Reduction of soil pH using Thiobacillus cultures

摘要

Occurrence of saline, alkaline and sulfur-deficient sods has become an important problem in the Indian subcontinent which has affected important cash crops like tea and potato. An attempt was made to reduce the soil pH by providing soils with oxidizable substrate like sulfur or pyrite alongwith inoculation of appropriate Thiobacillus cultures. It was seen that among the various soil amendments tested, treatment with sulfur + T. thiooxidans was found to be most efficient, followed by sulfur + T. ferrooxidans, uninoculated sulfur, and pyrite + T. ferrooxidans. With these treatments a decrease in soil pH by 0.5-2.5 units could be achieved. As the soil pH decreased, sulfate levels of the soils raised alongwith concomitant increase in solubilization of micronutrients such as manganese and calcium. Due to decrease in soil PH, a phytopathogenic strain of Streptomyces scabies was found to be completely inhibited. These results open up new possibilities of using Thiobacillus cultures in soil treatment for increased crop productivity and control of certain plant pathogens.