Restoration of Cirsio-Molinietum wet meadows by sod cutting

This study evaluates the prospects for restoration of the Cirsio-Molinietum orchietosum by sod cutting of an eutrophicated Cirsio-Molinietum stand and of a former agricultural grassland and an alder cart, respectively. Sod cutting of the former agricultural grassland and of the alder cart sufficed to restore this plant community, whereas sod cutting of the eutrophicated Cirsio-Molinietum was not successful. The unsuccessful restoration of the eutrophicated Cirsio-Molinietum might be due to prolonged inundation resulting from the sod cutting, causing anaerobic conditions under which no nitrification takes place. The chemical composition of the deep groundwater supplying the site changed from base-rich and SO₄²⁻-poor to base-rich and SO₄²⁻-rich. This change in chemical composition of the deep groundwater, discharging in the study area, might cause a higher nutrient availability in the root zone, and therefore, negatively influence the prospects for the restoration of the Cirsio-Molinietum. Furthermore, successful restoration of the Cirsio-Molinietum requires (1) water tables close to the soil surface during at least six months and (2) discharging base-rich groundwater in the root zone.