Processes of rainfall infiltration and sediment yield in soils containing different rock fragment contents

The presence of rock fragment has effects on some physical properties for homogeneous soil. As a result the processes of rainfall infiltration and sediment yield are changed. Knowledge of the processes affected by rock fragment is benefit to simulate and predict soil and water processes in stony-soil media. On the conditions of rainfall simulation, laboratory soils with four different rock fragment contents (gravimetric contents were 0%, 10%, 20%, and 30%, respectively) were constructed to study the processes of rainfall infiltration and sediment yield as affected by rock fragment. Results show that the maximum of infiltration rate presented at the rock fragment content was 10%, while the rock fragment content exceeded 10% the infiltration rate reduced on the contrary. The initial 0～20 min was the peak of sediment yields for four laboratory soils. After this sediment yields kept relatively steady and had hardly difference among four laboratory soils. During rainfall sediment concentration for soil with 10% rock fragment content held steady and at low level, and other laboratory soils were high at the beginning of rainfall and reduced remarkably within 0～10 min and then close to that of soil with 10% rock fragment content.