Aluminium release from acidic forest soil following deforestation and maize cultivation in Ghana, West Africa

Abstract

Acidic tropical soils often have high Al3+ concentrations in soil solutions, which can be toxic to plants and, thereby, reduce agricultural yields. This study focuses on the impact of deforestation and cultivation on the short and long-term Al geochemistry of acidic soils in Ghana, West Africa. Site-specific investigations were made at two sites covered with forest and one site cultivated with maize (Zea mays L.). The capacity of soil to resist acidification was investigated in a leaching experiment and the corresponding release of aluminium quantified. Field results revealed a significant aacidification and Al mobility in the root zone of the cultivated site as compared to the forest sites. The leaching experiment showed that further acidification would significantly enhance Al-release and, consequently, the presence of Al3+ in soil solution. It is concluded that deforestation and cultivation in the study area has resulted in increasing levels of Al3+ and a lowering of the soils capacity to resists further acidification. This may be critical in relation to land-use management and long-term agricultural productions.