Differential Impact of Land Use Types on Soil Productivity Components in Two Agro-ecological Zones of Southern Ghana

Abstract

The maintenance of soil productivity is important for sustained crop yield in low-input systems in the tropics. This study investigated the impact of four different land use types, namely, maize and cassava cropping, woodlot/plantations, and natural forests on soil productivity components, especially soil carbon accretion, at six sites within two agro-ecological zones of southern Ghana. Soil properties were significantly different between sites and ecological zones. The coastal savanna zone, which is a low rainfall zone had relatively lower soil carbon storage than the high rainfall forest-savanna transition zone. Soil productivity conditions in the latter zone were much more favorable for cropping than the former. Land use types significantly affected the soil carbon (SOC) storage within the two ecological zones. In the low rainfall zone, soil carbon accretion by maize cropping, cassava cropping, and plantations was 48%, 54%, and 60%, respectively, of the forest carbon stock (47,617 kg/ha). In the transition zone, the soil carbon accretion was over 90% of the forest value (48,216 kg/ha) for all land use types. In effect, the use of land use types in maintaining soil productivity must consider the conditions in a given ecological zone.