Tropical Africa escaped from the glaciers that covered the temperate parts of the world during the Ice Age. The legacy is that most of the parent materials of the soils of tropical Africa are old, highly weathered and devoid of bases and phosphate-bearing minerals. Traditional farming systems which were relatively stable and sustainable relied on long fallow periods after one to two years of cropping to maintain the productive capacity of the soils. In recent times and especially in densely populated areas, a sizeable class of 'landless' farmers have begun to cultivate marginal lands or to invade the 'forest reserves' thereby exacerbating the problems of land and environ­ mental degradation. of soil fertility that will facilitate the production of adequate quantities of the principle Maintaining a level staples has become a major challenge to agricultural scientists in tropical Africa. To increase the nutrient­ supplying power of soils requires the inputs of fertilizers. These can be organic or inorganic. The efficiency with which these externally supplied inputs can increase agricultural production and reduce soil and environmental deterioration is dependent on the ability of scientists to determine the right types and quantities of the products to apply to each soil, crop and cropping system as well as the ability of farmers to acquire requisite farm manage­ ment skills.

Inhalt

General papers.- Alleviating fertilizer policy constraints to increased fertilizer use and increased food production in West Africa.- Alleviating fertilizer supply constraints in West Africa.- Alleviating fertilizer technology transfer constraints.- Climatic constraints to crop production and fertilizer use.- Alleviating soil fertility constraints to food production in West Africa: Efficiency of nitrogen fertilizers applied to food crops.- Fate and efficiency of sulfur fertilizer applied to food crops in West Africa.- Overcoming soil fertility constraints to crop production in West Africa: Impact of traditional and improved cropping systems on soil fertility.- Management of fertilizer research data: General concepts.- Overcoming soil nutrient constraints to crop production in West Africa: Importance of fertilizers and priorities in soil fertility research.- Country papers.- Utilisation efficace des engrais azotés pour une augmentation de la production vivrière: L'expérience du Burkina Faso.- Utilisation efficace des engrais azotés pour une augmentation de la production vivrière: L'expérience de la Côte d'Ivoire.- Efficient fertilizer use for increased crop production: The Gambian experience.- Efficient fertilizer use for increased crop production: The Ghana experience.- Efficient fertilizer use for increased crop production: Use of phosphorus fertilizers in concretional soils of northern Ghana.- Efficient fertilizer use for increased crop production: The Liberia experience.- Efficient fertilizer use for increased crop production: The humid Nigeria experience.- Efficient fertilizer use for increased crop production: The sub-humid Nigeria experience.- Alleviating soil fertility constraints to increased crop production in West Africa: The experience in the Sahel.- Role of manures and crop residue in alleviating soil fertility constraints to crop production: With special reference to the Sahelian and Sudanian zones of West Africa.- Utilisation efficace des engrais pour accroître la production végétale: Efficience de l'urée apportée sur maïs (Senegal).- Efficient fertilizer use for increased crop production: The IFDC- Africa experience in Togo.