Understanding Cation Exchange Capacity Through the Landscape Lens of the Busoga Catena, Uganda

Abstract This study identifies the parent material (PM) and examines cation exchange capacity (CEC) across the Busoga catena. In 2022 and 2023, we described 32 pedons and collected 147 samples. Laboratory analyses were particle size analysis, organic carbon (OC) content, pH, and CEC. Results indicate that the Busoga catena occurs across a Precambrian granitic residuum plateau that is dissected by Holocene and modern aged nearly level alluvial valleys filled with sediment from the Nile River back flooding and local stream sediment. Connecting the residual plateau uplands with the alluvial valleys are colluvial backslopes. Alfisols and Oxisols dominated the residual and colluvial PM. In contrast, Entisols, Mollisols, Ultisols, and Vertisols dominated the alluvial PM in the lowland landscape positions. Pedotransfer analysis revealed CEC to be a function of OC, clay, and pH. The best‐fit multiple linear relationship was CEC predicted = 1.77 pH + 0.08% clay + 4.76% OC, n = 44, Adj. ( R 2 ) = 0.94**. In turn, clay and OC content could be explained using PM and landscape position.