Singh Neera
Division of Agricultural Chemicals, Indian Agricultural Research Institute, New Delhi 110012, India.
J Environ Qual. 2003 Sep-Oct;32(5):1743-9. doi: 10.2134/jeq2003.1743.
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.
施用有机肥和氮肥会影响农药在土壤中的吸附和迁移。本研究通过批量实验和柱实验，总结了在添加牛粪（2.5%和5.0%）和尿素（60和120 kg N ha(-1)）后，土壤中异丙甲草胺[2-氯-N-(2-乙基-6-甲基苯基)-N-(2-甲氧基-1-甲基苯基)乙酰胺]的吸附和淋溶情况。牛粪和尿素的施用均增加了土壤中异丙甲草胺的吸附。在土壤1中，处理T0、T1（有机肥）和T2（有机肥）的Freundlich吸附参数K(r)(1/n)值分别为2.31、3.32和3.96；在土壤2中分别为2.02、2.77和3.32；在土壤3中分别为1.10、1.46和2.02。同样，处理T1（尿素）和T2（尿素）在土壤1中的K(f)(1/n)值分别为2.37和2.84；在土壤2中分别为2.16和2.83；在土壤3中分别为1.50和1.70。使用土壤1进行的柱淋溶研究表明，施用有机肥显著降低了异丙甲草胺的淋溶损失，从50%（天然土壤）降至<1.0%（5.0%有机肥改良）。同样，施用尿素也降低了异丙甲草胺的迁移性，在施用60和120 kg N ha(-1)尿素的柱中，淋溶损失分别为33%和20%。异丙甲草胺淋溶损失的减少是通过增加有机肥和尿素改良土壤的吸附能力实现的。因此，在低有机质土壤中，将异丙甲草胺与牛粪或尿素肥料共同施用不会增强异丙甲草胺的迁移性，并减少其淋溶损失。
