Organic soil carbon in Austria – Status quo and foreseeable trends

We compiled information from different sources in order to establish a comprehensive map of the stock of soil organic carbon (SOC) in the upper 30 cm under different forms of land use for Austria. The information serves as a baseline for the evaluation of the potential of climate-change mitigation measures. SOC sequestration plays an important role in the discussion of terrestrial carbon (C) sinks and the size of the SOC pool is one of several quality measures for crop production and the national and regional food security. The baseline serves also for the evaluation of the effectiveness of adaptive land management in order to cope with climate change. Austrian croplands, grasslands, forests, and settlements contain 300 Mt SOC. Peatlands have the highest SOC density (220 t C/ha), yet cover only about 2% of the country. Forest soils store 106 t C/ha and comprise the largest pool due to the coverage of more than 4 Mha (48% of the country). Intensively and extensively managed grasslands cover 0.8 Mha (10%) and contain between 91 and 113 t C/ha, and cropland on 1.28 Mha (15%) hold on average 62 t C/ha. Due to the geographic heterogeneity of Austria with respect to climatic conditions, geology and soils, and topography the regional differences in SOC stocks are large. Measures to increase the SOC stock in cropland have been applied for 25 years within agri-environmental and climate-smart strategies. An increase of the total SOC pool is expected due to the afforestation and reforestation of marginal agricultural land and to a smaller extent due to the restoration of peatlands. A decline of the SOC stock is a consequence of land development for settlements and infrastructure.