The district lies entirely within the Voltarian sandstone basin dominated by sandstones, shales, siltstones and minor limestones. The northern tip of the district is underlain by lower Voltarian which consist of rocks, dominated by shales and sandstones. The soils are mainly savannah ochrosols, groundwater laterites formed over granite and Voltaian shales.
Small areas of savannah ochrosols with some lithosols and brunosols are also very low. The laterites are similar in acidity and nutrient level to the ochrosols, but are poorer in physical properties, with substantial amounts of concretionary gravel layers near the top horizons and more suited for road and other constructional works than supporting plant root systems.
Despite gentle slopes, the soils are highly vulnerable to sheet erosion, and in some areas, gully erosion also occurs. This condition occurs primarily because of the annual burning of the natural vegetation, leaving the soil exposed to the normally high intensity rains (up to 200mm per hour) at the beginning of the rainy season.
The continuous erosion over many years has removed most or all of the topsoil and depleted or destroyed its organic matter content. Such a situation does not allow the soil fauna to thrive and keep the topsoil layers open and aerated for healthy plant roots to develop. It results in serious compaction, with considerable reduction in rainfall infiltration rate.
These soils, even when affected by erosion and reduced fertility, have some potential for agriculture if their available nutrients and water are managed sensibly, including appropriate organic matter supplementation. Measures to restore a better soil water infiltration rate, will depend on the extent to which it is possible to manage the recurring annual bush fires and extend the rainfall surface retention time to facilitate increase in the amount that gets to the plant rooting zones, to the level of the soil water holding capacity.