Variability of soil physicochemical properties under different land use types in the Guinea savanna zone of northern Ghana

Abstract

Land use change has been a major global challenge since the twentieth century, especially the conversion of natural forests to agricultural and other uses. Such land use changes are considered to be among the major threats to soil quality and sustainability. In this study, we hypothesized that the physiochemical properties of soils in the Guinea Savanna zone of Northern Ghana would vary based on the land use type; with the protected area (PA) having better soil physiochemical properties than farmlands (FL) and fallowed areas (FA). Three communities (Mognori, Jagbo-Apleyi, Tugu) with different land use types (PA, FA and FL) were selected. A total of ninety-nine composite soil samples at three depths (0–15, 15–30, 30–45 cm) were collected for physiochemical analysis. The results indicated that the soil organic carbon, nitrogen, extractable bases (Ca, Mg, K) and effective cation exchange capacity were higher (P < 0.05) in the PA than in the FA and FL and decreased with soil depth. However, bulk density was similar among the land use types but increased with soil depth. Such physiochemical properties of FA could have consequential impact on farmers’ livelihoods, since majority (70%) of them depend on crops cultivation. In addition, it could pose a threat to PA since degraded soils could trigger increased encroachment on the existing protected areas. In conclusion, farmers should cultivate crops with shallow roots (within 0–15 cm), since good soil physiochemical properties and nutrients that support crop growth had their critical concentration levels within that soil depth.