Tolerance of phryganic species to free calcium carbonate of soils

Phryganic rangelands occupy large areas in Greece due to human activities, especially the combined effect of wildfires and overgrazing. It seems though that in addition to those factors the distribution of phryganic species is also affected by soil factors. To test the hypothesis, a controlled experiment was conducted in the Farm of the Forest Research Institute of Thessaloniki at Loutra Thermis. In this experiment, seeds of Phlomis fruticosa L. and Salvia fruticosa Miller (formerly Salvia triloba L.) were grown in pots with different amounts of calcium carbonate. More specifically, three levels of calcium carbonate were established by mixing 0, 20 and 40% of calcareous soil in the soil content of each pot. The seeds were sown in autumn and measurements of the germinated and grown plants were taken at the end of the following spring. They included aboveground height and biomass and root length. The levels of calcium carbonate were 1.5, 13.5 and 25.0% respectively for the three levels. It was found that the aboveground height differed significantly among the three treatments in both species but not biomass. Root length was longer than the aboveground part in both species but only in Salvia the differences were significant among treatments. It is concluded that Phlomis can grow well in soils with and without free calcium carbonate, a fact that explains its wide distribution. Salvia, on the contrary, seems to grow better on soils with abundant calcium carbonate in the soil profile.