Impact of Physico - Chemical Properties of Soil on Population of Nitrogen Fixing Bacteria

Physico-chemical properties of soil play a very important role in growth and survival of nitrogen fixing bacteria. Four soil samples [black, yellow, sandy and red soil] were collected from different parts of Madhya Pradesh region having different colour and different physico chemical properties. These soils were analyzed for soil texture, pH, electrical conductivity, water holding capacity, available nitrogen, available phosphorus and available potassium content. For a living organism to exist in soil, the environmental conditions should be ideal. The highest population of Rhizobium bacteria was found in black soil sample having high organic carbon content while sandy soil was found rich in Azotobacter bacteria. The lowest population of nitrogen fixing bacteria was recorded in red soil which may be due to low pH and high available nitrogen content.