贺兰山露天煤矿排土场生态修复限制因子及对策

Limiting Factors and Countermeasures of the Ecological Restoration of the Dump of Open-pit Coal Mine in the Helan Mountains

为明确贺兰山露天煤矿排土场的生态修复方向、选择更有针对性的修复措施、提高修复效果,本研究以贺兰山自然保护区内汝箕沟露天煤矿排土场为研究对象,对其气候、地形和土壤理化性质三个方面中存在的生态修复限制因子进行研究,并提出针对性的治理对策。结果表明:(1)研究区气候方面的限制因子主要为降水少(<200 mm)且分布不均、蒸发大(2000 mm)、气温低、有效积温少和大风天数多(≥150 d);(2)排土场地形限制因子为坡度大(30°−36°)、坡长长(10−44 m);(3)土壤限制因子主要为砂石(73.40%±2.18%)和粘粒(13.21%±1.37%)含量过高、孔隙度小(30.89%±0.83%),全氮(0.67±0.05 g kg^(-1))、水解性氮(14.23±0.48 mg kg^(-1))和有效磷(2.81±0.44 mg kg^(-1))含量少。该地区生态修复限制因子主要为干旱缺水、坡度大、坡长长、土壤质量差。针对以上限制因子,可以考虑采用坡脚支护、坡面水平拦挡和固结、坡面覆盖、植物措施和渣土改良等措施。本研究为贺兰山等干旱区露天煤矿排土场今后筛选适宜生态修复措施、提高修复效果提供了科学依据和理论支撑。

In order to clarify the ecological restoration direction,this study investigated the limiting factors of the ecological restoration of the dump of Rujigou Open-pit Coal Mine in the Helan Mountain Nature Reserve from the aspects of climate,topography,and soil physicochemical properties.The main results are as follows:(1)In terms of climate,the main limiting factors in the study area were low precipitation(<200 mm)with uneven annual distribution,high evaporation(2000 mm),low temperature,less effective accumulated temperature,and large number of gale days(≥150 days).(2)The topographic limiting factors were steep slope(30°-36°)and long slope length(10-44 m).(3)In terms of soil,the main limiting factors were high contents of sand(73.40%±2.18%)and clay(13.21%±1.37%),low porosity(30.89%±0.83%),and low contents of total nitrogen(0.67±0.05 g kg^(-1)),hydrolytic nitrogen(14.23±0.48 mg kg^(-1))and available phosphorus(2.81±0.44 mg kg^(-1)).The limiting factors of the ecological restoration of the study area mainly included drought and water shortage,less effective accumulated temperature,large number of days of strong wind,steep slope,long slope length,and soil depletion.In view of the above limiting factors,coun-termeasures such as slope foot support,slope level arrest and consolidation,slope cover,plant measures,and muck improvement can be considered.This study provides a scientific basis and theoretical support for the selec-tion of appropriate ecological restoration measures and improvement of restoration effectiveness for open-pit mine dumps in arid areas such as the Helan Mountains.