Restoring the Soil A Guide for Using Green Manure/Cover Crops to Improve the Food Security of Smallholder Farmers Roland Bunch Canadian Foodgrains Bank A Christian Response to Hunger Praise for Restoring the Soil Hundreds of thousands of small farmers in many countries are using, experimenting with, and sharing green manure/cover crops, thereby reducing fertilizer use while improving the sustainability of crop production systems. Restoring the soil by using these technologies to feed food-insecure people will have a tremendous impact on improving global food security. Roland Bunch brilliantly shows how green manure/ cover crops can best be used to achieve these objectives. —Elmer Lopez Rodriguez Secretary of Agrarian Affairs Government of Guatemala Roland Bunch’s book on cover crops and green manures could not have come at a better time. Decades of experimentation and experience by farmers, technicians and scientists are presented clearly and practically, making this work an essential contribution not just for world food security but for the food sovereignty of the 2 billion smallholders who produce the bulk of the world’s food. —Dr. Eric Holt-Gimenez Executive Director Food First/Institute for Food and Development Policy Roland Bunch’s book distills for us decades of rich field experience in countries all around the world, where millions of farmers have given practical meaning to the concept of synergy. Farmers are doing this by growing a great number of crops in intelligent and profitable association with a huge variety of green-manure/cover- crop plants. These marvelous plants enrich the soil at the same time that they enhance crop yields, conserve soil moisture, and save farmers’ labor. Thanks to Bunch’s keen observations, systematic analysis and critical thinking, this agroeco- logically-based strategy is now accessible to anyone who will read, digest and apply what is in this book. It fills a huge gap in our published knowledge about how to make the most of our land, labor and water for meeting our food needs in sustainable ways. —Dr. Norman Uphoff Professor of Government and International Agriculture Cornell University A timely and extremely valuable book from one of the world’s leading experts on green manures/cover crops. Clearly written, it is both practical and analytical, and richly illustrated with photographs from a great number of agroecosystems worldwide. Highly recommended. —Dr. Jules Pretty Author of Regenerating Agriculture University of Essex This is the book we have been waiting for. Restoring the Soil distils and condenses a lifetime of learning and a wealth of experience. It is a wonderful source of knowledge and advice about a vital and neglected area of huge potential, a treasure trove for small farmers around the world and those who work with them. Only Roland Bunch with his lifetime of learning and his unique worldwide experience could have written this. Restoring the Soil should have a major impact, widening farmers’ choices and enhanc- ing their sustainable production. It is practical, accessible and wide-ranging across an astonishing variety of green manures/cover crops. Let me hope that it will be widely available in several languages, and widely used. —Dr. Robert Chambers Institute of Development Studies University of Sussex Restoring the Soil A Guide for Using Green Manure/Cover Crops to Improve the Food Security of Smallholder Farmers Roland Bunch Copyright © Canadian Foodgrains Bank, 2012. All rights reserved. No part of this book may be reproduced in any form without permission from Canadian Foodgrains Bank. For more information, contact the Foodgrains Bank at [email protected] Library and Archives Canada Cataloguing in Publication Bunch, Roland, Restoring the soil: a guide for using green manure/cover crops to improve the food security for smallholder farmers / Roland Bunch. ISBN 978-0-9688546-4-8 1. Green manuring—Developing countries. 2. Green manure crops—Developing countries. 3. Soil fertility—Developing countries. 4. Soil management—Developing countries. 5. Food security—Developing countries. I. Canadian Foodgrains Bank II. Title. S661.B85 2012 631.8’74091724 C2012-905464-X Founded in 1983, Canadian Foodgrains Bank is a partnership of 15 churches and church-based agencies working together to end hunger. Members: ADRA Canada (Adventist Development and Relief Agency) • Canadian Baptist Ministries • Canadian Catholic Organization for Development & Peace • Canadian Lutheran World Relief • Christian and Missionary Alliance in Canada • World Renew (formerly Christian Reformed World Relief Committee of Canada) • Emergency Relief & Development Overseas (Pentecostal Assemblies of Canada) • Evangelical Missionary Church of Canada • Mennonite Central Committee Canada • Nazarene Compassionate Ministries Canada • Presbyterian World Service & Development • Primate’s World Relief & Development Fund (Anglican Church of Canada) • The Salvation Army • The United Church of Canada • World Relief Canada Canadian Foodgrains Bank A Christian Response to Hunger Canadian Foodgrains Bank Box 767, Winnipeg, MB Canada R3C 2L4 1.204.944.1993 www.foodgrainsbank.ca Canadian International Agence canadienne de Development Agency développement international Canadian Foodgrains Bank programs are undertaken with the financial support of CIDA. Design: Roberta Fast Cover Page Photo: Chris Woodring Book Photos: Roland Bunch Printed in Canada by CP Printing Solutions. Printed on recycled paper. Table of Contents Preface.................................................................................................................................i Acknowledgements.............................................................................................................ii How.To.Use.This.Book.......................................................................................................iv Introduction........................................................................................................................1 1. The Definition of Green Manure/Cover Crops............................................................3 2. A Brief History of Green Manure/Cover Crops...........................................................5 3. Existing Green Manure/Cover Cropping Systems Around The World.....................8 ....Advantages.of.Green.Manure/Cover.Crop.Systems.......................................................8 ....Disadvantages.of.Green.Manure/Cover.Crops.............................................................12 ....Green.Manure/Cover.Crops.Systems.are.Widespread.................................................14 ....Characteristics.of.Known.Green.Manure/Cover.Crop.Systems....................................14. ....Why.Not.Just.Use.Chemical.Fertilizer?.........................................................................15 4. Improving Soils: The Basic Rules.............................................................................17 5. Choosing The Right Green Manure/Cover Crop System For A Specific Area......19 ....What.About.Farmer.Participation?................................................................................19 ....How.to.Achieve.the.Adoption.of.Green.Manure/Cover.Crop.Systems..........................21 ....Collecting.the.Necessary.Information............................................................................24. 6. Using The Decision Tree............................................................................................27 ....How.to.Use.the.DecisionTree........................................................................................27 ....The.Green.Manure/Cover.Crop.Systems.Included.in.Decision.Tree............................27 ....Characteristics.of.the.Green.Manure/Cover.Crop.Systems.Recommended.................27 ....A.Note.About.Scientific.Names.....................................................................................29 7. Decision Tree...............................................................................................................30 ....Introduction....................................................................................................................30 ....Decision.Tree.Diagram..................................................................................................31 ....Decision.Tree.Guide......................................................................................................35 8. Green Manure/Cover Crop Systems..........................................................................57 ....Latin.America.Green.Manure/Cover.Crop.Systems......................................................57 ....African.Green.Manure/Cover.Crop.Systems.................................................................68 ....Asian.Green.Manure/Cover.Crop.Systems...................................................................72 .Annex 1: Glossary of Agricultural Terms....................................................................77 Annex 2: The Evidence..................................................................................................79 .Annex 3: List of Recommended Green Manure/Cover Crop Species.......................87 .Annex 4: Seed Sources for Green Manure/Cover Crops...........................................90 .Annex 5: Additional Resources on Green Manure/Cover Crops...............................94 i Restoring.the.Soil Preface As world population numbers tick ever higher, ensuring that food production keeps pace is one of the biggest challenges facing humanity. Large-scale