INFLUENCE OF CADMIUM ON DECOMPOSITION OF GLUCOSE AND CELLULOSE IN SOIL

Investigations were conducted to clarify the mechanism of inhibition of cadmium (Cd) on the decomposition of glucose and cellulose in soil. Gley soil was treated with CdCl2 at concentrations of 0 to 10-mu-mol Cd/g soil. After 1 day, the soil was amended with glucose or cellulose at 1% rate, and incubated at 28-degrees-C for 2 or 8 weeks, respectively. The amount of CO2 evolved, the amount of glucose or cellulose remaining in the soil, the numbers of bacteria and fungi, and the content of adenosine 5'-triphosphate (ATP) in the soil were determined periodically. Glucose was decomposed entirely within 3 days even with 10-mu-mol Cd/g soil. The amount of cellulose also decreased to the level in the control soil after 8 weeks for all the treatments. The amount of CO2 evolved from the soil amended with glucose or cellulose tended to decrease, whereas the number of fungi and ATP content of the soil tended to increase with the incease in the Cd concentration. These results suggest that the amount of carbon incorporated into the biomass, especially the fungal biomass, is increased by Cd addition and that the amount of CO2 evolved decreases as a consequence.