Faculteit Bio-ingenieurswetenschappen Academiejaar 2015 – 2016 Diversiteit en functie van arbusculaire mycorrhiza van Vicia faba in de tropische hooglanden van Ethiopië Reindert Devlamynck Promotor: Prof. dr. ir. Pascal Boeckx Copromotor: Dr. Olivier Honnay Tutor: Dr. Amsalu Nebiyu Masterproef voorgedragen tot het behalen van de graad van Master in de bio-ingenieurswetenschappen: Landbouwkunde English translation of the title: Diversity and function of arbuscular Mycorrhiza of Vicia Faba in the tropical highlands of Ethiopia Acknowledgements Ik ben iedereen dankbaar voor hun hulp en medeleven. Toch wil ik van de gelegenheid gebruik maken om één iemand speciaal te bedanken. Papa, bedankt voor de 22 prachtige jaren en voor je onvoorwaardelijke steun. Bedankt om je genen, normen en waarden door te geven aan mij. Wie ik ben, komt door wie jij was. Ik hoop dat je het resultaat van jouw boetseerwerk verder kunt volgen in de hemel en dat je fier bent op wat ik heb bereikt. i Table of contents Acknowledgements .................................................................................................................................. i Table of contents ..................................................................................................................................... ii List of symbols and abbreviations .......................................................................................................... iv Summary ................................................................................................................................................. v Samenvatting .......................................................................................................................................... vi 1. Introduction ................................................................................................................................... 1 1.1 Description of the study area ................................................................................................... 1 1.1.1 Soil characteristics ........................................................................................................... 2 1.1.2 Climate ............................................................................................................................ 3 1.1.3 Agricultural system ......................................................................................................... 3 2. Literature review ........................................................................................................................... 6 2.1 Faba bean ....................................................................................................................................... 6 2.1.1 Description ............................................................................................................................. 6 2.1.2 Faba bean for sustainable intensification................................................................................ 8 2.1.3 Nitrogen effects ...................................................................................................................... 9 2.1.4 Phosphorus effects ................................................................................................................ 10 2.1.5 Non-nutrient effects .............................................................................................................. 11 2.1.6 Limits of faba bean ............................................................................................................... 11 2.2 Arbuscular mycorrhizal fungi...................................................................................................... 11 2.2.1 Benefits from AMF colonization .......................................................................................... 13 2.2.2 The effects of AMF Diversity .............................................................................................. 14 2.3 Biological Nitrogen Fixation ....................................................................................................... 16 2.3.1 Interaction between AMF colonization and nodulation ....................................................... 16 2.4 Soil phosphorus ........................................................................................................................... 17 2.4.1 Phosphorus pools and dynamics ........................................................................................... 18 3. Material and methods ................................................................................................................. 21 3.1 Description of the project ............................................................................................................ 21 3.2 Soil rhizosphere parameters ........................................................................................................ 23 3.2.1 Phosphatase enzyme activity ................................................................................................ 23 3.2.2 Olsen-P ................................................................................................................................. 24 3.2.3 Total P .................................................................................................................................. 25 3.2.4 pH ......................................................................................................................................... 26 3.2.5 Resin P .................................................................................................................................. 26 3.2.6 E-value .................................................................................................................................. 26 3.3 Plant and AMF parameters .................................................................................................... 28 3.3.1 AMF diversity ...................................................................................................................... 28 ii 3.3.2 N/P ratio ............................................................................................................................... 30 3.3.3 BNF ...................................................................................................................................... 31 3.3.4 Nodules ................................................................................................................................. 32 3.3.5 Above ground biomass ......................................................................................................... 32 3.4 Data analysis................................................................................................................................ 32 4. Results........................................................................................................................................... 34 4.1 AMF identification ...................................................................................................................... 34 4.2 Rarefaction curves ....................................................................................................................... 34 4.3 Summary of collected data .......................................................................................................... 35 4.4 Non-metrical multidimensional scaling (NMDS) ....................................................................... 38 4.5 Effect of edaphic parameters on AMF diversity ......................................................................... 39 4.6 Effect of AMF diversity on plant P content and phosphatase activity ........................................ 41 4.7 Interaction between nodules and AMF colonization ................................................................... 42 5. Discussion ..................................................................................................................................... 45 5.1 Evaluation of collected data ........................................................................................................ 45 5.1.1 Diversity indices ................................................................................................................... 45 5.1.2 Soil parameters ..................................................................................................................... 48 5.1.3 N2-fixation parameters .......................................................................................................... 49 5.2 Hypotheses .................................................................................................................................. 50 5.2.1 The response of AMF community, richness, and diversity to edaphic factors. .................... 50 5.2.2 Effect of diversity and richness on the plant P uptake and phosphatase activity ................. 51 5.2.3 Interaction within the tripartite symbiosis of AMF, Rhizobia and Vicia faba ..................... 52 6. Conclusion .................................................................................................................................... 53 References ............................................................................................................................................. 54 Appendix ............................................................................................................................................... 70 iii List of symbols and abbreviations