PERENNIAL AGRICULTURE: AGROMONY AND ENVIRONMENT IN LONG-LIVED FOOD SYSTEMS by Maayan Kreitzman B.Sc., The University of British Columbia, 2008 M.Sc. The Hebrew University of Jerusalem, 2012 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Resources, Environment, and Sustainability) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) August 2020 © Maayan Kreitzman, 2020 The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: Perennial agriculture: agronomy and environment in long-lived food systems. submitted by Maayan Kreitzman in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Resources, Environment, and Sustainability Examining Committee: Dr. Kai Chan, Institute for Resources, Environment, and Sustainability Supervisor Dr. Kristin Mercer, College of Food, Agricultural, and Environmental Sciences, Ohio State University Supervisory Committee Member Dr. Claire Kremen, Institute for Resources, Environment, and Sustainability and Zoology University Examiner Dr. Terry Sunderland, Department of Forest and Conservation Science University Examiner ii Abstract Perennial agricultural systems are fundamentally characterized by their longevity, as they consist chiefly of long-lived woody plants with permanent root and shoot systems that can be managed for continuous ground cover. This is known to promote a host of ecosystem services, and indeed agricultural landscapes that include perennials have been shown to support wildlife, enhance pest regulation, sequester carbon, limit erosion and water pollution, and promote pollination. Yet, the agroforestry and agroecology literatures that characterize environmental benefits of perennials (which mostly involve non-food producing trees and grasslands, especially in temperate climates) are largely separate from agronomic literature about the management and yields of perennial crops themselves. Thus little is known about how tree crops actually support a range of ecosystem services and other benefits. This thesis takes a multi-disciplinary approach to study agronomic, nutritional, environmental, and social dimensions of perennial crops for human food. It first characterizes the distribution and yields of perennial staple crops worldwide, finding that perennial crops, many of which are not yet heavily commodified, can provide staple nutrition at yields comparable to those of annual staples while supplying more varied nutrition than common annual staples. Second, it surveys food production and environmental outcomes on fourteen perennial polyculture farms in the US Midwest, finding that these farms enhance biodiversity and several other ecosystem services, although these new plantings produce less food than neighboring annual cropland. Third, it explores the practices, livelihoods, and values of perennial farmers, finding that they implement iii sophisticated adaptive management and derive satisfaction from fulfilling largely relational values alongside livelihood needs. Perennial agriculture thus offers the potential to produce significant amounts of nutritionally important food in multifunctional landscapes. If managed in diversified systems, perennials can enhance multiple ecosystem services compared to simplified perennial management and annual cropland. More widespread transition to perennials in existing agricultural land should be informed by the specific ecological opportunities offered by perennial plants (including continuous groundcover), and by the knowledges and values of producers, to realize the potential of these systems for achieving sustainable food security. iv Lay Summary The accelerating climate and ecological crisis facing the world makes the challenge of feeding people while reducing humanity’s impacts on the planet and regenerating its damaged life support systems an urgent one. Perennial agriculture, where long-lived plants (that are often woody trees and bushes) produce food year after year, can mitigate many of the problems with annual agriculture. But, the advantages and challenges of transitioning land to perennial agriculture depend on many factors, including how much food and nutrition perennial crops produce, what type of landscape they replace, how many environmental benefits they generate, how they are managed, and how easy and cost-effective it is for farmers to change their practices and livelihoods. This thesis explores these contexts for transitioning to perennial crops through global data assembly and original data collection in the US Midwest. The multifunctional environmental and agronomic benefits of perennial crops justify including them as part of the pathway towards sustainable food security. v Preface This thesis is my original work. I identified the research problems, obtained research funding, designed the research program, gathered and analyzed the data (with some assistance, as specified below), and wrote the chapters. My advisory committee (Drs. Kai Chan, Sean Smukler, Kristin Mercer, and Navin Ramankutty) provided valuable feedback on my research design, initial results, and draft chapters. Chapters 2 through 4 were written as stand-alone pieces for publication in peer-reviewed journals. This has led to some overlap in the introductory content of the chapters. As the final publications will be co-authored, terms like “we” instead of “I” are used to reflect co-authorship for those chapters. The nature of my contribution and those of all co-authors to each chapter is explained below: Chapter 2 is a verbatim manuscript of an article that is soon to be submitted. I am the lead author and wrote the first draft of the paper. I developed the project idea and core arguments in collaboration with the second author, Eric Toensmeier, with the support of Dr. Navin Ramakutty. A research assistant, Santiago Tomassi was employed to review literature which formed the main data for the paper. Drs. Navin Ramankutty, Sean Smukler and I worked together to refine the analysis. Dr. Kai Chan contributed to reviewing the manuscript and incorporating relevant literature. Chapter 3 is based on my own empirical fieldwork. I oversaw all aspects of the study from design to final analysis, and am the lead author on the resulting manuscript, which is a version of the chapter herein. I developed the project idea and research methods; collected the data in the vi field with the Noah Sullivan and Harold Eyster; carried out the data analysis; and led the writing. Drs. Sean Smukler and Matthew Mitchell contributed to developing the fieldwork protocol. Keefe Keely contributed to finding fieldwork sites. Dr. Adrian Verster contributed to the genetic data analysis. Harold Eyster contributed to the biodiversity analysis. Aldona Czajewska carried out the counting and identification of arthropods. Drs. Matthew Mitchell, Kai Chan, and Sean Smukler, as well as my other committee members contributed to structuring the article. All the co-authors contributed to the interpretation of study results and provided feedback on multiple article drafts. Chapter 4 is also based on my empirical fieldwork. I led the writing the interview protocol, conducted the interviews, coded the interviews, and led the writing of the manuscript. Dr. Mollie Chapman, Dr. Kai Chan, Adrian Semmelink, and Dr. Leila Harris contributed to formulating the interview protocol (the latter two played an advisory role and are not co-authors on the paper). Keefe Keeley contributed to finding interview subjects. Drs. Mollie Chapman, Keefe Keeley and Kai Chan contributed to situating the work in relevant literatures, crafting the argument, and provided feedback on the manuscript. This work was approved by the UBC Human Research Ethics Board, certificate H17-03248-A002. vii Table of Contents Abstract ......................................................................................................................................... iii Lay Summary .................................................................................................................................v Preface ........................................................................................................................................... vi Table of Contents ....................................................................................................................... viii List of Tables .............................................................................................................................. xiv List of Figures ...............................................................................................................................xv List of Abbreviations ................................................................................................................ xvii Acknowledgements .................................................................................................................. xviii Dedication .....................................................................................................................................xx Chapter 1: Introduction ................................................................................................................1 1.1 Perennial agriculture in the global food system .............................................................. 1 1.2 Research objectives on two scales .................................................................................