Assessment Of Carbon Stock And Selected Soil Fertility Indicators In A Bush Encroached Savanna At Erichsfelde Farm, Namibia

Abstract

Bush encroachment is a form of land degradation common predominantly in semi-arid areas of the world. The resulting habitat degradation and loss of resource productivity make bush encroachment a serious environmental and economic problem in Namibia. Despite these negative effects, bush encroachment offers potential woody carbon stock storage, which can render Namibia a net carbon sink. This study was, therefore, aimed at quantifying potential woody carbon stock storage from different pools and assessing selected soil fertility indicators in low, medium and high bush-encroached sites at Erichsfelde farm in Otjozondjupa region. This was a quantitative study employing a stratified random sampling with systematic sampling along transects. For vegetation surveys in each site, five 20m x 10m plots were set up along two line transects, while established allometric equations were applied to related measured vegetation variables to estimate carbon stock. Additionally, five 1m x 1m soil pits were nested within the vegetation plots and soil samples collected at different soil depths for analysis. Across the three sites, the Kruskal-Wallis test showed no significant difference in the total (P=0.294>0.05) and above-ground (P=0.718>0.05) carbon stock. However, the belowground carbon stock was significantly higher in the medium encroached site (P