Water,nutrient and pollutant budgets in damaged Norway spruce stands in NE-Bavaria (F.R.G.) and their changes after different fertilization treatments

Water budgets and ecosystem balances of the main nutrients and pollutants were calculated in two Norway spruce forests at different states of decline in the Fichtelgebirge (F.R.G.) from summer 1984 through summer 1986. For that purpose, samples of precipitation, throughfall, litter seepage and soil solution were gathered weekly. Fluxes of main cations and anions were calculated by multiplying water fluxes through the different compartments with the appropriate ion concentrations. Both spruce stands are characterized by a sufficient water supply throughout the investigation period caused by high annual precipitation. Only in dry periods drastical restriction of plant available water may endanger those spruces growing on very stony podzols and cambisols. The calculation of deposition fluxes differentiates the damaged and the apparently healthy spruce stand. Input of SO₂ and H⁺ as well as canopy buffering and K-leaching of the canopies are significantly higher in the damaged spruce stand than in the healthy one. Additionally, the exchangeable base cation content of the soil on the damaged site is nearly exhausted and therefore buffering capacity in the soil differs from those of the healthy site. There was a low increase of N0₃-leaching with seepage after the fertilization with high amounts of lime.