title: Organic manure and urea effect on metolachlor transport through packed soil columns.
abstract: Application of organic manure (OM) amendments and nitrogen fertilizers can affect the sorption and movement of pesticides in soil. This study summarizes the sorption and leaching of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylphenyl) acetamide] in soils after cow (Bos taurus) manure (2.5 and 5.0%) and urea (60 and 120 kg N ha(-1)) amendments in batch and column experiments. Both cow manure and urea applications increased metolachlor sorption in soils. The values of the Freundlich adsorption parameter K(r)(1/n) for treatments T0, T1 (OM), and T2 (OM) were 2.31, 3.32, and 3.96 in Soil 1; 2.02, 2.77, and 3.32 in Soil 2; and 1.10, 1.46, and 2.02 in Soil 3, respectively. Similarly, K(f)(1/n) values for treatment T1 (urea) and T2 (urea) were 2.37 and 2.84 in Soil 1; 2.16 and 2.83 in Soil 2; and 1.50 and 1.70 in Soil 3, respectively. Column leaching studies using Soil 1 indicated that OM application drastically reduced the metolachlor leaching losses from 50% (natural soil) to < 1.0% (5.0% OM amendment). Likewise, urea application also decreased metolachlor mobility and leaching losses in columns treated with 60 and 120 kg N ha(-1) urea were 33 and 20%, respectively. The reduction in the metolachlor leaching losses was achieved through the increase in the sorption capability of the OM- and urea-amended soil. Therefore, coapplication of metolachlor with cow manure or urea fertilizers will not enhance metolachlor mobility and reduces metolachlor leaching losses in low-organic-matter soil.
authors.affiliation: Division of Agricultural Chemicals, Indian Agricultural Research Institute, New Delhi 110012, India. Drneerasingh@yahoo.com
authors.forename: Neera
authors.initials: N
authors.lastname: Singh
mesh_terms: D000081:Acetamides / Q000032:analysis* / Q000737:chemistry; D000327:Adsorption; D000818:Animals; D002417:Cattle; D006540:Herbicides / Q000032:analysis* / Q000737:chemistry; D008372:Manure; D012989:Soil Pollutants / Q000032:analysis*; D014508:Urea / Q000737:chemistry*; D014872:Water Movements; D014873:Water Pollutants / Q000032:analysis
chemical_list: D000081:Acetamides; D006540:Herbicides; D008372:Manure; D012989:Soil Pollutants; D014873:Water Pollutants; D014508:Urea; C051786:metolachlor