Biodegradation potentiality of metsulfuron-methyl in acclimated wheat rhizospheric soil

The degradation of metsulfuron-methyl in different soils,including acclimated and/or original wheat soil,rhizospheric and/or non-rhizospheric soil,was investigated by determining its residual concentration with HPLC.The results show that the degradation dynamics of metsulfuron-methyl in soil fitted to the first order reaction kinetics,the degradation rate constant was about 0.037-0.020 d-1 and the half life was about 18.7-34.7 d.The soil,which had been planted wheat previously,promoted the degradation of metsulfuron-methyl significantly.The difference of degradation rate constant between the rhizospheric and non-rhizospheric soil was significant at the 0.05 probability level.The biodegradability of microbe was enhanced by domestication.On the 20th day,the removal rate of metsulfuron-methyl in the domesticated soil was higher 6 to 12 percent than that without domestication.Furthermore,the low concentration of metsulfuron-methyl was benefit for its degradation,the degradation rate constant of metsulfuron-methyl increased with its concentration reducing.The result above provides a theoretical feasibility for accelerating the degradation of the sulfonylurea herbicides in plant rhizospheric soil.