西部某矿区土壤养分时空分异特征及自修复规律

The temporal-spatialotemporal differentiation characteristics and self-repairing law patterns of soil nutrients in a mining area in western China

为了探究煤矿开采扰动区环境变化特征,厘清生态自修复驱动因素,以西部某矿区为研究区域,测定了2014—2017年和2019年开采区及未开采区域的土壤养分、土壤酶指标,评价了土壤C、N、P化学计量特征。结果表明,工作面区和沉陷扰动区的全磷、碳氮比、氮磷比及碳磷比存在显著差异;随开采沉陷年限增加,工作面区和沉陷扰动区土壤因子变化规律相似,全磷浓度逐年提升,有机质、速效钾及脲酶等物质浓度呈先上升后下降趋势;根据随机森林分析,在不同年限下,土壤养分循环的关键因子为蔗糖酶、脲酶、速效钾、全氮、全磷、碳磷比、碳氮比及水溶性盐,在不同位置下为碳氮比、氮磷比、全磷、碱性磷酸酶及水溶性盐;工作面开采年限对土壤因子及土壤酶的影响路径存在差异。研究结果可为采煤沉陷区人工引导自修复方案提供参考,为西部矿区生态恢复提供技术支持。

This study explores the environmental changes in the disturbed area of coal mining and presents the driving factors of ecological self-restoration.Specifically,we measured the soil nutrient and soil enzyme indicators in the mining area and non-mining area from 2014 to 2017 and 2019,and evaluated the stoichiometric characteristics of soil carbon(C),nitrogen(N),and phosphorus(P).The experi-mental results show that the total phosphorus concentration gradually recovered with the increase of min-ing years,while organic matter,available potassium,and urease first increased and then decreased with the increase of mining years.There were significant differences in total phosphorus,C/N ratio,N/P rati-o,and C/P ratio between the working face and the subsidence disturbance zone.Random forest analysis showed that soil sucrase,urease,available potassium,total nitrogen,total phosphorus,C/P ratio,C/N ra-tio,and water-soluble salts were the key factors influencing soil nutrient cycling in different time peri-ods;while C/N ratio,N/P ratio,total phosphorus,alkaline phosphatase,and water-soluble salts were the key factors influencing soil nutrient cycling at different locations.Mining years of the working face has differing influence path on soil factors and soil enzymes.This study could provide theoretical proof for the artificial guided self-restoration plan in coal mining subsidence areas and for ecological restoration in western mining areas.