| Abstract | 第4-7页 |
| 摘要 | 第8-11页 |
| Abbreviations | 第11-19页 |
| 1 Introduction and literature review | 第19-48页 |
| 1.1 Background | 第19页 |
| 1.2 Sulfur in soil plant system | 第19-27页 |
| 1.2.1 Sulfur in soil | 第20-25页 |
| 1.2.1.1 Background | 第20页 |
| 1.2.1.2 Total soil sulfur | 第20-21页 |
| 1.2.1.3 Fractions of sulfur in soil | 第21-22页 |
| 1.2.1.4 Organic sulfur | 第22-23页 |
| 1.2.1.5 Inorganic sulfur | 第23-24页 |
| 1.2.1.6 Availability of sulfur in soil | 第24-25页 |
| 1.2.2 Sulfur in plants | 第25-27页 |
| 1.2.2.1 Main physiological roles of sulfur in plants | 第26-27页 |
| 1.2.2.2 Significance of sulfur as a plant nutrient | 第27页 |
| 1.3 Theories on biochar as a tool amendment of a soil | 第27-39页 |
| 1.3.1 Background | 第27-33页 |
| 1.3.1.1 Definition of biochar | 第28-29页 |
| 1.3.1.2 Importance of biochar | 第29-30页 |
| 1.3.1.3 The agricultural advantages of biochar | 第30-31页 |
| 1.3.1.4 The combination of biochar with the compost | 第31-32页 |
| 1.3.1.5 Environmental benefits and effects of biochar | 第32-33页 |
| 1.3.2 Production of biochar | 第33-39页 |
| 1.3.2.1 Physicochemical characterizations of biochar | 第34-36页 |
| 1.3.2.2 Pyrolysis techniques of biochar producing | 第36-38页 |
| 1.3.2.3 Biochar stove for small agricultural land | 第38-39页 |
| 1.3.2.4 Materials and tools | 第39页 |
| 1.4 Important points and inquiries | 第39-43页 |
| 1.4.1 What farmers need to know about biochar | 第39页 |
| 1.4.2 Are there any studies improved plant growth using biochar | 第39-40页 |
| 1.4.3 How much of the biochar is assumed to be applied | 第40-41页 |
| 1.4.4 What kind of biochar is most privileged, how to obtained | 第41-42页 |
| 1.4.5 Applications of biochar on soil and agricultural productivity | 第42-43页 |
| 1.5 Justification of problem and research progress | 第43-48页 |
| 1.5.1 Research background and significance | 第43-45页 |
| 1.5.2 Research content and objectives | 第45-47页 |
| 1.5.2.1 Research content | 第45页 |
| 1.5.2.2 Research objectives | 第45-47页 |
| 1.5.3 Research scheme | 第47-48页 |
| 2 Characterization of biochar and Methodology | 第48-66页 |
| 2.1 Introduction | 第48页 |
| 2.2 Experimental | 第48-51页 |
| 2.2.1 Raw materials and experimental design | 第49-50页 |
| 2.2.2 Reagents and instruments | 第50-51页 |
| 2.3 Measurement methods | 第51-53页 |
| 2.3.1 Biochar yields (%) | 第51页 |
| 2.3.2 The ash content | 第51-52页 |
| 2.3.3 The p H value | 第52页 |
| 2.3.4 Electrical conductivity (EC) | 第52页 |
| 2.3.5 The elemental composition of biochar | 第52页 |
| 2.3.6 Scanning electron microscope (SEM) | 第52页 |
| 2.3.7 The specific surface area (SSA) | 第52页 |
| 2.3.8 Analysis of FTIR | 第52-53页 |
| 2.3.9 X-ray diffraction (XRD) | 第53页 |
| 2.4 Sulfur form and content in biochar | 第53-54页 |
| 2.4.1 Water soluble sulfur | 第53-54页 |
| 2.4.2 Adsorption sulfur | 第54页 |
| 2.4.3 Hydrochloric acid soluble sulfur | 第54页 |
| 2.5 Data analysis | 第54页 |
| 2.6 Results and discussion | 第54-64页 |
| 2.6.1 Chemical characterization of biochar | 第54-59页 |
| 2.6.1.1 Biochar yields (%) | 第54页 |
| 2.6.1.2 Ash content (%) | 第54-55页 |
| 2.6.1.3 Elemental composition (%) | 第55-57页 |
| 2.6.1.4 p H and EC value of biochar | 第57页 |
| 2.6.1.5 Fourier transforms infrared spectroscopy (FTIR) | 第57-59页 |
| 2.6.2 Physical characterization of biochar | 第59-63页 |
| 2.6.2.1 Scanning electron microscopy (SEM) | 第59-60页 |
| 2.6.2.2 Specific surface area (SSA) | 第60-61页 |
| 2.6.2.3 X-ray diffraction (XRD) | 第61-63页 |
| 2.6.3 Effects of pyrolysis temperature on biochar characterization | 第63页 |
| 2.6.4 Sulfur content in biochar | 第63-64页 |
| 2.7 Conclusion | 第64-66页 |
| 3 Effects of biochar on maize physiological characteristics and loess soil | 第66-79页 |
| 3.1 Introduction | 第66-67页 |
| 3.2 Materials and Methods | 第67-69页 |
| 3.2.1 Soil samples | 第67-68页 |
| 3.2.2 Pot experiment | 第68-69页 |
| 3.3 Statistical analysis | 第69-70页 |
| 3.4 Results and discussion | 第70-78页 |
| 3.4.1 Effects of biochar on physiological characteristics of maize | 第70-74页 |
| 3.4.1.1 Effects of biochar on plant height | 第70-71页 |
| 3.4.1.2 Effects of biochar on stem diameter | 第71-72页 |
| 3.4.1.3 Effects of biochar on leaves number | 第72页 |
| 3.4.1.4 Effects of biochar on fresh and dry weight | 第72-73页 |
| 3.4.1.5 Effects of biochar on chlorophyll content of maize | 第73-74页 |
| 3.4.2 Effects of biochar application on soil properties | 第74-78页 |
| 3.4.2.1 Effects of biochar on soil p H | 第74-75页 |
| 3.4.2.2 Effects of biochar on electrical conductivity of soil | 第75-76页 |
| 3.4.2.3 Effects of biochar on urease enzyme | 第76-77页 |
| 3.4.2.4 Effects of biochar on catalase enzyme | 第77-78页 |
| 3.5 Conclusion | 第78-79页 |
| 4 Effects of sulfur addition in the presence of biochar on maize physiology and loess soil | 第79-96页 |
| 4.1 Background | 第79-80页 |
| 4.2 Materials and Methods | 第80-82页 |
| 4.2.1 Experimental materials and equipment’s | 第80-81页 |
| 4.2.2 Pot experiment | 第81页 |
| 4.2.3 Measurement and collecting data | 第81-82页 |
| 4.2.4 Sulfur content | 第82页 |
| 4.2.5 Extraction of sulfur | 第82页 |
| 4.3 Data analysis | 第82-83页 |
| 4.4 Results and Discussion | 第83-94页 |
| 4.4.1 Effects of sulfur addition in the presence of biochar on maize physiology | 第83-88页 |
| 4.4.1.1 Effects of sulfur addition on plant height | 第83-84页 |
| 4.4.1.2 Effects of sulfur addition on stem diameter and leaves number | 第84-86页 |
| 4.4.1.4 Effects of sulfur addition on chlorophyll content | 第86-87页 |
| 4.4.1.5 Effects of sulfur addition on leaves and roots of maize | 第87-88页 |
| 4.4.2 Effects of sulfur addition in the presence of biochar on soil properties | 第88-94页 |
| 4.4.2.1 Effects of sulfur addition on p H and EC of soil | 第88-90页 |
| 4.4.2.2 Effects of sulfur addition on MC and OM of soil | 第90-92页 |
| 4.4.2.3 Effects of sulfur addition on soil enzymes activity | 第92-93页 |
| 4.4.2.4 Effects of sulfur addition on soil total sulfur content | 第93-94页 |
| 4.5 Conclusion | 第94-96页 |
| 5 Conclusions and Prospects | 第96-99页 |
| 5.1 Conclusion | 第96-97页 |
| 5.2 Prospects | 第97-99页 |
| References | 第99-114页 |
| Research achievement during working for the degree | 第114-115页 |
| Acknowledgements | 第115页 |
