民勤人工梭梭林土壤微生物时空异质性与土壤非生物因子关系研究
发布时间：2018-10-13 15:14
【摘要】：土地沙化是目前我国面临的严重的生态环境问题之一。营造人工固沙林是当前防治土地沙化和恢复生态的有效措施之一。本文通过对甘肃民勤沙区不同年代营造的梭梭人工林植被、土壤微生物、土壤物理性质及土壤养分等因子变化的观测与分析研究,应用空间代替时间的研究方法分析人工林土壤微生物的时空异质性特征及其与土壤因子的相互关系,以期为我国西北干旱沙区防沙治沙和生态恢复建设提供科学依据。研究结果表明:1)流动沙地建立人工梭梭固沙林后,有效恢复了沙地的植被与生态,物种多样性不断丰富,植被组成由造林初期单一的人工灌木结构逐渐向草本植物占优势的草本-灌木结构演替。2)土壤中真菌、细菌、放线菌的数目以及微生物量碳含量呈现出先增加后缓慢降低的趋势,在造林30年后达到峰值。3)不同林龄人工梭梭固沙林地土壤颗粒组成存在显著差异(P0.05);成土作用明显。5个年代样地土壤含水量、pH表现出明显的层次性特征。另外,距离树干越近,土壤的pH值、含水量、粘、粉粒含量越大,沙粒含量越小。4)不同林龄梭梭人工固沙林土壤有机碳、氮、磷养分大量回归,表现为:土壤表层土壤的有机碳和氮磷全量明显高于中、下层;且随林龄的增长而增长;水平方向上,土壤有机碳和全磷在树干附近的含量要明显低于树冠下,全氮、有效磷和有效氮则表现出明显的龄级效应。5)因子分析显示,土壤各因子含量均随着梭梭人工林林龄的增长而增长。水平方向上在距树干0-50cm内养分占150cm范围内69.95%。垂直方向上,0-5cm土壤表层所存储的土壤养分最多;土壤养分含量与土层呈现出明显的负效应。6)土壤三大菌群以及微生物量碳与土壤pH值、有机碳、全氮、含水率、粘粒、粉粒的含量表现出极显著正相关关系,与土壤砂粒含量、碳氮比表现出负相关关系,与土壤全磷、有效磷、有效氮、硝态氮、氨态氮之间的相关性不显著。说明流动沙地建立人工梭梭林后,植被得到有效恢复,促进了成土过程,为微生物的发育提供了生境。
[Abstract]:Land desertification is one of the serious ecological environmental problems in China. Creating artificial sand fixation forest is one of the effective measures to control land desertification and restore ecology. In this paper, the changes of plant vegetation, soil microbes, soil physical properties and soil nutrients in different years of Haloxylon ammodendron plantation in Minqin Sandy area, Gansu Province, were observed and analyzed. The spatiotemporal heterogeneity of soil microorganism in artificial forest and its relationship with soil factors were analyzed by using the method of space instead of time in order to provide scientific basis for sand control and ecological restoration in arid sandy region of northwest China. The results showed that: 1) the vegetation and ecology of the sandy land were restored effectively after the establishment of the sand fixation forest of Haloxylon ammodendron on the mobile sandy land, and the species diversity was continuously rich. Vegetation composition from a single artificial shrub structure in the early stage of afforestation to herbaceous shrub structure succession. 2) soil fungi, bacteria, The number of actinomycetes and microbial biomass carbon content increased first and then decreased slowly. The peak value was reached after 30 years of afforestation. 3) there were significant differences in soil particle composition among different forest ages (P0.05); soil formation was obvious. The soil moisture content of five plots showed obvious stratification characteristics with pH. In addition, the closer to the trunk, the greater the soil pH value, water content, clay content and silt content, and the smaller the sand content. 4) the soil organic carbon, nitrogen and phosphorus nutrients were regressed in different forest ages of Haloxylon ammodendron artificial sand fixation forest. The results showed that the total amount of organic carbon and nitrogen and phosphorus in the topsoil was significantly higher than that in the middle and lower layers, and increased with the increase of forest age. In the horizontal direction, the contents of soil organic carbon and total phosphorus near the tree trunk were significantly lower than those under the tree crown. Available phosphorus and available nitrogen showed obvious age effect. 5) Factor analysis showed that the content of soil factors increased with the increase of forest age of Haloxylon ammodendron plantation. In horizontal direction, the nutrient content in 0-50cm was 69.95% in the range of 150cm. In the vertical direction, the soil nutrient stored in the surface layer of 0-5cm was the most, and the soil nutrient content and soil layer showed obvious negative effect. There was a significant positive correlation between the content of silt and soil sand content, C / N ratio, but no significant correlation with soil total phosphorus, available nitrogen, nitrate nitrogen and ammonia nitrogen. The results showed that after the establishment of the artificial Haloxylon ammodendron forest in the moving sandy land, the vegetation was restored effectively, the soil-forming process was promoted, and the habitat was provided for the development of microbes.
【学位授予单位】：甘肃农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S714.3
本文编号：2269081
[Abstract]:Land desertification is one of the serious ecological environmental problems in China. Creating artificial sand fixation forest is one of the effective measures to control land desertification and restore ecology. In this paper, the changes of plant vegetation, soil microbes, soil physical properties and soil nutrients in different years of Haloxylon ammodendron plantation in Minqin Sandy area, Gansu Province, were observed and analyzed. The spatiotemporal heterogeneity of soil microorganism in artificial forest and its relationship with soil factors were analyzed by using the method of space instead of time in order to provide scientific basis for sand control and ecological restoration in arid sandy region of northwest China. The results showed that: 1) the vegetation and ecology of the sandy land were restored effectively after the establishment of the sand fixation forest of Haloxylon ammodendron on the mobile sandy land, and the species diversity was continuously rich. Vegetation composition from a single artificial shrub structure in the early stage of afforestation to herbaceous shrub structure succession. 2) soil fungi, bacteria, The number of actinomycetes and microbial biomass carbon content increased first and then decreased slowly. The peak value was reached after 30 years of afforestation. 3) there were significant differences in soil particle composition among different forest ages (P0.05); soil formation was obvious. The soil moisture content of five plots showed obvious stratification characteristics with pH. In addition, the closer to the trunk, the greater the soil pH value, water content, clay content and silt content, and the smaller the sand content. 4) the soil organic carbon, nitrogen and phosphorus nutrients were regressed in different forest ages of Haloxylon ammodendron artificial sand fixation forest. The results showed that the total amount of organic carbon and nitrogen and phosphorus in the topsoil was significantly higher than that in the middle and lower layers, and increased with the increase of forest age. In the horizontal direction, the contents of soil organic carbon and total phosphorus near the tree trunk were significantly lower than those under the tree crown. Available phosphorus and available nitrogen showed obvious age effect. 5) Factor analysis showed that the content of soil factors increased with the increase of forest age of Haloxylon ammodendron plantation. In horizontal direction, the nutrient content in 0-50cm was 69.95% in the range of 150cm. In the vertical direction, the soil nutrient stored in the surface layer of 0-5cm was the most, and the soil nutrient content and soil layer showed obvious negative effect. There was a significant positive correlation between the content of silt and soil sand content, C / N ratio, but no significant correlation with soil total phosphorus, available nitrogen, nitrate nitrogen and ammonia nitrogen. The results showed that after the establishment of the artificial Haloxylon ammodendron forest in the moving sandy land, the vegetation was restored effectively, the soil-forming process was promoted, and the habitat was provided for the development of microbes.
【学位授予单位】：甘肃农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S714.3
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，本文编号：2269081
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