It was found that red clover utilizes from 1.1 to 1.4 kg of CO2 from the atmosphere to produce 1 kg of dry mattter. This means that 1400 to 1600m3 of atmospheric air become completely purified from carbon dioxide. Red clover plants usually lose 40.9% of their crop weight during the winter. This results from organic carbon loss equal (in CO2 units) to 41.8% for physiolopical processes. In the same period however, the ash fraction, larger grows as a simple consequence of actual carbon loss. It is reasonable to assume that the plants do intake mineral compounds from the deeper, not frozen horizons of the soil also during winter.