Gao Guang-Lei, Ding Guo-Dong, Wu Bin, Zhang Yu-Qing, Qin Shu-Gao, Zhao Yuan-Yuan, Bao Yan-Feng, Liu Yun-Dong, Wan Li, Deng Ji-Feng
College of Soil & Water Conservation, Beijing Forestry University, Beijing, China.
College of Soil & Water Conservation, Beijing Forestry University, Beijing, China ; Yanchi Research Station, Yanchi, China.
PLoS One. 2014 Feb 7;9(2):e88559. doi: 10.1371/journal.pone.0088559. eCollection 2014.
Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions.
METHODOLOGY/PRINCIPAL FINDINGS: To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of successional biological soil crusts (algae, lichens, and mosses crust), as well as the referenced sandland in the Mu Us Desert, Northern China. Relationships between fractal dimensions of soil particle size distribution and selected soil properties were discussed as well. The results indicated that biological soil crusts had significant positive effects on soil physical structure (P<0.05); and soil organic carbon and nutrients showed an upward trend across the successional stages of biological soil crusts. Fractal dimensions ranged from 2.1477 to 2.3032, and significantly linear correlated with selected soil properties (R(2) = 0.494∼0.955, P<0.01).
CONCLUSIONS/SIGNIFICANCE: Biological soil crusts cause an important increase in soil fertility, and are beneficial to sand fixation, although the process is rather slow. Fractal dimension proves to be a sensitive and useful index for quantifying changes in soil properties that additionally implies desertification. This study will be essential to provide a firm basis for future policy-making on optimal solutions regarding desertification control and assessment, as well as degraded ecosystem restoration in arid and semiarid regions.
生物土壤结皮是沙漠生态系统的常见组成部分；它们覆盖地表并与表土相互作用，有助于干旱和半干旱地区的荒漠化控制和退化土地恢复。
方法/主要发现：为了区分受生物土壤结皮影响的表土变化，我们比较了中国北方毛乌素沙漠三种演替阶段的生物土壤结皮（藻类、地衣和苔藓结皮）以及对照沙地的表土性质。还讨论了土壤粒径分布分形维数与选定土壤性质之间的关系。结果表明，生物土壤结皮对土壤物理结构有显著的积极影响（P<0.05）；土壤有机碳和养分在生物土壤结皮的演替阶段呈上升趋势。分形维数在2.1477至2.3032之间，与选定的土壤性质显著线性相关（R² = 0.494∼0.955，P<0.01）。
结论/意义：生物土壤结皮可显著提高土壤肥力，有利于固沙，尽管这一过程相当缓慢。分形维数被证明是量化土壤性质变化的一个敏感且有用的指标，这也意味着荒漠化。本研究对于为未来关于荒漠化控制与评估以及干旱和半干旱地区退化生态系统恢复的最佳解决方案的政策制定提供坚实基础至关重要。
