双龙沟废弃矿区修复年限对土壤物理性质和微生物群落结构的影响

Soil physical properties and microbial characteristics in Shuanglonggou abandoned mining area in different restoration years

摘要:

【目的】探讨天祝藏族自治县双龙沟矿区废弃矿区不同修复年限土壤物理性质与微生物特性。【方法】采用时空替代法，选择双龙沟不同修复年限（2 a、5 a、10 a）和未修复（CK）废弃矿区为研究对象，分析了不同修复年限土壤物理性质（容重、含水量、机械组成）和土壤微生物（微生物量碳、氮、磷及真菌、细菌、放线菌数量）变化特征。【结果】随着修复年限的延长，表层土壤容重呈减少趋势，并在修复 10 a 时达到最小，为 0. 921 g/cm³ ；土壤含水率随修复年限的延长呈增加的趋势，并在修复 10 a 时为对照样地的 2. 4 倍；土壤粒径随修复年限的增加整体向细化的方向发展；3 大类微生物数量随修复年限的延长均整体呈增加的趋势，其中细菌占微生物总数量的 96. 74%，而放线菌和真菌仅占 0. 29% 和 0. 003%，并且放线菌和真菌具有明显的表聚现象；土壤微生物量碳和土壤微生物量磷呈逐渐增加的趋势，并分别在修复 2 a 和 5 a 时超过对照样地，最大值分别达到 385. 562、24. 414 mg/kg，而微生物量氮呈先增加后减少的趋势，变化范围为 14. 295~132. 388 mg/kg。【结论】在双龙沟矿区废弃地修复使土壤质量有了显著的提升，加速了矿区生态系统的恢复。

Abstract:

【Objective】In order to explore the soil physical properties and microbial characteristics in the abandoned land in Shuanglonggou mining area of Tianzhu Tibetan Autonomous County over different restoration years， the abandoned mining area with different restoration years （2 a，5 a，10 a，and ck） in Shuanglonggou was selected as the research objects.【Method】The temporal and spatial substitution method was used to analyze the characteristics of soil physical properties， including （unit weight， water content and mechanical composition）， and soil microbial biomass （microbial biomass carbon， nitrogen， phosphorus， and the number of fungi， bacteria， and actinomycetes） in different remediation years.【Result】 The results indicated that the bulk density of topsoil decreased with the extension of remediation years， reaching the minimum （0. 921 g/cm³ ） after 10 years of remediation. Soil moisture content increased with the extension of the remediation period， reaching 2. 4 times that of the original land after 10 years of remediation. Soil particle size developed towards refinement with the increase in restoration years. The numbers of three types of microorganisms increased with the extension of the restoration period， with bacteria accounting for 96. 74% of the total number of microorganisms，while actinomycetes and fungi only accounted for 0. 29% and 0. 003%，respectively， showing obvious surface aggregation. Soil microbial biomass carbon and phosphorus exhibited a trend of gradual increase，exceeding the control sample plots，with the maximum values of 385. 562 mg/kg and 24. 414 mg/kg，respectively，after remediation for 2 and 5 years. Microbial biomass nitrogen showed a trend of first increase and then decrease，with a range of 14. 295~132. 388 mg/kg.【Conclusion】 Through the remediation of abandoned land in Shuanglonggou mining area has significantly improved the soil quality and accelerated the restoration of the mining area ecosystem to a certain extent. This research provides theoretical and scientific bases for ecological restoration and improvement of soil quality in the mining area.