Anti-scourability of purple soil on hillslopes with different land uses

A large-scale flume (40 cm x 10 cm x 10 cm) was used to determine soil anti-scourability of 4 different land uses of purple soil in hilly areas of Sichuan, China under artificial removal of vegetation to examine the effects of land uses on sediment production by runoff. The results showed that soil anti-scourability declined with the increase of slope gradients in the form of power function, but there was a significant difference in the effects of slope gradients on anti-scourability between different land uses. The ratio of the mean values of soil anti-scourability was 1:2.2:2.5:3.6 for forest land, new waste pasture, old waste pasture, crop land respectively, indicating that forest and grass use can significantly improve soil anti-scourability. Compared with the observations from the runoff plots located at the same sites in this region, an inconsistent result was found between anti-scourability and anti-erodibility in hilly areas of Sichuan. Essential causes of the differences in soil anti-scourability were further discussed based on analyzing the influence of inherent soil characteristics induced by different land uses on soil anti-scourability.