Effects of biological soil crusts on soil detachment process by overland flow in the Loess Plateau of China
Effects of biological soil crusts on soil detachment process by overland flow in the Loess Plateau of China
复制标题
黄土高原生物土壤结皮对地流土壤滑脱过程的影响
DOI：
10.1002/esp.3870
复制
发表时间：
2016
影响因子：
3.3
通讯作者：
Wang Hao
中科院分区：
文献类型：
--
作者：
Liu Fa;Zhang Guanghui;Sun Long;Wang Hao
自1999年黄土高原退耕还林工程实施以来，生物土壤结皮覆盖了草原60%~70%的土壤表面。然而，很少有研究量化BSCs对黄土高原坡面径流土壤剥离过程的影响。本研究探讨了BSCs对土壤剥离能力(DC)的潜在影响，以及通过细沟可蚀性和临界剪应力反映的土壤对流水侵蚀的抗性。对黄土高原发育的两种主要类型(演替晚期苔藓和演替早期蓝藻与苔藓混合)进行了天然土壤样品的对比试验。样品在6种不同的剪应力下进行了水流冲刷，剪切力从7.15到24.08Pa.结果表明，无论是苔藓结皮还是混合结皮，Dc值均随着结皮覆盖度的增加而显著降低。裸土(0.823 kg m−2s−1)的平均Dc值是苔藓覆盖土壤(0.017~0.284 kg m−2s−1)的2.9~48.4倍，是混合覆盖土壤(0.021~0.641 kg m−2s−1)的4.9~149.6倍。与裸土相比，BSC的相对脱附率随BSC覆盖度的增加呈指数下降。Dc值可以通过水流剪切力、内聚力和平衡平衡中心覆盖率使用幂函数来模拟(NSE≥0.59)。细沟侵蚀性也随着两种结皮类型的复盖而降低。细沟侵蚀性裸土是苔藓复盖土壤的3~74倍，是混合复盖土壤的2~165倍。细沟侵蚀性也可以用黄土高原的土壤盐分覆盖度(NSE≥0.91)来估算。结皮覆盖度对临界剪应力的影响不显著。版权所有©2015 John Wiley&Sons，Ltd.
Biological soil crusts (BSCs) cover up to 60 to 70% of the soil surface in grasslands after the ‘Grain for Green’ project was implemented in 1999 to rehabilitate the Loess Plateau. However, few studies exist that quantify the effects of BSCs on the soil detachment process by overland flow in the Loess Plateau. This study investigated the potential effects of BSCs on the soil detachment capacity (Dc), and soil resistance to flowing water erosion reflected by rill erodibility and critical shear stress. Two dominant BSC types that developed in the Loess Plateau (the later successional moss and the early successional cyanobacteria mixed with moss) were tested against natural soil samples collected from two abandoned farmland areas. The samples were subjected to flow scouring under six different shear stresses ranging from 7.15 to 24.08 Pa. The results showed thatDcdecreased significantly with crust coverage under both moss and mixed crusts. The meanDcof bare soil (0.823 kg m−2s−1) was 2.9 to 48.4 times greater than those of moss covered soil (0.017–0.284 kg m−2s−1), while it (3.142 kg m−2s−1) was 4.9 to 149.6 times greater than those of mixed covered soil (0.021–0.641 kg m−2s−1). The relative detachment rate of BSCs compared with bare soils decreased exponentially with increasing BSC coverage for both types of BSCs. TheDcvalue can be simulated by flow shear stress, cohesion, and BSC coverage using a power function (NSE ≥ 0.59). Rill erodibility also decreased with coverage of both crust types. Rill erodibility of bare soil was 3 to 74 times greater than those of moss covered soil and was 2 to 165 times greater than those of mixed covered soil. Rill erodibility could also be estimated by BSC coverage in the Loess Plateau (NSE ≥ 0.91). The effect of crust coverage on critical shear stress was not significant. Copyright © 2015 John Wiley & Sons, Ltd.