Microfungi in coniferous forest soils treated with lime or wood ash

Summary Microfungal species composition was studied in coniferous forest soils which had been treated with lime or wood ash. The pH increased by about 2.5 units at the highest rate of application. Fungi were isolated 4–5 years after the treatments using a soil washing technique. At one site, Öringe, clear differences in species composition due to liming were found. Penicillium spinulosum, Oidiodendron cf. truncatum, Mortierella spp., and two sterile taxa decreased in abundance in limed areas, while Geomyces pannorum, Penicillium cf. brevicompactum, Trichoderma polysporum, and Trichosporiella sporotrichioides increased in isolation frequency. At another site, Torrmyra, the effect of liming was less pronounced, although the pH changes due to the treatments were larger compared to the Öringe site. However, T. polysporum increased, while a sterile taxon decreased in abundance in lime- and wood ash-treated plots. The changes in microfungal species composition after liming were similar to those found earlier in urea-treated soils, and opposite to those found in artifically acidified or ammonium nitrate-fertilized soils.