Ecology, Environment and Conservation Paper

SURVIVAL OF RHIZOBIUM IN SOIL AT DIFFERENT PH, TEMPERATURE AND MOISTURE LEVELS

A.K. Dekal , P. Azad and S.C,Paira

Abstract

Six different Rliizobium strains viz. A1' ' C G Gn" Gri and S isolated from different pulses and legumes grown in acid soils of Assam were tested for their survival in sterile but adverse soil environment. The strain Gn, showed the best survival at pH 6.5 with a population of 83.'00 X 10s cfu gl soil at 14th day of incubation which was 26.40 per cent more than its initial population. The same strain Gn2 showed the best thriving at pH 4.5 with a population of 19.33 X 108 cfu g.' soil which was only 56.72 per cent lower than its initial population unlike the other strains the population of which declined drastically at 14th day of incubation. At soil temperature 15"C, the strain S, could survive best with a viable count of 6.33 X 108 cfu gl soil on 14th day of incubation. At a soil moisture level of 25 per cent of Field Capacity strain Cmshowed only 23.81 per cent decrease from its initial population 14.00 X 108 cfu gl soil at 14th day of incubation. The same strain Cm exhibited maximum survival at Field Capacity also with a population of 9.00 X108 cfu g-1 soil at 14th day of incubation which was about 6 times more than its initial population.