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    荒漠化地区道路人工防护林土壤改良效果的研究

    Study on the soil enhancement impact of artificial shelterbelts for roads in desertification areas

    • 摘要: 为探究人工防护林对荒漠化地区道路土壤的改良效果,本研究以嘉峪关地区连云港—霍尔果斯高速道路旁造林7年的沙枣与杨树人工防护林为对象,以该地区道路旁荒漠化土壤为对照,测定土壤理化性质及微生物群落特征。结果表明,与对照相比,沙枣和杨树人工防护林土壤pH显著降低2.51%和3.84%,有机质质量分数显著增加40.87%和33.77%;细菌OTU分别提高11.01%和15.14%,真菌提高23.31%和22.70%;细菌Chao1指数分别提高20.92%和13.90%,真菌提高26.05%和15.23%,真菌香农指数降低5.91%和8.61%;门分类水平上,细菌中变形菌门和酸杆菌门丰富度增加,放线菌门丰富度下降,真菌中接合菌门丰富度明显增加;属分类水平上,优势细菌属为鞘氨醇单胞菌属,优势真菌属为地孔菌属、微座孢属;基于LDA得分值3.5进行的LEfSe差异性分析显示,两种人工防护林土壤细菌差异性物种相同且均在沙枣土壤中丰度更高;RDA分析发现,沙枣土壤真菌群落结构与有机质最相关。综上,建议在荒漠化地区道路人工防护林建设中优先推广沙枣种植,以增强水土保持功能并改善土壤微生物群落结构。

       

      Abstract: Background Artificial shelter forest planting is regarded as a crucial strategy for sand fixation, windbreak, and soil and water conservation. Populus and Elaeagnus angustifolia are more frequently utilized to create plantations in the soil of road protection forests in desertification areas. It is vital to investigate how different planted forests affect soil microbial ecosystems in order to choose appropriate tree species for road protection forests in Jiayuguan area. Methods The rhizosphere soil of 7-year-old Elaeagnus angustifolia, and Populus artificial shelter forest on the north side of the Lianyungang-Khorgos Expressway in this area was chosen as the research object, with soil at the same depth beside the desertified roads in the same area serving as controls. Each biological duplicate soil was randomly partitioned into two sections. The physical and chemical parameters of the soil were assessed in one portion, while the bacterial and fungal populations in the other were identified using 16SrDNA and ITS high-throughput sequencing technologies. The data were examined using SPSS and other tools. Results 1) Elaeagnus angustifolia and Populus plantation soil pH decreased by 2.51% and 3.84%, soil organic matter increased by 40.87% and 33.77%. 2) The soil bacterial OTUs of Elaeagnus angustifolia and Populus plantation increased by 11.01% and 15.14%, respectively, while the fungal OTUs increased by 23.31% and 22.70%, respectively. 3) Bacterial Chao1 index in Elaeagnus angustifolia and Populus plantation soil increased by 20.92% and 13.90% respectively, fungal Chao1 index increased by 23.31% and 22.70%. 4) After artificial shelter forest planting. In bacteria, the abundance of Proteobacteria and Acidobacteria in the soil increased, while Actinobacteria decreased. In fungi, the richness of Ascomycota slightly decreased, Basidiomycota slightly increased, and Zygomycota significantly increased at the phylum classification level. 5) The dominant bacterial genera in artificial forests are Sphingomonas and Gemmatimonadaceae unclassified. The dominant fungal genera are Geopora and Ascomycota_unclassified. 6) The three dominant bacterial genera in the soil are Gaiellales_unclassified, Actinobacteria_unclassified, and others. The fungal genus is mainly Geopora, and some bacterial groups have not been classified. 7) LEfSe analysis indicated that Elaeagnus angustifolia and Populus plantations shared 7 kinds of high-abundance bacteria, with significant differences compared to the control. There was a significant difference in enriched species between the fungal plantation forest and the control. 8) RDA analysis showed that soil bacterial and fungal communities were driven by pH, organic matter and total potassium respectively, and the associations between the dominant bacterial genera and key environmental factors of different vegetation types were significantly different. Conclusions The artificial shelter forest of Elaeagnus angustifolia significantly enhances the diversity of soil microorganisms and the abundance of Proteobacteria. The distribution of its genera is more closely related to pH and organic matter. The artificial shelter forest of Elaeagnus angustifolia has a better effect on soil improvement, and it is the preferred tree species for the highway shelter forest in Jiayuguan area.

       

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