Soil Porosity Differences Among Grass-Covered and Exposed Soils Measured by High Resolution X-Ray Computed Microtomography (microCT)

High resolution X-ray computed microtomography (microCT) is a non-destructive method for assessing soil structure as influenced by land use and management. A microCT soil scan produces data and information, in microscale, on the shape, size, distribution, volume, area and pore connectivity of the soil, and allows a 3D visualization of the soil sample and its structure. The objective of this work is to use microCT to compare the porosity distribution and pore connectivity density between a soil with grass cover and a soil without vegetation cover, both Ferralsols. Four undisturbed samples of each soil treatment were collected and analyzed by microCT. The microCT 3D scans and derived data show a clear difference in soil porosity between the grass-covered and the bare soil, with the former having more pores and higher pore connectivity than the latter. The soil pore distribution and soil structure are difficult properties to measure and visualize. The microCT offers a non-destructive alternative to measure soil porosity and pore connectivity efficiently and monitor the effects of vegetation cover on the structure of soils undergoing erosional processes.