By SADC Today 12 October 2009
The African Soil Information Service (ASIS), based in Kenya, will produce the digital map of 42 of Africa's 53 countries revealing soil type and its component nutrients.
Information gathered will guide farmers and policymakers on efforts to improve the fertility of Africa's soils, some of which are the most depleted in the world.
Coverage and detail of existing soil maps are poor, particularly in large, sparsely populated countries in Africa, says Alfred Hartemink a soil scientist with the ASIS.
"The maps that do exist are 10 - 30 years old. That poses a problem, because the soil properties of interest -- like pH, carbon or phosphorus content -- change over time."
The project will gather existing local soil maps and combine them with new measurements to produce the digital map, which will be freely accessible on the web in a user-friendly format.
The new measurements will include those derived from remote sensing, which involves analysing the features of satellite images - such as colour and radiation - to infer the characteristics of the soil.
These calculations are then calibrated against actual soil samples from the particular region.
The African map is the first stage of an initiative -- GlobalSoilMap.net, to map all the globe's soils to help informed decisions not only about agriculture, but also to monitor the effects of climate change, environmental pollution and deforestation. '