Since negative impacts of global warming become ever more pressing, immediate climate change mitigation measures are increasingly needed. The application of biochar to soils is a promising technology for long-term carbon sequestration as well as for improving the soil fertility. However, non-CO2 greenhouse gases have to be considered as well. Therefore, this thesis aims at exploring the effect of biochar (derived from wheat straw, wood chips and vineyard pruning) on greenhouse gas (GHG) emissions (CH4, CO2 and N2O) from three Austrian agricultural soils (Planosol, Cambisol and Chernozem). The main goal was to evaluate the mitigation potential of biochar and finally to calculate GHG abatement costs. Greenhouse gas fluxes were measured by collecting gas samples from closed chambers at regular intervals from a pot experiment at several stages of plant development (of mustard and barley). Based on these results and a comprehensive literature review, the cost-effectiveness of biochar from straw and woodchips to mitigate GHG emissions in Austria has been assessed. Measurements of CO2 emissions from soil indicate that biochar C is rather stable in soil and only insignificant biochar degradation occurred for the first six months after application. In addition, significant effects of biochar were found for N2O fluxes, which were suppressed by about 50% over the course of the experiment. These results were the starting point for the evaluation of the cost-effectiveness of biochar technology, revealing average GHG abatement costs between EUR 90 and 420 t-1 CO2 equivalents (CO2e) depending on factors such as fast or slow pyrolysis and different plant sizes. A sensitivity analysis showed that biochar yield and feedstock costs are the key factors for the GHG abatement costs. Based on the biomass potential of straw and woodchips, biochar could potentially off-set between 0.54 to 1.34 Mt CO2e a-1 in Austria, or between 7 and 18% of GHGs caused by agriculture.