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首页> 外文期刊>Journal of Agricultural and Food Chemistry >Soil pH on mobility of imazaquin in oxisols with positive balance of charges
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Soil pH on mobility of imazaquin in oxisols with positive balance of charges

机译：土壤pH值对异氮唑中吡喹嗪迁移率的影响。

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The influence of soil pH on the leaching potential of the ionizable herbicide imazaquin was assessed on the profile of two highly weathered soils having a net positive charge in the B horizon, in contrast to a soil having a net negative charge in the whole profile, using packed soil column experiments. Imazaquin leached to a large extent and faster at K-d values lower than 1.0 L kg(-1), a much more lenient limit than usually proposed for pesticides in the literature (K-d < 5.0 L kg(-1)). The amount of imazaquin leached increased with soil pH. As the soil pH increased, the percentage of imazaquin in the anionic forms, the negative surface potential of the soils, as well as imazaquin water solubility also increased, thus reducing sorption because of repulsive electrostatic forces (hydrophilic interactions). For all surface samples (0-0.2 m), imazaquin did not leach at soil pH values lower than pK(a) (3.8) and more than 80% of the applied amount was leached at pH values higher than 5.5. For subsurface samples from the acric soils, imazaquin only began to leach at soil pH values > zero point of salt effects (ZPSE > 5.7). In conclusion, the use of surface K-oc values to predict the amount of imazaquin leached within soil profiles having a positive balance of charges may greatly overestimate its actual leaching potential.
机译：相对于整个剖面均带净负电荷的土壤，使用两种在B层带正净电荷的高度风化土壤的剖面，评估了土壤pH值对可电离的除草剂伊马扎喹的浸出潜力的影响。填充土柱实验。当K-d值低于1.0 L kg（-1）时，Izazaquin会大量浸出并更快地浸出，比文献中通常建议的农药（K-d＆LT; 5.0 L kg（-1））宽得多。浸出的伊马喹的量随土壤pH值的增加而增加。随着土壤pH值的升高，阴离子形式的吡喹啉的百分比，土壤的负表面电势以及吡喹啉的水溶性也增加，从而由于排斥静电力（亲水相互作用）而降低了吸附。对于所有表面样品（0-0.2 m），在土壤pH值低于pK（a）（3.8）的条件下，阿马西喹均不会浸出，而在pH值高于5.5时，浸出量的80％以上。对于来自酸性土壤的地下样品，阿马西喹仅在土壤pH值＆GT时才开始浸出。零盐效应（ZPSE＆GT; 5.7）。总而言之，使用表面K-oc值来预测具有正电荷平衡的土壤剖面中浸出的吡虫啉的量可能会大大高估其实际浸出潜力。

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