Effect of Nutrient Sources Particularly of Phosphorus on Growth and Productivity of Summer Blackgram Under Lateritic Soil

An experiment was conducted at the Instructional Farm of Rathindra KrishiVigyan Kendra, Visva-Bharati, Sriniketan, Birbhum during the summer season 2014–15, to study the different nutrient management practices with special emphasis on effect of phosphorus on growth, productivity, soil fertility and economics of summer black gram. The treatments were T1= Control (No source of nutrient), T2= Vermicompost (V.C) @ 2.5 t/ha, T3= V.C + Biofertiliser (B.F) (Rhizobium and Phosphorus Solubilising Bacteria), T4= V.C + BF+ Sea weed extract (10%), T5= DAP @100 kg/ha, T6= DAP +BF, T7= DAP + BF + Sea weed extract (10%), T8=Urea (20kg/ha)+SSP (40 kg/ha), T9= Urea+SSP +BF, T10= Urea+SSP +BF +Sea weed extract (10%). The experiment was conducted in randomised block design with 3 replications. The soil was acidic (pH-6.18) in reaction, sandy loam in texture with low organic carbon, availablephosphorus and medium in potassium content. The maximum increase in growth attributes was found with the application of T10 i.e. Urea+SSP+Biofertiliser+Sea weed extract treatment followed by T4 and T7. The significantly higher grain yield (9.45 q/ha) and yield attributes were obtained under treatment of T10 than those of other treatments. The maximum net return (Rs. 24, 050/-ha) and BC ratio (1: 2.04) was obtained from the treatment T10.