Dry forests in Sub-Saharan Africa (SSA) cover approximately 43% of the continent. They are inhabited by nearly 236 million people, many of these the poorest in the world. A majority of the population of these regions is dependent on traditional energy sources (i.e., firewood, charcoal and organic wastes), subsistence farming, generally free-ranging livestock, and products harvested from the dry forests. Growing pressure on dry forest resources to meet human and socioeconomic development needs mean that dry forests are increasingly being utilised unsustainably.

African farmers are poorly resourced, highly diverse and aground by poverty traps making them rather impervious to change. As a consequence R4D efforts usually result in benefits but also trade-offs that constraint adoption and change. A typical case is the use of crop residues as mulches or as feedstock. Here we linked a database of household surveys with a dynamic whole farm simulation model, to quantify the diversity of trade-offs from the alternative use of crop residues.

This volume presents major results obtained since the publication of volume 1 and 2 and updates national data on trypanotolerant cattle. The first part analyses populations and their trends between the two surveys and reviews research activities and development activities. It also gives recent information available on the potential and utilisation of trypanotolerant livestock. Part two presents recent data for the 18 study countries, as well as for Equatorial Guinea which was not covered in volume 2.

This audiotutorial unit (cassette, printed script, 76 color slides, study guide, self-evaluation test), prepared by the Communications Support Unit at CIAT, is available for use with a manually or automatically synchronized slide projector/cassette tape reccorder. Each unit is a vailabIe from the Distribution Office at a cost of US$ 50; photocopies of the study guide alone can be obtained from the Cassava Information Center. The objective of this unit is to present some of the results of research conducted by the physiology Section of CIATs Cassava Program.

Summarises past and present experiences with livestock performance testing in sub-Saharan Africa and outlines the role of networks in improving on-farm testing through the use of standardised testing methods and rapid data handling and feedback. Includes data on the distribution of cattle and sheep populations by ecological zone in sub-Saharan Africa. Presents current programmes for on-farm and on-station performance recording.

This paper provides the general objectives of the special issue: secondary forests in Asia: their diversity, importance and role in future environmental management. It provides a brief overview of the renewed attention to tropical secondary forests and sketches the history of research on this subject.

Information on trypanotolerant livestock in Senegal, the Gamia, Guinea Bissau, Guinea, Sierra Leone, Liberia, Mali, Upper Volta, Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroon, Central African Republic, Gabon, Congo and Zaire, particularly livestock numbers & distribution, information available on trypanotolerant cattle, sheep & goats, research and development activities, w. a selected bibliography.

The results of a survey conducted in 1983 among 416 farmers participating in the integrated rural development project (DRI, Colombia) in Atlantico (60), Bolivar (66), Cordoba (156), and Sucre (134), on land use and importance of cassava within the farming system, are presented. Except for Bolivar, where cassava and yam plantings decreased, increased land use attributable to increased credit availability was observed. In general, 1.7 ha cassava was planted per farm in 1982-83, mainly in association with yam, maize, and plantains; 55 percent of the land planted included cassava.

Presents and discusses research results on feed resources, agroindustrial by-products utilisation, forage production, use of crop residues, dairy feeding systems, feeding strategies, introduction and adoption of improved forage technologies, nutritive value of different forages, effects of management on animal performance, effect of supplements on feed utilisation, potential of agricultural by-products as animal feeds, and effects of management on pasture grasses & legumes; and evaluates the utilisation of these results by smallholders.