New plant ecological scales of soil reaction for Leningrad region and St. Petersburg based on Ramensky’s method

Abstract

The main biogeochemical processes are influenced by soil pH. For assessing pH by the method of vegetation indication a new database of the ecological scales of plant species describing the correlation between classes of species coverage and pH. Field data was collected at 800 sample plots. At sample plots the coverages of plant species and pH of organic upper soil horizons extracted by KCl solution were determined. Synoptic tables with average coverage for each species were compiled for forest types. The range of pH (2.5–5.5) was divided into 7 classes differ by 0.5 unit of pH each. For each species coverage class, the first and third quartile of pH were established. Ecological scales included these two values as minimum and maximum values (amplitude) of the pH for a given coverage class. Determining of soil pH using the ecological scales was a solution of the system of inequalities that are the set of amplitudes of the pH values corresponding to the coverages of species of the certain plant community. Comparing measured and indicated pH values using data for 45 sample plots that were not used for compilation of scales showed excellent match of measured and indicated values.