Microbial application for the amelioration of sodic and saline-sodic soils may reduce the economic and environmental costs of chemical amendments. The effect of microbial application on saturated hydraulic conductivities of four different saline-sodic soils which were being ameliorated with gypsum was studied. Suspensions of three fungal isolates (Aspergillus spp. FS 9, 11 and Alternaria spp. FS 8) and two bacterial strains (Bacillus subtilis OSU 142 and Bacillus megaterium M3) at 10(4) spore/ml and 10(9) CFU/ml, respectively, were mixed with leaching water and applied to the soil columns. The measured saturated hydraulic conductivities of soil columns after the treatment indicated that saturated hydraulic conductivity of saline-sodic soils increased significantly (P < 0.01) by application of the microorganisms. Average increase for all soils was 68%. The data suggest that microorganisms tested in the present study may have potential to help improve water movement through saline-sodic soils
