COS 46-1 - Spekboom planting in degraded areas improves soil properties in the Eastern Cape Province of South Africa

Tuesday, August 8, 2017: 8:00 AM
B115, Oregon Convention Center


Sheunesu Ruwanza, University of Venda; Bryce Panter, Rhodes University


In its intact state, the Saltaire Karroid Thicket is dominated by fragmented clumps of thickets, which can support game farming, pastoralism, ecotourism and local communities with firewood. However, substantial browsing by animals has transformed some parts of the Saltaire Karroid Thicket, leading to soil and vegetation degradation. This leaves ecological restoration as the best possible option to restore this degraded Thicket. In this study, we assessed whether Portulacaria afra (spekboom) planting improves soil physico-chemical properties in the Saltaire Karroid Thicket. We collected topsoil samples from a spekboom planted site and compared them to an adjacent natural and degraded site. Soil were analyzed for gravimetric soil moisture, pH, soil resistivity, soil penetration, soil P, total C, total N, cations of K, Ca, Mg and Na and soil water repellency. Soil water repellency was measured using the Water Droplet Penetration Time (WDPT) method.


Results show significant (p < 0.05) increase in soil P, total C, total N, Ca and soil moisture in the spekboom planted site compared to the degraded site. Both soil compaction and water repellency were significantly (p < 0.001) high in the degraded compared to the spekboom planted site. Only the measured cations of Na and Mg and soil resistivity showed no significant (p > 0.05) differences between the sites. Since C, N and P are indices of soil fertility and were significantly (p > 0.001) higher in the spekboom planted site compared to the degraded site, we conclude that the planting of spekboom truncheons in degraded sites does improve soil properties. This potentially make the soil properties underneath planted spekboom ideal for its own growth and could contribute to the success of the Subtropical Thicket Restoration Project.