Annual element budget of soil in snow-dominated forested ecosystem

Seasonal fluctuation of concentration and flux of major inorganic ions in t hroughfall, stem flow, snowpack and soil solution was investigated at a nat ural cool temperate mixed forest in Hokkaido, northern Japan, in order to c larify the effect of snowmelt on the solute dynamics in the forest soil in snow-dominated region. Na+, Ca2+, Mg2+, Cl- and SO42- concentrations in soi l solution showed a large fluctuation in the snowmelt period. The percentag e of output of these elements from soil during the snowmelt period in the a nnual output was as follows. Mg2+: 51%, Na+ and Cl-: 59 and 60%, SO42-: 65% , Ca2+: 77%. Our results indicated that the snowmelt event was very importa nt to quantify the annual elemental budgets in this region. Although the le aching of base cat ion from the soil was larger than that of inputs and acc umulation into the vegetation, annual decreasing rate of acid neutralizatio n capacity (triangle ANC((s))) from the soil was mostly affected by the bas e cation accumulation into the vegetation, related that the base cations we athering accompanied with bicarbonate was slow due to the acidic and weathe red soil in the studied site. It is suggested that the weakly acidic soil w hich has tow triangle ANC((s)) in snow-dominated region will be relatively sensitive to the future increase of acidic deposition.