A field experiment was conducted to workout the effect of different organic manure, biofertilizer and phosphorus on yield attributes, yield, nutrient concentration, physico-chemical properties, nutrient availbability, dynamics of soil microbial biomass and enzymes activity of mungbean in loamy sand soil at Agronomy farm, S.K.N. College of Agriculture, Jobner during kharif seasons of 2010 and 2011. The result revealed that under application of 2.5 t vermicompost ha-1, effective nodule, total nodules per plant, nitrogen fixing percentage at flowering stage, nodule index, seed and straw yield as well as phosphorus use efficiency of mungbean increased significantly. Inoculation with PSB + VAM significantly increased effective and total nodules per plant, nitrogen fixing percentage at flowering stage, nodules index, seed and straw yield, phosphorus use efficiency. The application 40 kg P2O5 ha-1 significantly enhanced the effective and total nodules per plant, nitrogen fixing percentage at flowering stage, nodules index, seed and straw yield over all the lower levels of phosphorus. Phosphorus use efficiency significantly higher with 20 kg P2O5 ha-1. The combined use of vermicompost (2.5 t ha-1) with PSB + VAM and vermicompost (2.5 t ha-1) with 40 kg P2O5 ha-1 significantly increased the seed and straw yield indicating saving of 20 kg P2O5 ha-1 by the use of vermicompost @ 2.5 t ha-1 and dual inoculation of PSB + VAM. The optimum dose of phosphorus was predicted as 53.00 kg P2O5 ha-1 with mean optimum yield of 1012.61 kg ha-1.