Short-term Effects of Organic Manure and Microbial Biofertilizer Doses on Soil Properties under Cluster Bean Cultivation in Southern Odisha, India

Aims: To evaluate the impact of different doses of organic amendments (FYM and vermicompost), with or without Rhizobium inoculation, on soil physical and chemical properties during clusterbean (Cyamopsis tetragonoloba) cultivation. Design of Study: A field-based factorial randomized block design (RBD) with nine treatments and three replications. Place and Duration of Study: The experiment was conducted during the summer of 2025 at the Organic Research Farm, M.S. Swaminathan School of Agriculture, Centurion University of Technology and Management, Paralakhemundi, Odisha, India. Methodology: Nine treatments involved combinations of FYM and vermicompost at 100% and 150% recommended levels, with and without Rhizobium inoculation. Soil samples were collected at 30, 60, and 90 days after sowing (DAS) from the 0–15 cm depth. Physical (bulk density, texture) and chemical (pH, SOC, and available N, P, K) properties were analyzed using standard procedures. Results: All organic treatments reduced soil bulk density, with 150% vermicompost + Rhizobium showing the lowest values (1.22 g/cm³ at 90 DAS). The texture remained sandy loam, with minor improvements in silt and clay fractions. pH was moderated most effectively by combined organic + Rhizobium treatments, maintaining near-neutral values. SOC increased across all treatments, with 100% FYM showing the highest (0.88% at 90 DAS). Available N, P, and K also improved significantly, with 150% vermicompost + Rhizobium consistently showing superior nutrient levels, especially for phosphorus (25.44 mg/kg) and potassium (206.08 mg/kg) at 90 DAS.