西部矿区微地形改造对土壤质量的影响及驱动分析

Impact of micro-topography reconstructions on soil quality and driving mechanisms in coal mining areas of western China

  • 摘要: 微地形生态修复是改良退化土壤功能的重要途径之一,但其对土壤质量提升的驱动机制尚不明确。为探究微地形改造后土壤质量的变化特征及其驱动机制,以我国西部某矿区0~60 cm深度的土壤为研究对象,测定分析土壤理化性质,采用最小数据集法综合评价土壤质量,并利用随机森林模型识别土壤质量的关键驱动因子。研究结果表明:与原始坡面相比,微地形改造后的土壤含水率(SWC)、pH值、电导率(EC)、全氮(TN)、总磷(TP)、有机质(SOM)、碱解氮(SAN)和有效磷(SAP)含量及土壤质量指数(SQI)均增加,而全钾(TK)含量降低,其中鱼鳞坑的SWC更高,而水平沟的TN、TP、SOM、SAN和SAP含量更高;土壤质量驱动因子呈现显著分异,鱼鳞坑以TP、SWC和SOM为主导,水平沟则依赖SOM、TP和SAP的共同作用。研究结果为西部矿区微地形改造在生态修复和土壤改良中的应用提供了理论依据。

     

    Abstract: Micro-topography ecological restoration is one of the important ways to improve the functions of degraded soil, but the driving mechanism of its improvement on soil quality remains unclear. To explore the variation patterns of soil quality and its driving mechanisms under micro-topographic reconstructions, the physicochemical properties of the soil were measured and analyzed by taking the soil at a depth of 0-60 cm in a mining area in western China as the research object. A minimum data set method was applied for comprehensive soil quality assessment, and random forest analysis was used to identify the key driving factors of soil quality. Results indicate that compared with the original slope surface, significant changes in soil physicochemical properties under micro-topography reconstructions were observed, with increases in soil water content (SWC), pH, electrical conductivity (EC), total nitrogen (TN), total phosphorus (TP), soil organic matter (SOM), soil alkali-hydrolyzed nitrogen (SAN), and soil available phosphorus (SAP) contents, yet with a decrease in total kalium (TK) content. Fish-scale pits showed higher content of SWC while horizontal trenches exhibited higher contents of TN, TP, SOM, SAN and SAP. The soil quality index (SQI) of both horizontal ditches and fish scale pits significantly increased. The driving factors of soil quality showed significant variations: fish-scale pits were dominated by TP, SWC and SOM, while horizontal trenches were driven by the synergistic effect of SOM, TP and SAP. This study provides a theoretical basis for the application of micro-topographic reconstructions in ecological restoration and soil improvement in coal mining areas in western China.

     

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