In this paper,we regard that soil is divided into two porous media,one for matrix flow,one for macropore flow,and a macropore is assumed extend vertically from soil surface down to desired depth,macropore density is also imported into model to describe the complex distribution of macropore in soil.

In order to understand and appraise the potential effect of rock fragment on the macropore formation deeply,the variety of the contents of rock fragments and macroporosity and their effects of rock fragments on the macroporostiy and the radius and density of macropore are studied in the Liupan Mountains and the results indicate that the increase o.