Pore system changes of damaged Brazilian oxisols and nitosols induced by wet-dry cycles as seen in 2-D micromorphologic image analysis

Abstract

Soil pore structure characterization using 2-D image analysis constitutes a simple method to obtain essential information related to soil porosity and pore size distribution (PSD). Such information is important to infer on soil quality, which is related to soil structure and transport processes inside the soil. Most of the time soils are submitted to wetting and drying cycles (W-D), which can cause important changes in soils with damaged structures. This report uses 2-D image analysis to evaluate possible modifications induced by W-D cycles on the structure of damaged soil samples. Samples of three tropical soils (Geric Ferralsol, GF; Eutric Nitosol, EN; and Rhodic Ferralsol, RF) were submitted to three treatments: 0WD, the control treatment in which samples were not submitted to any W-D cycle; 3WD and 9WD with samples submitted to 3 and 9 consecutive W-D cycles, respectively. It was observed that W-D cycles produced significant changes in large irregular pores of the GF and RF soils, and in rounded pores of the EN soil. Nevertheless, important changes in smaller pores (35, 75, and 150 μm) were also observed for all soils. As an overall consideration, it can be said that the use of image analysis helped to explain important changes in soil pore systems (shape, number, and size distribution) as consequence of W-D cycles.

Software for micromorphometric characterization of soil pores obtained from 2-D image analysis

“…Analysis in two dimensions (2-D) are frequently employed to investigate soil porosity, due to their low cost and easy access (Pires et al, 2008(Pires et al, , 2009Passoni et al, 2014).…”

“…In the case of soil images, the target may be quantitative data extracted from the pore system. The Noesis Visilog software was used for evaluating the pore system of weathered soils when they are subjected to wetting and drying cycles (Pires et al, 2009). The opensource software ImageJ was successfully used to quantify the total porosity (%), total number of pores and pore size distribution for two Brazilian soils by using soil samples impregnated with resin (Passoni et al, 2014).…”

Estrutura Do Solo Sob Feijão Irrigado E Diferentes Manejo Do Solo

“…O impacto da compactação na estrutura do solo pode ser analisado com o estudo micromorfológico, que utiliza análise de imagens digitalizadas 2-D, que geram índices quantitativos quanto à forma e complexidade dos poros (Souza et al, 2006;Pires et al, 2009;Cooper et al, 2010). Assim, a estrutura do solo pode ser representada por tamanho, forma e arranjo das partículas primárias, com materiais agregados ou não, e seu respectivo espaço poroso (Castro et al, 2003;Cooper et al, 2010Cooper et al, , 2012.…”

Software Image J to study soil pore distribution

“…However, in order to better understand the water dynamics in the soil, it is necessary to study this medium pore distribution as well as the total porosity (Ringrose-Voase; Bullock, 1984;Kutilek, 2004;Cássaro et al 2011). …”

“…In the soil science, a direct method that allows the study of soil pore distribution is the bi-dimensional (2D) digital image analysis obtained via impregnated samples optical microscopy or CCD camera (Pires et al, 2009). Such technique (micro-morphology) provides quantitative results of porosity via image, enabling the visualization of changes in the soil voids such as: shape, pore number and size (Stoops, 2003;Pagliai;Kutilek, 2008;Silva, et al 2012).…”