| 摘要 | 第6-8页 |
| 英文摘要 | 第8-16页 |
| Chapter 1 Introduction | 第16-23页 |
| 1.1 Ecological intensification | 第16页 |
| 1.2 Soil bacterial community composition and diversity | 第16-17页 |
| 1.3 Soil fungal community composition and diversity | 第17-18页 |
| 1.4 N cycling microbial populations | 第18-19页 |
| 1.5 Microbial biomass C,N,and extracellular enzyme activities | 第19-20页 |
| 1.6 Importance of North-central and Northeast China | 第20页 |
| 1.7 Need of present study | 第20-21页 |
| 1.9 Research hypothesis | 第21页 |
| 1.10 Thesis objective | 第21-22页 |
| Road map of research | 第22-23页 |
| Chapter 2 Response of soil bacterial community composition and diversity to ecological Intensification in spring maize and summer maize system | 第23-40页 |
| 2.1 Material and methods | 第23-26页 |
| 2.1.1 Experimental sites | 第23-24页 |
| 2.1.2 Experimental design | 第24页 |
| 2.1.3 Determination of soil chemical and biological properties | 第24-25页 |
| 2.1.4.Bioinformatics analyses | 第25-26页 |
| 2.1.4.1 DNA extraction and PCR amplification | 第25页 |
| 2.1.4.2 Illumina MiSeq sequencing | 第25-26页 |
| 2.1.5 Statistical analyses | 第26页 |
| 2.2 Results | 第26-35页 |
| 2.2.1 Influence of EI and FP management on soil chemical and biological properties and maize yield | 第26-28页 |
| 2.2.2 Influence of EI and FP management on bacterial alpha diversity | 第28-29页 |
| 2.2.3 Influence of EI and FP management on bacterial community composition | 第29-32页 |
| 2.2.4 Links among soil chemical properties,soil biological properties,soil bacteria and maize yield | 第32-35页 |
| 2.3 Discussions | 第35-39页 |
| 2.3.1 Soil chemical properties and maize yield | 第35-36页 |
| 2.3.2 Bacterial alpha diversity | 第36-37页 |
| 2.3.3 Bacterial community structure | 第37-38页 |
| 2.3.4 Relationship between soil properties versus bacterial diversity and community structure | 第38-39页 |
| 2.4 Summary | 第39-40页 |
| Chapter 3 Response of soil fungal community composition and diversity to ecological intensification in spring maize and summer maize system | 第40-49页 |
| 3.1 Material and methods | 第40-42页 |
| 3.1.1 Soil DNA extraction | 第40-41页 |
| 3.1.2 Quantitative real-time PCR(qPCR) | 第41页 |
| 3.1.3 Illumina MiSeq sequencing | 第41页 |
| 3.1.4 Statistical analysis | 第41-42页 |
| 3.2 Results | 第42-47页 |
| 3.2.1 Influence of NE and FP management on crop yield and fungal alpha diversity | 第42-43页 |
| 3.2.2.Influence of NE and FP management on fungal community composition | 第43-47页 |
| 3.3 Discussions | 第47-48页 |
| 3.3.1 EI management maintained fungal diversity | 第47-48页 |
| 3.3.2 Shifts in fungal community structure in response to EI and FP management | 第48页 |
| 3.4 Summary | 第48-49页 |
| Chapter 4 Response of nitrogen transformation related gene expressions to ecological intensification in spring maize and summer maize system | 第49-56页 |
| 4.1 Material and methods | 第49-50页 |
| 4.1.1 Potential nitrification activity and potential denitrification activity | 第49-50页 |
| 4.1.2 DNA extraction and qPCR | 第50页 |
| 4.1.3 Statistical analyses | 第50页 |
| 4.2 Results | 第50-53页 |
| 4.2.1 Effect of the EI and FP management on PNA,PDA,and N cycling genes | 第50-51页 |
| 4.2.2 Relationship between soil properties and PNA,PDA,and N cycling genes | 第51-53页 |
| 4.3 Discussions | 第53-55页 |
| 4.4 Summary | 第55-56页 |
| Chapter 5 Response of soil extracellular enzyme activities and microbial community composition to ecological intensification in summer maize system | 第56-69页 |
| 5.1 Material and method | 第56-58页 |
| 5.1.1 Site description and sampling | 第56-57页 |
| 5.1.2 Chemical analysis | 第57页 |
| 5.1.3 Extracellular enzyme activities | 第57页 |
| 5.1.4 PLFA analysis | 第57-58页 |
| 5.1.5 Statistical analyses | 第58页 |
| 5.2 Results | 第58-65页 |
| 5.2.1 Soil biochemical properties and crop yield | 第58-60页 |
| 5.2.2 Extracellular enzyme activities | 第60-62页 |
| 5.2.3 Microbial community composition | 第62-63页 |
| 5.2.4 Driving forces of enzyme activities,bacterial,and fungal change | 第63-65页 |
| 5.3 Discussion | 第65-68页 |
| 5.3.1 Distinct response of MBN and neutral response of MBC | 第65-66页 |
| 5.3.2 Carbon-cycling enzyme activity is more susceptible to soil pH and SOC than is nitrogen-cycling enzyme activity | 第66-67页 |
| 5.3.3 Soil bacteria are more active than fungi in response to soil pH and SOC | 第67-68页 |
| 5.4 Summary | 第68-69页 |
| General Discussion and Conclusions | 第69-71页 |
| 6.1 Key Findings | 第69-70页 |
| 6.2 Study Limitations and Future Study | 第70-71页 |
| References | 第71-83页 |
| Acknowledgements | 第83-84页 |
| Candidate CV | 第84页 |
