Location of soil substrate properties in the plane of the first two principal components. Abbreviations: STP – soil total phosphorus, STN – soil total nitrogen, SOC – soil organic carbon, CO₂ – soil respiration, SIC – soil inorganic carbon, TDS – total dissolved solids, Wc, Wg, Wf – capillary, hygroscopic and field water contents, resp., D-soil density, Ds – density of solids, Pl – labile phosphorus content.