Discovering Soils in the Tropics: Soil Classification in Ghana

Abstract

Early soil surveyors in the tropics encountered unique environmental conditions. Soil survey was challenging in dense tropical vegetation because it was difficult to observe the landscape without clearing survey lines. Cecil Frederick Charter, a British geographer (1905–1956), proposed an interim scheme for the classification of tropical soils on the basis of Neustruev's soil genetic model where soil is a function of climate, vegetation, relief and drainage, parent material, and age. Charter's interim system was hierarchical, with five levels: Order, Suborder, Soil Group Family, Great Soil Group, and Soil Series. Starting in 1937, Charter worked on soil surveys for Trinidad; British Honduras; Antigua and Barbuda, Leeward Islands; and Tanganyika. From 1951 to 1956, Charter directed the Soil Research Institute in Ghana (formerly Gold Coast). He created 37 soil survey regions based on major drainage basins that were mapped using the semi-detailed reconnaissance method (1:250,000). In 1962, Hugh Brammer published soils information related to agriculture and land use in Ghana and summarized Charter's Interim system. Correlation of Ghana's soil classification system with the three widely used international systems (FAO, WRB, and U.S. soil taxonomy) is also described. Comparing of national soil maps through time provides insights about the development of soil geography and soil classification concepts for a country. We paper examine three of the eight national maps of Ghana and discuss theoretical developments in the classification of tropical soils in West Africa. Research in soil morphology and genesis is important for soil mapping and classification with applications for land use and management in the tropics.