Species-rich grasslands may potentially increase carbon (C) storage in soil and an experiment was established to investigate C storage in highly productive temporary multi-species grasslands. Plots were established with three mixtures: 1) a herb mixture containing salad burnet (Sanguisorba minor L.), fenugreek (Trogonella foenum-gruecum), chicory (Chicorium intybus L.), caraway (Carum carvi L.), birdsfoot trefoil (Lotus corniculatus L.), chervil (Anthriscus cerefolium L.), plantain (Plantago lanceolata L.), lucerne (Medicago sativa L.) and melilot (Melilotus officinalis), 2) 50% of the herb mixture and 50% of a white clover (Trifolium repens L.)/perennial ryegrass (Lolium perenne L.) mixture, and 3) 5% of the herb mixture and 95% of the white clover/ryegrass mixture. Management factors were number of cuts per year and fertilizer application. Aboveground biomass increased considerably with increasing content of herbs and with fertilizer application in plots with a 4-cut strategy. With a 6-cut strategy without fertilizer herbs had no effect on the aboveground biomass. In the herb mixture biomass of small roots was lower than in mixtures with white clover and ryegrass. There was a tendency towards increased biomass in the large root fraction with increasing herb content. The experiment indicated increased CO2 evolution following cultivation of multispecies grasslands
