Understanding soil change when restoring severely degraded land is important to be able to determine when and if the ecosystem services that ‘healthy’ soil provides are restored. Carbon sequestration is an important benefit from soil restoration. This thesis studies the trends in soil carbon sequestration and mineral assemblies over a time period of just 65 years when using Betula pubescens for restoration of severely degraded land.
The soils did not reach the undisturbed soil carbon concentrations in the area in 65 years, indicating that the sequestering period is significantly longer. The total sequestration rate was calculated as 0.466 t C ha-1. Effects of significant inputs of aeolian material were seen in the increased variance in 5-15 cm compared to 0-5 and 15-30. This shows the need to account for rapid aeolian deposition in future carbon sequestration models and emphasises the challenges of modelling processes in such a dynamic environment.
Significant changes in the depth distribution of carbon and clays were seen over this short time period, showing the rapid soil forming processes in Andisols compared to other soil orders. Rapid aeolian deposition in the area masks the change in clay contents but the trends for increased concentrations to a greater depth with age were stronger in the more dynamic carbon contents. The soils are multi-genetic, dominated by aeolian transferred material in the surface horizons and fluvial/direct tephra deposition in the subsurface horizons.