西部煤矿区生物土壤结皮的生态修复作用及其碳中和贡献

Ecological restoration effect and carbon neutrality contribution of biological soil crusts in western mining area

我国西部是典型的生态脆弱敏感区和水土流失严重区,煤炭的资源开发与干旱脆弱的自然环境叠加作用使西部煤矿区地表损伤及生态碳汇能力下降的问题日趋严重,探索一种与生境契合度高、贴合地形变化快速复绿的生态修复+碳汇技术成为当务之急。生物土壤结皮是由土壤微生物、隐花植物如蓝藻、真核藻类、地衣、苔藓等与土壤表层颗粒胶结而成的复杂有机体,广泛分布于我国西部地区。生物土壤结皮作为干旱半干旱地表生物覆被层的最初主要构建者,是陆地生态系统中重要的碳汇,能够改变土壤表面的微地形,增加降水入渗,延缓或减少径流的发生,影响菌类和土壤动物的生存和繁衍,并在土壤生态水文过程、土壤生物过程和地球化学循环过程中发挥重要作用。为此,结合西部煤矿区生态环境所面临的主要问题,从生物土壤结皮影响土壤养分累积、氮固定、风蚀水蚀过程、植物萌发与生长等方面对其生态功能进行概述。阐述生物藻结皮对沙地沙尘控制、采煤沉陷地裂缝修复、乔灌草立体生物修复等新技术模式。通过试验研究发现,与藻结皮层相比,苔藓结皮层有机碳含量显著高于90.3%,丛枝菌根真菌与苔藓结皮种子土3∶1~5∶1(质量比)配比时有机碳含量增加107%。提出了丛枝菌根真菌与苔藓结皮种子土3∶1~5∶1联合最佳配比固碳、生物土壤结皮与草灌乔立体组合生物固碳、生物土壤结皮长期修复土壤累积固碳等碳中和的贡献潜力,旨在为碳中和背景下西部煤矿区土地复垦与生态修复提供新的参考和技术支撑。

Western China is one of typical ecologically fragile and sensitive areas with the most serious soil erosion problem.The problems of surface damage and ecological carbon sink decline caused by the superimposition of coal resource exploitation and drought fragile natural environment is becoming more severe in the western mining areas.Thus,it is necessary to explore a kind of ecological restoration and carbon sequestration technology with high habitat compatibility and rapid greening in accordance with terrain change.Biological soil crusts widely distributed in western China,are complex organic integrities formed by soil microorganisms,cryptogamic plants,e.g.cyanobacteria,eukaryotic algae,lichens and mosses,as well as gluing soil surface particles together.As primary builders of topsoil biological cover in arid and semi-arid,biological soil crusts are important carbon sinks in terrestrial ecosystems,which could change the micro-topography of topsoil,increase rainfall infiltration and delay or reduce runoff,as well as influence the survival and reproduction of soil micro-organism and animals.Meanwhile,it plays an important role in soil eco-hydrological,soil biological and geochemical cycle processes.As for the primary problems of ecological environment in the western mining areas,the influence of biological soil crusts on soil nutrient accumulation,nitrogen fixation,wind and water erosion in ecological function were reviewed in this study.In addition,the diversified ecological restoration models,including dust control by cyanobacterial biocrust,mining subsidence crack restoration,three-dimensional configuration restoration of biological soil crust and herbs,shrubs and arbors,were expounded.Based on the experimental results,the organic carbon content in moss biocrust was significantly higher than that in cyanobacterial biocrust by 90.3%,and the organic carbon content was increased by 107%at the mycorrhizal fungi and artificial moss biocrust combined with 3∶1-5∶1 ratio.Moreover,the contributions of carbon sequestration of biological soil crusts to carbon neutralization in the coal mining areas,including mycorrhizal fungi and artificial moss biocrust combined with 3∶1-5∶1 ratio of carbon sequestration,biological soil crust combined with and arbors,shrubs,and herbs for carbon sequestration,long-term remediation of biological soil crusts for soil carbon sequestration,were proposed.These works provide some diversified theoretical references and technical support for land reclamation and ecological restoration in the western mining areas under the background of carbon neutrality,so as to accelerate the sustainable development of ecological environment restoration in the western mining areas.