Effect of Phosphate Dissolving Bacteria Applied with Rock Phosphate on Nodulation and Yield of Rainfed Soybean Under Different Agroclimatic Conditions

Field experiments were conducted during kharif 1988–92 with soybean under rainfed condition at six locations viz. Bangalore, Ranchi, Pant Nagar, Parbhani, New Delhi ami Sehore. Superphosphate @ 60 kg P₂O₅ ha⁻¹ significantly improved all the parameters except yield at New Delhi. It was equally effective with rock phosphate @ 30 kg P₂O₅ ha⁻¹ + Pseudomonas striata (PDB) inoculation for nodule number, nodule dryweight and yield at most of the locations where soil P was low to medium except yield at New Delhi. However, rock phosphate without PDB inoculant was found effective only at Ranchi. Maximum net return, phosphorus use efficiency, relative agronomic effectiveness and relative economic effectiveness were found with rock phosphate @ 30 kg Pps ha⁻¹ + PDB inoculation.