Degradation and Sorption of Fluometuron and Metabolites in Conservation Tillage Soils
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- 作者：Martin A. Locke ; Robert M. Zablotowicz ; R. Wade Steinriede ; William L. Kingery
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2007
- 出版时间：February 7, 2007
- 年：2007
- 卷：55
- 期：3
- 页码：844 - 851
- 全文大小：158K
- 年卷期：v.55,no.3(February 7, 2007)
- ISSN：1520-5118
文摘
Soil sorption and dissipation of fluometuron (FLM) and three metabolites, desmethyl fluometuron(DMF), trifluoromethyl phenyl urea (TFMPU), and trifluoromethyl aniline (TFMA), were assessed inconservation tillage soils. In study I, surface Dundee silt loam soils from no-tillage (NT) and reduced-tillage (RT) areas were treated with 14C ring-labeled FLM or TFMA or unlabeled DMF, incubated for34-42 days, extracted, and analyzed. Mineralization and volatilization of 14C-labeled FLM or TFMAwere monitored. In study II, batch sorption assays (solute concentrations 2-50 
mol L-1; 2:1 solution:soil; 18 h) were conducted using various soils from reduced- (RT) and conventional-tillage (CT) areasto determine the relative affinity of FLM and metabolites for soils with differing characteristics.Mineralization of FLM (3%, day 42) or TFMA (4%, day 34) and FLM volatilization (~2%) were low forboth soils. FLM and DMF dissipated more rapidly in RT soil than in NT soil. In FLM-treated RT soil,DMF and TFMPU accumulated more rapidly than in NT as FLM degraded. TFMA dissipated rapidly,primarily as nonextractable residues (~70%, day 42) and volatilization (~16%). For all respectivesoils in study II, sorption of all four compounds was higher for organic C-enriched RT soils than forCT soils, indicating strong relationships between organic C and FLM and metabolite sorption. Foreither tillage treatment, the percentage sorption was greater for metabolites (e.g., at lowest initialdosing concentration, TFMPU range, 45-91%; DMF range, 45-90%; and TFMA range, 45-98%)than for FLM (RT soils range, 19-65%). Nonsubstituted amino groups likely facilitated sorption toorganic C, with nonsubstituted aniline in TFMA having the greatest affinity. NMR spectra of humicacid extracts from NT and CT Dundee soils indicated similar patterns of humic acid functional groups,but the potential capacity for sorption was greater in NT than in CT. The greater capacity for FLMand metabolite sorption in NT soil helps explain their longer persistence.
mol L-1; 2:1 solution:soil; 18 h) were conducted using various soils from reduced- (RT) and conventional-tillage (CT) areasto determine the relative affinity of FLM and metabolites for soils with differing characteristics.Mineralization of FLM (3%, day 42) or TFMA (4%, day 34) and FLM volatilization (~2%) were low forboth soils. FLM and DMF dissipated more rapidly in RT soil than in NT soil. In FLM-treated RT soil,DMF and TFMPU accumulated more rapidly than in NT as FLM degraded. TFMA dissipated rapidly,primarily as nonextractable residues (~70%, day 42) and volatilization (~16%). For all respectivesoils in study II, sorption of all four compounds was higher for organic C-enriched RT soils than forCT soils, indicating strong relationships between organic C and FLM and metabolite sorption. Foreither tillage treatment, the percentage sorption was greater for metabolites (e.g., at lowest initialdosing concentration, TFMPU range, 45-91%; DMF range, 45-90%; and TFMA range, 45-98%)than for FLM (RT soils range, 19-65%). Nonsubstituted amino groups likely facilitated sorption toorganic C, with nonsubstituted aniline in TFMA having the greatest affinity. NMR spectra of humicacid extracts from NT and CT Dundee soils indicated similar patterns of humic acid functional groups,but the potential capacity for sorption was greater in NT than in CT. The greater capacity for FLMand metabolite sorption in NT soil helps explain their longer persistence.