| Acknowledgements | 第1-5页 |
| 摘要 | 第5-6页 |
| Abstract | 第6-12页 |
| Chapter 1 Introduction | 第12-28页 |
| 1 Soil organic matter pool | 第12-18页 |
| ·Soil organic matter resources | 第13页 |
| ·Composition and structure of soil organic matter | 第13-15页 |
| ·Labile and stabilized soil organic matter pools | 第15-16页 |
| ·Stabilization mechanisms of soil organic matter | 第16页 |
| ·Factors affecting the decomposition of soil organic matter | 第16-18页 |
| ·Effect of land-use change on soil organic carbon | 第18页 |
| 2 Soil dissolved organic matter | 第18-24页 |
| ·Origins and compositions of dissolved organic matte | 第19页 |
| ·Dissolved organic matter extraction | 第19-20页 |
| ·Dissolved organic matter mineralization | 第20页 |
| ·Factors controlling dissolved organic matter mineralization | 第20-21页 |
| ·Analysis methods of dissolved organic matter | 第21-24页 |
| ·Isolation of dissolved organic matter | 第21页 |
| ·UV-vis absorption | 第21-22页 |
| ·Fluorescence spectroscopy | 第22页 |
| ·Fourier transform infrared spectroscopy | 第22-23页 |
| ·Nuclear magnetic resonance spectroscopy | 第23页 |
| ·Pyrolysis and related techniques | 第23-24页 |
| 3 Light and heavy fractions of soil organic matter | 第24-25页 |
| 4 Soil microbial biomass | 第25-26页 |
| 5 Soil basal respiration | 第26页 |
| 6 Soil metabolic quotient | 第26-28页 |
| Chapter 2 Site description and experimental design | 第28-32页 |
| 1 Site description | 第28页 |
| 2 Experimental designs | 第28-32页 |
| Chapter 3 Spectroscopic characterization of water extractable organic matter from soils under four different vegetation types along an elevation gradient | 第32-48页 |
| 1 Introduction | 第32-33页 |
| 2 Materials and methods | 第33-34页 |
| ·Soil sampling and analysis | 第33页 |
| ·Hot-water soluble organic matter extraction | 第33页 |
| ·Soil microbial biomass C | 第33页 |
| ·Soil basal respiration and metabolic quotient (qCO_2) | 第33-34页 |
| ·Spectroscopic analysis | 第34页 |
| ·Statistical analysis | 第34页 |
| 3 Results and discussion | 第34-46页 |
| ·Soil properties | 第34-38页 |
| ·HWEOC, MBC and qCO_2 | 第38页 |
| ·UV absorption of HWEOM | 第38页 |
| ·Fluorescence spectroscopic analysis | 第38-44页 |
| ·Fourier-transform infrared spectroscopic analysis | 第44-46页 |
| ·HWEOM spectroscopic properties in relation to soil properties and biological propertie | 第46页 |
| 4 Conclusions | 第46-48页 |
| Chapter 4 Biodegradation and chemical characteristics of water extractable organic matter from soils under four different vegetation types along and elevation gradient | 第48-63页 |
| 1 Introduction | 第48-49页 |
| 2 Materials and methods | 第49-51页 |
| ·Hot-water soluble organic matter extraction | 第49页 |
| ·Incubation experiment | 第49-50页 |
| ·Analytical methods | 第50页 |
| ·Calculations and statistics | 第50-51页 |
| 3 Results | 第51-61页 |
| ·Quantities and chemical characteristics of HWEOM | 第51-54页 |
| ·Dynamics of HWEOC biodegradation | 第54页 |
| ·HWEOC biodegradation in relation to its chemical characteristics | 第54-59页 |
| ·UV absorption and humification index changes during biodegradation | 第59-61页 |
| 4 Discussion | 第61-62页 |
| 5 Conclusions | 第62-63页 |
| Chapter 5 Light and heavy fractions of soil organic matter as related to altitude, vegetation and soil properties | 第63-73页 |
| 1 Introduction | 第63-64页 |
| 2 Material and methods | 第64-65页 |
| ·Soil sampling and analysis | 第64页 |
| ·Soil temperature and moisture | 第64页 |
| ·Litter and fine root biomass | 第64页 |
| ·Density separation | 第64页 |
| ·Statistical analysis | 第64-65页 |
| 3 Results | 第65-72页 |
| ·Soil properties | 第65页 |
| ·Soil temperature and moisture, litter and fine root biomass, microbial biomass C | 第65页 |
| ·Carbon and nitrogen concentrations in density fractions | 第65-69页 |
| ·Contribution of the light and heavy fractions to SOM pool | 第69页 |
| ·Altitude, organism inputs and soil properties in relation to density fractions | 第69-72页 |
| 4 Discussion | 第72页 |
| 5 Conclusions | 第72-73页 |
| Chapter 6 Summary and Conclusions | 第73-74页 |
| References | 第74-85页 |
| 详细摘要 | 第85-88页 |
