This publication is an attempt to distil current information on irrigation methods that might be appropriate, and to offer some ideas on the possible adoption and adaptation of such methods by small-scale farmers in the semi-arid areas of sub-Saharan Africa. At issue is a vast region greatly in need of enhanced and more stable agricultural production. Yet the irrigated sector here has, to date, suffered from underdevelopment. Numerous efforts to develop the sector have foundered in the past, possibly because the approach has been inappropriate to the physical and socio-economic conditions prevailing in the region.
There can be no single panacea to the problem of ensuring food security
in Africa, nor to the task of developing irrigation there. The continent is too varied for
any single approach to apply in all cases. A multiplicity of possibilities exists, and the
most appropriate ones depend in each case on local agronomic, economic and social
conditions. In some cases, large-scale systems, centrally controlled (by commercial or
government enterprises) may be the quickest way to increase production. Concurrently,
however, the development of irrigation should take place on small-scale farms operated by
individual farmers or by associations of farmers. It is to promote the latter form of
development that this publication is primarily directed.
A positive and realistic approach, in awareness of the real problems but undeterred by them, is called for. The aim of this publication is to present practical options that are consistent with such a new approach. An effort is made to do so in simplified but not simplistic terms, in a manner that may be useful to a wide spectrum of potential readers, from policy-makers to extension workers in the field, and that is consistent with FAO's Special Programme for Food Security in Africa.
As the reader will quickly notice, this presentation is not a purely technical how to handbook. It is, rather, a what and why elucidation of the conceptual foundations of modern irrigation that should underlie decision-making in the area of irrigation development. Whereas ready-made prescriptions tend to be specific and inflexible, and hence rarely apply as new problems arise in changing circumstances, a basic understanding of principles should enable practitioners to adjust their thinking and actions to unforeseen situations. The ultimate purpose is therefore to foster an informed awareness of both the potentialities and the limitations of modern irrigation methods, and thus to guide the selection and adaptation of appropriate technologies for greater sustainable production and better resource utilization.
In taking this approach I have avoided dealing with traditional surface irrigation methods (including border, basin and furrow methods) that have been described repeatedly in the past and are generally well known in the region. Such methods have long served for the irrigation of crops such as rice, sugar cane and cotton. Rather, attention is concentrated on the development of irrigation for such food crops as fruit, grain, legume and vegetable crops (including root crops) that can be grown in water-scarce semi-arid or arid areas. It is in such areas of sub-Saharan Africa that small-scale, low-volume, low-cost, partial-area, high-frequency irrigation methods appear to offer considerable possibilities that are yet to be realized.
As author of this report, I wish to express my gratitude, first of
all, to Dr Jacques Diouf, Director-General of the Food and Agriculture Organization of the
United Nations, whose personal interest and determination to make the work of FAO more
relevant to the field have inspired this project.
I also acknowledge the valuable advice and encouragement of Messrs Wim Sombroek, formerly Director of the Land and Water Development Division, Robert Brinkman, present Director, and Hans Wolter, Chief of the Water Resources Development and Management Service within that Division. Other members of the Division - especially Messrs Lucien Vermeiren, Arum Kandiah and Bo Appelgren - offered information and advice as well. The drawings were made with the able and willing assistance of Mr Han Kamphuis, who deserves special thanks. So does Dr Cynthia Rosenzweig, who gave much of her time to help in shaping this publication.
Finally, I acknowledge with deep appre-ciation the support granted me by the Rockefeller Foundation of New York.