Adsorption and degradation of four neonicotinoid insecticides in yellow soil, and accelerated degradation of dinotefuran through the application of organic matter
2014
Yoshimura, Y. | Ootake, T. | Kasuya, M.
We clarified the adsorption and disappearance curves of four neonicotinoid insecticides (acetamiprid, imidacloprid, clothianidin, and dinotefuran) in yellow soil. We determined low soil sorption constants(Koc) and weak adsorption in yellow soil for all four of the neonicotinoid insecticides. In addition, we showed that adsorption was weaker in yellow soil than in andosol. In yellow soil with variable soil carbon content through the application of cattle manure, we found no marked differences between the adsorption of imidacloprid and dinotefuran. The estimated half-life of clothianidin in yellow soil was approximately 97 days, which was the longest in the present study. Imidacloprid and dinotefuran had estimated half-lives of approximately 85 days and 72 days, respectively. Acetamiprid had the shortest half-life of approximately 4 days. In yellow soil that was continuously supplemented with cattle manure, pesticide degradation was accelerated and the half-lives were shorted. In the case of dinotefuran, the reduction in the half-life was statistically significant. Accelerated degradation of dinotefuran resulted in an increase in soil biomass carbon content. Thus, the remaining dinotefuran in the soil will continue to be decomposed by soil microorganisms.
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