The land is limited entity of the country, which compel us to increase production and productivity of land per unit area and to rehabilitate the problematic soil for crop production, forestation and to maintain friendly ecosystem. In our country land is subjected to various types of degradation out of which 9.38mha suffered from sodicity and alkalinity. It is developed by accumulation of excessive salts in upper surface of soil. Sodic soil has high concentration of CO3,HCO3 and excess of Na on the exchangeable site of clay particles. They are deficient in nitrogen, phosphorous and zinc such...

Biological nitrogen fixation is an important aspect of nitrogen nutrition in crop production throughout the world. The process saves a huge sum of money, which otherwise would have to the pumped into agricultural productivity to consistently sustain an increasing world population. Among the various symbiotic associations, the Rhizobium - legume association is the most common in both temperate and tropical climates.The importance is not only limited to plant nutrition, but increasing environmental concerns indicate that high input of nitrogen fertilizers in agriculture may lead to many...