Effect of Soil Water Content on the Distribution of Diuron into Organomineral Aggregates of Highly Weathered Tropical Soils

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• 作者：Jussara B. Regitano ; Wadson S. D. Rocha ; Eloana J. Bonfleur ; Debora Milori ; Luís R. F. Alleoni
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2016
• 出版时间：May 25, 2016
• 年：2016
• 卷：64
• 期：20
• 页码：3935-3941
• 全文大小：481K
• 年卷期：0
• ISSN：1520-5118

文摘

We evaluated the effects of soil water content on the retention of diuron and its residual distribution into organomineral aggregates in four Brazilian oxisols. ¹⁴C-Diuron was incubated for days at 25, 50, and 75% of maximum water-holding capacity for each soil. After 42 days, the physical fractionation method was used to obtain >150, 53–150, 20–53, 2–20, and <2 μm aggregate sizes. Diuron retention increased with increasing soil water content for all soils. At lower soil water content, diuron’s retention was higher in the sandier soil. It was mostly retained in the fine (<20 μm) aggregates of sandier soil, and for clayed soils, retention was higher in the coarse aggregates (>53 μm). The sorption coefficients (K_d and K_oc) generated by batch studies should be carefully used because they do not provide information about aggregation and diffusion effects on pesticides soil sorption.