不同土地利用方式对石山坡地土壤微生物多样性的影响

Effects of Different Land Use Patterns on Soil Microbial Diversity of Stone Mountain Slope

摘要: 为了揭示不同土地利用方式对桂西北石山坡地土壤微生物多样性的影响，为岩溶地区土地资源的可持续利用提供理论支持，以罗城县某地相互邻接、地形地貌基本一致的植被严重破坏的裸地、山野葡萄栽培地和植被保护良好的封山育林地作为研究对象，测定了不同样地的土壤理化特性及蔗糖酶、脲酶、过氧化氢酶、碱性磷酸酶活性，利用高通量测序技术对三个不同样地的土壤微生物DNA序列进行测定，并对土壤理化特性与土壤微生物多样性的相关性进行了分析。结果表明：1) 不同土地利用方式对石山坡地土壤微生物多样性具有重要的影响，适度干扰可以提高调查样地土壤微生物的物种多样性；2) 土壤理化性质对土壤微生物丰度具有重要的影响，不同理化因子对土壤微生物多样性的影响不同，其中，放线菌门、疣微菌门、硝化螺旋菌门与土壤pH呈显著正相关；变形菌门与土壤含水量、有机质、碱解氮、全钾含量、蔗糖酶活性呈显著正相关；放线菌门、疣微菌门、硝化螺旋菌门与脲酶和碱性磷酸酶活性呈显著正相关；酸杆菌门与土壤含水量呈显著负相关，与土壤pH呈负相关，但不显著；3) 在门水平上，LCS1和LCS2样地的优势菌门均为酸杆菌门，LCS3样地的优势菌门为变形菌门；在属水平上，三种不同样地的优势菌属均为DA101；在种水平上，三种不同样地的优势菌种均为未指明的菌属Candidatus_Nitrososphaera_SCA1170。由此可见，不同土地利用方式，可以使土壤微生物多样性的组成和结构发生较大差异；人为干扰比较严重的样地LCS1和LCS2，其土壤微生物优势菌门为酸杆菌门，破坏程度较轻的自然植被样地LCS3，其土壤微生物优势菌门为变形菌门；本研究的三种不同土地利用方式调查样地，其土壤微生物多样性仅在门水平有较大的差异，而在属、种水平则优势菌一致，但丰度不同。岩溶地区生态环境脆弱，过度的人为干扰破坏，不利于土壤生态系统的恢复和土地资源的可持续利用。

Abstract: In order to reveal the impact of different land-use patterns on the soil microbial diversity of the stone mountain slope in northwestern Guangxi, and to provide theoretical support for the sus-tainable use of land resources in karst areas, the place in Luocheng County adjacent to each other with basically the same topography and landforms, the bare land with severely damaged vegetation, the wild grape cultivation land, and the closed hillside forest land with good vegetation protection were taken as the research objects. The physical and chemical properties of the soil and the activities of sucrase, urease, catalase, and alkaline phosphatase were measured in different places, and the DNA sequences of three different soil microorganisms were determined using high-throughput sequencing technology, and the correlation between soil physical and chemical properties and soil microbial diversity was analyzed. The results show that: 1) different land-use patterns have an important impact on the soil microbial diversity of the stone mountain slopes, and moderate interference can increase the soil microbial species diversity of the investigated sample plots; 2) the physical and chemical properties of soil have an important influence on soil microbial abundance, and different physical and chemical factors have different effects on soil microbial diversity. Among them, Actinomycetes, Verrucomicrobia, Nitrospirillum and soil pH are significantly positively correlated; Proteobacteria are significantly positively correlated with soil water content, organic matter, alkali hydrolyzed nitrogen, total potassium content, and sucrase activity; Actinomycetes, Verrucomicrobia, Nitrospira phyta have a significant positive correlation with urease and alkaline phosphatase activities; Acidobacteria have a significant negative correla-tion with soil water content, and a negative correlation with soil pH, but not significant; 3) at the phylum level, the dominant phyla of the LCS1 and LCS2 plots are both Acidobacteria, and the dominant phyla of the LCS3 plot are the Proteobacteria; at the genus level, the dominant bacteria in the three different survey plots are DA101; at the species level, the dominant bacteria in the three different survey plots are the unspecified genus Candidatus_Nitrososphaera_SCA1170. It can be seen that different land-use patterns can make great differences in the composition and structure of soil microbial diversity; the sample plots LCS1 and LCS2 with more serious human interference have the Acidobacteria as the dominant soil microbe phylum, and the damage is less in the natural vegetation plot LCS3, the dominant soil microbial phyla is the Proteobacteria; the three different land-use survey plots in this study have significant differences in soil microbial diversity only at the phylum level; at the genus and species level, the dominant bacteria are the same, but the abundance is different. The ecological environment of karst areas is fragile, and excessive human disturbance is not conducive to the restoration of soil ecosystems and the sustainable use of land resources.