Glyphosate is the most widely used herbicide in Argentina. The strong sorption of glyphosate to the mineral fraction of the soil can be affected by environmental conditions and agricultural management, such as the application of fertilisers. This work aimed to study the effect of pH and the presence of inorganic phosphate on the affinity of glyphosate for nine different surface soils of Argentina. The effect of pH on glyphosate sorption was investigated by batch experiments with pH adjusted between 3 and 12. The greatest glyphosate adsorption occurred at a certain pH value and then adsorption decreased with increasing or decreasing pH. The effects of pH on adsorption could be described by a model that includes changes in electrical potential. The effect of inorganic phosphate on glyphosate adsorption was studied by batch experiments in the presence of 0.5 or 1 mM phosphate. The results showed a significant competition between phosphate and glyphosate in all soils. The Freundlich glyphosate coefficients decreased by 40%–65% with phosphate in solution, and the amount of glyphosate adsorbed decreased between 1% and 5%, depending on the particular characteristics of the soil. For the glyphosate-phosphate competition, the competition terms were not reciprocal with each other because the competition between ions for adsorption sites also involves electrical effects.

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土壤pH值的变化和无机磷酸盐的添加影响农业土壤中草甘膦的吸附

草甘膦是阿根廷使用最广泛的除草剂。草甘膦对土壤矿物质部分的强烈吸附会受到环境条件和农业管理（例如化肥的应用）的影响。这项工作旨在研究 pH 值和无机磷酸盐的存在对阿根廷九种不同表层土壤的草甘膦亲和力的影响。通过批次实验研究了 pH 值对草甘膦吸附的影响，pH 值调节在 3 到 12 之间。最大的草甘膦吸附发生在一定的 pH 值，然后随着 pH 值的增加或降低，吸附减少。pH 对吸附的影响可以通过一个包括电势变化的模型来描述。在 0.5 或 1 mM 磷酸盐存在下，通过批量实验研究了无机磷酸盐对草甘膦吸附的影响。结果表明，在所有土壤中磷酸盐和草甘膦之间存在显着的竞争。Freundlich 草甘膦系数随溶液中的磷酸盐降低 40% 至 65%，草甘膦的吸附量降低 1% 至 5%，具体取决于土壤的特定特性。对于草甘膦 - 磷酸盐竞争，竞争项彼此不相互，因为吸附位点的离子之间的竞争也涉及电效应。根据土壤的特殊特性，草甘膦的吸附量下降了 1% 到 5%。对于草甘膦 - 磷酸盐竞争，竞争项彼此不相互，因为吸附位点的离子之间的竞争也涉及电效应。根据土壤的特殊特性，草甘膦的吸附量下降了 1% 到 5%。对于草甘膦 - 磷酸盐竞争，竞争项彼此不相互，因为吸附位点的离子之间的竞争也涉及电效应。