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首页> 外文期刊>African Journal of Biotechnology >Imidacloprid adsorption by soils treated with humic substances under different pH and temperature conditions
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Imidacloprid adsorption by soils treated with humic substances under different pH and temperature conditions

机译：在不同pH和温度条件下用腐殖质处理过的土壤对吡虫啉的吸附

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The?mobility of a pesticide in soil is determined by the extent and strength of sorption,?which?is influenced by either the existing soil humus or exogenous humic substances. Exogenous humic acids?(HAs)?were added to soil to enhance the amount of soil organic carbon?(SOC)?by 2.5, 5.0 and 10.0 g kg-1. Imidacloprid sorption of the treated soils was studied at three pH levels?(4.5, 6.0 and 7.5)?and two temperatures (15 and 25°C). Soil imidacloprid adsorption was related to pH and the type and quantity of added HAs. Humic acid?(HA)?and fulvic acid?(FA)?derived from peat had different effects on adsorption of imidacloprid. When soil solution pH was 6, the amount of adsorbed imidacloprid was enhanced with increasing exogenous HA.?On the contrary,?the amount of adsorbed imidacloprid decreased with increasing quantity of exogenous FA. Adsorption of imidacloprid in the FA treatment at 5.0 and 10.0 g kg-1?was lower than the controls?(untreated soil or treatment with HAs at 0 g kg-1)?when the soil solution pH was 6.0. However adsorption of imidacloprid in the HA treatment was higher than the controls. Imidacloprid adsorption was usually higher under lower pH and/or lower temperature at same condition. Imidacloprid sorption fitted the Freundlich isotherm, indicating that exogenous humic substances influenced adsorption of imidacloprid, which in turn was affected by environmental conditions such as pH and temperature. Thus, exogenous HA can be used to control the mobility of soil pesticide under appropriate conditions to decrease pesticide pollution diffusion and probably increase effectiveness of pesticides.
机译：农药在土壤中的迁移率取决于吸附的程度和强度，而吸附的程度和强度则受现有土壤腐殖质或外源腐殖质的影响。向土壤中加入外源腐殖酸（HAs），使土壤有机碳（SOC）的含量增加2.5、5.0和10.0 g kg-1。在三个pH值（4.5、6.0和7.5）和两个温度（15和25℃）下研究了吡虫啉对土壤的吸附。土壤吡虫啉的吸附与pH值以及添加的HAs的类型和数量有关。泥炭来源的腐殖酸（HA）和富里酸（FA）对吡虫啉的吸附作用不同。当土壤溶液的pH值为6时，吡虫啉的吸附量随外源HA的增加而增加。反之，吡虫啉的吸附量随外源FA的增加而降低。当土壤溶液的pH值为6.0时，FA处理的吡虫啉在5.0和10.0 g kg-1的吸附量低于对照（未处理的土壤或0 g kg-1的HA处理）。然而，HA治疗中吡虫啉的吸附高于对照。在相同条件下，pH较低和/或温度较低时，吡虫啉的吸附通常较高。吡虫啉的吸附符合Freundlich等温线，表明外源腐殖质影响吡虫啉的吸附，而吡虫啉的吸附又受pH和温度等环境条件的影响。因此，在适当的条件下，外源HA可用于控制土壤农药的迁移率，以减少农药污染扩散并可能提高农药的有效性。

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