X-ray microtomography to investigate thin layers of soil clod

In this paper we present an equipment and a methodology for soil non-invasi ve investigation at the microscale. We developed a micrometric scale tomogr aph to work at a resolution of at least 100 mu m. A microtomography of 1 mm sand grains and 1 mm grass roots is presented. Inside one of the grains, a crack 110 mu m wide per 460 mu m long can be observed. Pores of 100 mu m c an be studied. A microtomography of a little soil clod is shown, in which g rains of densities up to 4.5 g cm(-3) can be seen. Pores ranging from 200 t o 800 mu m can also be detected in the tomography. As an example of the pot ential of the method and equipment, soil crusting and sealing can be observ ed in a natural sample in soil investigations. The image shows three layers of different densities and soil textures. The thicknesses of the layers fr om top to bottom are, respectively, 1000, 500 and 1700 mu m. (C) 1998 Elsev ier Science B.V. All rights reserved.