Importance of forest buffers for preserving soil carbon and nutrient stocks in farmed landscapes along two river sites in the savannas of the Volta basin, Ghana

Abstract

ABSTRACTUnderstanding the impacts of agricultural land use is desired for proper management of riparian forests buffers (RFs) in savannas. In this light, we analyzed the relationship between woody plant diversity and soil properties of RFs in farmlands (FAs) and protected areas (PAs) along Afram (Guinean zone) and Tankwidi (Sudanian zone) Rivers located within the Volta sub-basin of Ghana. ALOS-AVNIR imageries were used to map RFs to facilitate sampling of soil and woody vegetation (dbh ≥5 cm) using stratified randomized design (72 plots; size: 500 m2 each) for the analysis of soil physical and chemical properties and Shannon-Wiener plant species diversity. Although the fractions of sand, silt, and clay varied between the PAs and FAs, they were predominantly categorized as sandy loam. Along the Afram River, there were no significant differences in the concentrations and nutrient stocks of soil C, N, P, and K as well as the pH, moisture content, and bulk density between PA and FA. For the Tankwidi River, the concentrations and nutrient stocks of C and K significantly decreased from PA to FA while N, P, pH, bulk density, and moisture content were not different. Of the soil attributes measured C, N, P, pH, ground slope, and soil moisture had significant relationships with the diversity and density of the riparian woody plants. Controlling agricultural activities in riparian forests could preserve soil properties similar to that found in protected areas.