Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 2008 Diversity, productivity, and stability in perennial polycultures used for grain, forage, and biomass production Valentín Daniel Picasso Risso Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agricultural Science Commons, Agronomy and Crop Sciences Commons, Ecology and Evolutionary Biology Commons, and the Horticulture Commons Recommended Citation Picasso Risso, Valentín Daniel, "Diversity, productivity, and stability in perennial polycultures used for grain, forage, and biomass production" (2008). Retrospective Theses and Dissertations. 15849. https://lib.dr.iastate.edu/rtd/15849 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Diversity, productivity, and stability in perennial polycultures used for grain, forage, and biomass production by Valentín Daniel Picasso Risso A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Sustainable Agriculture Program of Study Committee: E. Charles Brummer, Co-major Professor Matt Liebman, Co-major Professor Philip Dixon Brian Wilsey Kevin de Laplante Iowa State University Ames, Iowa 2008 Copyright ©Valentín Daniel Picasso Risso, 2008. All rights reserved UMI Number: 3291999 UMI Microform 3291999 Copyright 2008 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, MI 48106-1346 ii To Lucia, Mati and Santi, and all the children of this planet. Ad Maiorem Dei Gloriam Om Mani Padme Hum iii TABLE OF CONTENTS ACKNOWLEDGEMENTS v ABSTRACT ix RESUMEN (ABSTRACT IN SPANISH) x CHAPTER I. INTRODUCTION 1 CHAPTER II. HISTORY AND PHILOSOPHY OF THE BIODIVERSITY– ECOSYSTEM FUNCTIONING DEBATE IN ECOLOGY 3 INTRODUCTION 3 BACKGROUND: THE DIVERSITY-STABILITY DEBATE 4 The 1950s and 1960s 5 The 1970s and 1980s 6 The 1990s 8 Diversity-stability relationships and environmental policy 9 Diversity-stability relationships and the holism-reductionism debate in ecology 10 BIODIVERSITY AND ECOSYSTEM FUNCTIONS: KEY CONCEPTS 11 Biodiversity 12 Ecosystem function 15 THE BIODIVERSITY-ECOSYSTEM FUNCTIONING DEBATE 25 The Program begins (early 1990s) 26 Critical response (late 1990s) 30 “War among ecologists” 31 Conciliation and synthesis 33 RECENT WORK IN BIODIVERSITY-ECOSYSTEM FUNCTIONING 35 Refining the mechanisms 35 Second generation biodiversity experiments 37 Balancing the synthesis 37 Quantitative synthesis 38 Other issues 39 DISCUSSION: INTERPRETATIONS OF THE BIODIVERSITY-ECOSYSTEM FUNCTIONING DEBATE 40 Success or failure? 40 A new paradigm for ecology? 41 Ecology, agriculture, and Darwin’s legacy 41 CONCLUSION 44 CHAPTER III. CROP SPECIES DIVERSITY AFFECTS PRODUCTIVITY AND WEED SUPPRESSION IN PERENNIAL HERBACEOUS POLYCULTURES UNDER TWO MANAGEMENT STRATEGIES 46 ABSTRACT 46 INTRODUCTION 47 iv MATERIALS AND METHODS 50 Experimental design 50 Data analysis 53 RESULTS 54 Effect of driver species on biomass of seeded species 56 Weed biomass 57 Functional composition effects on biomass of seeded species and weeds 58 DISCUSSION 59 CHAPTER IV. DIVERSITY AFFECTS PRODUCTIVITY OVER TIME THROUGH COMPLEMENTARITY AND STABILITY IN PERENNIAL POLYCULTURES 73 ABSTRACT 73 INTRODUCTION 74 MATERIALS AND METHODS 75 Experimental design 75 Data analyses 78 RESULTS 81 Richness x year interaction 81 Overyielding and mechanisms 82 Stability analysis 83 DISCUSSION 83 Effect of richness over time 84 Complementarity and selection effects 84 Stability, productivity, and adaptation 86 CHAPTER V. SEED YIELD, FORAGE PRODUCTION, AND COMPETITIVE ABILITY OF PERENNIAL CROPS IN POLYCULTURES 95 ABSTRACT 95 INTRODUCTION 96 MATERIALS AND METHODS 98 Experimental design 98 Statistical analyses 101 RESULTS AND DISCUSSION 102 Monocultures 102 Bundleflower – wheatgrass binary mixture 103 Polyculture performance 104 Weed suppression in polycultures 105 Seed yields of perennial grains 106 Promising perennial polycultures 107 Future research directions 108 CHAPTER VI. GENERAL CONCLUSIONS 114 REFERENCES 117 v ACKNOWLEDGEMENTS Starting and finishing this PhD program was possible because of the support of lots of people. Now it is the time to thank each and every one of you. Trying to name all involves the risk of forgetting those who were located in the neurons that I permanently burnt and lost in this process. However, I will do my best. First, I want to thank my PhD Program of Study Committee: E. Charles Brummer, Matt Liebman, Philip Dixon, Brian Wilsey, and Kevin de Laplante. Thanks Charlie for being my sensible mentor, reasonable boss, and good friend. Thanks for giving me the freedom to pursue my own research and teaching interests while providing guidance when I needed it, and showing me that an academic life can be enjoyable and fun. I hope we continue working together in the summer of either hemisphere. Thanks Matt for being the ideal balance between a hard core scientist focused on practical solutions for farming problems and a passionate person fired up in the construction of a more just and sustainable world. Thanks for your patience, advice, and friendship. “Keep up the good work.” Thanks Phil, the most sensible priest in the religion of statistics, for providing timely and practical solutions to my life threatening statistical questions, without making me feel guilty in the process and always teaching me something new. It was always a blessing hearing your “OK!”. Thanks Brian, for your practical advice on community ecology matters and helping me bridge the gap between ecologists and agronomists. See you in the pampas of Uruguay some time soon. Thanks Kevin, for broadening my perspective of the science of Ecology and opening the door to understanding the philosophical debates within the human quest for sustainability. You probed to be a person “de la planta”. Several other Iowa State faculty members contributed to enrich to my PhD experience, including Mary Wiedenhoeft, my Preparing Future Faculty mentor, Gretchen Zdorkowski, Ricardo Salvador, Neal and Jan Flora, Jean-Luc Jannink, Lorna M. Butler, Tom Richards, Clare Hinrichs, Whitney Sanford, John Miranowki, Richard Gladon, Kathleen Delate, Donna Kienzler, Matt Helmers, Heidi Asbjornsen, Betty Wells, Clark Wolf, our grandparents Fred Kirschenmann and John Pesek, and others in the Graduate Program in Sustainable Agriculture. I am grateful for all I learned from you. vi Thanks also to my friends and colleagues from the international Brummer’s forage lab gang: Julia Olmstead, Muhammet Sakiroglu, Xue-hui Lee, Babita Thapa, Fred Iutzi, Joe Robins, Mindi W., Heathcliffe Riday, Baldomero Alarcón, and also our Jannink’s lab cousins: Murli Gogula, Yoon-Soup So, Shengqiang Zhong, Dong Hong Pei, Alona Chernyshova, Massiel Orellana, and Lucia Gutierrez, for sharing so many fun and boring moments in the computer lab, the seed lab, and the field. It is over and we survived! I am grateful also to my fellow students in the glorious Graduate Program in Sustainable Agriculture, especially the 2003 cohort: Ann Finan, Cassi Johnson, Emily Newman, Karie Wiltshire, Matt Haan, Mathew Muma, Enrique Ortiz, and the famous Andy Heggenstaller. Also to Carlos Khatounian, Amy (the) Best, Sarah Carlson, Pete Lammers, Ryan Atwell, Denis Reich, Mary Nyasimi, and many other future world leaders in the quest for a more sustainable planet. The vision and inspiration for this research came from The Land Institute think-tank. Thanks to my friends: Wes and Joan Jackson, Jerry Glover, Cindy Cox, Lee DeHaan, David van Tassel, Stan Cox, and all the Natural Systems Agriculture fellows and participants of the Summer Workshops 2003-2006. The Uruguay Fulbright Commission and the Institute for International Education at the Rocky Mountains Office, provided encouragement and financial support to start this graduate studies in the USA. Financial support for this research project came from the people of the State of Iowa through their taxes, The Land Institute Natural Systems Agriculture Graduate Fellowship, North Central Region – Sustainable Agriculture Research and Education (SARE) Graduate Student Grant, the Raymond Baker Center for Plant Breeding at Iowa State University, and the ISU Agronomy Department Endowment (thanks Kendall Lamkey!). Thanks to Norman Mc Coy and his kind mother Miriam for opening the gates of their farm to perennial polyculture alternatives and their kitchen for delicious meals, and to Rick Exner for helping with the on farm research among other fun things. Jean-Luc Jannink, Jode Edwards, Ken Moore, and Lucia Gutierrez provided advice on statistical issues throughout the research project. David Correl and Miguel Carriquiry provided advice for the economic comparisons of perennial cropping systems. Carol Williams helped with spatial representation and analyses of the experiment. Thank you so much. vii Thanks to Mark Smith for all his help in the field, for taking great care of my experimental plots, and teaching me all I will ever know about agricultural machinery and