Senthil Kumar. R and Panneerselvam. A
Totally 10 different paddy field soils were collected from in and around Thiruvarur district, Tamilnadu and their physico-chemical properties and population density of Azospirillum were analyzed. Among them, 5 samples were sandy clay loamy soil, while 3 samples were loamy soil and 2 samples were sandy loam. The pH (7.2-8.2), bulk density (1.11g/cm3 -1.60g/cm3), water holding capacity (33.41% - 18.31%), electrical conductivity (0.89 - 0.24), organic carbon (0.97% - 0.57%), total nitrogen (1.72% - 0.75% ), phosphorus content (0.185% - 0.125%), potassium (1.85% - 1.18%) also available micronutrients like Zn (2.03% - 1.16%), Cu (3.68% - 1.27%), Fe (9.16% - 7.40%), Mn (5.21% - 3.10%), B (0.590% - 0.390%), available nitrogen (191.0kg/acre - 110.5kg/acre), phosphorous (9.6kg/acre - 4.5kg/acre), potassium (295.0kg/acre - 190.5kg/acre) were in all sampling station. The population density of Azospirillum was maximum observed in sandy loam soil at Kudavasal. The minimum population density was observed in loamy soil at Thiruthuraipoondi
