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 ofthat time were released in 1973. Soil resource inventories
started in 1933 LProvisional soil map of East AfriCa) followed by a reconnaissance soil resources inventory between
1955 to 1960. There have been also more detailt:d 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 fix~tion, rotations, agroforestry and proper soil and water practices.