Wang Yuan, Zhao Yun-Ge, Yao Chun-Zhu, Zhang Pei-Pei
Ying Yong Sheng Tai Xue Bao. 2014 Mar;25(3):647-56.
Soil surface roughness exerts profound influence on runoff and sediments yield from slopes. Biological soil crusts (BSCs) are ubiquitous living cover in the open spaces between plants in arid and semiarid ecosystems, which considerably impact the surface roughness. Aimed to determine the effect of biological crusts on the surface roughness and its influence factors, this study investigated the surface roughness of soil with BSCs at their different successional stages by using the chain method. Besides, the impacts of slope aspects, soil water content and freezing and thawing on surface roughness were also investigated. Then, the correlations between roughness and soil chemical and physical properties were evaluated. The results showed that soil surface roughness decreased at the initial successional stage of BSCs but increased along with BSCs' development in the region. Soil roughness tended to be stabile since BSCs developed ten years later. The roughness was reduced by 47.0% by the light cyanobacteria-dominated crust and 20.4% by the dark cyanobacteria-dominated crust (moss coverage < 20%), compared with the bare soil. Soil moisture significantly impacted surface roughness. The surface roughness of BSCs changed obviously with soil moisture in the early development, but only slightly in their later succession. Freezing-thawing also affected surface roughness with BSCs. Roughness was more susceptible to freezing-thawing in the early de- velopment of BSCs, with an increase of 29.7% compared with the bare soil. The surface roughness of late successional BSCs exhibited a slight change only after repeated freezing-thawing. The surface roughness of BSCs showed a statistically significant relationship with the coverage of moss (P < 0.1).
土壤表面粗糙度对坡面径流和产沙量有着深远影响。生物土壤结皮（BSCs）是干旱和半干旱生态系统中植物间开阔空间普遍存在的活覆盖层，对地表粗糙度有显著影响。为了确定生物结皮对地表粗糙度的影响及其影响因素，本研究采用链条法调查了不同演替阶段有生物结皮土壤的表面粗糙度。此外，还研究了坡向、土壤含水量以及冻融对表面粗糙度的影响。然后，评估了粗糙度与土壤化学和物理性质之间的相关性。结果表明，在该地区，生物土壤结皮演替初期土壤表面粗糙度降低，但随着生物结皮的发育而增加。生物结皮发育十年后粗糙度趋于稳定。与裸土相比，以浅色蓝藻为主的结皮使粗糙度降低了47.0%，以深色蓝藻为主的结皮（苔藓覆盖率<20%）使粗糙度降低了20.4%。土壤湿度对表面粗糙度有显著影响。生物土壤结皮在发育早期，其表面粗糙度随土壤湿度变化明显，但在后期演替中变化较小。冻融也会影响有生物土壤结皮的表面粗糙度。生物土壤结皮在发育早期粗糙度对冻融更敏感，与裸土相比增加了29.7%。后期演替的生物土壤结皮仅在反复冻融后表面粗糙度有轻微变化。生物土壤结皮的表面粗糙度与苔藓覆盖率呈显著统计学关系（P<0.1）。
