Rock fragments are widely founded in soils of whole world. The contents and size of rock fragments are increased with the slope gradient, and are influenced by the Lithology itself and tillage practices. There are linear, exponential, and logarithm relations between contents of rock fragment in topsoil and the slope gradient. The water contents in soils containing rock fragments are associated with origin, content, size, and porosity of rock fragments and its position in the soil profile. The rock fragment of topsoil can reduce loss of water and soil by increasing soil infiltration, retarding runoff’s formation and decreasing soil water evaporation Therefore, the presence of rock fragments not only modifies the soil physical and chemical properties and the agronomical characteristics, but also restricts a series of soil processes.
