Comparison of the effects of litter covering and incorporation on infiltration and soil erosion under simulated rainfall

• Published in: Hydrological processes 2020-06, Vol.34 (13), p.2911-2922
• Main Authors: Wang, Lunjiang, Zhang, Guanghui, Zhu, Pingzong, Wang, Xue
• Format: Article
• Language: English
• Subjects: Ecosystem assessment; Erosion control; Erosion processes; Erosion resistance; Hydrologic processes; Hydrology; Hydrophobicity; Infiltration; Infiltration rate; Leaves; Litter; litter type; Morphology; Pest control; Rain; Rainfall; Rainfall intensity; Rainfall simulators; Repellency; Repellents; runoff; Simulated rainfall; Simulation; Slope gradients; Slopes; Soil erosion; soil erosion resistance; Soil layers; Soil loss; Soil resistance; Soil surfaces; Soil water; water repellency
• ISSN: 0885-6087; 1099-1085
• DOI: 10.1002/hyp.13779

Plant litter can either cover on soil surface or be incorporated into top‐soil layer in natural ecosystems. Their effects on infiltration and soil erosion are likely quite different. This study was performed to compare the effects of litter covering on soil surface and being incorporated into top‐soil layer on infiltration and soil erosion under simulated rainfall. Four litter types (needle‐leaf, broad‐leaf, brush, and herb) were collected from fields and applied to cover on soil surface or to be incorporated into top‐soil layer (5 cm) at the same rate (0.2 kg/m2). The simulated rainfalls (40 and 80 mm/hr) were run at two slope angles (10° and 20°). The results showed that the mean infiltration rate of litter covering treatment was 1.4 times as great as that of litter incorporated. Litter covering enhanced infiltration via protecting surface from soil sealing. Whereas, litter incorporation affected infiltration by its water repellency. Soil erosion of litter incorporated treatment was 5.4 times as large as that of litter covered treatment, which was attributed to the changes in surface litter coverage and soil erosion resistance. Litter type affected soil erosion through the variations in litter coverage and litter morphology. For litter covering treatment, litter coverage can explain the major variance of soil loss on the slopes. Whereas, for litter incorporated treatment, both the influences of litter coverage and litter length on soil erosion resistance were considered necessary to well explain the variance of soil loss. The results also showed that the benefits of litter to control soil erosion declined with rainfall intensity and slope gradient for both covering and incorporated treatments. The results of this study are helpful to understand the mechanisms of litter influencing hydrological and erosion processes on hillslopes. Infiltration rate decreased with litter water repellency for litter incorporation treatment. Soil loss rates on litter incorporated slopes were much greater than those of litter covering slopes. The difference in soil loss rate was due to surface litter coverage and soil erosion resistance. The figures show the comparison of the mean infiltration rates (mean ± SD) between litter covering and litter incorporated treatments (a), and the relationship between soil loss rate and stream power of the two treatments (b).