X-ray computed microtomography in the evaluation of the porous system of soils

Abstract

Analysis of shapes, sizes, continuity, orientation and irregularities of pores can help in the study of soil structural modifications induced by soil management. The study of the inter- and intra-aggregate porous space of urban and rural soils by tomographic images is the objective of this work. A morphometric characterization of the pores was carried out with the analysis of distribution of their size, shape and inclination in these two types of soil. The urban soil showed smaller percentage of inter-aggregate voids and more intra-aggregate voids compared with the rural soil. The cumulative distribution of void volumes showed little pore diversity in the urban soil and great presence of large pores (48%), almost twice the voids with same size in the rural soil. The urban soil, compared to rural soil, also had a higher percentage of flattened pores (29.41%) and a smaller percentage of rounded voids (6.97%), as well as a greater percentage of horizontal voids (44.49%). Hence, the urban soil proved to be more compacted than the rural soil.

3D analysis of the soil porous architecture under long term contrasting management systems by X-ray computed tomography

“…1). Similar results of a high contribution of complex pores to the overall porosity have also been previously measured for Brazilian soils (Ferreira et al, 2018;Borges et al, 2018;Costa et al, 2018;Pires et al, 2017;Passoni et al, 2015).…”

“…In terms of pore size distribution, the contribution of pores <10 mm to porosity was around 4% for F, 8% for ZT, 2% for CT and 3% for RT. This indicates that a large part of the porosity is composed of large inter-aggregate pores as observed by Costa et al (2018). Ferreira et al (2018) recently showed that >90% of porosity for a soil under ZT consisted of a main pore network as observed in our study.…”

“…Cássaro et al (2011), in another work in the same site, identified a great concentration of large pores under ZT and CT management systems. The greatest contribution of unclassified pores to porosity is also indication of the presence of a main pore network composed by large pores (Costa et al, 2018;Jefferies et al, 2014). Garbout et al (2013) determined that the volume of connected pores constituted 91% and 85% for drilling and ploughing areas, which indicates the great contribution of a main pore network to the overall porosity.…”