平朔黄土露天矿区复垦地表层土壤微生物与酶活性分析

矿区是当今世界陆地生态系统被破坏和退化最严重的区域之一,在进行露天煤矿土地复垦与生态重建时不仅要恢复地表植被和生物,还应重视地下土壤微生物生态系统的构建,而国内外相关研究多集中在植被重建及土壤理化性质监测方面,利用土壤微生物及酶活性揭示矿区重构土壤状况的研究尚不多见。通过8个样地24个土壤剖面的采样分析,采用时空替代法和单因素方差分析法对平朔矿区不同复垦年限的排土场和原地貌0—20 cm表层土壤中细菌、真菌、放线菌的数量及蔗糖酶、脲酶和磷酸酶活性及变化进行研究,旨在分析其特征及差异。研究结果表明:(1)从微生物数量及酶活性特征来看,无论复垦年限的时间长短,细菌数量在3类微生物中占有绝对优势,占微生物总数的99.20%以上,其次是放线菌,真菌的数量最少;脲酶活性在3种酶中活性最大,其次是蔗糖酶活性,磷酸酶活性最低。(2)从微生物数量和酶活性的变化状况来看,3类微生物数量和3种酶活性在0—20 cm土层随复垦年限的变化趋势相一致,均随复垦年限的变化先增长后降低,而后又随着复垦年限的增长不断增加。(3)在0—20 cm土层,复垦27年的南排土场的土壤细菌、放线菌和真菌数量在复垦后达到了189.3333×10⁵ cfu/g、0.1312×10⁵ cfu/g和1.1463×10⁵ cfu/g,复垦效果达到原地貌3类土壤微生物数量的65.88%、66.46%和67.74%;蔗糖酶、脲酶和磷酸酶活性分别达到1.9600 mg 100 g^-1 h^-1、6.3600 mg 100 g^-1 h^-1和1.4533 mg 100 g^-1 h^-1,复垦效果分别达到原地貌83.40%、86.30%和86.85%。因此开展矿区土地复垦后土壤微生物及酶活性的相关研究,能够在一定程度上及时反映土地复垦后的土壤质量以及生态系统的恢复状况,以便采取更加合理的复垦方法来提高矿区生态恢复的速度和效果。

Characteristics and differences of surface soil microbial population and enzyme activities in opencast mining area of Pingshuo

The mining area is one of the most severely damaged and degraded regions in the world. In the process of land reclamation and ecological reconstruction of opencast coal mine, not only should the surface vegetation and organisms be restored, but also the construction of underground soil microbial ecosystems should be paid attention to. However, the related researches at domestic and abroad are mainly focused on vegetation reconstruction and soil physical and chemical property monitoring. There are few studies on the use of soil microorganism and enzyme activities to reveal the status of soil reconstruction in mining areas. Through the sampling analysis of 24 soil profiles in 8 plots, the number of bacteria, actinomycetes, and fungus and the activity changes of sucrase, urease and phosphatase in the dump and 0-20 cm topsoil of Pingshuo mining area were studied by spatio-temporal substitution method and one-way analysis of variance, to analyze their characteristics and differences. The results showed that (1) From the microorganism population and enzyme activity characteristic, regardless of the time of reclamation, the number of bacteria was absolutely dominant among the three types of microorganisms, accounting for more than 99.20% of the total microorganisms, followed by actinomycetes. The number of fungus was the least; the urease activity was the highest among the three enzyme activities, followed by sucrase activity, and phosphatase one the lowest. (2) From the point of view of the changes of the number of microorganisms population and the density of enzyme activity, the change trend of the number of three kinds of microorganisms and the activity of three enzymes in 0-20 cm topsoil was consistent with the reclamation years, which followed an up-down manner in line with time changes in reclamation and then kept going upward as reclamation years increases. (3) In the 0-20 cm soil layer, the microbial numbers in the southern dump after 27 years of reclamation reached 189.33×10⁵ cfu/g, 0.1312×10⁵ cfu/g and 1.1463×10⁵ cfu/g, and the reclamation effect reached 65.88%, 66.46% and 67.74% of the microbial numbers in the original landform, respectively. The activities of sucrase, urease and phosphatase reached 1.96 mg 100 g^-1 h^-1, 6.36 mg 100 g^-1 h^-1 and 1.45 mg 100 g^-1 h^-1, respectively, and the reclamation effects reached 83.40%, 86.30% and 86.85% of that from the original landform, respectively. Therefore, the relevant research on soil microorganisms and enzyme activities after land reclamation in mining area could reflect the soil quality and ecosystem restoration status in time to a certain extent, so as to adopt more reasonable reclamation methods to improve the speed and effect of ecological restoration in mining area.