Assessing ecosystem services of weeds in organic vs. conventional systems within the Montepaldi Long-Term Experiment, Tuscany Emmelie A.H. Mohrmann MSc. Thesis Report December 2015 Farming Systems Ecology Group (FSE) Dipartimento di Scienze delle Produzioni Wageningen University, The Netherlands Agroalimentari e dell’Ambiente (DISPAA) Droevendaalsesteeg 1 – 6708 PB Wageningen University of Florence, Italy Piazzale delle Cascine, 18 - 50144 Firenze i Assessing ecosystem services of weeds in organic vs. conventional systems within the Montepaldi Long-Term Experiment, Tuscany Emmelie A. H. Mohrmann Reg. No. 920615576010 MSc Thesis Farming Systems Ecology (FSE80436) Study Program: MSc. Organic Agriculture Specialization: Agroecology Supervisors: dr. ing. Johannes MS Scholberg and dr. Cesare Pacini Examiner: Dr. Egbert Lantinga ii Table of Contents Acronyms ............................................................................................................................................................................... v Preface ...................................................................................................................................................................................vi Executive summary: ....................................................................................................................................................... vii 1. Introduction ..................................................................................................................................................................... 1 1.1 Agriculture and ecosystem services .............................................................................................................. 1 1.2 Weeds and ecosystem services ........................................................................................................................ 2 1.3 Management system effect on crop-weed competition ......................................................................... 3 1.4 Trait based approach ........................................................................................................................................... 5 1.5 Knowledge gap and research questions ....................................................................................................... 5 1.6 Thesis structure ...................................................................................................................................................... 6 2. Material and methods .................................................................................................................................................. 7 2.1 Framework ............................................................................................................................................................... 7 2.2 Experimental site, design and cultural practices ................................................................................... 11 2.2.1 Experimental site ....................................................................................................................................... 11 2.2.2 Experimental design ................................................................................................................................. 14 2.2.3 Cultural practices and rotation ............................................................................................................. 17 2.3 Sampling methodology, data analysis and statistical analysis ......................................................... 20 2.3.1 Sampling methodology ............................................................................................................................ 20 2.3.2 Data compilation and analysis .............................................................................................................. 20 2.3.3 Statistical analysis ...................................................................................................................................... 21 3. Results ............................................................................................................................................................................. 23 3.1 Yields ........................................................................................................................................................................ 23 3.2 Mass total weeds (MTW) ................................................................................................................................. 25 3.3 Mass total weeds vs. crop yield ..................................................................................................................... 33 3.3.1 Relative amount of mass total weeds compared to crop ........................................................... 34 3.4 Number of weed species .................................................................................................................................. 35 3.5 Functional trait differences amongst management systems for different crops. .................... 36 3.5.1 Provisioning services ................................................................................................................................ 36 iii 3.5.2 Regulating services .................................................................................................................................... 42 3.5.3 Supporting services ................................................................................................................................... 48 4. Discussion ...................................................................................................................................................................... 54 4.1 Framework ............................................................................................................................................................ 54 4.1.1 Limitations .................................................................................................................................................... 54 4.1.2 Strengths ........................................................................................................................................................ 55 4.2 Dataset ..................................................................................................................................................................... 55 4.3 Mass total weeds and prevailing species .................................................................................................. 56 4.4 Research questions ............................................................................................................................................ 57 4.4.1 Research question 1 .................................................................................................................................. 57 4.4.2 Research question 2 .................................................................................................................................. 58 4.4.3 Research question 3 .................................................................................................................................. 60 4.5 Contextualization ................................................................................................................................................ 62 5. Conclusion ..................................................................................................................................................................... 62 6. Limitations and future research recommendations .................................................................................... 64 7. References ..................................................................................................................................................................... 66 8. Appendices .................................................................................................................................................................... 75 Appendix 1 – Functional trait and service relations explained............................................................... 75 Appendix 2 – Trait source information and selection methodology .................................................... 83 Appendix 3 – 95% confidence interval for mean LDM values of crops ............................................... 85 Appendix 4. Overview of crop-weed complementarity in terms of functional traits .................... 86 Appendix 5 – Mean values and significance of management system effect across crops ............ 89 iv Acronyms MTW Mass Total Weeds (g) (may be referred to as total weed biomass) MTR Mass Tap Root species (g) MFR Mass Fibrous Root species (g) MNF Mass N-Fixating species (g) ELI Mean Ellenberg Nitrogen Index MLD Mass Nitrophilous (ELI > 7) species (g) AWH Average Weed Height (cm) MPC Mass Protruding (above Crop) species (g) ENI Mean Ellenberg Light Index MNP Mass Light Demanding (ENI > 7) species (g) MCT Mass Climbing Type species (g) MCR Mass Competitive Ruderal species (g) LDM Mean Leaf Dry Matter Content (g g-1) GDM Mass Greater LDM (than crop) species (g) MSS Mass Syrphid Supporting species (g) FPR Flowering Phenology Richness (No.) IPR Insect Flowering Phenology Richness (No.) MIP Mass Insect Pollinated species (g) DDM Mass Different LDM (than crop) species (g) MFT Mass Forb-Type species (g) NWS Number of weed species SAC Same as Crop DFC Different