榆神府覆沙矿区采煤塌陷地表层土壤理化性质演变

以榆神府覆沙矿区采煤塌陷地表层土壤为研究对象,运用野外调查取样和实验室分析检测方法,研究不同采煤塌陷年限下(1、2、5、10 a和未塌陷区)土壤理化性质演变特征,探讨采煤塌陷过程中土壤理化性质的响应及其机制。结果表明:(1)与未塌陷地相比,采煤引起地表塌陷初期(1~2 a)土壤体积质量、硬度、黏粒含量、含水量、有机质、速效氮、速效钾、有效磷、全磷和全钾含量均有显著减小,而土壤孔隙度、p H和沙粒含量增加,全氮含量变化不明显,土壤质量总体表现出一定的退化趋势;(2)塌陷区自然恢复条件下上述土壤指标在塌陷5 a后呈现出改善的趋势,其中土壤物理性质、全效养分和土壤水分指标恢复较快,在塌陷10 a后即可恢复至塌陷前水平;但土壤速效养分、p H和有机质经过10 a的土壤自修复仍未完全恢复,采煤塌陷对土壤质量的损害具有一定延续性。(3)采煤塌陷后土壤质量演变过程分析表明,自然恢复条件下塌陷区土壤大体经过3个演替阶段,即退化期(塌陷后1~2 a)→改善期(塌陷后5 a)→部分恢复期(塌陷后10 a)。

Evolution of Topsoil Physical-chemical Properties After Coal Mining Subsidence in Yu-Shen-Fu Sand Covered Mining Area

The soil samples in different years of coal mining subsidence (1, 2, 5, 10 a, and un-subsidence area) at Yu-Shen-Fu Mining areas were collected, and the soil physical-chemical properties were measured. The results showed that soil quality showed a degradative trend in subsidence area compared with un-subsidence area. Soil bulk density, hardness, contents of clays, moisture, organic matter, available nitrogen, available phosphorus, available potassium, total phosphorus and total potassium were significantly decreased, while soil total porosity, pH, and sand content increased in the early stages of subsidence (1–2 a). However, the change of soil total nitrogen was not obvious in the research period. The above soil indexes showed an improving trend after 5 years natural restoration, soil physical properties, moisture and total nutrients recovered rapidly and reached up to the level before subsidence in 10 years; while available soil nutrients, pH and organic matter has not yet reached level of un-subsidence area. The succession of soil quality under natural restoration can be divided into three stages, namely the degradation stage (1–2 a)→improvement stage ( about 5 a )→partial recovery stage (after 10 a). Those results implied that coal mining subsidence had a certain sustaining damage on soil properties at Yu-Shen-Fu Mining area.