Estimating orientation and width of channels and cracks at soil polished blocks—a stereological approach

Abstract

In most cases soil structure is anisotropic, i.e., its properties depend on the direction in which it is observed. This is true for important soil functions such as rooting potential and transport processes. The interpretation of micromorphometric results from two-dimensional sections is often biased by anisotropy of the investigated structural elements. Channels and cracks are elongated components of the soil pore system. They may often cause anisotropy of soil structure. In this paper parameters and stereological procedures are presented for the estimation of 3D orientation and width distributions of channels and cracks when measurements are taken from 2D polished blocks. Moreover, a method of image analysis is presented by which measuring is done directly on the microscopic image. The results are illustrated by an example.