土壤自养微生物固碳量及其同化碳在土壤理化组分中的含量与分配特征

发布时间：2018-07-05 05:43

本文选题：自养微生物同化碳 + 活性有机碳库　；参考：《湖南农业大学》2015年硕士论文

【摘要】：自养微生物在土壤中广泛存在,且具备光合固碳(同化大气CO2)功能。然而,在不同土壤利用方式下,自养微生物同化碳在土壤有机碳各组分及物理和化学组分中的分配目前尚不明确。为此,本研究采用碳同位素(14C-C02)连续标记技术结合室内模拟培养试验,采用土壤有机质、物理和化学分组方法,研究了3种不同稻田和旱地土壤自养微生物的固碳量及其在供试土壤物理和化学组分中的含量与分配特征。结果表明：1.在稻田与旱地土壤中,自养微生物同化碳的含量为6.21～67.85 mg·kg-l,对土壤有机碳的贡献(14C-SOC/SOC)达6.21-67.85%。其中,在土壤的活性有机碳库中,自养微生物同化碳在土壤微生物量碳(14C-MBC)中的含量为5.10～17.87 mg·kg-1,大于自养微生物同化碳在土壤可溶性有机碳(14C-DOC)中的含量(0.71-4.02 mg-kg-1).土壤自养微生物同化碳对土壤微生物量碳的贡献(14C-MBC/MBC)为1.14～10.07%,对可溶性有机碳的贡献(14C-DOC/DOC)为0.93～8.94%,即MBC的贡献大于DOC的贡献。与此同时,在稻田土壤中自养微生物同化碳(14C-SOC)、土壤微生物量碳(14C-MBC)的含量大于旱地,而土壤可溶性有机碳(14C-DOC)在旱地土壤中的含量大于稻田土壤。2.土壤自养微生物同化碳,主要分布在土壤0.02-0.2mm和0.2-2.0mm大团聚体的重组组分大颗粒中,在土壤0.002-0.02mm和0.002mm小团聚体重组分中的含量较少,表现出明显的碳汇效应。同时,自养微生物同化碳对土壤大团聚体及其土壤重组组分的贡献,要分别大于土壤小团聚体及其重组组分；同时,无论是土壤大团聚体或小团聚体,自养微生物同化碳对其重组组分的贡献大于轻组组分。此外,各团聚体自养微生物同化碳在稻田土壤中的含量大于旱地土壤。3.在稻田与旱地土壤中,土壤自养微生物同化碳,均不同程度地进入土壤腐殖质的胡敏素(HM)、胡敏酸(HA)和富啡酸(FA)组分；胡敏素、胡敏酸和富啡酸的白养微生物同化碳含量分别为2.21～49.52 mg·kg-1、2.71～12.75 mg·kg-1和1.74～17.37 mg·kg-1。同时,胡敏素组分中14C-SOC对土壤总14C-SOC含量和胡敏素组分SOC含量的贡献也较其他组分大,分别为33.05～77.48%和0.07-0.57%。此外,稻田土壤中的腐殖质各组分自养微生物同化碳含量,大于旱地土壤中的腐殖质各组分自养微生物同化碳含量。
[Abstract]:Autotrophic microorganisms exist widely in soil and have the function of carbon sequestration (assimilation of atmospheric CO _ 2). However, under different soil use patterns, the distribution of assimilated carbon from autotrophic microorganisms in soil organic carbon components, physical and chemical components is still unclear. Therefore, in this study, carbon isotope (14C-C02) continuous labeling technique was used in combination with laboratory simulated culture experiments, and soil organic matter, physical and chemical grouping methods were used. Carbon sequestration of three autotrophic microorganisms in paddy and dry land soils and their physical and chemical components and their distribution characteristics were studied. The result shows that 1: 1. The assimilation carbon content of autotrophic microorganisms was 6.2167.85 mg 路kg ~ (-1), and the contribution to soil organic carbon (14C-SOC / SOC) was 6.21-67.85 mg 路kg ~ (-1) in paddy field and dry land soil. In the soil active organic carbon pool, the content of autotrophic microbial assimilation carbon in soil microbial biomass carbon (14C-MBC) was 5.10 ~ 17.87 mg / kg ~ (-1), which was higher than that in soil soluble organic carbon (14C-DOC) (0.71-4.02 mg-kg-1). The contribution of soil autotrophic microbial assimilation carbon to soil microbial biomass carbon (14C-MBC / MBC) was 1.1410.07, and that to soluble organic carbon (14C-DOC / DOC) was 0.93C / DOC 8.94.The contribution of MBC was greater than that of DOC. At the same time, the contents of soil microbial biomass carbon (14C-MBC) and soil soluble organic carbon (14C-DOC) in paddy soils were higher than those in dryland soils. Soil autotrophic microbes assimilate carbon mainly in the recombined fractions of soil 0.02-0.2mm and 0.2-2.0mm aggregates and in the small aggregates of 0.002-0.02mm and 0.002mm with less carbon sequestration effect. At the same time, the contribution of autotrophic microbial assimilation carbon to soil macroaggregates and soil recombination components was greater than that of soil small aggregates and their recombined components, respectively, and the contribution of autotrophic microorganism assimilation carbon to soil macroaggregates and soil recombination components was greater than that of soil aggregates and their recombined components. The contribution of carbon assimilation by autotrophic microorganisms to its recombined components was greater than that of light components. In addition, the assimilation carbon content of autotrophic microorganisms in paddy soil was higher than that in dryland soil. Soil autotrophic microbes assimilate carbon into soil humus (HM), Hu Min acid (HA) and enkephalic acid (FA) in paddy and dryland soils. The assimilation carbon contents of Hu Min acid and fulvic acid were 2.2149.52 mg / kg ~ (-1) kg-1 and 1.74 ~ 17.37 mg / kg ~ (-1), respectively. At the same time, the contribution of 14C-SOC to soil total 14C-SOC and humin component SOC content was also greater than that of other components (33.05% 77.48% and 0.07-0.57%, respectively). In addition, the assimilation carbon content of autotrophic microorganisms in paddy soil was higher than that in dryland soil.
【学位授予单位】：湖南农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S154.3

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