Biological soil crusts decrease erodibility by modifying inherent soil properties on the Loess Plateau, China
Biological soil crusts decrease erodibility by modifying inherent soil properties on the Loess Plateau, China
复制标题
生物土壤结皮通过改变中国黄土高原的土壤固有特性来降低可蚀性
DOI：
10.1016/j.soilbio.2016.11.009
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发表时间：
2017-02-01
影响因子：
9.7
通讯作者：
Zhao, Yunge
中科院分区：
文献类型：
--
作者：
Gao, Liqian;Bowker, Matthew A.;Zhao, Yunge
土壤侵蚀和随后的土地退化在过去造成了社会崩溃，是干旱和半干旱地区荒漠化的主要原因。生物土壤结皮是许多干旱半干旱生态系统中普遍存在的生物覆盖物，在土壤稳定和水土流失防治中具有重要作用。退耕还林工程促进了中国黄土高原地区植被的恢复，生物结皮大面积发育。黄土高原是世界上水土流失最严重的地区之一。在黄土高原一个面积很大、侵蚀严重的地区，生物结皮的扩大有助于减少土壤流失。我们假设生物结皮的发育会改变土壤有机质（SOM）和土壤粒度分布（PSD），从而降低土壤的可蚀性和土壤流失。选取黄土高原区56个被动复植草地样地和3个裸土样地为样本，采用侵蚀生产力影响计算器（EPIC）模型结合模拟降雨对上述假设进行了验证。不同生物结皮类型和演替阶段的PSD和SOM含量差异显著。苔藓型和蓝藻型土壤有机质含量分别是裸地的4倍和1.5倍。与裸地相比，生物结皮中细颗粒（< 0.01 mm）较多，粗颗粒（0.05 ~ 0.25 mm）较少。模拟土壤可蚀性随着生物结壳生物量的增加而显著降低，这主要是由于SOM含量的增加，使预测的土壤流失量降低了90%。最后，黄土高原区苔藓生物结皮率比蓝藻更能预测土壤可蚀性。我们得出结论，生物结皮是土壤侵蚀初始减少的决定性因素，在黄土高原土壤流失预测和管理模型中必须明确考虑这一点。(C) 2016 Elsevier Ltd.版权所有。
Soil erosion and subsequent land degradation contributed to societal collapse in the past and are a leading cause of desertification in arid and semi-arid regions. Biological soil crusts (biocrusts) are ubiquitous living covers in many arid and semiarid ecosystems that have an important role in soil stabilization and erosion prevention. The "Grain for Green" ecological project improved vegetation recovery, and led to an extensive development of biocrusts across the Loess Plateau region in China, one of the most eroded regions in the world. The expansion of biocrusts was instrumental in reducing soil loss in a very large, severely eroded region of the Loess Plateau. We hypothesized that development of biocrusts would change soil organic matter (SOM) and soil particle size distribution (PSD), thereby reducing soil erodibility and soil loss. We sampled 56 sites that were passively revegetated grasslands on former croplands and 3 bare soil sites in the Loess Plateau region, and used the erosion productivity impact calculator (EPIC) model combined with simulated rainfall to test our assumption. The PSD and SOM content varied significantly among biocrust types and successional stages. The SOM content was 4 times higher in moss dominated biocrust and 1.5 times greater in cyanobacterially dominated biocrust than bare soil. More fine-particles (< 0.01 mm) and fewer coarse-particles (0.05-0.25 mm) were present in biocrusts than in bare soil. Modeled soil erodibility decreased significantly as biocrust biomass increased, mainly due to increase in SOM content, reducing the predicted soil loss by up to 90%. Finally, the prevalence of moss biocrust was a better predictor of soil erodibility than cyanobacteria in the Loess Plateau region. We conclude that biocrusts were a decisive factor for the initial reduction of soil erosion, which must be considered explicitly in models that aim to predict and manage soil loss on the Loess Plateau. (C) 2016 Elsevier Ltd. All rights reserved.