Chemical analyses of mineral soils, O horizons and tree
foliage
The mineral soil, O horizon and foliage samples were analyzed for total
carbon and total nitrogen concentration using LECO
TruMac® CNS analyzer. The inorganic C content in
mineral soil samples was calculated based on the carbonate content
measured with the gas-volumetric Scheibler method. The organic C
(Corg) content was then calculated as a difference
between the total C and the inorganic C. Total phosphorus
(Pt) was determined colorimetrically by the molybdate
blue method from aqua regia extracts by Varian CARY 300 Conc
UV–Visible Spectrophotometer.
The texture of mineral soil samples was determined by hydrometer using
Bouyoucos method. The pH of the samples was measured in
H2O (pHH2O) and 1 M KCl solution
(pHKCl) (soil/liquid ratio 1:5, w/v) at 20° C using a
digital pH meter (CPC-411, ELMETRON). Data on the texture and pH of the
studied soils are presented in supplementary material (Table S1).