高寒矿区排土场不同坡向植被和土壤特征研究

针对高寒矿区排土场人工植被恢复问题,选取青海江仓矿区南北2个排土场的4个坡面(南坡、北坡、东南坡与东坡)为研究对象,进行了不同坡向立地条件下植被与土壤的调查分析。结果显示:除幼苗高度外,不同坡向植被高度、盖度、地上生物量、生殖枝数量具有显著差异(P0.05),东南坡与南坡(阳坡)长势较好。土壤全氮、有效磷含量及pH在不同坡向差异不显著(P0.05),土壤全磷、碱解氮、速效钾、有机质、含水量在不同坡向具有显著差异(P0.05)。北坡土壤有机质含量比其他3个坡面平均高出127.95 g/kg(P0.05),土壤含水量在北坡与东坡(阴坡)显著高于南坡与东南坡(P0.05)。土壤细菌与放线菌数量在东南坡显著高于其他3个坡面(P0.05)。利用随机森林方法得出,土壤细菌数量、含水量、碱解氮含量、全磷含量、有机质含量及植被高度是影响露天煤矿排土场不同坡向立地条件下植被与土壤特性的主要因子。因此,为减小矿区排土场复绿过程中坡向不同带来的影响,在人工建植初期应加大东坡与北坡(阴坡)的种子播量,适时追施氮肥,并选择加厚无纺布(50 g/m~2)覆盖。

Characteristics of Vegetations and Soils Under Different Aspects of Slag Mountain in Alpine Mining Area

Aiming at artificially restoring vegetation in an alpine mine-dump area in Qinghai, four slope sites facing southeast, south, north and east at two dumps in the Jiang-Cang mining area, Qinghai, were selected as the study area, and the characteristics of artificial vegetation and soil at the four sites were investigated and analyzed. The results showed that at different slope orientations, there were significant differences (P<0.05) in vegetation height, coverage, aboveground biomass, and the number of reproductive branches except seedling height. Vegetation on the southeast slope and south slope (positive slope) grew better than on other slopes. There was no significant difference in soil N, P content and pH among the slopes of different orientations (P sample 0.05). The total P and available N, available K, organic matter, moisture content showed a significant difference (P < 0.05) among the four sites. Organic matter content on the north-facing slope was 127.95 g/ kg higher than other three sites (P < 0.05), soil moisture content on the north and east slopes was significantly higher than on the south and southeast slopes (P < 0.05). The number of soil bacteria and actinomycetes was significantly higher on the southeast slope than on the other three slopes (P<0.05). Results of Random Forest analysis reveal that soil bacteria, water content, available N, total P, height of vegetation and soil organic matter content at the four slope sites were the main influencing factors of vegetation and soil characteristics in the open-cast coal mine drainage field under different slope conditions. Therefore, in order to reduce the impacts of different slopes in the re-greening process of the mine drainage area, the quantity of seeds sowed on east and north slopes (overcast slope) should be increased at the initial stage of artificial planting, nitrogen fertilizer should be applied in time, and thick non-woven fabric (> 50g /m2) should be used to cover the field to boost the seed germination rate.