Bio-fertilizer contains microorganisms which promote the adequate supply of nutrients to the host plants and ensure their proper development of growth and regulation in their physiology. The production of bacterial bio-fertilizer essentially requires the selection of appropriate strains for a particular crop in a given agro-climate. As agro-climatic conditions and soil characteristics vary widely, a large range of strains of each bio-fertilizer needs to be isolated for each area. Bio-fertilizers are eco-friendly, one of the best modern tools for agriculture and are used to improve the fertility and quality of the soil. It offers an economically attractive and ecologically sound route for augmenting nutrient supply.. Leguminous crops have the ability to fix nitrogen (N) biologically from the atmosphere. This can benefit not only the legumes themselves but also any intercropped or subsequent crops.