Apportioning above- and below-ground effects of moss biocrusts on soil detachment by overland flow in a subtropical climate Apportioning above- and below-ground effects of moss biocrusts on soil detachment by overland flow in a subtropical climate

最小化 最大化

Vol18 No.10: 2646-2655

Title】Apportioning above- and below-ground effects of moss biocrusts on soil detachment by overland flow in a subtropical climate

Author】ZHANG Guan-hua1,2*; YI Liang3; DING Wen-feng1,2; LEI Xu3; WANG Yi-ran1,2; SUN Bao-yang1,2; LI Jian-ming1,2

Addresses】1 Soil and Water Conservation Department, Changjiang River Scientific Research Institute, Wuhan 430010, China; 2 Research Center on Mountain Torrent & Geologic Disaster Prevention of Ministry of Water Resources, Wuhan 430010, China; 3 Central-Southern Safety & Environment Technology Institute Co., Ltd, Wuhan 430071, China

Corresponding author】ZHANG Guan-hua

Citation】Zhang GH, Yi L, Ding WF, et al. (2021) Apportioning above- and below-ground effects of moss biocrusts on soil detachment by overland flow in a subtropical climate. Journal of Mountain Science 18(10). https://doi.org/10.1007/s11629-021-6888-y

DOI】https://doi.org/10.1007/s11629-021-6888-y

Abstract】Biocrusts affect soil detachment through above-ground (top crust's surface covering) and below-ground (sub-crust's binding and bonding, B&B) effects, which might vary with biocrust development or coverage. However, these effects in humid climates are still unclear. This study was conducted to apportion and quantify the surface covering and B&B effects of moss biocrusts with five coverage levels (1%–20%, 20%–40%, 40%–60%, 60%–80%, and 80%–100%) on soil detachment by overland flow in a subtropical humid climate. Two treatments with one being intact moss crusts and one removing the above-ground moss tissues were designed for each coverage level, and bare soil was used as the baseline. The results indicated that soil detachment capacity (Dc) and rill erodibility (Kr) decreased with biocrust coverage. After removing the above-ground moss tissues, the impeding effect of biocrusts on soil detachment weakened, but still increasing soil erosion resistance relative to bare soil. For intact crust, Dc was reduced by 50%–95% compared with bare soil, wherein 36%–55% and 14%–40% were attributed to the surface covering and B&B, respectively. The top crust contributed more than sub-crust to the soil detachment reduction, which were related to but not linear with biocrust coverage. When biocrust coverage reached mid-to-higher level (40%–100%), both top crust and sub-crust steadily contributed to soil detachment reduction with 60% and 40%, respectively. The findings advancea better understanding of the influencing mechanism of biocrusts on soil erosion in humid climates and highlight the importance of saving biocrusts as ecosystem functions.

Keywords】Soil detachment; Rill erodibility; Effect apportionment; Contribution rate; Three Gorges