發(fā)布時間：2021-05-11 06:33

　　水溶性有機碳是一種最活躍的土壤有機碳,它在全球碳循壞中起著極其重要的作用。然而,根據(jù)密度分組,土壤有機質(zhì)又可分為輕組和重組兩組分。本文通過紫外、熒光和傅立葉變換紅外光譜來表征熱水可提取有機質(zhì)的化學(xué)結(jié)構(gòu)特征。同步熒光光譜顯示了熱水可提取有機質(zhì)中主要存在芳香性氨基酸,富里酸和具有高度共軛體系的聚環(huán)芳香結(jié)構(gòu)。紅外光譜表明熱水可提取有機質(zhì)中主要包含脂肪族的C-H鍵,芳香族的C=C鍵,以及碳水化合物中的C-O鍵三種官能團結(jié)構(gòu)。針葉林土壤熱水可提取有機質(zhì)（0-10 cm土層）的芳香性,腐殖化指數(shù)（HIXem, HIXsyn）和熒光效率都明顯高于其他三種植被類型,并且這四項光譜參數(shù)均隨土壤深度的增加而減小。常綠闊葉林和亞高山矮曲林土壤中的熱水可提取有機碳的生物降解程度較高,大約有20%的熱水可提取有機碳被礦化,且熱水可提取有機碳庫的易變組分占到13-15%。然而,針葉林土壤的熱水可提取有機碳最難被降解,其中只有12%的熱水可提取有機碳被礦化。研究表明,較高的熱水可提取有機碳的生物降解能力主要取決于較低的土壤C/N比,較低的芳香性和腐殖化程度,較低比例的酚類化合物含量,以及較高比例的親水碳含量。高山草... 

【文章來源】：南京林業(yè)大學(xué)江蘇省

【文章頁數(shù)】：88 頁

【學(xué)位級別】：博士

【文章目錄】：
Acknowledgements
摘要
Abstract
Chapter 1 Introduction
    1 Soil organic matter pool
        1.1 Soil organic matter resources
        1.2 Composition and structure of soil organic matter
        1.3 Labile and stabilized soil organic matter pools
        1.4 Stabilization mechanisms of soil organic matter
        1.5 Factors affecting the decomposition of soil organic matter
        1.6 Effect of land-use change on soil organic carbon
    2 Soil dissolved organic matter
        2.1 Origins and compositions of dissolved organic matte
        2.2 Dissolved organic matter extraction
        2.3 Dissolved organic matter mineralization
        2.4 Factors controlling dissolved organic matter mineralization
        2.5 Analysis methods of dissolved organic matter
            2.5.1 Isolation of dissolved organic matter
            2.5.2 UV-vis absorption
            2.5.3 Fluorescence spectroscopy
            2.5.4 Fourier transform infrared spectroscopy
            2.5.5 Nuclear magnetic resonance spectroscopy
            2.5.6 Pyrolysis and related techniques
    3 Light and heavy fractions of soil organic matter
    4 Soil microbial biomass
    5 Soil basal respiration
    6 Soil metabolic quotient
Chapter 2 Site description and experimental design
    1 Site description
    2 Experimental designs
Chapter 3 Spectroscopic characterization of water extractable organic matter from soils under four different vegetation types along an elevation gradient
    1 Introduction
    2 Materials and methods
        2.1 Soil sampling and analysis
        2.2 Hot-water soluble organic matter extraction
        2.3 Soil microbial biomass C
        2.4 Soil basal respiration and metabolic quotient (qCO_2)
        2.5 Spectroscopic analysis
        2.6 Statistical analysis
    3 Results and discussion
        3.1 Soil properties
        3.2 HWEOC, MBC and qCO_2
        3.3 UV absorption of HWEOM
        3.4 Fluorescence spectroscopic analysis
        3.5 Fourier-transform infrared spectroscopic analysis
        3.6 HWEOM spectroscopic properties in relation to soil properties and biological propertie
    4 Conclusions
Chapter 4 Biodegradation and chemical characteristics of water extractable organic matter from soils under four different vegetation types along and elevation gradient
    1 Introduction
    2 Materials and methods
        2.1 Hot-water soluble organic matter extraction
        2.2 Incubation experiment
        2.3 Analytical methods
        2.4 Calculations and statistics
    3 Results
        3.1 Quantities and chemical characteristics of HWEOM
        3.2 Dynamics of HWEOC biodegradation
        3.3 HWEOC biodegradation in relation to its chemical characteristics
        3.4 UV absorption and humification index changes during biodegradation
    4 Discussion
    5 Conclusions
Chapter 5 Light and heavy fractions of soil organic matter as related to altitude, vegetation and soil properties
    1 Introduction
    2 Material and methods
        2.1 Soil sampling and analysis
        2.2 Soil temperature and moisture
        2.3 Litter and fine root biomass
        2.4 Density separation
        2.5 Statistical analysis
    3 Results
        3.1 Soil properties
        3.2 Soil temperature and moisture, litter and fine root biomass, microbial biomass C
        3.3 Carbon and nitrogen concentrations in density fractions
        3.4 Contribution of the light and heavy fractions to SOM pool
        3.5 Altitude, organism inputs and soil properties in relation to density fractions
    4 Discussion
    5 Conclusions
Chapter 6 Summary and Conclusions
References
詳細(xì)摘要



本文編號：3180915