Comparison of 2D and 3D images of fractures in a Vertisol

Use of sequential images of an impregnated soil block (6 x 2 x 2 cm) were u sed to compare two dimensional (2D) and three dimensional (3D) aspects of p ores in an Italian Vertisol. Standard image analysis methods are used to re present and measure the properties of the pores represented in the images. It is clear that not all 3D properties can be predicted with the same preci sion using 2D images. This is largely due to anisotropy of the Vertisol por e structure. However, it was found that many properties such as porosity, p ore width distribution can be adequately assessed using five to ten 2D sect ions in the 3D block. Measurements such as fractal dimension can be determi ned with fewer 2D images. However, pore connectivity and percolation thresh old dimensions cannot be predicted using a small percentage of the soil blo ck volume in 2D images. Connectivity observed in 2D and 3D images is very d ifferent in this soil example. (C) 1999 Elsevier Science B.V. All rights re served.