Pires Luiz F, Villanueva Felipe C A, Dias Nivea M P, Bacchi Osny O Santos, Reichardt Klaus
Laboratório de Física Aplicada a Solos e Ciências Ambientais, Universidade Estadual de Ponta Grossa, PR, Brasil.
An Acad Bras Cienc. 2011 Sep;83(3):1097-108. doi: 10.1590/s0001-37652011005000032. Epub 2011 Aug 5.
Wetting and drying (W-D) cycles can induce important elemental migrations in soils. The main purpose of this work was to study the possible existence of soil chemical elemental migrations in samples submitted to repeated W-D cycles during evaluations of soil water retention curve (SWRC). The experimental measurements were carried out by Atomic Absorption Spectrometry (AAS) for Ca(2+), Mg(2+) and K(+) on samples of three different Brazilian tropical soils (Geric Ferralsol, Eutric Nitosol and Rhodic Ferralsol). Results demonstrate an increase in the electrical conductivity of the water extracted from the samples and significant losses of Ca(2+), Mg(2+) and K(+) during the applications of up to nine W-D cycles. It was also observed differences in SWRC for all soils when samples submitted to the application of several W-D cycles were compared with samples not submitted to it. These differences occurred at the region of both structural and textural pores. A possible explanation for these results could be the soil chemical migration during the sequences of W-D cycles, which can affect the soil structure development.
干湿循环（W-D）会在土壤中引发重要的元素迁移。这项工作的主要目的是研究在土壤水分保持曲线（SWRC）评估期间，经受反复干湿循环的样品中是否存在土壤化学元素迁移。通过原子吸收光谱法（AAS）对三种不同的巴西热带土壤（强风化铁铝土、饱和粘壤土和暗红色铁铝土）样品中的Ca(2+)、Mg(2+)和K(+)进行了实验测量。结果表明，在进行多达九次干湿循环的过程中，从样品中提取的水的电导率增加，Ca(2+)、Mg(2+)和K(+)显著流失。当将经受多次干湿循环的样品与未经受干湿循环的样品进行比较时，还观察到所有土壤的土壤水分保持曲线存在差异。这些差异出现在结构孔隙和质地孔隙区域。这些结果的一个可能解释是干湿循环过程中的土壤化学迁移，这可能会影响土壤结构的发育。
