黄土沟壑区采煤塌陷地不同土地利用类型土壤性质损害特征

Damage Characteristics of Soil Properties in Different Land Use Types under Mining Subsidence Areas in Loess Hilly Area

【目的】探究半干旱榆神府矿区采煤塌陷地不同土地利用类型地表土壤损害程度和机理。【方法】选择榆神府矿区黄土沟壑地貌下林地、耕地、园地和草地4种不同土地利用类型,分析地表塌陷前后土壤物理、化学和生物学性质的变化特征,通过主成分分析和排序探讨采煤塌陷对不同土地利用类型土壤性质的影响。【结果】4种土地利用类型地表塌陷1~2年内土壤性质均朝着水分、养分减小的方向发展,但不同土地利用类型塌陷地土壤损害特征具有明显差异,其中草地的土壤机械组成和养分含量、林地的速效养分特征、园地的砂粒含量各自变化较显著;土壤机械组成、有机质和水分含量是影响榆神府矿区土壤质量变化的关键因子;在矿区损害地土壤系统修复过程中,除必要的塌陷地充填外,草地还需采取人工施肥、补水和微地形改造等措施,林地还需施加氮磷肥辅以相应的微生物菌剂,园地和耕地损害较小可减小人工干预。【结论】半干旱或干旱区煤炭开采塌陷地在生态修复过程中,针对不同土地利用类型土壤损害程度与成因采取对应的恢复措施,有利于矿区生态环境高效和高质量恢复。

[Objective] The degree and mechanism of surface soil damage under different land use types need to be explored in the semi-arid Yulin-Shenmu-Fugu mining subsidence area. [Method] Four different land use types,including forest land, cultivated land, orchard land and grassland, were selected in Yulin-Shenmu-Fugu mining area at loess gully landform. The change characteristics of soil physical, chemical and biological properties before and after surface collapse were analyzed, and the influence of coal mining subsidence on soil properties of different land use types was discussed by principal component analysis and sorting. [Results] Within 1-2 years after the surface subsidence of four land use types, the soil properties all developed towards the direction of decreasing water and nutrients. However, there were obvious differences in soil damage characteristics among different land use types. The soil particle composition and nutrient content of grassland, available nutrient characteristics of forestland, and sand particle content of orchard land changed significantly in their own respectively. Soil mechanical composition, organic matter and water content were the key factors affecting soil quality changes in the Yulin-Shenmu-Fugu mining area. In the process of soil system restoration of damaged land in mining area, in addition to the necessary filling of the collapsed land, measures such as artificial fertilization, irrigation and micro-topographic reconstruction should also be adopted for grassland, and forestland soil should be mainly applied with nitrogen and phosphate fertilizer supplemented by corresponding microbial agents. The less damaged orchard land and cultivated land could reduce manual intervention. [Conclusion] In the process of ecological restoration in coal mining subsidence areas in semiarid or arid areas, according to the degree and causes of soil damage of different land use types, taking corresponding restoration measures is beneficial to the efficient and high-quality restoration of the ecological environment of mining areas.