Impacts of biocrusts on sheet erosion and its detachment- and transport-limited processes: A case study from the Loess Plateau, China

Understanding sheet erosion processes and improving estimates of soil erosion on bio-logical soil crustal (biocrustal) slopes requires a deep understanding of the factors influ-encing sheet erosion and its detachment-and transport-limited processes. Simulated rainfall experiments were conducted on plots of biocrust to simultaneously measure the rates of splash detachment and sheet erosion with 0%, 20%, 40%, 50%, 60%, and 80% of coverage at 90 mm h-1 rainfall intensity and 15 degrees slope. The splash detachment rate decreased rapidly during the first 5 min of rainfall and stabilised as rainfall continued, while the sheet erosion rate increased gradually and eventually became relatively stable. The rates of splash detachment and sheet erosion decreased substantially as biocrusts coverage increased and average values of them can be effectively weakened when bio-crusts coverage increased from 20% to 40%. Transport-limited processes, dynamic equi-libria between detachment-and transport-limited processes, and detachment-limited processes all occurred on biocrustal slope within the same rainfall event. The mean duration of transport-limited processes was longer (16.3 min vs. 9.1 min) when bare slopes were covered by biocrusts, and the latest change in the time from transport-limited to detachment-limited processes appeared at 40% biocrusts coverage. The existence of bio-crusts could effectively affect the sheet erosion and its detachment-and transport-limited processes, especially when the coverage was close to 40%. These results can improve our understanding of impacts of biocrusts on sheet erosion processes, and aid an effective way of reducing sheet erosion in arid and semiarid regions.(c) 2022 IAgrE. Published by Elsevier Ltd. All rights reserved.