Title: Assessment of soil carbon in reclaimed land in south-west Iceland

Reclamation of degraded land using revegetation is one way of sequestering carbon into the soils. In this study an assessment was done to estimate the status of soil carbon amounts after revegetation with trees and grass in South-West Iceland (Hafnarmelar). Natural woodland and eroded plots were part of the assessed plots as controls, making four plots in all. Soil samples were collected from all the plots and were analysed for bulk density, soil texture and carbon content. Total % carbon (C) was analysed using a vario MAX CN analyser (measured % C) and Loss on Ignition (LOI; calculated % C). The results showed that natural woodland, tree, grass and eroded plots had 9.32%, 4.91%, 1.12% and 0.76% C, respectively, with the natural woodland different from the tree plot (p = 0.0001) and the tree plot different from the grass plot (p = 0.0001). The grass and eroded plots did not differ (p = 0.0566). Notably, the grass plot had carbon below the minimum expected levels of 1.5% in Icelandic Andosol under vegetation. The natural woodland and the tree plot had a finer soil texture than the grass and eroded plot. Results suggest that where land has been properly restored or kept in its natural condition, soil properties improve significantly, especially when trees are part of the restored vegetation. Therefore more restoration efforts are encouraged. The results also showed that LOI is a good but not very accurate estimator of soil organic carbon unless equations are developed with respect to the known carbon content of a particular soil type.