SOIL ACIDIFICATION IN AN EXPERIMENTAL BEECH PLOT IN A PERIOD OF RISING pH IN BULK DEPOSITION

Measurements of chemical parameters of soil samples collected in 2005, in an experimental mountainous beech plot, showed that the soil was acidified with regard to soil samples collected in 1995 despite the rising pH values in bulk deposition during the last 10 years. Specifically, values of pH and base saturation in the new samples were significantly lower than the corresponding values in the old samples for the OH horizon soils, and the first 20 cm of mineral soil. Also, in the new samples, concentrations of exchangeable aluminum were significantly higher than those in the old samples. The reasons for acidification can be attributed either to the low amounts of base cations in total deposition, and/or to the reduction of amounts of base cations in litterfall during recent years.