优势植物根系构架对矿区排土场新构土体土壤抗侵蚀的影响机理

A large number of reconstructed soils formed by mining are extremely unstable influenced by seasonal extreme rainfall in open-pit coal mine of northern China. The optimal allocation of shrub and grass is an effective mode resisting soil erosion in the reconstructed soil of dumps, and root is the key to enhance soil erosion resistance. However, the mechanism of the root framework on soil erosion resistance is not clear. Based on the preliminary study, which found that the presence of root framework can significantly enhance the soil erosion resistance, the project selects Amorpha fruticosalinn.and Medicago sativa roots in the Shanxi-Shaanxi-Inner Monglia mining area as the study object. Using field observation method and the flume under a wide range of slope gradient and flow rate and 3D X-ray technology, this project is proposed to analyze the features of root framework in constructed soils of the mining dumps; Effect of plant root framework on soil physical properties, chemical properties and microbial characteristics of the mining area will be investigated; Moreover, the project will study the interaction between root framework and soil, as well as its effect on soil erosion process and its mechanism. This project will clarify the formation mechanism and framework characteristics of plant roots in the combination of shrub and grass in the mine dumps; At the same time, the effect of plant root framework on soil physical and chemical properties, as well as microbial characteristics will be clarified; At last, the coupling effect of root framework and soil properties on soil erosion resistance and its mechanism will be revealed. The project proposed may provide a scientific evidence for the mechanism of soil reinforcement by plant roots and vegetation reconstruction in the dumps of open-pit mining areas in northern China.

北方露天矿开采形成的大量排土场新构土体受季节性极端降雨作用极不稳定。灌草优化配置是阻控排土场新构土体土壤侵蚀的有效模式，其中根系固土抗蚀作用是关键，但目前关于根系构架对土壤抗侵蚀的影响机理尚不明确。本项目拟在前期研究发现根系构架的存在能够显著增强土壤抗侵蚀能力的基础上，以晋陕蒙矿区优势植物紫穗槐、紫花苜蓿根系为对象，采用野外定位观测、变坡试验水槽径流冲刷及3-DX射线扫描技术相结合的方法，研究矿区排土场新构土体优势植物根系构架特征；植物根系构架对矿区排土场土壤物理性质、化学性质和微生物特征的影响；植物根系构架和土壤性质相互作用及其影响土壤抗侵蚀过程和机理。阐明矿区排土场优势植物根系构架特征及其形成机理；明确植物根系构架对新构土体土壤物理性质、化学性质和微生物特征的影响；揭示植物根系构架和土壤性质耦合作用对土壤抗侵蚀能力的影响机理。为北方露天矿区排土场植物根系固土机理及植被重建提供科学依据。

北方露天矿开采形成的大量排土场新构土体受季节性极端降雨作用极不稳定。灌草优化配置是阻控排土场新构土体土壤侵蚀的有效模式，其中根系固土抗蚀作用是关键，但目前关于根系构架对土壤抗侵蚀的影响机理尚不明确。本项目拟在前期研究发现根系构架的存在能够显著增强土壤抗侵蚀能力的基础上，以晋陕蒙矿区优势植物紫穗槐、紫花苜蓿根系为对象，采用野外定位观测、变坡试验水槽径流冲刷及3-DX射线扫描技术相结合的方法，研究矿区排土场新构土体优势植物根系构架特征；植物根系构架对矿区排土场土壤物理性质、化学性质和微生物特征的影响；植物根系构架和土壤性质相互作用及其影响土壤抗侵蚀过程和机理。为北方露天矿区排土场植物根系固土机理及植被重建提供科学依据。主要结论包括：.（1）在前期根系构架概念提出，根系构架类型划分的基础上，引入Amoeba图形法，从根系形态、数量和空间三个维度综合建立“根系构架指数（RFI，%）”，以量化表征根系结构特征。通过定位观测苜蓿（H-型）、柳枝蓟（M-型）和混播（H+M型）根系发育特征，实例验证的结果表明：建立的H、M和H+M型根系构架指数分别为0.38、0.86和1.68，能够较好地反映根系结构特征；根系构架指数的参数包括根系构架作用系数、根系密度Rd（kg/m3）、根系构架度S（无量纲）和土壤容重ρ（kg/m3），表达式为。.（2）受西北风力的长期作用，研究区凋落物分布以沙柳基部为中心，在地表空间上近似存在同心圆、扇形和月牙形格局现象。随着距沙柳基部距离的增大（30cm、60 cm和90cm），凋落物生物量呈显著减小趋势；与同心圆格局相比，扇形和月牙形格局的凋落物生物量呈西北减少，东南增加趋势，增幅介于4.4-10.4%，尤以月牙形最为显著；沙柳群落中叶和果实在西北风力作用下沿地面的迁移和再分配是形成凋落物三大格局的主要原因。.（3）本研究一种北方地区煤矿排土场植被恢复的方法，属于造林绿化技术领域；所述方法包括以下步骤：在煤矿排土场的土壤中施用土壤调理剂；在施用土壤调理剂后，种植改良植物；所述改良植物包括沙棘、沙冬青、草木樨、沙打旺、猪毛菜和中科羊草；在种植改良植物的土壤表面覆盖水土保持毯；对种植后的改良植物进行管护。针对煤矿排土场新构土体具有分散性、粗质性和贫瘠性的特点，本发明集成了煤矿排土场改土-稳坡-植草-覆毯-护苗的植被配置与建造技术体系，为植物群落建造实践与生态建