Changes in soil organic matter, microbial biomass C and ergosterol under a fairy ring of Marasmius oreades

Samples were taken from the F/H-, A1-, and A2-horizon in the outer zone, ring zone and inner zone of a fairy ring formed by Marasmius oreades (Bolt.) Fr. on a garden lawn. The mineral component of the soil was mainly derived from loess. The amounts of soil organic C, total N, microbial biomass C, and ergosterol were reduced by 46 to 54% in the ring zone and by 25 to 37% in the inner zone relative to the non-invaded outer zone. The water-to-soil organic C ratio was markedly reduced only in the A1-horizon of the ring zone. Ergosterol and microbial biomass C were very closely correlated (r = 0.97) although some horizon-specific differences occurred from zone to zone. An enhanced ergosterol-to-biomass C ratio in the F/H- and A2-layer of the ring zone clearly reflected the invasive growth of M. oreades.