植被复垦对露天煤矿排土场土壤化学及生物学特性的影响

为探讨农牧交错带煤矿排土场不同植被复垦模式对土壤肥力的影响,以黑岱沟露天煤矿排土场不同植被类型(山杏+苜蓿(A1)、杨树+苜蓿(A2)、杨树+沙棘(A3)、杨树+披肩草+苜蓿(A4)、未复垦(CK))土壤为研究对象,通过简单相关分析和通径分析研究浅层(0—20cm)土壤化学性质和酶活性与土壤微生物量间的相关关系,揭示不同植被复垦下土壤微生物量差异的驱动因子,并采用土壤恢复指数(RI)评价不同植被复垦对露天煤矿排土场土壤质量的影响。结果表明:(1)与未复垦(CK)相比,不同植被复垦样地土壤有机质含量、碱解氮含量、土壤酶活性和微生物量均显著增加(p<0.05),但pH无明显变化规律且差异不显著(p>0.05),并且0—10cm明显高于10—20cm土层。(2)土壤微生物量碳、氮与土壤酶活性和有机质含量呈显著或极显著正相关关系,与pH和有效磷含量则均未表现出相关性。由于土壤微生物量碳和氮对有机质含量和蔗糖酶活性变化比较敏感,因此对土壤性质变化具有指示作用。(3)不同植被复垦土壤恢复指数在0—10,10—20cm土层分别表现为A3>A2>A4>A1和A3>A2>A1>A4。因此,杨树+沙棘(A3)和杨树+苜蓿(A2)复垦方式对矿区排土场土壤质量的改善较好。

Effect of Vegetation Restoration on Soil Chemical Biological Properties in the Opencast Coal Mine

In order to explore the influence of different vegetation restoration patterns on soil fertility in the coal mine dump of ecotone between agriculture and pasture, five vegetation types, Prunus armeniaca+Alfafa(A1), Poplar+Alfafa (A2), Poplar + Seabuckthorn (A3), Poplar +Elymus nutans+Alfafa (A4), Abandoned land (CK), were selected as research samples in Heidaigou Opencast Coal Mine. We mainly analyzed soil basic chemical properties, enzymes activities and microbial biomass with the method of their relations using correlation analysis and path analysis hoping to uncover the driving factors of the differences between soil microbial biomass under different vegetation restoration. The effect of different vegetation restoration on soil quality of Opencast Coal Mine was evaluated by soil reclaimation index (RI). The results showed that:(1) Compared with the abandoned land (CK), soil organic matter, alkali solution nitrogen content, soil microbial biomass and soil enzymes activities were significantly increased(p<0.05), but soil pH had no obvious change and no significant difference (p>0.05) under different vegetation restoration. Soil organic matter, alkali solution nitrogen content, soil microbial biomass and soil enzymes activities decreased from 0-10 cm to 10-20 cm soil layer. (2) The content of soil microbial biomass carbon and nitrogen were significantly correlated with enzymes activities and organic matter content. Soil microbial biomass carbon and nitrogen were sensitive to the changes of soil organic matter content and enzymes activities which could be used as microbial indicators for changes in soil quality. (3) The soil recovery index in 0-10 cm and 10-20 cm layers under different vegetation restoration were A3 > A2 > A4 > A1 and A3 > A2 > A1 > A4 respectively. Therefore, the reclamation mode of Poplar + Seabuckthorn (A3) and Poplar + alfalfa (A2) improved the soil quality of the coal mine dump.