4. Conclusions
In this study, erosion and rill morphology for four soils in the Loess
Plateau, China, were compared under different artificial conditions.
Results indicated that soil erosion differences among SL, LL and ML were
mainly caused by different rill erosion processes. Soil erosion rates
recorded varying degrees of increase with rill erosion under the four
soil types: SL recorded a sharp increase, LL recorded a strong increase,
and ML and HL recorded slight increases. HL was the most prone to the
occurrence of rills; SL, LL and ML are prone to the occurrence of rills
under heavy rain. The development of rills under SL was mainly
characterized by an increase in Wa and N; the development of rills under
HL were mainly characterized by an increase of CDL, J and N. Rill
development indices for LL and ML were between those of SL and HL. The
sensitivity of rill parameters to rainfall intensity was in the order
of: N > DS > J > Wa
> CDL ≈ Ha, and sensitivity to slope was in the order of:
Ha > Wa ≈ J > DS ≈ N > CDL. Soil
properties may affect rill formation by changing the distribution of
slope flow and the stability of soil particles being stripped and
scoured. At the same time, soil properties may also affect the
relationship between rill morphology, rainfall intensity and slope by
changing soil structure stability; rill morphology enhances the
difference of different types of soil erosion by changing the
distribution of water flow between and within rills. In addition, an
empirical relationship based on soil characteristic factors, rill shape
parameters and soil erosion were established to reflect the influence of
soil characteristics and rill shape on soil erosion. These results
improve our understanding of the effects of soil properties on soil
erosion and rill morphology in the Loess Plateau.