A Study of the Relationship Between Erosion-Rainfall-Vegetation on Purple Soil Based on Long-Term Experiments

Three stages of natural restoration of vegetation in Suining group purple soil were analyzed and, as a result, the patterns of parent material erosion in it were summarized as follows: (1) This slope was found to suit the rain-vegetation-erosion rule from Langbein-Schumm relation. The parent material erosion was controlled by increasing vegetation, runoff and erosion being reduced by 12.06% and 35.81%, respectively, in Stage 2, and by 39.61% and 83.46% in Stage 3; (2) Of all the influencing factors, rainfall was the dominant factor for runoff and erosion, and the influence of other factors changed with increasing vegetation; (3) With increasing vegetation, the runoff and erosion was reduced. The critical rainfall causing runoff increased to 16.21 mm in Stage 2 and to 21.14 mm in Stage 3 from 13.70 mm in Stage 1.