Effect of phosphorus, molybdenum and Rhizobium on quality of greengram, available nutrient status and microbial count of soil in loamy sand

A field experiment entitled, “Effect of phosphorus, molybdenum and Rhizobium on quality of greengram, available nutrient status and microbial count of soil in loamy sand” was conducted at Agronomy Instructional Farm, Chimanbhai Patel College of Agriculture, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar during kharif, 2019 and 2020 in different adjoining similar sites. The soil of the experimental field was loamy sand in texture, normal in pH and EC, low in available nitrogen, medium in available phosphorus and potassium and deficient in available molybdenum. The experiment comprised of eighteen treatment combinations i.e. three levels of phosphorus (P1: 20 kg P2O5 ha-1, P2: 40 kg P2O5 ha-1 and P3: 60 kg P2O5 ha-1); three levels of molybdenum (Mo0: 0.0 kg Mo ha-1, Mo1: 0.5 kg Mo ha-1 and Mo2: 1.0 kg Mo ha-1) and two levels of Rhizobium (R0: without rhizobium inoculation and R1: with rhizobium inoculation) were evaluated with GM 4 cultivar of greengram in randomized block design (R.B.D.) in factorial concept with three replications. Application of phosphorus did not exert any significant effect on protein content in seed and chlorophyll content in leaf at 45 DAS. Application of P significantly improved available P2O5 status of soil at harvest stages, but available N, K2O and Mo content of soil did not found significant. The molybdenum content of soil after harvest of greengram was increased significantly with the addition of molybdenum up to 1.0 kg ha-1, but total microbial count increased significantly up to 0.5 kg Mo ha-1 over control. Nutrient status of soil did not exert any significant effect, but total microbial count increased significantly. Application of 40 kg P2O5 ha-1 along with 0.5 kg Mo ha-1 and seed inoculation with Rhizobium were found to be most beneficial for greengram variety GM 4 grown in the light textured soils of north Gujarat.