Mary Tiffen, Michael Mortimore and Francis Gichuki , Environmental Recovery in Kenya MORE PEOPLE, LESS EROSION Overseas Development Institute MORE PEOPLE, LESS EROSION Environmental Recovery in Kenya MARYTIFFEN MICHAEL MORTIMORE Overseas Development Institute, London, UK and FRANCIS GICHUKI Department of Agricultural Engineering, University of Nairobi, Kenya Kenyan Edition )(T.)PRESS AFRICAN CENTRE FOR TECHNOLOGY STUDIES Nairobi, Kenya edi ACTS Press in association with the Overseas Development Institute, London 1994 Copyright © Overseas Development Institute London, 1994 This edition is for distribution in Kenya only and is published by ACTS Press in association withthe Overseas Develppment Institute. This book was first published in the UK by John Wiley & Sons Ltd. Chichester. All rights reserved. No part ofthis book may be reproduced by any means, or transmitted, or translated into a machine language without the written permission of the publishers. Kenyan Edition published by ACTS Press, 1994 P.O. Box 45917 Nairobi, Kenya Library ofCongress Cataloguing-in-Publication Data Tiffen, Mary More people, less erosion: environmental recovery in Kenya I Mary Tiffen, Michael Mortimore, and Francis Gichuki p. cm. Includes bibliographical references and index. ISBN 9966-41-082-1 1. Soil conservation - Kenya - Machakos (District) 2. Water conservation - Kenya -Machakos (District). 3. Land use, Rural- Kenya - Machakos (District) - Management 4. Arid regions - Kenya -Machakos (District) - Management I. Mortimore, M. J., 1937- 11. Gichuki, Francis. III. Title. S625.K4T54 1994 333.76'16'096762 - dc20 93-2192. CIP ISBN 996641-082-1 Typeset in 1O/12pt Times from authors' disks by MHL Typesetting Ltd, Coventry Printed and bound in' Nairobi by English Press Contents Acronyms and Currencies vii Foreword ix Acknowledgements xi PART I INTRODUCTION 1 Machakos Then and Now 3 2 The District and the Study 13 PART II PROFILES OF CHANGE 3 Rainfall 33 4 Population 44 5 Land Use and Tenure 64 6 Crop and Livestock Production 77 7 Soils 98 8 Vegetation 119 PART HI MANAGEMENT AND MANAGERS 9 Akamba Social Institutions 131 10 Household Farming and Income Systems 155 11 Soil Conservation 178 12 Water Conservation 204 13 Tree Management 213 14 Technological Change 226 vi Contents PART IV WHAT WORKED AND WHY 15 Interventions and Policies 249 16 Population Growth and Environmental Degradation: Revising the Theoretical Framework 261 17 Replicability, Sustainability and Policy 275 References 286 Index 301 FRONTISPIECE. Soil and water conservation activities in Machakos District (based on a drawing by Alex Odour). I, Weather road; 2, protection of denuded land; 3, windbreak and live fence; 4, ridge and furrow tillage; 5, sisal hedgerow; 6, gully checkdams; 7, intercropping; 8, agroforestry; 9, woodlot; 10, paddocking; 11, improved pasture; 12, forward sloping benches; 13, cut-off drain; 14, pasture establishment; 15, excavated level bench terraces; 16, gazetted forest; 17, earth dam; 18, roof water catchment; 19, river bank protection; 20, stall feeding; 21, coffee plantation; 22, crop residue management; 23, waterway; 24, soil profile; 25, river or stream; 26, gully erosion Foreword A collaborative research effort between the University of Nairobi and the Overseas Development Institute (ODI) produced an in-depth series of studies on land management in eastern Kenya which appeared as working papers of the ODI in 1990-1992. These proved so useful that they were compiled into a book co-authored by Mary Tiffen, Michael Mortimer and Francis Gichuki. More People. Less Erosion: Environmental Recovery in Kenya was published by John Wiley & Sons in the United Kingdom in 1993. The study contributes substantial data, historical analysis and provocative arguments regarding possible causes and solutions to land degradation. The study doubtless will form the basis fOl: much research and policy debate in the future. It is in the interest of making this information available in Kenya and at a reasonable retail price that The Roekefeller Foundation agreed to fund the Kenyan edition by the African Centre for Technology Studies (ACTS). Lack of access to recent research limits the debate, the intellectual challenge and consensus-building necessary for developing sound development strategies. ACTS and ACTS Press have sought to redress this problem through an active publishing programme over the past six years and through the recently established Consortium for African Scholarly Publishing. It is the objective of this Kenyan edition of More People. Less Erosion to make current research accessible to researchers and participants in Kenya. The challenges facing sustainable development in Africa are usually framed around the triad ofrapid population growth, the intensification ofagricultural production and maintenance of the natural resource base, especially soil, water, forests, rangeland and genetic resources. The literature on these processes at a continental level paints a picture ofunprecedented rates of population growth, the inability of food production to keep pace with demand and a resultant clearing offorests, overgrazing ofrangelands, erosion and nutrient depletion of soils and destabilization of hydrological systems. However, only at a local level can these processes and the relationships between them be explored, and only then can conclusions be drawn about the inevitability of environmental degradation and the social, economic, technological and policy factors that could lead to investment in, rather than degradation of, these resources. The case study of Machakos in this volume represents such a beginning. The study demonstrates just how dynamic agricultural change can be in Africa, the importance of a relatively long time-frame in exploring this nexus ofissues and the difficulty in assembling a consistent set of longitudinal data and studies that allows firm conclusions to be drawn. The authors draw a very positive picture of the adaptive response ofsmallholder farmers to changes in land availability, agricultural output and labour markets, technological options and x Foreword institutional innovations and their ability to invest in the agricultural resource base. Whether Machakos is on a sustainable growth path and how representative Machakos is of agricultural intensification processes in the rest of Africa, or even Kenya, is in this reviewer's opinion still open to question. Nevertheless, it is only with more studies like this that a more informed debate on agricultural intensification in Africa can take place. This Kenyan edition has benefited from the willing co-operation of the co-publishers, John Wiley & Sons, and the om. Dr Francis Gichuki, of the University of Nairobi, assisted in making the initial arrangements for the Kenyan side ofthis collaboration. This research work benefited enormously from the efforts of the team ofKenyan collabora­ tors from the University of Nairobi and of the farmers and others from Machakos who assisted in the initial field work and subsequent workshop. It is hoped that this Kenyan edition will inspire more local researchers to produce more such studies. Nairobi, August 1994 Dr John K. Lynam The Rockefeller Foundadon Acknowledgements This study was initiated in 1990 as an element in the World Bank's Dryland Management Research Programme. Funding was provided by the Bank's Environment Department (drawing on a grant from the Government ofNorway for research into the problems ofdryland areas in the Sudano­ Sahelian Region), the British Government's Overseas Development Administration and the Rockefeller Foundation (for the University of Nairobi component). It was sponsored in Kenya by the Ministry of Reclamation and Development of Arid, Semi-Arid Areas and Wastelands (MRDASW). The aim ofthe first phase ofthe study was to quantify change in Machakos District, Kenya, where there was a good database, as accurately as possible, in a series of profiles which would give a sound foundation for developing policy lessons. This was carried out through collaboration between researchers at the Overseas Development Institute (ODI) and a team of scientists at the University ofNairobi. The project was led at OD! by Mary Tiffen, in association with Michael Mortimore, who took particular charge ofcoordinating the environmental studies. Kate Wellard (OD!) assisted the initial study of technology change. The University of Nairobi team were (in the order in which their contributions appear): • Rainfall: Dr S. K. Mutiso, Department of Geography. • Land use: Professor R. S. Rostom, Professor in the Department of Surveying and Photogrammetry. He was assisted by J. K. Yego and G. C. Mulaku. The photo-interpretation and photogrammetric and cartographic work was undertaken by the staffofthe Department, assisted by Mr J. o. Ojuok (Ministry of Water Resources, Machakos District). • Agricultural production: ProfessorA. C. Ackello-Ogutu and Dr S. G; Mbogoh, Department of Agricultural Economics. • Soil fertility: Dr J. P. Mbuvi, Department of Soil Science. • Soil erosion: Professor D. B. Thomas, Department of Agricultural Engineering. We owe him·particular thanks for sharing his experience of the District since the 1950s, and for his substantial contributions to the photographic record. • Vegetation: Dr Kassim O. Farah, Department of Range Management. • Institutions and land tenure: Professor Judith Mbula Bahemuka, Department of Sociology, Mr J. W. Kaluli, Department ofAgricultural Engineering, Jomo Kenyatta University College Of Agriculture and Technology, researched