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The biogeochemical model MAGIC was applied to simulate long-term (1880–2050) soil and stratified soil solution (30 and 90cm depth) chemistry at a spruce dominated site in the western Ukraine (Pop Ivan, 1480m a.s.l.) to evaluate the effects of acid deposition on soil acidification in a less polluted region of Europe. Since 2008, sulphur (S) deposition of 9kgha−1 year−1 and nitrogen (N) deposition of 8.5kgha−1 year−1 have been measured at Pop Ivan. The recent deposition of S and N is about 30% and 50% of those values estimated for the early 1980s, respectively. Acidic deposition caused the depletion of base cations (Ca, Mg, Na, K) from the soil cation exchange complex, which resulted in a decrease of calcium and magnesium saturation between 1935 and 2008 in the top mineral soil (0–30cm) and deeper mineral soil (30–80cm) by 67% and 88%, respectively. Base cation leaching acted as the major buffer mechanism against incoming acidity, therefore the measured inorganic aluminium (Al) concentration in soil solutions is ca. 10μmolL−1 and the subsequent molar (Ca+Mg+K)/Al ratio above 1. Recovery of the soil solution pH and Al is expected within the next 40 years, whereas the soil base saturation will only increase slowly, from 6% to 9.8% in the top soil and from 5.5% to 11% in the deeper mineral soil. Since the 1960s, modelled inorganic N leaching (as NO3) has started to increase following the trend in N deposition. Modelling and experimental evidence suggest that N availability from mineralization and deposition exceeds the rate of microbial and plant immobilization. Thus, soil N accumulation since the 1960s has been limited. A significant increase in nitrophilous species as well as a decrease of herb layer diversity was observed between 1936 and 1997. [Copyright &y& Elsevier]

Abstract: The precipitation chemistry, deposition, nutrient pools and composition of soils and soil water, as well as an estimate of historical deposition of sulphur (S) and inorganic nitrogen (N) for the period 1860–2008, were determined in primeval deciduous and coniferous forests at the sites Javornik and Pop Ivan, respectively. Measured S throughfall inputs of 10kgha−1 year−1 in 2008 were similar to those estimated for the period 1900–1950 at both sites. The highest estimated S inputs were in the 1980s. Measured bulk deposition of N in 2008 was lower at Pop Ivan (5.6kgha−1 year−1) compared to Javornik (12kgha−1 year−1). Significantly lower NO3 deposition was both estimated and measured at Pop Ivan. Higher soil base cation concentrations were observed at well-buffered Javornik underlain by flysch (Ca pool of 2046kgha−1 and base saturation of 29%) compared to Pop Ivan underlain by crystalline schist (Ca pool of 186kgha−1 and base saturation of 6.5%). The soil pool of organic carbon (C) was higher at Pop Ivan (212tha−1) compared to Javornik (127tha−1). The C concentration was positively correlated with organic N in the soil (p <0.001) at both sites, but the mass average C/N ratio in the forest floor was lower at Javornik (22) than at Pop Ivan (26). High N leaching of 17kgha−1 year−1 at the 90cm depth was measured in the soil water at Javornik, suggesting high mineralization and nitrification rates in old growth deciduous forests in the area. Despite relatively low Al concentrations in the soil water, a low soil water Bc/Al ratio (0.9) (Bc=Ca+Mg+K) was found in the upper mineral soil at Pop Ivan. This suggests that the spruce forest ecosystems in the area are vulnerable to anthropogenic acidification and to the adverse effects of Al on forest root systems. [Copyright &y& Elsevier]