Chemical migration during soil water retention curve evaluation

• Published in: Anais da Academia Brasileira de Ciências 2011-09, Vol.83 (3), p.1097-1108
• Main Authors: Pires, Luiz F, Villanueva, Felipe C A, Dias, Nivea M P, Bacchi, Osny O Santos, Reichardt, Klaus
• Format: Article
• Language: English
• Subjects: analytical methods; Calcium - analysis; ciclos de umedecimento e de secamento; estrutura do solo; física do solo; Magnesium - analysis; MULTIDISCIPLINARY SCIENCES; métodos analíticos; Potassium - analysis; Soil - chemistry; soil physics; soil structure; Spectrophotometry, Atomic; Water Movements; wetting-drying cycles
• ISSN: 0001-3765; 1678-2690; 1678-2690
• DOI: 10.1590/S0001-37652011005000032

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.