Rill morphological change characteristics and influencing factors on
different soil types in the Loess Plateau, China
Soil properties play an important role in rill development and erosion.
In this investigation, rill morphology developmental processes under
sandy loam (SL), light loam (LL), medium loam (ML) and heavy loam (HL)
soils on the Loess Plateau, China, were compared using laboratory
experiments. Experimental analysis included two rainfall intensities (90
and 120 mm/h) and four slope treatments (0°, 15°, 20° and 25%). Results
indicate that HL is the most prone to rill development, and SL, LL and
ML are prone to rill development under heavy rain, with SL rill erosion
being the most sensitive to heavy rain. The development of rills in SL
are mainly characterized by an increase in rill width and merging nodes;
rills in HL were mainly characterized by an increase in rill length,
merging nodes and rill number. LL and ML rill development indices were
between SL and HL. Differences in runoff collection caused by rill
morphology differences further promoted differences in soil erosion.
Rainfall intensity has a positive effect on rill shape parameters of all
soils; slope has a positive and negative double effect on SL, LL and ML
rill shape parameters, and only a positive effect on HL rill shape
parameters. The sensitivity of rill parameters to rainfall intensity and
slope angle depends on soil infiltration performance, surface soil
stability and soil structure stability. Based on soil characteristic
factors and rill morphological parameters, an empirical model of slope
erosion in the loess region was established.