Published Paper Details:

Soil deficiencies of essential elements can dramatically decrease legume nodulation, nitrogen fixation, nitrogen accumulation and yield. Eighteen different locations were selected in Cuddalore and Nagai district for the nodulation pattern of Black gram in rainfed areas. The three locations namely Pandaravadai, Vallampadugai and Kokkur supported good nodulation and also supported fairly in high native rhizobial populations of 112x106, 98 x106 and 91x106 cells g -1 moisture free soil respectively. The cell count was minimum in the soil sample of Pinnathur (2 X106 cells g-1 moisture free soil). The present study clearly established the existence of a parallelism between the native soil population of rhizobia and natural nodulation. All these eighteen locations viz., Were analysed for the pH, EC nitrogen content, potassium content and phosphorus content. These data were used to correlate the natural population pattern and native rhizobial populations of these locations Pandaravadai having the soil pH - 7.1, EC - 0.60 and NPK 150,30,412.5 kg/ha recorded high nodule number and native rhizobial population the properties of this soil seems to be very congenital for the multiplication's of rhizobia and for the nodulation and nitrogen fixation.