Sediment Load in Runoff from Small Plots: Laboratory and Field Rainfall Simulation Tests on Chinese Loess Soils

摘要

The soils of the Chinese loess plateau are affected by severe soil erosion. Near Luoyang (Henan province, China) field plots were constructed to measure soil erosion rates under different tillage practices. In addition to the erosion measurements under natural rainfall conditions, rainfall simulations were carried out on the field and in the laboratory. Rainfall simulations in the lab were used to find a sediment transport equation for short slopes. A strong correlation was found between the stream power of the runoff water and the unit sediment load. This relationship was similar to the one found for Belgian soils. Comparison with other sediment transport equations in literature showed differences due to rainfall impact. Without rainfall impact lower sediment load values were found. Rainfall experiments on the field were used to verify the results of the laboratory experiments. Preliminary results showed also a good correlation between stream power and unit sediment load. Additional field rainfall experiments are carried out to confirm these results and to extend the sediment transport equation for higher stream power values. Runoff measurements are also continuing for field plots under natural rainfall to validate the results from the laboratory and field experiments.