通过对神木北部矿区塌陷1,2,5,10 a和未塌陷区植物群落调查和土壤因子的测试,采用因子分析法评价不同塌陷年限下土壤质量和植被群落结构优劣,同时利用冗余和聚类分析研究植物与土壤之间的相互关系及其演变过程,并基于植被—土壤耦合模型判定不同塌陷年限土壤因子与植物群落耦合协调性。结果表明:1采煤塌陷导致土壤质量与植被群落结构退化,随塌陷时间的推移呈自然恢复趋势,但10 a后植物群落结构和土壤因子仍不能恢复至塌陷前水平;2塌陷区土壤有机质、水分和微生物是决定土壤质量和植物群落特征的关键因素,土壤硬度、速效养分和酶类是影响植物群落生产力和多样性的主要因子,而全效养分影响力相对较小;3塌陷区植物群落和土壤质量大体经过退化、改善和初步恢复3个不同的演化阶段;4植被与土壤的耦合协调性塌陷2 a后逐渐恢复,但至塌陷10 a仍未达到未塌陷地良好的耦合协调水平。神木北部矿区采煤对生态环境损害具有一定延续性,且生态系统自修复能力较弱,因此减少采动损害、实行自然与人工修复相结合应作为该区生态环境保护的指导原则。

The quality of soil and plant community structure were analyzed using factor analysis based on the investiga- tion of plant community characteristics and the examination of soil properties in different years of coal mining subsid- ence (1,2,5,10 a,and un-subsidence area) at northern Shenmu mining area. Meanwhile,redundancy analysis and cluster analysis were used to study the relationship and succession process between plants and soil. The vegetation-soil coupling model was used to determine the coordination of soil properties and plant community in five periods of coal mining subsidence. The results show that:① Disturbance of the subsidence was an important reason for the degradation of the soil quality and the vegetation structure in the subsided area. There was a natural restoration trend of plant-soil ecosystem with the passage of subsidence time. Unfortunately,the plant community structure and soil properties could hardly be restored to the pre-collapse level after even 10 years of natural succession. ② Soil organic matter,water,and microbes were the core of soil nutrient cycling process and the key factors to determine plant community characteristics. And soil hardness,available nutrients and enzymes were the major influence factors of plant community productiv- ity and diversity. However,the total nutrient was proved to be not so important factors for plant community. ③ Plant communities and soil properties at subsidence area under natural restoration could be divided into three stages,namely the degradation,improvement,and initial recovery stage. ④ There was a trend of recovery for the coordination of vege- tation and soil after two years of subsidence. However,it could hardly be well-coordinated ecotype in even 10 years of coal mining subsidence. The results indicated that coal mining had continuity damage to the ecological environment, and the self-healing of ecosystem was weak at northern Shenmu mining area. Therefore reducing the mining damage and achieving the combination of natural and artificial restoration should be the guiding principle of the ecological en- vironment protection in this area.