Acid soils affect nutrient uptake, microbial activity, crop growth, biomass and yield. Thus, the maintenance and management of acid soils are very much important to obtain higher productivity. In this study, possibility of using low cost liming materials like LD slag to ameliorate acid soil was investigated and its impacts on total heterotrophic bacterial population, total P-solubilizing bacteria population, microbial biomass carbon (MBC) and dehydrogenase activities (DHA) of rhizosphere of groundnut were assessed under tropical monsoon climate of eastern India. The LD slag was applied @ 0.3 LR along with vermicompost and inorganic fertilizers in different rates viz., 50, 75 and 100% of recommended dose of fertilizer (RDF). LD slag was applied one day before sowing of the crop and results were compared among treatments. Soil amelioration along with recommended organics addition (vermicompost) positively improved the soil reaction, culturable microbial population (heterotrophic and P-solubilizing bacteria) and Psolubilization efficiency. But MBC and DHA activities were improved more with integrated application of LD slag with inorganics and VC.