Effects of incorporated plant litter on soil resistance to flowing water erosion in the Loess Plateau of China

• The incorporated plant litter has great influences on erosion processes.
• Soil detachment capacity decreased exponentially with incorporated plant litter rate.
• A threshold litter incorporation rate of 0.35 kg m−2 existed to protect soil effectively from flowing water erosion.
• Rill erodibility decreased with incorporated plant litter rate exponentially.
• Critical shear stress increased with litter incorporation rate.

Plant litter can be incorporated into top soil via different approaches, which probably influence soil erosion processes controlled by overland flow. However, few studies have been conducted to quantify the effects of incorporated plant litter on the soil detachment process by overland flow. This study was performed to investigate the effects of incorporated litter rate on soil detachment capacity and soil resistance to flowing water erosion using undisturbed soil samples taken from 16 plots (three plant litter species by five incorporation rates, and one bare control) and were subjected to six different flow shear stresses in the Loess Plateau. The results showed that soil detachment capacity decreased exponentially with incorporated plant litter rate. A threshold of 0.35 kg m−2 of litter needed to be incorporated to provide protection of soil from overland flow erosion. The effects of litter incorporation rate on soil detachment capacity was not significant when the incorporation rate was greater than 0.35 kg m−2. Rill erodibility also decreased exponentially with the incorporated plant litter rate. The shape of plant litter fragments was hypothesised to account for the variations in the effects of different incorporated litter species on soil detachment capacity and rill erodibility. A distinguishable increasing linear trend was observed between critical shear stress and litter incorporated rate, but with a weak correlation. Critical shear stress also increased with incorporated rate and was related to soil cohesion.