EFFECT OF THE SYSTEM OF RICE INTENSIFICATION (SRI) ON ...

Table of contents
Preface..................................................................................................................................................5
Acknowledgements..............................................................................................................................5
1. Introduction......................................................................................................................................9
1.1 Research objectives and hypotheses ........................................................................................11
1.2 Delimitations............................................................................................................................12
1.3 Structure of the report ..............................................................................................................12
2. The role of Soil Organic Matter (SOM) in flooded rice soils........................................................13
2.1 Definition of SOM ...............................................................................................................13
2.2 Decomposition and effects of OM in flooded soils .............................................................14
2.3 Storing of C in soils .............................................................................................................15
3. Greenhouse gas emissions and possible ways of mitigation .........................................................17
3.1 GHG emissions through time...............................................................................................17
3.2 The effect of organic amendments and chemical fertilizers on GHG emissions.................19
3.3 Management practices and their effect on GHG emissions.................................................20
3.4 Drainage periods and GHG emissions.................................................................................21
4. The System of Rice Intensification (SRI)..................................................................................22
4.1. The history of SRI...............................................................................................................22
4.2 The concepts of SRI.............................................................................................................22
4.3 The differences between SRI and a traditional/conventional rice system ...........................24
4.4 Difficulties associated with SRI...........................................................................................26
5. Rice in Cambodia.......................................................................................................................26
5.1 The history of rice in Cambodia ..........................................................................................26
5.2 Rice cropping systems .........................................................................................................27
5.3 SRI in Cambodia..................................................................................................................29
6. Development Paradigms ............................................................................................................30
6.1 Development strategies........................................................................................................30
6.3 Sustainability in rural livelihood strategies..........................................................................31
7. Study and experimental implementation site.............................................................................33
7.1 Prey Veng province..............................................................................................................33
7.2 Climatic conditions ..............................................................................................................34
8. Materials and methods ...................................................................................................................35
8.1 Soil sampling............................................................................................................................36
8.2 Interviews.................................................................................................................................38
8.3 Statistical analyses ...................................................................................................................39
9. Results and discussion ...................................................................................................................39
9.1 Soil pH, Carbon and Nitrogen – the biophysical environment................................................39
9.2. Identified Livelihood strategies ..............................................................................................44
9.3. Household assets.....................................................................................................................47
9.4. Compost production................................................................................................................48
9.5. Application of amendments ....................................................................................................49
9.5. SRI ..........................................................................................................................................51
9.6. Can SRI mitigate GHGs and at the same time increase soil quality through C sequestration?
........................................................................................................................................................65
10. Conclusion ...................................................................................................................................71
11. References....................................................................................................................................73
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