Soil properties and tree growth performance along a slope of a reclaimed land in the rain forest agroecological zone of Ghana

Abstract

Reforestation of degraded forest lands has always involved the use of multipurpose tree species. However, understanding the relations between tree growth and soil fertility attributes along slopes of degraded mine sites by reforestation is limited, especially in Ghana. Therefore, a study was carried out at a rehabilitated degraded land to determine the influence of slope on soil fertility attributes and growth performance of trees. Plots were laid in the upslope, midslope and downslope, with an adjacent undisturbed forest as a control for sampling purposes. Soil samples were collected (0–15 and 15–30 cm depth) from the various sampling locations to determine soil properties, as well as tree growth parameters (e.g., height, basal area, and biomass). Slope positions impacted on tree growth (above and below ground biomass, and basal area) and soil properties. Highest soil organic carbon (1.80%), total N (0.22%), available P (6.92 mg kg−1), exchangeable K (0.20 cmolckg−1), and NO3−-N (19.03 mg N kg−1) were observed at the midslope position, whilst the upslope recorded the least values. The results also revealed that the midslope position recorded the highest tree growth characteristics. Aboveground biomass ranged from 17.67 to 21.73 mg ha−1, indicating the trees’ potential as carbon sinks. Furthermore, principal component analysis revealed that 3 components had their eigenvalues > 1, and accounted for 79.50% of the total variance. These results clearly demonstrate that spatial variations in soil properties are influenced by slope, and gives reference for future rehabilitation processes by reforestation.