The soils of sub-Saharan Africa are deficient in many nutrients, but lack of N is the most serious constraint to higher productivity from these soils. Fertilizer N is expensive and its availability sporadic; these two factors might have contributed to its limited use in the subregion.
Research over the past few decades has revealed the enormous potential of forage legumes for increasing both crop and livestock production. In cropping systems forage legumes are a cheap source of N whose presence in the soils boosts crop yields, and because of their high content of protein, they can be used to supplement animal diets.
The main objectives of the workshop were:
· To bring together scientists from sub-Saharan Africa and other parts of the world to share information on forage legumes.· To identify production limitations specific to sub-Saharan Africa and its various production systems: and
· To recommend areas of further work where intensified research is justified in terms of scientific and practical benefits.
More than 60 scientists and development agents representing 18 countries participated in the discussions, sharing experiences and making useful suggestions. The countries represented were Austria, Australia, Congo, England, Ethiopia, Gambia, Italy, Kenya, Malawi, Nigeria, Sierra Leone, Sudan, Swaziland, Syria, Tanzania, Zaire, Zambia and Zimbabwe.
We wish to acknowledge the efforts of the authors and co-authors of papers in compiling the relevant information. We are also gratful to session chairmen John Totlill, R.X. Jones, S.R.A. Danso, A.T. Ayoub and Philip Cocks. They and other members of working groups were helpful in synthesising the discussions and developing the recommendations of the workshop.
We are grateful to Dr P. Brumby, Director General of ILCA, and Dr Frank Anderson, Team Leader, Highlands Programme, whose continued support and help made the workshop and this publication possible. Staff of ILCA's Highlands Programme, the Soils and Plant Nutrition and Forage Agronomy Sections, ILCA's Training Division, Outreach Department, the Publications and Audio-Visual and Mapping Sections and last but not the least those working in the Cafeteria and Hostels, all contributed substantially to the success of the workshop and the publication of this volume.
I. Haque
S. Jutzi
P.J.H. Neate
Addis Ababa, August 1986.
Nutrient and water constraints to forage legume growth
