Handbook for Integrated Soil Fertility Management

164 Pages·2015·9.45 MB·English

Manuel dek G fesrt iIon Intégrée
Handboo o ntegrated
de la Fertilité des Sols
l F y M
Soi ertilit anagement
Edited by Thomas Fairhurst
Edité par Thomas Fairhurst
Africa Soil Health Consortium: Handbook for Integrated Soil Fertility Management
André Bationo (AGRA), Thomas Fairhurst (TCCL), Ken Giller (WUR), Valerie Kelly (MSU), Rodney Lunduka (CABI),
Abdoulaye Mando (IFDC), Paul Mapfumo (SOFECSA), George Oduor (CABI), Dannie Romney (CABI), Bernard
Vanlauwe (IITA), Lydia Wairegi (CABI), Shamie Zingore (IPNI).
Edited by Thomas Fairhurst
© CAB International 2012
Please cite this publication as: Fairhurst, T. (ed.) (2012) Handbook for Integrated Soil Fertility Management. Africa
Soil Health Consortium, Nairobi.
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Limits of liability
Although the authors have used their best efforts to ensure that the contents of this book are correct at the time of
printing, it is impossible to cover all situations. The information is distributed on an ‘as is’ basis, without warranty.
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About the publisher
The Africa Soil Health Consortium (ASHC) mission is to improve the livelihoods of smallholder farmers through
adoption of integrated soil fertility management (ISFM) approaches that optimize fertilizer use effi ciency and
effectiveness.
ASHC books are available at special discounts for bulk purchases. Special editions, foreign language translations
and excerpts can also be arranged.
ISBN (e-book): 978 1 78064 285 7
ISBN (paperback): 978 1 78064 291 8
Typeset by Thomas Fairhurst, with SPi, Pondicherry, India.
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able of Contents
T
d
Forewor vii
Acknowledgements
ix
1 Introduction
1
1.1 Introduction 2
1.2 What is integrated soil fertility management (ISFM)? 2
1.3 How the handbook came about 2
1.4 Who are these materials designed for? 3
1.5 Contributors 4
2 The need for ISFM
5
2.1 Introduction 6
2.2 The context 6
2.3 Farming systems development in sub-Saharan Africa (SSA) 7
2.4 Targeting technologies – from ‘silver bullets’ to ‘best fi ts’ 7
2.5 Conclusions 9
2.6 Reading list 9
3 Principles of ISFM
12
3.1 Introduction 13
3.2 History of approaches to soil fertility management in SSA 13
3.2.1 Focus on mineral fertilizer use 14
3.2.2 The use of low-input methods for soil fertility improvement 15
3.2.3 Towards the integration of fertilizer and organic resource use 16
3.3 Defi nition of ISFM 16
3.3.1 Use of mineral fertilizers 19
3.3.2 Use of organic inputs 19
3.3.3 Use of improved germplasm 19
3.3.4 Effect of combining the use of fertilizer, organic inputs and germplasm 20
3.3.5 Importance of local adaptation 21
3.3.6 Optimizing agronomic effi ciency 22
3.3.7 Sound agronomic principles 23
3.3.8 Sound economic principles 24
3.4 Conclusions 25
3.5 Reading list 25
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4 Soil fertility management practices
30
4.1 Introduction 31
4.2 Use of organic inputs 31
4.2.1 Organics as sources of nutrients 31
4.2.2 The role of SOM in soil fertility 33
4.2.3 Advantages and disadvantages of organic inputs as fertilizers 33
4.3 Use of mineral fertilizers 34
4.3.1 Fertilizer materials 34
4.3.2 Soil amendments 38
4.4 Fertilizer use effi ciency 38
4.5 The ‘4Rs’ for effective fertilizer use 41
4.5.1 Right fertilizer product 41
4.5.2 Right fertilizer rate 41
4.5.3 Right time for fertilizer application 43
4.5.4 Right placement of basal fertilizer 43
4.5.5 A fi fth ‘right’ for fertilizer use in SSA – targeting the most remunerative options 44
4.6 Fertilizer use and the environment 44
4.6.1 Fertilizer use and sustainability 45
4.7 Minimizing losses of added nutrients 45
4.7.1 Water and wind erosion 45
4.7.2 Leaching 46
4.7.3 Gaseous losses through denitrifi cation and volatilization 46
4.7.4 Crop residue management 46
4.8 Use of improved germplasm 47
4.8.1 Genetic yield potential 47
4.8.2 Pest and disease resistance 47
4.8.3 Nutrient use effi ciency 48
4.8.4 Availability and quality of planting materials 48
4.8.5 Finding and selecting improved germplasm for use in ISFM 48
4.9 Harnessing the benefi ts of N -fi xing legumes 48
2
4.9.1 The components of a successful N -fi xing symbiosis 49
2
4.9.2 The need for inoculation with rhizobia 50
4.9.3 Legume contributions to soil fertility 50
4.10 Use of arbuscular mycorrhizal fungi (AMF) inoculants 51
4.11 Other soil fertility management practices 52
4.11.1 Conservation agriculture (CA): a silver bullet? 53
4.12 Organic agriculture 54
4.13 Adaptiveness of interventions 54
4.14 Economics 55
4.15 Conclusions 57
4.16 Reading list 57
5 Targeting ISFM options
69
5.1 Introduction 70
5.2 Farming systems analysis (FSA) 70
5.2.1 History of past activities 73
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5.2.2 Collection of biophysical data 74
5.2.3 Identifi cation of dominant farming systems in each domain 74
5.2.4 Clustering farmers in groups 74
5.2.5 Land:labour ratio 75
5.2.6 Assessment of risk 75
5.3 Cropping systems analysis 75
5.3.1 Field inspection 75
5.3.2 Estimation of yield gaps 76
5.3.3 Frequency and timing of visits 76
5.3.4 Farm record keeping 77
5.3.5 Use of a cropping calendar 77
5.3.6 Use of participatory budgeting 77
5.4 Soil fertility assessment 77
5.4.1 Flows of resources between and within farms 79
5.4.2 Defi ciency symptoms 80
5.4.3 Indicator plants 80
5.4.4 Soil sampling 80
5.5 Markets and socio-economic drivers 81
5.5.1 Policy environment and the role of governments 82
5.5.2 Markets 83
5.6 Market development 87
5.7 Ex ante analysis of ISFM technology performance 87
5.7.1 Agronomic effi ciency (AE) 89
5.7.2 Economic incentives 89
5.7.3 Market performance 90
5.7.4 Data required for ex ante analysis 90
5.8 On-farm testing of ISFM technologies 93
5.9 Ex post analysis of ISFM technology performance 93
5.10 Scaling up and scaling out adoption of ISFM solutions 93
5.10.1 Development of a communication strategy 94
5.11 Development of extension materials 94
5.11.1 Communicating directly with farmers 95
5.11.2 Extension service providers 95
5.11.3 Types of media 95
5.12 Use of information and communication technologies (ICT) 96
5.12.1 Mobile phones 96
5.12.2 Computers for Internet access 97
5.12.3 Video 98
5.12.4 Data storage 98
5.13 Conclusions 99
5.14 Reading list 99
6 Soil and crop production – an introduction
108
6.1 Introduction 109
6.2 Soil function and quality including quality indicators 109
6.2.1 Basic soil functions 109
6.2.2 Soil fertility 110
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6.3 Soil as a source of water and nutrients for crop production 110
6.3.1 Mineral fraction 111
6.3.2 Organic fraction 112
6.4 Function of nutrients in plant production 114
6.4.1 Macronutrients 114
6.4.2 Micronutrients 116
6.5 Defi nition of soil fertility 117
6.6 Measurement of soil fertility 117
6.7 Conclusions 118
6.8 Reading list 118
7 Tables and r ence information
efer 120
7.1 Introduction 121
7.2 Soil sampling 121
7.3 How to determine soil bulk density 122
7.4 How to determine soil texture in the fi eld 122
7.5 Farming systems analysis 124
7.6 Soil fertility management 127
7.7 Crop nutrition 131
7.8 Fertilizer use 136
7.9 Crop agronomy 141
7.10 Farm economics 141
7.11 General 142
7.12 Reading list 142
Glossary
144
onyms and abbreviations
Acr 149
Index
151
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Foreword
The continent of Africa continues to grapple with many episodes of hunger and low crop productivity in multiple
locations. With the ever-growing population in the continent, farmers continue to grow crops on the same land
year after year. Under such continuous use, soil fertility declines if nutrients removed in crop products are not
returned to the soil. To deal with this problem mineral fertilizers are essential. But as fertilizers are more expensive
in Africa than anywhere else, most farmers use none at all. In response, many countries have subsidized fertilizers,
yet often ignore supportive agricultural practices, institutions and policies. Increasing the productivity of smallholder
farmers requires a good understanding of yield gaps (i.e. differences between actual, obtainable and potential yield
under prevailing economic conditions) as well as biophysical and socio-economic factors constraints that hinder
the closing of exploitable gaps.
Integrated soil fertility management, commonly referred to as ISFM, is presented in this handbook as a key
contributor to Africa’s low soil and crop productivity and especially for the main staples in the continent that
include maize, beans, rice, cassava, bananas, sorghum, millet and other crops. In this context ISFM is defi ned as
a set of soil fertility management practices that include the integrated use of mineral fertilizers, organic inputs and
improved germplasms combined with the knowledge on how to adapt these practices to local conditions which are
aimed at optimizing effi cient agronomic use of the applied nutrients and thereby improving crop productivity. In this
defi nition, all inputs need to be managed following sound agronomic and economic principles. ISFM cannot work if
not supported by governments that are responsible for fertilizer imports, an enabled extension service that is critical
to delivering the technology to the farmers, as well as a vibrant agro-dealer private sector that ensures effi cient
fertilizer and seed availability and distribution.
Over the past 10 years, many publicly funded research initiatives have been conducted on ISFM across sub-
Saharan Africa (SSA). Work on ISFM has mainly been written in technical reports and scientifi c papers published
in peer-reviewed journals. The idea for a practical ISFM handbook emerged from a needs assessment and
consultations undertaken in preparation for a grant application to the Bill & Melinda Gates Foundation by CABI.
The concept of an Africa Soil Health Consortium (ASHC) was proposed earlier by a group of ISFM experts in
a consultation meeting held at Wageningen, The Netherlands, in 2010. These experts form the nucleus of the
Consortium’s technical advisory group (TAG), which provides both advice and technical capacity to support the
creation of ISFM information materials such as this handbook. The handbook synthesizes the learning that has
accumulated on ISFM in a publication that can be used to train practitioners.
The funding to produce this handbook and other learning materials under the ASHC has been provided by the Bill
& Melinda Gates Foundation, which commits the Consortium, coordinated by CABI, to work in collaboration with
experts to develop core reference materials on ISFM principles (referred to as Level 1 products) in English, French
and Portuguese versions. This is what has culminated in the production of this handbook. The fi rst consultative
meeting on the book was held in May 2011 during the launch of the project in Nairobi, Kenya.
The majority of work to develop this handbook was undertaken at a write-shop held in Nairobi in October 2011 with the
key authors working with Thomas Fairhurst, ASHC’s technical editor. In November 2011, Paul Van Mele of Agro-Insight,
a private communication company, visited six countries in West, Central and East Africa to make a fi lm (with narration
in English, French and Portuguese) that refl ects the principles of ISFM outlined in the handbook illustrated by the
footage from the project’s priority cropping systems. The fi lm can be viewed online at http://www.cabi.org/ashc.
This book is meant for training of extension workers in soil fertility management techniques in SSA and for workers
involved in rural development that would like to learn more about the principles and practices of ISFM. This
handbook is also a useful primer on ISFM for education organizations such as universities and technical colleges,
organizations involved in the development of policy on agriculture and rural development that need reference
materials on ISFM techniques, and other government and non-government organizations (NGOs) seeking to
implement ISFM.
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The ISFM handbook is organized into seven sections that include: an introduction, the need for ISFM, the principles
of ISFM, soil fertility management practices, targeting ISFM options, an introduction to soil and crop production
and a section containing tables, defi nitions and reference information. The entire project team that includes the
TAG hopes that the reader fi nds this handbook a useful tool for tackling soil fertility and management on the
continent and elsewhere where similar factors of production are at play.
Signed:
Peter Okoth (CIAT) Shamie Zingore (IPNI) André Bationo (AGRA) Thomas Fairhurst (TCCL)
Ken Giller (WUR) Rebbie Harawa (AGRA) Jeroen Huising (CIAT) Bashir Jama (AGRA)
Richard Jones (IFDC) Valerie Kelly (MSU) Abdoulaye Mando (IFDC) Paul Mapfumo (SOFECSA)
Paul Van Mele (Agro-Insight) Kabirou Ndiaye (AfricaRice) George Oduor (CABI) Bell Okello (ICRW)
Bernard Vanlauwe (IITA)
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Acknowledgements
The preparation of this handbook was supported by the Bill & Melinda Gates Foundation.
The authors wish to thank Simon Ndonye for the wonderful illustrations, Leonard Rusinamhodzi for preparing the
glossary and Priscilla Sharland for proof reading the handbook. Thanks also go to the following organizations for
the time the authors spent writing the different sections of the handbook (in alphabetical order):
1. Alliance for a Green Revolution in Africa (AGRA)
2. CAB International (CABI)
3. International Center for Soil Improvement and Agricultural Development (IFDC)
4. International Institute of Tropical Agriculture (IITA)
5. International Plant Nutrition Institute (IPNI)
6. Michigan State University (MSU)
7. Soil Fertility Consortium for Southern Africa (SOFECSA)
8. Tropical Crop Consultants Ltd (TCCL)
9. Wageningen University (WUR)
Photographs used in this handbook were provided by André Bationo, Ken Giller, Bernard Vanlauwe,
Thomas Fairhurst, Paul Mapfumo, Shamie Zingore, Abdoulaye Mando, Pablo Tittonell, Paul Van Mele, Lieven
Claessens, Jeff Bentley, Dannie Romney, Lydia Wairegi and George Oduor.
Some of the figures used are based on published resources.
Tables 7.2–7.4, 7.6–7.33, 7.36, 7.38, 7.39, 7.41 and 7.42 have been reproduced from Soil Fertility Kit, with kind
permission from IPNI.
About CTA
The Technical Centre for Agricultural and Rural Cooperation (CTA) is a joint international institution of the African,
Caribbean and Pacific (ACP) Group of States and the European Union (EU). Its mission is to advance food and
nutritional security, increase prosperity and encourage sound natural resource management in ACP countries.
It provides access to information and knowledge, facilitates policy dialogue and strengthens the capacity of
agricultural and rural development institutions and communities.
CTA operates under the framework of the Cotonou Agreement and is funded by the EU.
For more information on CTA, visit www.cta.int
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