Abstract:

In the early stages, Uganda's soils were considered fertile and little was done to improve productivity in a systematic way. However it was soon realized that crop yields in Uganda declined under continuous cultivation due to soil degradation like anywhere else. Initial studies on liming and fertilizers indicated little crop response. Efforts then turned to understanding processes associated with land rests which revealed the importance of both soil chemical and physical properties. The result were recommendations to use a combination of organic materials, crop rotations, grass rests and soil and water conservation practices to improve and sustain soil productivity. Studies were also conducted to understand the causes of infertile patches in the country like ' lunyu' soils in central Uganda and sterile acid swamps. Research on fertilizer use was intensified after the second world war and focused on the annual cropping systems. Interim fertilizer recommendations for the major crops of that time were released in 1973. Soil resource inventories started in 1933 Provisional soil map of East Africa) followed by a reconnaissance soil resources inventory between1955 to 1960. There have been also more detailt soil surveys for specific clients. More recent soils research has focused on integrating soil productivity management through use of organic and inorganic fertilizers, biological ·nitrogen fixation, rotations, agroforestry and proper soil and water practices.