1ST-RESULTS ABOUT EFFECTS OF LIMING ON SAPROPHYTIC FUNGAL COMMUNITIESIN THE AH-HORIZON OF A SPRUCE FOREST SOIL IN FRANCE (VOSGES)

Little attention has been paid to effects of deposition of acidic air pollutants on development and/or activity of soil microorganisms. Soil fungi, including mycorrhiza, are strongly affected by soil chemical p arameters such as the ratio of calcium and/or magnesium to aluminium a nd the pH-value. So, it was very interesting to compare the rhizospher ic microfungal flora between a declining spruce stand and a healthy sp ruce stand. The site chosen for this investigation was situate in the Vosges in the northeast of France. The rhizospheric soil, from the Ah- horizon of a sandy loam podzol, limed (the healthy spruce stand) or un limed (the declining spruce stand) was sampled in a 65-year-old Norway spruce (Picea abies [L.] Karst.) forest. The study was made 7 years a fter liming. Fungal isolations were performed using the dilution plate method. Pronounced differences in abundance and composition were foun d between the limed and the unlimed stands. Of the 49 isolated species (24 from declining spruce plot and 34 from healthy spruce plot) only nine were found at both plots. The greatest diversity, estimated by th e number of species per 100 isolates (33.6 for the limed plot and 21.2 for the unlimed plot), is observed at the healthy spruce stand; it ma y be due to the marked changes of chemical characteristics after limin g. This study indicates that soil microfungi could be sensitive to inc reased acidity of the rain with subsequent effects.