Chemical migration during soil water retention curve evaluation

Abstract

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.

Effects of surface‐applied and soil‐incorporated lime on some physical attributes of a Dystrudept soil

“…The chemical attribute effects on θ were also dependent upon the soil water matric potential and can be explained by different processes (Pires et al ., ). At saturation and at −10 and −33 kPa, the increase in soil pH, Ca 2+ and Mg 2+ and reduction in H+Al and Al 3+ are consequences of alterations in the soil structure (BD and Ma reduction, and TP and Mi increase) provided by liming (Table ).…”

Performance assessment of nanoparticulate lime to accelerate the downward movement of calcium in acid soil

“…Thus, significant long‐distance movement of Ca in soil depends on mass flow—the physical movement of lime particles (Scott, Ridley, & Conyers, ; Shin & Kang, ; Whitten et al., ). Contributory factors include liming rate (Brown, Koenig, Huggins, Harsh, & Rossi, ; Edwards et al., ; Nduwumuremyi et al., ), pore size distribution and the degree of water saturation (Dierolf, Arya, & Yost 1997; Pires, Villanueva, Dias, Bacchi, & Reichardt, ). Furthermore, [Ca 2+ ] is highly pH‐dependent, and Ca becomes less reactive and slows to a halt before it reaches even 10 cm when the soil pH is > 5.9 (Fenton, ; Gazey, Davies, & Masters, ; Hollier, ).…”

Quantificação Mineralógica Da Fração Fina Da Argila De Um Latossolo Pelo Método De Rietveld

“…Foram utilizadas amostras oriundas de um LVA submetidas a ciclos de U-S estudadas anteriormente por Pires et al (2011). Elas são separadas em quatro tratamentos em relação aos ciclos de U-S, a saber: Testemunha (sem ciclos) Test, T1 (três ciclos), T2 (seis ciclos), T3 (nove ciclos).…”

“…Com isso utilizase uma ferramenta essencial nos estudos e análise de difratogramas de pó de estruturas cristalinas com dados obtidos por Difração de Raios X (DRX) que é o Método de Rietveld (MR) [1]. Pires et al (2011) [2] estudaram amostras de um Latossolo VermelhoAmarelo (LVA) submetidas a ciclos de umedecimento e secamento (U-S) e constataram a existência de migração de elementos químicos (Ca, Mg e K) e perdas significativas dos elementos químicos entre as amostras submetidas e as não submetidas aos ciclos U-S. Portanto, investigar sua constituição mineral para auxiliar em um estudo relacionado ao desenvolvimento da estrutura do solo após os ciclos torna-se importante.…”