Effects Of Three Kinds Of Fertilizers On Degradation Of Herbicide Chlorsulfuron

Chlorsulfuron , which is widely used in China ,was first introduced in 1982 by DuPont Agricultural Products; it is widely used for controlling grasses , broadleaf and brush weeds in crops. The rate of degradation of chlorsulfuron in soil is strongly dependent upon pH, moisture content , temperature of the soil and so on. Residue of chlorsulfuron in soil can significantly influence the growth rates of some crops, and even do great harm to crops. The gas chromatography analysis, purification, and effects of fertilizers on degradation of chlorsulfuron were studied in this paper. A method was developed for determining chlorsulfuron by direct gas chromatography. Samples were treated with NaHCO3 solution, then extracted with CH2C12. The value of pH was adjusted to being acid, and chlorsulfuron was extract again with CH2C12. Chlorsulfuron was decomposed into p-chlorobenzen sulfonamide in injection port, and was measured by electron capture detector. The method, its process was much simple, quickly used and saved much more solvent than previous methods, could be employed to determine chlorsulfuron in sand culture samples, industrial products and formulations It was investigated that chlorsulfuron was purified from industrial product as standard sample. The melting point, refractive dioptre,, and IR of the purified chlorsulfuron were the same as that of imported chlorsulfuron standard sample, and the content of chlorsulfuron ,which was measured with gas chromatography and deration ,of purified sample and imported standard sample were both above 0.9800. The purified chlorsulfuron from industrial product can be used as the standard sample of analysis of chlorsulfuron residue and commodity inspection instead of imported standard sample of chlorsulfuron.The experiments of effects of fertilizers on degradation of chlorsulfuron were composed of two chlorsulfuron levels: 330 g/g and 33 g/g. The degradation curves of chlorsulfuron were subject to parabola equation in the control, and spiked with 800 u g/g (NH2)2CO, 800 P g/g NH4HCO3, 800 g/g Ca(H2PO4)2 separately, when sand samples were spiked with 330 g/g chlorsulfuron, and the half-lives of chlorsulfuron were respectively 26.7, 30.5, 116, and 23.4 days. The degradation curves of chlorsulfuron of four treatments when sand samples were spiked with 33 g/g chlorsulfuron also followed parabola equation except sample spiked (NH2)2CO, and the half-lives of chlorsulfuron were respectively 19.2, 81.6, and 10.8 days. The degradation curve of chlorsulfuron of treatment of 33 g/g chlorsulfuron and (NH2)2CO showed it decline fast in the initiate 10 days and going up ,so there was a peak in the second 10 days and decline slowly again. Results demonstrate that hight initial concentration of chlorsulfuron made chlorsulfuron degrade difficultly; Ca(H2PO4)2 faciliated the degradation of chlorsulfuron because pH of sample solution increased; on the contrary NH4HCO3 hindered the degradation of chlorsulfuron because pH of sample solution increased; (NH2)2CO easily combined with chlorsulfuron into some kinds of compound-"Chemical Time Bomb", which was first quickly, later slowly decomposed by microbe et al, may do great harm to the next crops and may be the one reason why chlorsulfuron and metsulfuron-methyle were prohibited from using in Yancheng District, Jiangsu Province, and must be played much emphasis on.