Drip irrigation - World Agroforestry Centre

72 Pages·2004·0.9 MB·English

TECHNICAL HANDBOOK No. 24
DRIP IRRIGATION
Options for smallholder
farmers in eastern and
southern Africa
Isaya V. Sijali
Published by Sida(cid:146)s Regional Land Management Unit, 2001
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Drip irrigation
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Technical Handbook 24
The Technical Handbook Series of the Regional Land Management Unit
1. Curriculum for In-service Training in Agroforestry and Related Subjects in Kenya. Edited by Stachys N. Muturi, 1992
(ISBN 9966-896-03-1)
2. Agroforestry Manual for Fxtension Workers with Emphasis on Small-Scale Farmers in Fasterrn Province, Zambia. By
Samuel Simute, 1992. (ISBN 9966-896-07-4)
3. Guidelines on Agroforestry Extension Planning in Kenya. By Bo Tengn(cid:228)s, 1993 (ISBN 9966-896-11-2)
4. Agroforestry Manual for Extension Workers in Southern Province, Zambia. By Jericho Mulofwa with Samuel Simute
and Bo Tengn(cid:228)s, 1994 (ISBN 9966-896-14-7)
5. Useful Trees and Shrubs for Ethiopia: Identification, Propagation and Management for Agricultural and Pastoral Communities.
By Azene Bekele-Tessema with Anne Birnie and Bo Tengn(cid:228)s, 1993 (ISBN 9966-896-15-5)
6. Useful Trees and Shrubs for Tanzania: Identification, Propagation and Management for Agricultural and Pastoral Communities.
By L.P. Mbuya, H.P. Msanga, C.K. Rufo, Ann Birnie and Bo Tengn(cid:228)s, 1994 (ISBN 9966-896-16-3)
7. Soil Conservation in Arusha Region, Tanzania: Manual for Extension Workers with Emphasis on Small-Scale Farmers. By
Per Assmo with Arne Eriksson, 1994 (ISBN 9966-896-19-8)
8. Curriculum for Training in Soil and Water Conservation in Kenya. Edited by Stachys N. Muturi and Fabian S. Muya,
1994. (ISBN 9966-896-20-1)
9. The Soils of Ethiopia: Annotated Bibliography. By Berhanu Debele, 1994 (ISBN 9966-896-21-X)
10. Useful Trees and Shrubs for Uganda: Identification, Propagation and Management for Agricultural and Pastoral Communities.
By A.B. Katende, Ann Birnie and Bo Tengn(cid:228)s, 1995 (ISBN 9966-896-22-8)
11. Agroforestry Extension Manual for Northern Zambia. By Henry Chilufya and Bo Tengn(cid:228)s, 1996 (ISBN 9966-896-
23-6)
12. Useful Trees and Shrubs in Eritrea: Identification, Propagation and Management for Agricultural and Pastoral Communities. By
E. Bein, B. Habte, A. Jaber, Ann Birnie and Bo Tengn(cid:228)s, 1996 (ISBN 9966-896-24-4)
13. Facilitators(cid:146) Manual for Communication Skills Workshop. By Pamela Baxter, 1996 (ISBN 9966-896-25-2)
14. Agroforestry Manual for Extension Workers in Central and Lusaka Provinces, Zambia. By Joseph Banda, Penias Banda
and Bo Tengn(cid:228)s, 1997 (ISBN 9966-896-31-7)
15. Integrated Soil Fertility Management on Small-Scale Farms in Eastern Province of Zambia. Edited by Thomas Raussen,
1997 (ISBN 9966-896-32-5)
16. Water Harvesting: An Illustrative Manual for Development of Microcatchment Techniques for Crop Production in Dry Areas.
By M.T Hai, 1998 (ISBN 9966-896-33-3)
17. Agroforestry Extension Manual for Eastern Zambia. By Samuel Simute, C.L. Phiri and Bo Tengn(cid:228)s, 1998 (ISBN
9966-896-36-8)
18. Banana Production in Uganda: An Essential Food and Cash Crop. By Aloysius Karugaba with Gathiru Kimaru,
1999 (ISBN 9966-896-39-2)
19. Wild Food and Mushrooms of Uganda. By Anthony B. Katende, Paul Ssegawa, Ann Birnie with Christine
Holding and Bo Tengn(cid:228)s, 1999 (ISBN 9966-896-39-2)
20. Uganda Land Resources Manual: A Guide for Extension Workers. By Charles Rusoke, Antony Nyakuni, Sandra
Mwebaze, John Okorio, Frank Akena and Gathiru Kimaru, 2000 (ISBN 9966-896-44-9)
21. Agroforestry Handbook for the Banana-Coffee Zone of Uganda: Farmers(cid:146) Practices and Experiences. By I. Oluka-Akileng,
J. Francis Esegu, Alice A. Kaudia and Alex Lwakuba, 2000 (ISBN 9966-896-51-1)
22. Rainwater Harvesting for Natural Resource Management: A planning guide for Tanzania. Edited by Nuhu Hatibu,
Henry F. Mahoo; Contributors John W. Gowing, Geophrey J. Kajiru, Evelyn A. Lazaro, Omari B. Mzirai,
Johan Rockstr(cid:246)m, Filbert B. Rwehumbiza, Ephraim M. Senkondo, 2000 (ISBN 9966-896-52-X)
23. Water from Sand Rivers: A Manual on Site Survey, Design, Construction and Maintenance of Seven Types of Water Structures
in Riverbeds. By Erik Nissen-Petersen, 2000 (ISBN 9966-896-53-8)
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DRIP IRRIGATION
Options for smallholder farmers in
eastern and southern Africa
Isaya V. Sijali
Regional Land Management Unit (RELMA)
2001
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Published by:
Regional Land Management Unit, RELMA/Sida
ICRAF House, Gigiri
P.O. Box 63403, Nairobi, Kenya
' 2001 Regional Land Management Unit (RELMA), Swedish International
Development Cooperation Agency (Sida)
Cover photographs
Top: A drum system showing the beds and young plants (photo: I.V. Sijali)
Middle: Close-up of a drip lateral next to a sweet-pepper plant (photo: Tom Mwangi)
Bottom: A drip lateral in an orchard (photo: I.V. Sijali)
Illustrations
Logitech Ltd., P.O. Box 79177, Nairobi
Cataloguing-in-publication data
Sijali I V. Drip irrigation: options for smallholder farmers in eastern and southern Africa.
2001. RELMA Technical Handbook Series 24. Nairobi, Kenya: Regional Land Man-
agement Unit (RELMA), Swedish International Development Cooperation Agency
(Sida). 60 p. + x p.; includes bibliography
ISBN 9966-896-77-5
The contents of this manual may be reproduced without special permission. However,
acknowledgement of the source is requested. Views expressed in the RELMA series of
publications are those of the authors and do not necessarily reflect the views of RELMA/
Sida.
Printed by The Regal Press Kenya Limited, Bunyala Road, P.O. Box 46166, Nairobi
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Contents
Foreword................................................................................... vii
Acknowledgments...................................................................... viii
Preface....................................................................................... ix
Acronyms .................................................................................... x
Chapter 1
Introduction...............................................................................11
1.1 Irrigation potential in sub-Saharan Africa......................................................11
1.2 Major methods of irrigation............................................................................11
Chapter 2
The soil(cid:150)water plant relationship .................................................16
2.1 Introduction.....................................................................................................16
2.2 Environmental conditions ...............................................................................16
2.3 Relating crop water use to meteorological data.............................................19
Chapter 3
Drip irrigation............................................................................24
3.1 Historical perspective ......................................................................24
3.2 Principles of the drip irrigation method .....................................26
3.3 Advantages of drip irrigation ..........................................................................26
3.4 Disadvantages associated with drip irrigation.................................................28
3.5 Components of a drip irrigation system.........................................................29
3.6 Simplified drip systems...................................................................................34
Chapter 4
Smallholder drip irrigation systems ..............................................36
4.1 Introduction......................................................................................................36
4.2 General features and management aspects.....................................................37
4.3 Bucket systems..................................................................................................39
4.4 Drum systems ...................................................................................................44
4.5 Farm kits ...........................................................................................................51
4.6 Low-cost drip systems under development ....................................................57
Glossary ....................................................................................59
Bibliography...............................................................................60
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ANNEXES ..................................................................................63
Annex 1 Climatic, soil and water requirements for selected crops......................64
Annex 2 The pan evaporation method for estimating ET0.................................66
Annex 3 The Blaney-Criddle temperature method for estimating ET0 .............67
Annex 4 Length of stages of development for selected crops (days) ..................68
Annex 5 Drip irrigation system suppliers and useful addresses...........................69
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Foreword
Smallholder farmers in the semi-arid regions of east and central Africa depend on
erratic, unreliable and low rainfall for their livelihoods. Staple food crops are generally
grown under rain-fed conditions and normally not marketed for cash.
There is a growing interest in complementing this risky rain-fed staple-food produc-
tion with cultivation of high-value vegetable crops and fruits that can improve nutrition
and also be a source of cash income. In most cases, such small-scale vegetable gardens
and fruit orchards must be irrigated in order to assure a minimum return on investment.
Water sources vary, but can be shallow wells, boreholes or seasonal streams. These
sources usually supply adequate amounts of water for domestic needs, but once irriga-
tion is initiated the risk of water deficit becomes very high due to the great crop-water
requirements. This means that increasing the efficiency of water use in irrigation is of
the utmost importance for maximizing the return from vegetable and fruit production.
Water collected from surface run-off and stored in low-cost tanks(cid:151)often underground(cid:151)
is ideal for efficient micro-irrigation.
The potential area that could be used for irrigation in sub-Saharan Africa is calcu-
lated to be some 40 million hectares, of which only15% is actually irrigated.
The easiest way of saving water is to minimize non-productive water losses such as
those from evaporation from the soil, runoff and use by weeds. Drip irrigation is one
way of doing this. There is growing interest in the technique and rapid expansion in its
use, but until recently drip irrigation technology has been associated with large invest-
ments available only to large commercial farms. This is now changing, and many efforts
are being made around the world to develop low-cost, simple, drip irrigation systems
for smallholder farmers.
There was little readily available information on these systems and a request made
to RELMA by agricultural extension workers led to the development of this manual. It
describes some of the small-scale drip irrigation methods of which the author and the
other contributors have practical experience. It also gives a brief overview of methods
that have been used successfully in other parts of the world with details of how to
obtain further information or order equipment.
The production of the manual was a joint effort by the author and the other con-
tributors, the Kenya Agricultural Research Institute (KARI) and RELMA. Dr Johan
Rockstr(cid:246)m, former Water and Soil Fertility Advisor with RELMA, was instrumental in
initiating the project and successfully guiding the book during the first stages of produc-
tion.
¯ke Barklund
Director, RELMA
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A c -
k n o w l -
e d g -
m e n t s
I am grateful to the Director of KARI for allowing me to undertake this project and for
his role in promoting smallholder drip irrigation technology in Kenya. I am also grate-
ful to the following contributors: Dr Gerrie Albertse of Waggon Wheel; Professor R.K.
Sivanappan for sharing his experiences and for providing information on interesting work
by IDE and Water Technology Centre; Mr Charles Johnston of ATIF (K) Ltd. for pro-
viding information on the Hydrogol system; Mr Richard Chapin for contributions on
the history of development of these irrigation technologies and salinity; Mr Ndigah
Bundi of Amiran Kenya for his contribution on Netafim(cid:146)s Family drip irrigation system;
and Mr Allan Kamuti for sharing information on the IIS kit.
I also thank the following for their support: Mr Arnie Schlissel, Mr Noah Lusaka,
Mr Bob Wagner, Dr Hubert Blank and Ms Jane Ndinya.
Dr Francis Gichuki reviewed a draft of the book and made many useful comments
which have been incorporated in the final version. Finally, the book has also benefited
from the experience of individuals with whom I have come in contact by virtue of my
involvement in the KARI Small-Scale Drip Irrigation Project. I thank them all.
I also acknowledge the support of the Regional Land Management Unit (RELMA)
whose fellowship allowed me time to develop the handbook. My thanks to Dr Johan
Rockstr(cid:246)m, who acted as technical adviser, and other RELMA staff who supported me
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i n
m a n y
w a y s .
Isaya V. Sijali
Irrigation and Soil Physics Specialist
Kenya Agricultural Research Institute (KARI)
P r e f -
a c e
This technical handbook presents drip irrigation options for extension officers in east-
ern and southern Africa. It describes the most interesting low-cost drip irrigation meth-
ods being used today. It has been prepared to support field extension workers by giving
examples of small-scale drip irrigation systems in use in sub-Saharan Africa as well as
elsewhere in arid areas of the world.
Chapter 1 is a general review of the potential for irrigation in Africa and methods
that can be used. Chapter 2 describes in more detail the environmental factors govern-
ing crop production and crop water requirements. Chapter 3 describes the concept of
drip irrigation. Chapter 4 presents irrigation methods suitable for use by smallholder
farmers.
Many of the methods described are relatively inexpensive, and some have been
further adapted by farmers in the field in order to make them even less costly, e.g. by
making simple home-made dripper lines or by using simple filters in place of expen-
sive filtering systems.
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