Crop Rotation on Organic Farms A PLANNING MANUAL Charles L. Mohler & Sue Ellen Johnson, editors Sustainable Agriculture Research and Education (SARE) Plant and Life Sciences Publishing (PALS) CROP ROTATION ON ORGANIC FARMS a planning manual CHARLES L. MOHLER AND SUE ELLEN JOHNSON, EDITORS Published by the Sustainable Agriculture Research and Education (SARE) program. SARE is supported by the National Institute of Food and Agriculture, U.S. Deparment of Agriculture. Formerly published by Plant and Life Sciences Publishing (PALS). NRAES-177 Published July 2009 (NRAES-177) Reprinted 2020 This book was first published in 2009 by the Natural Resource, Agriculture, and Engineering Service (NRAES). As of 2020 it is published by the Sustainable Agriculture Research and Education (SARE) program. SARE is supported by the USDA’s National Institute of Food and Agriculture under award No. 2019-38640-29881. Learn more about NRAES and SARE on pages 155-156. ISBN 978-1-933395-21-0 Library of Congress Cataloging-in-Publication Data Crop rotation on organic farms : a planning manual / Charles L. Mohler and Sue Ellen Johnson, editors. p. cm. -- (Cooperative Extension NRAES ; 177) Includes bibliographical references and index. ISBN 978-1-933395-21-0 1. Crop rotation--Handbooks, manuals, etc. 2. Organic farming--Handbooks, manuals, etc. I. Mohler, Charles L., date II. Johnson, Sue Ellen, date III. Natural Resource, Agriculture, and Engineering Service. Cooperative Extension. IV. Series: NRAES (Series) ; 177. S603.C756 2009 631.5’82--dc22 200901605 Disclaimer The SARE program provides information to everyone, without regard to race, religion, national origin, sex, age, disability, familial or veteran status. Every effort has been made to make this publication as complete and as accurate as possible. It is only a guide, however, and should be used in conjunction with other information sources. The editors/authors and publisher disclaim any liability, loss or risk, personal or otherwise, which is incurred as a consequence, directly or indirectly, of the use and application of any if the contents of this publication. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the USDA or SARE. Ordering information For online orders visit www.sare.org/webstore. Call (301) 779-1007 to order by phone with credit card payment. To pay by check or purchase order, make payable to Sustainable Agriculture Publications and send to: SARE Outreach Publications c/o International Fulfillment Corporation 3570 Bladensburg Rd. Brentwood, MD 20722 Cost: • $24 for orders of 1-9 books • $18 for 10-24 books (a 25% discount) • $12 for 25 or more books (a 50% discount) Shipping: • $6.95 for first book (within the United States). Add $2 s/h for each additional book—up to nine books—shipped within the United States. • For s/h on orders of 10 or more books, call (301) 779-1007 or visit www.sare.org/WebStore. International orders: Call (301) 779-1007 or visit www.sare.org/WebStore. ii CONTENTS Acknowledgments…………………………………………………………………………….…………………………v About the Authors……………………………………………………………………………..………………………...vi Chapter 1: Introduction………………………………………………………..…………….…………………1 Charles L. Mohler How This Manual Was Constructed……………………….…………………………………….…………2 How to Use This Manual………………………………………………………………………………………2 Chapter 2: How Expert Organic Farmers Manage Crop Rotations……………………………………3 Sue Ellen Johnson and Eric Toensmeier Why Rotate Crops?……………………………………………………………………………………………3 Basics of Crop Rotation………………………………………………………………………………………5 Crop Rotation and Farm Management………………………….………….……………………………6 The NEON “Managing a Crop Rotation System” Chart……….………………………………………9 Key Responsibilities and Related Tasks in the Chart………………………………………………...10 Chapter 3: Physical and Biological Processes in Crop Rotation………………………….………....…21 What This Chapter Is About ……………………………………………………………....………………21 Charles L. Mohler Crop Rotation and Soil Tilth………………………………………………………..…………………....…23 Harold van Es Crop Rotation Effects on Soil Fertility and Plant Nutrition………….………………..…………...…27 Anusuya Rangarajan Managing Plant Diseases with Crop Rotation……………………………………………………....…32 Margaret Tuttle McGrath Management of Insect Pests with Crop Rotation and Field Layout……………..………………41 Kimberly A. Stoner The Role of Crop Rotation in Weed Management………………………….………..………….…..44 Charles L. Mohler Chapter 4: Crop Sequences from Expert Farmers’ Fields……………………………….....……..……47 Sue Ellen Johnson Reading the “Real Fields on Real Farms” Tables………………………………………...……………47 Observation on the Sample Sequences……………………………………………..……....…………56 Summary……………………………………………………………………………………………...…………57 iii Chapter 5: A Crop Rotation Planning Procedure……………………….…………………..……………58 Charles L. Mohler Tips for Sequencing Crops……………………………………………………………………....…….……59 A Complete, Step-by-Step Rotation Planning Guide……………………………………..…………69 A More Complex Example: Summer Acres Vegetable Farm………………………………………83 Chapter 6: Crop Rotation during the Transition from Conventional to Organic Agriculture………………………………………..……………………..………91 Charles L. Mohler Transition from Old Sod to Vegetable Production……………………………………………....……91 Transition from Conventional Cropping on a Farm with Forages……………………………...…92 Transition to Cash Grain or Vegetables on a Farm without Forages…………….………….…...93 Chapter 7: Guidelines for Intercropping…………………………………………………………………...95 Charles L. Mohler and Kimberly A. Stoner Interplanting Crops with Partially Overlapping Growing Seasons……………………………......96 Intercropping Legumes with Nonlegumes……………………………………………………....……..96 Using Tall Crops to Reduce Drought or Heat Stress of Shorter Crops……………………....…….96 Using Intercropping to Disrupt Host Finding by Some Host-Specific Insect Pests…………......98 How Intercrops Affect Populations of Beneficial Parasitoids and Pest Predators………….....99 Using Trap Crops to Reduce Pests………………………………………………………………….....….99 A Glossary of Intercropping Terms………………………………………………………………….......100 Appendix 1: Characteristics of Crops Commonly Grown in the Northeastern United States....101 Charles L. Mohler and Anusuya Rangarajan Appendix 2: Crop Sequence Problems and Opportunities…………………………………….....…104 Charles L. Mohler Appendix 3: Sources of Inoculum for Crop Diseases in the Northeastern United States……....124 Margaret Tuttle McGrath Appendix 4: Characteristics of Common Agricultural Weeds Relevant to Crop Rotation.....…138 Charles L. Mohler Appendix 5: Crop Disease Pathogens Hosted by Common Agricultural Weeds………….…....142 Charles L. Mohler and Margaret Tuttle McGrath Appendix 6: Linking a Field Map and Spreadsheet in Microsoft Excel…………………………....148 Jody Bolluyt, Peter Lowy, and Charles L. Mohler References………………………………………………………..………………………………………………………..150 About SARE……..………………………………………………………………………………………………………155 About PALS .......................................................................................................................................................... 156 iv ACKNOWLEDGMENTS Production of Crop Rotation on Organic Farms: A Planning Manual was made possible with funding from Sustainable Agriculture Research and Education (SARE). See page 155 for more information about SARE. This project was a collaboration between researchers, extension educators, and growers. The authors especially thank the twelve farmers who participated in the DACUM process, and whose efforts created the foundation for this project: Polly Amour, Four Winds Farm, Gardiner, NY; Paul Arnold, Pleasant Valley Farm, Argyle, NY; David Blyn, Riverbank Farm, Roxbury, CT; Roy Brubaker, Village Acres Farm, Mifflintown, PA; Jean-Paul Courtens, Roxbury Farm, Kinderhook, NY; Jim Gerritsen, Wood Prairie Farm, Bridgewater, ME; Brett Grohsgal, Even Star Organic Farm, Lexington Park, MD; Jack Gurley, Calvert’s Gift Farm, Sparks, MD; Don Kretschmann, Kretschmann Farm, Rochester, PA; Drew Norman, One Straw Farm, White Hall, MD; Eero Ruuttila, Nesenkeag Farm, Litchfield, NH; and Will Stevens, Golden Russet Farm, Shoreham, VT. Tina Overtoom, The Center on Education and Training for Employment, The Ohio State University, was the DACUM facilitator, and Eric Toensmeier, then with the New England Small Farm Institute, assisted her. Many additional growers reviewed and verified the DACUM chart: Frank Albani, Jay Armour, Mike and Terra Brownback, Judy Dornstreitch, Pam Flory, Darrell Frey, Les and Debbie Guile, Rick Hood, Jason Kafka, Dwain Livengood, Bryan O’Hara, Robin Ostfeld, L. Smith, Ed Stockman, Paul Volcklawen, and several anonymous reviewers. The authors also thank the following reviewers for the many improvements they suggested: Brian Caldwell, farm education coordinator, NOFA-NY; Kathryne L. Everts, associate professor, Plant Pathology, University of Maryland and University of Delaware; Caragh B. Fitzgerald, extension educator, Maryland Cooperative Extension; Eric Gallandt, assistant professor, Weed Ecology and Management, University of Maine; Vern Grubinger, vegetable and berry specialist, University of Vermont Extension and regional coordinator, Northeast SARE; Jerzy Nowak, professor, Horticulture Department, Virginia Polytechnic Institute and State University; Ginny Rozenkranz, extension educator, Maryland Cooperative Extension; Elsa Sanchez, assistant professor, Horticulture Systems Management, The Pennsylvania State University; Abby Seaman, senior extension associate, Cornell Cooperative Extension; Eric Sideman, organic crop specialist, Maine Organic Farmers & Gardeners