Guo Ya-Li, Zhao Yun-Ge, Gao Li-Qian, Yang Kai, Sun Hui, Gu Kang-Min
College of Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China.
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2022 Jul;33(7):1871-1877. doi: 10.13287/j.1001-9332.202207.008.
Biological soil crusts (biocrusts) are the common cover in arid and semiarid areas. Together with plants, biocrusts affect runoff and flow velocity. However, few studies have focused on the effects of the co-covering of plant and biocrust (plant+biocrust) on the flow velocity, with a knowledge gap in the study of driving factors for slope erosion in arid and semiarid areas. In this study, simulated rainfall experiments were used to investigate the effects of biocrust and three types of biocrusts (more cyanobacteria less moss, more moss less cyanobacteria, and moss) on the flow velocity of revegetated grassland in the hilly Loess Plateau. The results showed that plant and plant+biocrust significantly reduced flow velocity, with that of plants and plant+biocrust being 70.7% and 83.1% lower than bare soil. The reduction benefits of plant and biocrust on flow velocity were 70.7% and 12.4%, respectively, when they were co-covered. Biocrust composition under plant cover affected flow velocity. The reduction benefits of more cyanobacteria less moss, more moss less cyanobacteria, and moss crust on flow velocity were 11.5%, 12.4%, and 19.4%, respectively. There was a significant negative correlation between flow velocity and moss coverage and a significant positive correlation between flow velocity and cyanobacteria coverage. The relationship between moss cove-rage () and flow velocity () was =-2.081+0.03 (=0.469). The moss coverage was a key factor affecting the flow velocity of co-covering of plant and biocrust slope with similar plant coverage (40%±10%). In conclusion, biocrusts under plant cover significantly slowed flow velocity, and the effect magnitude was related to its composition, implying that the role of biocrusts should be considered in understanding the mechanism underlying slope erosion in revegetated grassland.
生物土壤结皮（生物结皮）是干旱和半干旱地区的常见覆盖物。生物结皮与植物一起影响径流和流速。然而，很少有研究关注植物与生物结皮共同覆盖（植物+生物结皮）对流速的影响，干旱和半干旱地区坡面侵蚀驱动因素的研究存在知识空白。本研究利用模拟降雨试验，研究了生物结皮及3种生物结皮类型（蓝藻多苔藓少、苔藓多蓝藻少和苔藓结皮）对黄土丘陵区植被恢复草地流速的影响。结果表明，植物和植物+生物结皮显著降低了流速，植物和植物+生物结皮的流速分别比裸土低70.7%和83.1%。植物与生物结皮共同覆盖时，它们对流速的降低效益分别为70.7%和12.4%。植物覆盖下的生物结皮组成影响流速。蓝藻多苔藓少、苔藓多蓝藻少和苔藓结皮对流速的降低效益分别为11.5%、12.4%和19.4%。流速与苔藓盖度之间存在显著负相关，与蓝藻盖度之间存在显著正相关。苔藓盖度（）与流速（）的关系为=-2.081+0.03（=0.469）。在植物盖度相似（40%±10%）的情况下，苔藓盖度是影响植物与生物结皮坡面共同覆盖流速的关键因素。总之，植物覆盖下的生物结皮显著减缓了流速，其影响程度与结皮组成有关，这意味着在理解植被恢复草地坡面侵蚀机制时应考虑生物结皮的作用。
