| Acknowledgements | 第4-9页 |
| 摘要 | 第9-11页 |
| Abstract | 第11-15页 |
| Chapter 1 Background | 第16-55页 |
| 1.1 Soil as a resource | 第16-17页 |
| 1.2 Soil degradation | 第17-18页 |
| 1.3 Soil erosion by water | 第18-35页 |
| 1.3.1 Causes of soil- water erosion | 第19-24页 |
| 1.3.2 Hydrological basis of water erosion process | 第24-25页 |
| 1.3.3 Effects of water erosion | 第25-26页 |
| 1.3.4 Variation in water erosion | 第26-29页 |
| 1.3.5 Type of soil erosion by water | 第29-33页 |
| 1.3.5.1 Splash Erosion | 第30页 |
| 1.3.5.2 Sheet Erosion | 第30-32页 |
| 1.3.5.3 Rill Erosion | 第32页 |
| 1.3.5.4 Gully Erosion | 第32-33页 |
| 1.3.5.5 Tillage Erosion | 第33页 |
| 1.3.6 Soil erosion rate in China and over world | 第33-35页 |
| 1.4 Water erosion control by pasture vegetation | 第35-49页 |
| 1.4.1 Principles of water erosion control by vegetation | 第36-37页 |
| 1.4.2 Action of vegetation leaves and stems on rainfall | 第37-40页 |
| 1.4.3 The Role of ground litter cover | 第40-44页 |
| 1.4.4 Plant roots and erosion control | 第44-49页 |
| 1.5 On-farm fertilization to improve crop yield | 第49-55页 |
| 1.5.1 Chemical fertilization and soil erosion | 第49-51页 |
| 1.5.2 Sustainable agriculture fertilization | 第51页 |
| 1.5.3 Soil organic matter | 第51-53页 |
| 1.5.4 Litter decomposition (Mineralization) and Nutrients uptake | 第53-55页 |
| Chapter 2 Materials and Methods | 第55-63页 |
| 2.1 Materials and experiment design | 第55-59页 |
| 2.1.1 Study area | 第55-56页 |
| 2.1.2 Objectives and expectations | 第56-57页 |
| 2.1.3 Design for erosion rate assessment | 第57页 |
| 2.1.4 Fertilization experimental design and treatments | 第57-58页 |
| 2.1.5 Pastures cover experimental design | 第58-59页 |
| 2.1.6 Soil collection and packing | 第59页 |
| 2.2 Measurements methods | 第59-63页 |
| 2.2.1 Box plot experiment measurement | 第59-61页 |
| 2.2.2 Farm plot experiment measurement | 第61-62页 |
| 2.2.3 Data analysis | 第62-63页 |
| Chapter 3 Results and Discussion | 第63-95页 |
| 3.1 Assessment of water and soil loss from purple soil surface | 第63-74页 |
| 3.1.1 Runoff from different treatments | 第63-66页 |
| 3.1.2 Soil erosion responses to slope angle and rainfall intensity | 第66-70页 |
| 3.1.3 Purple soil surface hydrological characteristics: Analyze and discussion | 第70-74页 |
| 3.2 Runoff, Nitrogen and Phosphorus losses under rating fertilization | 第74-86页 |
| 3.2.1 Rainfall events and Runoff volumes | 第74-78页 |
| 3.2.2 Runoff and sediment yield relationship | 第78-82页 |
| 3.2.3 Nitrogen and phosphorus losses | 第82-86页 |
| 3.3 Effects of pastures grass cover on runoff and sediments reduction | 第86-95页 |
| 3.3.1 Runoff and sediment yield | 第86-89页 |
| 3.3.2 Runoff reduction benefit (RRB) and sediment reduction benefit (SRB) | 第89-92页 |
| 3.3.3 Ratio between runoff and sediment reduction (RRSR) | 第92-93页 |
| 3.3.4 Relationship vegetation cover and runoff-sediments process | 第93-95页 |
| Chapter 4 Conclusion and recommendations | 第95-99页 |
| 4.1 Conclusion | 第95-96页 |
| 4.1.1 Water and Soil loss on purple soil surface | 第95页 |
| 4.1.2 Purple soil erosion responses when rating fertilization | 第95-96页 |
| 4.1.3 Effectiveness of pastures vegetation covers to control erosion | 第96页 |
| 4.2 Recommendations | 第96-99页 |
| References | 第99-118页 |
