Studies on the Effect of Tribenuron-Methyl and 2,4-D on Soil Microorganisms

The effect of tribenuron-methyl and 2,4-D on the population of soil microorganisms was studied in lime soil by potted plant. Results showed that the reaction of soil microorganisms to these two herbicides was different. High concentration of tribenuron-methyl inhibited bacteria's growth significantly in the first 3 days, then it stimulateed their growth, especially towards the end of cultivation, the activity ratio inereased to 917.6%, and low concentration of tribenuron-methyl also stimulated bacteria's growth significantly. Tribenuron-methyl stimulated actinomyces growth and inhibits fungi remarkably, with the maximum inhibition ratio of 100%, and the quantity of fungi failed to fall back to that of the control at the end of cultivation. The effect of 2,4-D on actinomyces remained changing between inhibition to activation, while on fungi and bacteria it was significant.