Dr. A. PRASANTHIK. DUNDI SAI ROHAN2024-05-222024-05-222024-05-22D6576https://krishikosh.egranth.ac.in/handle/1/5810209356Combined application of biofertilizers and fertilizers was evaluated for crop response, soil fertility and enzyme activity in black gram through field experiment during rabi, 2021 in Wetland farm at S.V. Agricultural College, Acharya N.G. Ranga Agricultural University, Tirupati, Andhra Pradesh. The experimental soil was slightly alkaline, non-saline, low in organic carbon and nitrogen and medium in available phosphorus and potassium. The experiment was laid out in a randomized block design with ten treatments and three replications. The treatments include control (0% RDF) (T1), 100% RDF (T2), 75 % RDF + Seed treatment with liquid Rhizobium + liquid PSB + liquid KSB (T3), 100 % RDF + Seed treatment with liquid Rhizobium + liquid PSB + liquid KSB (T4), 75 % RDF + Seed treatment with solid Rhizobium + solid PSB + solid KSB (T5), 100 % RDF + Seed treatment with solid Rhizobium + solid PSB + solid KSB (T6), 75 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T7), 100 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T8), 75 % RDF + Soil application of solid Rhizobium + solid PSB + solid KSB (T9) and 100 % RDF + Soil application of solid Rhizobium + solid PSB + solid KSB (T10). The recommended dose of fertilizers for rabi black gram is 25:50:25 kg N:P2O5:K2O ha-1 Combined application of 100 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T8) recorded numerically the highest plant growth parameters viz., dry matter production, plant height, number of branches plant-1 , number of nodules plant-1 at 30 DAS, 60 DAS and harvest stages. Yield parameters like number of pods plant-1 and number of seeds pod-1 were registered numerically the highest under combined application of 100 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T8) treatment. xvi Significantly the highest seed yield and straw yield was noticed in 100 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T8) treatment. Combined application of 100 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T8) resulted in the highest numerical values of N, P and K uptake by plant at all growth stages of crop. The highest soil microbial population (bacteria, fungi and actinomycetes) were observed at 30 DAS, 60 DAS and harvest stages with the application of 100 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T8). The microbial activity was increased from 30 DAS to 60 DAS later on decreased at harvest Combined application of 100 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T8) showed numerically the highest values of soil urease, alkaline and acid phosphatase and dehydrogenase enzyme activity at all growth stages of crop. All these enzymes activity was increased from 30 DAS to 60 DAS and decreased at harvest stage of crop. Numerically the highest values of available N, P2O5 and K2O in soil were exhibited due to combined application of 100 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T8) treatment at all stages of crop growth. The pH, EC, OC, exchangeable Ca and Mg, available sulphur and DTPA extractable micronutrients (Fe, Mn, Zn, Cu) were not significantly affected by combined application of inorganic fertilizers along with biofertilizers after harvest. The highest gross returns, net returns, benefit-cost ratio were obtained under combined application of 100 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T8) followed by T3, T4 and T7 treatments. In conclusion, the study indicated that application of 100 % RDF + Soil application of liquid Rhizobium + liquid PSB + liquid KSB (T8) to black gram crop is found to be ecologically and economically feasible nutrient management practice to achieve sustainable yields in Southern Agroclimatic Zone of Andhra Pradesh.EnglishThesis