露天矿区排土场重构土壤典型物理性质空间分异特征与植被恢复响应

It is important for the improvement of ecological environment in mining area to research the interaction between reconstructed soil and vegetation and their spatial heterogeneity. The basic theories of soil reconstruction and ecology, practical results of land reclamation are dependent on, and the realistic problem of reclaimed land degradation is aimed. There will be eight belt transects and several quadrats built on the reclaimed land of dump site, and the Ground Penetrating Radar (GPR) will be used to detect the 1.0-1.5 m depth of soil profiles, and the vegetation cover, plant community diversity will be investigated in different quadrats. Some methods, such as variance analysis, geographical weight regression analysis, knowledge trend analysis, spatial interpolation analysis, etc, will be adopted to analyze the heterogeneity traits and mechanisms of typical physical properties of reconstructed soil, including soil thickness, soil texture, soil gravel content, soil bulk density and soil water content, explore the influence mechanisms to vegetation cover, plant community diversity based on the spatial heterogeneity traits of typical physical properties, and construct the quantitatively characteristic models of typical physical properties adopting vegetation cover, plant community diversity. The common influence mechanism of spatial heterogeneity of one typical physical property under topography conditions, vegetation statuses and other typical properties will be discovered, and the influence thresholds of vegetation cover, plant community diversity affected by typical physical properties of reconstructed soil under different topographies will be resolved. The results on one hand will be useful to be rich of the basic theories of soil reconstruction and ecological restoration and the interactive mechanisms between reconstructed soil and vegetation, on the other hand will be helpful to support non-destructive detection of typical physical properties of reconstructed soil.

本项目立足矿区土壤重构原理与生态学基础理论及复垦案例，瞄准复垦地局部退化这一现实问题，在8条排土场复垦地样带上建立多个多尺度植被调查样方，通过1.0-1.5米深度内重构土壤典型物理性质（土层厚度、土壤质地、砾石含量、土壤容重、土壤含水量）的探地雷达探测与植被覆盖度、植物群落多样性调查，采用方差分析、地理加权回归分析、降趋势对应分析、空间插值分析等，研究重构土壤典型物理性质空间分异特征与形成机理，探索其空间分异特征对植被覆盖度、植物群落多样性的影响，构建典型物理性质的植被定量表征模型。重点揭示单个重构土壤典型物理性质空间分异特征受地形条件、植被状况及其它典型物理性质共同影响的机理，解决不同地形条件下典型物理性质对植被恢复状况的影响临界。研究成果既可丰富矿区排土场土壤重构的基本原理及重构土壤典型物理性质与植被恢复作用机理；还可为复垦地重构土壤典型物理性质无损监测提供技术支持。

为了促进矿区生态修复的理论研究与实践，本项目以中煤平朔安太堡露天矿南排土场为研究对象，通过不同坡向样带的野外采样，开展了重构土壤典型物理性质雷达图像特征解析、分异特征与机理分析、植被生长状况表征。主要研究结果如下：. （1）根据探地雷达图像中局部存在的强弱多变的强反射信息，可分析土壤体积含水率的空间差异性。在土壤体积含水率较小时，土壤容重与介电常数成正比，可分析土壤容重的相对大小。图像中存在连续性较好的低频信号可表征复垦地有效土层厚度。通过对图像中孤立碎石信号数量的统计，可分析表层土壤的砾石含量。利用探地雷达的三维图像可详查重构土壤典型物理性质在小区域上的空间分异特征。. （2）研究区表层重构土壤典型物理性质在整体上发生了一系列变化，并且在地形方面均表现出了一定差异。表层土壤典型物理性质的变异系数均处在中等变异性状态，结合差异性特征分析了地形差异形成的原因。研究区剖面重构土壤典型物理性质在深度上存在很大的不均质性，基本为中高等变异水平，并存在明显的空间变异。植被生长状况在不同小区域间差异性显著。研究区高程和立地显著作用于土壤容重、土壤质量含水率。高程和坡向是影响植被生长状况的主要因素，土壤因子中对植被影响最大的物理性质是砾石含量。. （3）植被覆盖度与表层重构土壤典型物理性质之间关系显著，在一定土壤物理性质或植被覆盖度范围内，二者存在相对应的表征关系。在不同坡向，植被覆盖度与土壤物理性质的关系呈现一定的差异性。这主要是与不同坡向水热条件的差异所致。阳坡、半阳坡植被覆盖度对土壤物理性质表征的敏感性较高，即在阳坡、半阳坡一定程度地改善土壤物理性质，对植被生长状况的改善会比较明显，同时植被生长状况的改善也有利于土壤物理性质的提升。. 本项目研究成果既丰富了矿区重构土壤基本原理与土壤-植被之间的作用机理，又促进了复垦地重构土壤典型物理性质无损探测技术的发展。