Soil properties were analyzed using Russian traditional methods
(Arinushkina, 1970). Soil organic carbon wasmeasured using 0.4 N potassium
bichromate (the Tyurin method modified by Simakov). Soil
particle size distribution (silt and clay content) was determined by the
pipette method after the pyrophosphate treatment. Cation exchange capacity
(CEC) of the soil was determined using 1 M ammonium chloride
(the Bobko–Askinazi method). The exchangeable potassium was determined
by the Machigin (molybdenum blue) method. Adsorbed Na was
analyzed by flame atomic adsorption spectrophotometry (FAAS). Soil
pH was measured with a pH electrode using a 1:5 suspension of a soil
to water ratio. Exchangeable calcium and magnesium were measured
by the titration at pH 12.5–13 and 10 respectively. Carbonates were
measured by the Kudrin method using 0.005 NH2SO4 and then an excess
of the acid was titrated with alkali.