Abstract: Accelerating artificial vegetation growth by soil covering was a critical technique to recover vegetation in minefields located in high-elevation frigid areas. In this study,a vegetation restoration experiment was carried out on a coalmine spoils in Jiangcang coal minefield of Muli,Qinghai Province. The properties of surface soil matrix in alpine mining areas covered with 0,5,10 or 15cm soil were determined. The study would provide reference for reconstructing soil in alpine mining area. The results showed that soil covering on the spoils regulated the bulk density of substrate soil and formed a physical structure which is conducive to vegetation growth. Covering the spoils with soil increased the total nitrogen content and the supply of available nutrients in the matrix soil. The effect of surface soil reconstruction became increasingly more obvious with recovery period. The available nitrogen content in the three soil-covered spoils increased,respectively,from 40.3±5.13 mg·kg^-1 (FT-5),85.0±14.9 mg·kg^-1 (FT-10),and 57.3±11.1 mg·kg^-1 (FT-15) in 2016 to 101.0±8.54 mg·kg^-1,192.0±33.6 mg·kg^-1,and 168.7±17.0 mg·kg^-1in 2017. The available nutrients in the soil-covered spoils increased first then declined with the increase of the thickness of the covering soil.The maximum value of available nutrients reached in the second year of reconstruction. The content of available phosphorus in FT-10 had the largest change. The total nitrogen content of surface matrix soil was positively correlated with its available nitrogen and available potassium (r=0.905,r=0.733;P<0.01),and negatively correlated with soil pH (r=-0.753,P<0.01). Overall,covering the spoils with soil at a depth of 10 cm was the optimal method for reconstructing coalmine spoils in alpine areas.

Key words: Spoil covering with soil, Alpine coalmining area, Surface soil matrix, Coalmine spoils

摘要： 通过覆土措施加速人工植被建植是高寒矿区植被恢复的关键技术问题。本文通过在青海木里煤田江仓矿区排土场建立植被恢复试验小区，比较覆土0 cm（对照）、覆土5 cm、覆土10 cm和覆土15 cm等不同覆土处理对高寒矿区排土场渣山表层土壤基质特征的影响，为高寒矿区土壤重构提供参考。结果表明，覆土可调节表层土壤基质容重，有利于形成植被生长的土壤物理结构。覆土增加了土壤基质中的全氮含量和速效养分的供给，随着处理时间的延长（2016-2018年），覆土效果愈来愈明显。不同覆土处理速效氮含量分别由2016年的40.3±5.13 mg·kg^-1，85.0±14.9 mg·kg^-1，57.3±11.1 mg·kg^-1增加至2017年的101.0±8.54 mg·kg^-1，192.0±33.6 mg·kg^-1，168.7±17.0 mg·kg^-1。覆土处理的速效养分出现先上升后下降的总体变化趋势，第二年达到速效养分最大值，覆土10cm速效磷含量变化幅度相对最大。表层土壤基质全氮含量与速效氮、速效钾含量呈极显著正相关（r=0.905，r=0.733；P<0.01），与pH呈极显著负相关（r=-0.753，P<0.01）。覆土10cm可作为高寒矿区土壤重构理想的覆土措施。

关键词: 覆土, 高寒煤矿区, 表层土壤基质, 排土场渣山