Effect of organic farming on soil erosion and soil structure of reclaimed Tepetates in Tlaxcala, Mexico [Elektronische Ressource] / eingereicht von Mathieu Haulon

Informations

• Publié par: justus-liebig-universitat_giessen
• Publié le: 01 janvier 2008
• Nombre de lectures: 11
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Aus dem Institut für Bodenkunde und Bodenerhaltung
der Justus-Liebig-Universität Gießen
Prof. Dr. Peter Felix-Henningsen
Effect of organic farming on soil erosion and soil structure
of reclaimed Tepetates in Tlaxcala, Mexico
Dissertation zur Erlangung des Doktorgrades der Agrarwissenschaften
am Fachbereich 09
- Agrarwissenschaften, Ökotrophologie und Umweltmanagement -
der Justus-Liebig-Universität Gießen
eingereicht von Mathieu Haulon
aus Brüssel/Belgien
Gießen 2008This thesis was accepted as an Inaugural Dissertation by the Justus-Liebig-University
Giesssen, Fachbereich 09 “Agrarwissenschaften, Ökotrophologie und Umweltmanagement”Index i
Index
Index_____________________________________________________________________ i
Zusammenfassung__________________________________________________________v
Abstract _________________________________________________________________ vi
List of Figures ___________________________________________________________ vii
List of tables______________________________________________________________ ix
List of abbreviations ______________________________________________________ xii
1. Introduction ___________________________________________________________1
1.1. Tepetates and erosion________________________________________________1
1.1.1. Tepetates: hardened volcanic horizons with agriculture potential _______________________ 1
1.1.1.1. Definition ________________________________________________________________ 1
1.1.1.2. Distribution ______________________________________________________________ 1
1.1.1.3. Origin, hardening and conditions of formation ___________________________________ 2
1.1.1.4. Emergence due to erosion ___________________________________________________ 4
1.1.1.5. Properties ________________________________________________________________ 5
1.1.1.6. Tepetate rehabilitation ______________________________________________________ 6
1.1.2. Structure, erosion and organic farming ___________________________________________ 9
1.2. Objectives ________________________________________________________12
2. Tlaxcala: a state affected by tepetates _____________________________________13
2.1. Physiographic overview _____________________________________________13
2.2. Climate __________________________________________________________13
2.3. Geology __________________________________________________________14
2.4. Soils _____________________________________________________________15
2.5. Soil use and agriculture _____________________________________________16
2.5.1. Agriculture ________________________________________________________________ 16
2.5.2. Forest ____________________________________________________________________ 16
2.6. Sociodemographic context___________________________________________16
2.6.1. Economy and employment ____________________________________________________ 17
2.6.2. Migration _________________________________________________________________ 18
2.6.3. Farm unit structure __________________________________________________________ 18
3. Materials and methods _________________________________________________19Index ii
3.1. Tlalpan experimental site ___________________________________________19
3.2. Managements _____________________________________________________19
3.3. Crops and fertilization______________________________________________20
3.4. Methods__________________________________________________________21
3.4.1. Soil loss and runoff__________________________________________________________ 21
3.4.2. Rain erosivity ______________________________________________________________ 23
3.4.3. Vegetation cover____________________________________________________________ 24
3.4.4. Aggregate stability __________________________________________________________ 24
3.4.4.1. Percolation stability _______________________________________________________ 24
3.4.4.2. Aggregate size distribution _________________________________________________ 25
3.4.4.3. Sampling _______________________________________________________________ 26
3.4.4.4. Statistical analysis ________________________________________________________ 26
3.4.5. Particle size distribution ______________________________________________________ 26
3.4.6. Porosity and pore size distribution ______________________________________________ 27
3.4.7. Soil Organic Carbon_________________________________________________________ 27
4. Results_______________________________________________________________28
4.1. Erosivity and soil erosion____________________________________________28
4.1.1. Rainfall erosivity ___________________________________________________________ 28
4.1.1.1. Annual precipitation_______________________________________________________ 28
4.1.1.2. Monthly precipitation______________________________________________________ 29
4.1.1.3. Rainfall patterns in Tlalpan _________________________________________________ 30
4.1.2. Runoff and soil loss _________________________________________________________ 31
4.1.3. Vegetation cover____________________________________________________________ 32
4.1.3.1. 2002 ___________________________________________________________________ 33
4.1.3.2. 2003 ___________________________________________________________________ 33
4.1.3.3. 2004 ___________________________________________________________________ 35
4.1.3.4. 2005 ___________________________________________________________________ 35
4.2. Soil properties and crop production___________________________________36
4.2.1. Soil Organic Carbon_________________________________________________________ 36
4.2.2. Soil water content___________________________________________________________ 38
4.2.3. Crop production ____________________________________________________________ 39
4.3. Soil structure______________________________________________________39
4.3.1. Particle size distribution ______________________________________________________ 39
4.3.2. Aggregation _______________________________________________________________ 42
4.3.2.1. Dry aggregate size distribution ______________________________________________ 42
4.3.2.2. Aggregate stability ________________________________________________________ 44
4.3.3. Porosity and pore size distribution ______________________________________________ 48Index iii
4.3.3.1. Total porosity and bulk density ______________________________________________ 48
4.3.3.2. Pore size distribution ______________________________________________________ 49
4.3.3.3. Effect of depth on porosity__________________________________________________ 50
4.3.3.4. Effect of ridge and furrow systems on porosity __________________________________ 51
4.4. Statistical analysis _________________________________________________52
4.4.1. Relationship between SOC, aggregate stability and erodibility ________________________ 52
4.4.2. Soil loss and runoff prediction _________________________________________________ 53
4.4.2.1. About the data set_________________________________________________________ 53
4.4.2.2. About the variables _______________________________________________________ 54
4.4.2.3. Relationship between erosivity and erosion_____________________________________ 55
4.4.2.4. Soil loss and runoff prediction _______________________________________________ 55
5. Discussion: Effect of organic farming on soil erosion and soil structure _________59
5.1. Erosivity _________________________________________________________59
5.2. Effect of organic farming on soil erosion _______________________________59
5.2.1. Carbon dynamic in reclaimed tepetates __________________________________________ 59
5.2.1.1. Incorporation and accumulation of SOC _______________________________________ 59
5.2.1.2. Carbon losses ____________________________________________________________ 61
5.2.2. Vegetation cover____________________________________________________________ 63
5.2.2.1. Crop development and vegetation cover _______________________________________ 63
5.2.2.2. Crop association__________________________________________________________ 65
5.2.2.3. Mulching _______________________________________________________________ 66
5.2.3. Runoff and erosion rates in reclaimed tepetates____________________________________ 66
5.2.4. Evolution of erosion rates_____________________________________________________ 68
5.3. Effect of organic management on soil structure _________________________70
5.3.1. Aggregate stability dynamic and organic management ______________________________ 70
5.3.2. Porosity and infiltration ______________________________________________________ 73
5.3.2.1. Presence and effect of fragments on porosity in recently reclaimed tepetates. __________ 73
5.3.2.2. Effect of management on soil porosity ________________________________________ 74
5.3.3. About tillage and residue management___________________________________________ 75
6. Conclusion ___________________________________________________________77
Summary ________________________________________________________________80
References _______________________________________________________________82
Acknowledgements ________________________________________________________93
Appendix 1. Rain erosivity________________________________________________95
Appendix 2. Soil loss and runoff ___________________________________________97
Appendix 3. Vegetat