The livelihoods of millions of Ugandans are rooted in the highlands – the mountainous or elevated regions of the East African country. Scattered along the eastern and western borders, the highlands of Uganda are home to about 40 per cent of the country’s 46 million people. These regions play a significant role in agriculture, which is the main source of income for many Ugandans, including for 70 per cent of working women, according to the country’s Ministry of Agriculture, Animal Industry and Fisheries. These regions are also recognized as one of the key hotspots where land degradation, due to soil erosion, is rampant.
The vital grounds that sustain life were the subject of a study recently completed by the National Agricultural Research Laboratories (NARL) in the capital Kampala with support from the IAEA, in partnership with the Food and Agriculture Organization of the United Nations (FAO). Experts assessed erosion rates in the highlands using nuclear techniques, to inform policy makers, farmers and other stakeholders on actions to take to reverse or at least reduce land degradation. “Through the Technical Cooperation Programme, NARL is an institute under the National Agricultural Research Organization, has benefited in developing capacity for erosion research since 2013. During 2016-17, the staff at NARL completed training in soil sampling, analysing the caesium-137 (Cs-137) radionuclide in soil, which can serve as an erosion tracer, and using relevant equipment,” said Valentina Varbanova, IAEA Programme Management Officer.
The study included sampling slope transects across terraced fields in the Rubanda District in the southwestern highlands. The results revealed that most of the terraces were eroded – having lost about 12.6 cm of topsoil in the last 60 years – indicating that the effects of traditional terracing techniques to conserve soil on steep slopes of Uganda highlands are insufficient.
“The highlands are densely populated and intensively exploited by agriculture because they receive high rainfall and have moderate temperatures, convenient for settlement,” said Emil Fulajtar, a soil scientist at the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture. “The land is dominated by small family farms on steep slopes of about 30 to 40 degrees.” As the rain can easily wash off the topsoil, the most fertile part of the soil profile, these areas are threatened by land degradation.