical growth stages. Significantly highest seed and straw yield of black gram were obtained under I-2 (irrigation at branching, at flowering, at pod formation and at grain filling stage) as compared to other. Phosphorus application @ 40 kg P2O5 ha(-1) (P-2) produced significantly the highest seed yield (1246 kg ha(-1)) and straw yield (3271 kg ha(-1)), which were increased to extent of 38.44 and 30.21 % respectively over treatment P-0 (0 kg P2O5 ha(-1)). The higher net realization of (Rs. 34922 ha(-1)) with BCR value of 3.08 was recorded with treatment I-2 and in treatment P-2 40 kg P2O5 ha(-1)) (Rs. 35686 ha(-1)) with BCR 3.26.