陇中黄土高原典型草原生物土壤结皮发育对土壤养分的影响

为了解生物土壤结皮发育与土壤养分特征的关系，该研究选取处于不同发育阶段和不同盖度的藓结皮(M-crust)和地衣结皮(L-crust),对其结皮层生物体及结皮下层3 cm土壤进行养分分析。结果显示：(1)藓结皮生物体对土壤全氮(TN)、全磷(TP)、铜(Cu)和锌(Zn)的生物富集作用较强，其富集系数分别高达807.4%、175%、122.4%和244.5%,而地衣结皮生物体对TN、TP和钙(Ca)的生物富集作用较强，其富集系数分别高达950.8%、126.2%和208.6%;除Ca外，藓结皮生物体中TP、钠(Na)、钾(K)、Cu、铁(Fe)、镁(Mg)、锰(Mn)和Zn均显著高于地衣结皮。(2)土壤生物结皮盖度与其对应的土壤养分含量之间无显著线性相关关系，但发育有不同盖度藓结皮的土壤其平均TN、TP、Cu、Fe、K、Na和Ca含量均高于地衣结皮。研究表明，不同类型生物土壤结皮对养分吸收、富集效率不同，处于发育后期的藓结皮较发育中期的地衣结皮具有更强的养分累积效应，提高了土壤的养分贮存量，对黄土高原典型草原生态系统的恢复与重建具有潜在的重要影响。

Effect of Biological Soil Crusts Development on Soil Nutrients in a Typical Grassland on the Loess Plateau of Central Gansu

To understand the relationship between the development of biological soil crusts and soil nutrient characteristics, this study selected moss crust (M-crust) and lichen crust (L-crust) at different stages of development, and analyzed the nutrients in the crust layer and the 3cm soil below the crust. The results show that: (1) the moss crust organisms were more bioenriched for TN, TP, Cu and Zn with enrichment coefficients up to 807.4%, 175%, 122.4% and 244.5%, respectively, while the lichen crust organisms were more bioenriched for TN, TP and Ca with enrichment coefficients up to 950.8%, 126.2% and 208.6%, respectively. And TP, Na, K, Cu, Fe, Mg, Mg and Zn except for Ca were significantly higher in moss crust organisms than in lichen crust organisms. (2) There was no significant linear correlation between the coverage of soil biological crusts and their soil nutrient contents in microhabitats, but the average TN, TP, Cu, Fe, K, Na and Ca contents in soils with different coverage of moss crusts were higher than those in lichen crusts. This study showed that different types of biological soil crusts have different nutrient uptake and enrichment efficiencies, and moss crusts in the late stage of development have stronger accumulation effects on nutrients than lichen crusts in the middle stage of development, which improve the nutrient storage capacity of soil and have potentially important impacts on the restoration and reconstruction of typical grassland ecosystems in Loess Plateau.