Agricultural and Biological Research

Enhancing soil fertility, yield, and quality in green gram (Vigna radiata L. Wilczek) through integrated nutrient management

Vijay Kumar*

A field experiment was conducted at on clay loam soil. The experiment was laid out according to factorial randomized block design with three replications. The experiment comprised four fertility levels (75% Recommended Dose of Fertilizers (RDF), 75% RDF+Vermicompost (VC) at 2 t ha^-1, 100% RDF and 100% RDF+VC at 2 t ha^-1) and four biofertiliizers levels (control, Rhizobium, Phosphate Solubilizing Bacteria (PSB) and Rhizobium+PSB) were applied to the green gram variety SML-668. The RDF was 20 kg Nitrogen (N₂ ) and 40 kg Phosphorus Pentoxide (P₂ O₅ ) per hectare. The soil of the experimental site was clay loam in texture, slightly alkaline in reaction, medium in available nitrogen and phosphorus, while high in potassium and Diethylene Triamine Pentaacetic Acid (DTPA) extractable micronutrients sufficiently above the critical limits. The main findings of investigation are summarized as: The application of fertility level significantly increased the dry matter accumulation, number of pods per plant, number of seeds per pod, chlorophyll content, seed and haulm yields, nitrogen, phosphorus, potassium, copper, zinc, iron and manganese content and uptake in seed and haulm, protein content in seed, number of total and effective root nodules, fresh and dry weight of root nodules, leghemoglobin content in root nodules and net returns up to 75% RDF+VC at 2 t ha^-1 however, their further increase with application of 100% RDF+VC at 2 t ha^-1 was non-significant. The increase in test weight was found non-significant. The organic carbon, available nitrogen, phosphorus, potassium, copper, zinc, iron and manganese in soil increased significantly with the application of fertility levels at harvest of the crop, but Electrical Conductivity (EC) and pH remain non-significant. Seed inoculation with Rhizobium+PSB significantly increased the dry matter accumulation, number of pods per plant, number of seeds per pod, chlorophyll content, seed and haulm yields, nitrogen, phosphorus, potassium, copper, zinc, iron and manganese content and uptake in seed and haulm, protein content in seed, number of total and effective root nodules, fresh and dry weight of root nodules, leghemoglobin content in root nodules and net returns and the test weight and harvest index were found non-significant. The organic carbon, available nitrogen, phosphorus, potassium, copper, zinc, iron and manganese in soil significantly increased with inoculation of Rhizobium+PSB at harvest stage of the crop, but EC and pH remain non-significant. The interactive effect of fertility levels and biofertilizers significantly influenced the seed and haulm yield, nitrogen, phosphorus, potassium uptake by seed and net returns and maximum being with the application of 100% RDF+VC at 2 t ha^-1 and Rhizobium+PSB combination (F₄B₃), which was at par with 75% RDF+VC at 2 t ha-1 and Rhizobium+PSB combination (F₂B₃ ).