Soil carbon sequestration during the establishment phase of Miscanthus × giganteus: a regional‐scale study on commercial farms using ¹³C natural abundance

The use of biomass for energy production is considered a promising way to reduce net carbon emissions and mitigate climate change. However, land‐use change to bioenergy crops can result in carbon emissions from soil and vegetation in amounts that could take decades to compensate. Perennial grasses such as M iscanthus offer a possible solution to this problem as measurements on experimental plots planted with M iscanthus have shown significant carbon sequestration in the soil. It can, however, be expected that sequestration potentials in commercial use might differ from those measured in experimental plots due to different farming practices and soil characteristics. For this study, M iscanthus plantations on 16 farms in SE I reland as well as on‐farm controls representing the former land‐use (grassland and tillage) have been examined. The M iscanthus plantations were 2–3 years old. Soil organic carbon ( SOC ) content and a number of soil properties were measured and the amount of M iscanthus ‐derived carbon was determined using the 13 C natural abundance method. On both former tillage fields and grasslands, although there were no significant differences in SOC contents between M iscanthus and control sites, it was shown that 2–3 years after M iscanthus establishment, 1.82 ± 1.69 and 2.17 ± 1.73 Mg ha −1 of the SOC under former‐tilled and former grassland respectively were M iscanthus ‐derived. Mixed‐effects models were used to link the total SOC concentrations and M iscanthus ‐derived carbon to the land‐use parameters as well as to soil properties. It was shown that on control sites, pH had an effect on total SOC . In the case of M iscanthus ‐derived carbon, the initial SOC content, pH , former land‐use and crop age had significant effects.