The Residue And Degradation Of Bensulfuron-methyl In Tobacco Field And Effect On The Tobacco Growth And Quality

Bensulfuron-methyl is a kind of sulfonylurea herbicide, currently it is recommended using as a rice herbicide in China, this kind of herbicides was widely used in crops before Hunan tobacco field on rice. In order to evaluate whether its residual in the tobacco field threatened to environment, this paper systematically studied bensulfuron-methyl and its preparation influencing on plant growth and the quality and production of tobacco leaves after used in tobacco field, its residual and degradation situation in plant tobacco soil, and its adsorption in soil and the influence on root growth. These studies have important significance for the comprehensive accurate evaluation of ecological environment security of bensulfuron-methyl in tobacco field residues, guiding its scientific and reasonable using in tobacco production; Also provide the scientific basis for cigarette manufacturing enterprise on choosing and buying of quality tobacco. The main conclusions were as follows:1) Bensulfuron-methyl in the tobacco field soil digestion followed a dynamic equation of chemical reaction dynamics. Before in tobacco transplanting 1-2 d, one-time spraying 10%bensulfuron-methyl with 300g/hm2, tobacco field soil in Changsha, Hunan the half-life 2.06d respectively, belong to easily degradable herbicide (T1/2<30 d).2) In five plant tobacco soil, the adsorption equilibrium time of bensulfuron-methyl was 14-16 h, the adsorption size order of five plant tobacco soil:the black soil in Heilongjiang> the red soil in Changsha> the yellow and brown soil in Xinyang Henan> the moist soil in Changsha> the brown soil in Taian Shandong. The weakest mobility of bensulfuron-methyl in plant tobacco soil was the black soil in Heilongjiang, the strongest mobility of bensulfuron-methyl in plant tobacco soil was the brown soil in Taian Shandong. The pH and Kf of soil was negatively correlated; content of soil organic matter and CEC have positive correlation with the Kf of soil. The main influential factor of bensulfuron-methyl in plant tobacco soil was organic matter content and pH. In five plant tobacco soil, the adsorbent reactive free energy of bensulfuron-methyl was 15.93-18.53 kJ/mol, less than 40 kJ/mol, showed that the adsorption of bensulfuron-methyl play with physical function mainly in five plant tobacco soil.3) Through the research of bensulfuron-methylon fresh weight of tobacco root, oxidation force of root and CEC of root, the results showed that, in certain range, bensulfuron-methyl was harmful to the growth of tobacco root, with the passage of time, the influence weakened. Bensulfuron-methyl against to the oxidation force of root had same inhibition, but not very apparent, as tobacco growth, the oxidation force of tobacco root strengthened ceaselessly, the influence of bensulfuron-methyl was weakened. Bensulfuron-methyl against to the CEC of root had inhibition too, in experimental concentration range, the CEC of root increased with the concentration of bensulfuron-methyl. Overall, bensulfuron-methyl had larger inhibition for the growth of tobacco root, and in a certain range, the inhibition of growth of tobacco root increased with the bensulfuron-methyl residual augmentation enhanced.4)After application of bensulfuron-methyl in tobacco field, it had a apparent inhibition for the growth of tobacco in the whole tobacco growth, and high concentration dealing had larger inhibition than low concentration dealing. This showed that in the former season tobacco field, the residues of bensulfuron-methyl had inhibition to tobacco growth, and the inhibitory effect increased with the residual bensulfuron-methyl. After bensulfuron-methyl was applied in tobacco field, had Significant impact to tobacco leaves production, and the high concentration dealing was larger than low concentration dealing; Meanwhile bensulfuron-methyl would lead to lower quality of tobacco leaves, the high concentration dealing was more obvious reduction effects than low concentration dealing. After application of bensulfuron-methyl in tobacco field, whether in high concentration dealing or low concentration dealing, its main chemical compositions compared with contrast the content of nicotine decreased, in certain concentration range, the content of nicotine decreased with the increasing of bensulfuron-methyl concentration, other major chemical constituents content had no obvious difference. It showed that bensulfuron-methyl had certain influence to the quality of tobacco leaves, its using in tobacco field would lead to the quality of tobacco leaves decline.