Managing Agrodiversity the Traditional
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Managing agrodiversity the traditional way This book presents part of the findings of the international project “People, Land Management, and Environmental Change”, which was initiated in 1992 by the United Nations University. From 1998 to 2002, the project was supported by the Global Environment Facility with the United Nations Environment Programme as Implementing Agency and the United Nations University as Executing Agency. The views expressed in this book are entirely those of the respective authors, and do not necessarily reflect the views of the Global Environment Facility, the United Nations Environment Programme, and the United Nations University. Managing agrodiversity the traditional way: Lessons from West Africa in sustainable use of biodiversity and related natural resources Edited by Edwin A. Gyasi, Gordana Kranjac-Berisavljevic, Essie T. Blay, and William Oduro © United Nations University, 2004 The views expressed in this publication are those of the authors and do not necessarily reflect the views of the United Nations University. United Nations University Press The United Nations University, 53-70, Jingumae 5-chome, Shibuya-ku, Tokyo, 150-8925, Japan Tel: ϩ81-3-3499-2811 Fax: ϩ81-3-3406-7345 E-mail: [email protected] (general enquiries): [email protected] www.unu.edu United Nations University Office at the United Nations, New York 2 United Nations Plaza, Room DC2-2062, New York, NY 10017, USA Tel: ϩ1-212-963-6387 Fax: ϩ1-212-371-9454 E-mail: [email protected] United Nations University Press is the publishing division of the United Nations University. Cover design by Rebecca S. Neimark, Twenty-Six Letters Printed in the United States of America UNUP-1098 ISBN 92-808-1098-7 Library of Congress Cataloging-in-Publication Data Managing agrodiversity the traditional way : lessons from West Africa in sustainable use of biodiversity and related natural resources / edited by Edwin A. Gyasi... [et al.]. p. cm. Includes index. ISBN 92-808-1098-7 (pbk.) 1. Agrobiodiversity—Africa, West. 2. Agrobiodiversity—Africa, West—Case studies. 3. Biological diversity conservation—Africa, West. I. Gyasi, Edwin A. (Edwin Akonno), 1943– S494.5.A43M352 2004 333.95Ј16Ј0966—dc22 2004014198 Contents List of tables and illustrations . viii List of colour plates . xiii Maps A Major ecological/vegetation zones of West Africa . xiv B Major agro-ecological zones and PLEC demonstration sites in Ghana . xv C Gyamfiase-Adenya demonstration site . xvi D Sekesua-Osonson demonstration site . xvii E Amanase-Whanabenya demonstration site . xviii Preface Edwin A. Gyasi . xix Foreword Harold Brookfield . xxiii Acknowledgements Edwin A. Gyasi, Gordana Kranjac-Berisavljevic, Essie T. Blay, and William Oduro . xxvii Part I Methodological approaches and knowledge systems 1 Methodological approaches to the book Edwin A. Gyasi . 3 2 Philosophical foundations of biophysical resource use with special reference to Ghana Alfred A. Oteng-Yeboah . 8 v vi CONTENTS 3 Traditional methods of resource assessment relative to the scientific approach Stephen Nkansa Buabeng . 14 4 Farmer strategies of managing agrodiversity in a variable climate in PLEC demonstration sites in southern Ghana Edward Ofori-Sarpong and Felix Asante . 25 5 Demonstration sites and expert farmers in conservation of biodiversity Edwin A. Gyasi . 38 Part II Cropping systems and related case studies 6 Management regimes in southern Ghana Edwin A. Gyasi . 53 7 Yams: Traditional ways of managing their diversity for food security in southern Ghana Essie T. Blay . 69 8 Sustaining diversity of yams in northern Ghana Gordana Kranjac-Berisavljevic and Bizoola Z. Gandaa . 84 9 Conservation of indigenous rice varieties by women of Gore in the northern savanna zone, Ghana Paul B. Tanzubil, Joseph S. Dittoh, and Gordana Kranjac- Berisavljevic . 97 10 Vegetables: Traditional ways of managing their diversity for food security in southern Ghana Essie T. Blay . 106 11 The proka mulching and no-burn system: A case study of Tano-Odumasi and Jachie Charles Quansah and William Oduro . 119 12 Managing the home garden for food security and as a germplasm bank Lewis Enu-Kwesi, Edwin A. Gyasi, and Vincent V. Vordzogbe . 135 13 Management of trees in association with crops in traditional agroforestry systems John A. Poku . 155 CONTENTS vii 14 Preliminary observations on effects of traditional farming practices on growth and yield of crops Leonard Asafo, Ebenezer Laing, Lewis Enu-Kwesi, and Vincent V. Vordzogbe . 165 15 Effects of four indigenous trees canopy covers on soil fertility in a Ghanaian savanna Charles Anane-Sakyi, Abubakari Sadik Abdulai, and Saa Dittoh . 177 16 Comparative management of the savanna woodland in Ghana and Guinea: A preliminary analysis Lewis Enu-Kwesi, Vincent V. Vordzogbe, Diallo Amirou, and Diallo Daouda . 187 17 Agrodiversity within and without conserved forests for enhancing rural livelihoods Essie T. Blay, Benjamin D. Ofori, John Heloo, Joachim B. Ofori, and Emmanuel Nartey . 203 Part III Social dimensions of resource management 18 Aspects of resource tenure that conserve biodiversity: The case of southern and northern Ghana Edwin A. Gyasi and William J. Asante . 217 19 Resource access and distribution and the use of land in Tano-Odumasi, central Ghana John A. Bakang, William Oduro, and Kwaku A. Nkyi . 228 20 Women environmental pacesetters of Jachie Olivia Agbenyega and William Oduro . 242 Part IV Conclusion 21 Lessons learnt and future research directions Edwin A. Gyasi . 253 Contributors . 257 Index . 259 List of tables and illustrations Tables 3.1 Scientific classification of soils . 16 3.2 Indicator plants . 18 3.3 Scientific indicators of water quality . 19 3.4 Indicators used traditionally by communities to assess maturity of crops . 20 3.5 Examples of techniques used for quantifying product yield . 21 5.1 Essentially traditional management practices/regimes in PLEC demonstration sites in Ghana . 43 5.2 Demonstration activities in Ghana . 46 6.1 Farm management regimes and organizational aspects at demonstration sites . 55 6.2 Selected management regimes/practices and their advantages in PLEC demonstration sites in southern Ghana . 58 6.3 Matrix for quantitative analysis of variations in biodiversity . 66 7.1 Yam maintenance strategies . 82 8.1 Yam accessions in a PLEC demonstration site in northern Ghana . 85 8.2 Yam types observed during the 1999 growing season at Bongnayili-Dugu-Song . 89 8.3 Vegetative characteristics of yam types collected at Bongnayili-Dugu-Song . 91 viii LIST OF TABLES AND ILLUSTRATIONS ix 8.4 Percentage moisture, ash, protein, starch, and minerals in 22 yam types grown in Bongnayili-Dugu-Song . 92 8.5 Factors leading to erosion of some yam types in a PLEC demonstration site in northern Ghana . 94 8.6 Factors leading to maintenance of some yam types in a PLEC demonstration site in northern Ghana . 94 9.1 Differences in production practices between men and women farmers at Gore (2000 field survey) . 100 9.2 Characteristics of indigenous rice varieties grown by women farmers at Gore in the Bawku area of Ghana as mentioned by farmers . 102 9.3 Yield of rice varieties in on-farm trials at Gore (mean for 1998 and 1999 growing seasons) . 102 9.4 Records on cultivation of indigenous rice varieties by Gore women farmers, 2001 . 103 10.1 Major fruiting vegetable cultivars grown in the demonstration sites . 108 11.1 Diversity and heterogeneity indices for various land-use forms (for three plot sizes) in Tano-Odumasi . 123 11.2 Soil physical properties under various land-use stages at Tano-Odumasi . 125 11.3 Soil chemical proprieties under various land-use stages at Tano-Odumasi . 126 11.4 Residual effect of treatments and initial soil value (0–15 cm depth) . 127 11.5 Residual effect of treatments and initial soil value (15–30 cm depth) . 128 11.6 Nutrient runoff and soil losses due to different mulching rates . 130 11.7 Maize grain yield under slash-and-burn and no-burn . 131 11.8 Maize grain and cassava tuber yield under slash-and-burn and no-burn land management systems at Nkawie . 132 12.1 Questionnaire for survey of home gardens . 137 12.2 Distribution of home gardens and associated settlements and compound houses . 138 12.3 Management and organizational characteristics of home gardens in PLEC demonstration sites in southern Ghana (shown by percentage) . 141 12.4 Weighted averages of life-forms in Odorkor Agbo’s home garden 144 12.5 Use and other value of species in Odorkor Agbo’s home garden . 145 12.6 Major items that could be sold from Odorkor Agbo’s garden . 152 13.1 Tree species left in situ in farms in the forest zone . 157 13.2 Tree species left in situ in farms in the transitional zone . 159 x LIST OF TABLES AND ILLUSTRATIONS 13.3 Tree species left in situ in farms in the Guinea savanna zone . 161 13.4 Tree species left in situ in farms in the Sudan savanna zone . 162 13.5 Tree species left in situ in farms in the coastal savanna zone . 163 14.1 Trees left in situ or regenerating on farms in the study area . 168 14.2 Relative abundance of non-tree germinating species . 169 14.3 Crop yields (kg) in relation to distance from the trunk/bole of tree . 170 14.4 Results of soil analyses in the slash-no-burn proka and slash-and-burn fields . 172 14.5 Total yield (kg) of maize obtained from proka and slash-and-burn fields . 175 15.1 Four indigenous tree species and their socio-economic importance in the north-eastern savanna zone of Ghana . 179 15.2 Nitrogen, phosphorus, and potassium contents of the leaves of the four indigenous trees . 181 15.3 Mean values Ϯ 90 per cent confidence interval of soil chemical properties under four indigenous trees canopies and in the open grassland on luvisol in the north-east savanna zone of Ghana .