Element budgets of a heavily damaged Norway spruce ecosystem at Hohe Matzen in the Fichtel Mountains/FRG were studied over 3 years. The trees show severe symptoms of decline and Mg deficiency. The soil is a typic Dystrochrept derived from granite with sandy texture, high stone content, and low base saturation. The budgets show high releases of N, S and Al from the ecosystem as a result of input, buffering and turnover processes. After an increase of proton fluxes in the organic surface layer, a strong reduction of protons in the B horizon was found. This process was accompanied by the release of Al, whereas reactive Al(OH)3 was exhausted in the A horizon. The low ANC is also shown in pH-stat.-titrations. The data indicate a strong mineralisation in the humus layer, which results in a net release of NH4, SO4 and TOC. Nitrification takes place mainly in the A horizon. With respect to the N-budget, the ecosystem is approaching the state of N saturation. The processes of N turnover lead to an internal proton production exceeding the atmospheric input, and thus contributing to soil acidification.
10 Figures and Tables
Table 1. Nutritional status of the 60-years old Norway spruce stand at Hohe Matzen
Fig. 1. Element budget of the 60-year-old Norway spruce ecosystem at Hohe Matzen site in the Fichtel Mountains/FRG (values in keqha -] yr -1, for TOC in kgha -1 yr-t) .
Table 2. Element concentrations in mineral soil input and soil solution in 25 cm and 70 cm soil depth (mean values of the period August 1988 to October 1990)
Fig. 2. Temporal proton buffering of the mineral soil horizons Ae, Bs and By (pH-stat.-titration with HCI, pH-level 3).
Table 3. Chemical parameters of the typic Dystrochrept derived from granite at the Hohe Matzen site (O = forest floor, Ae = eluvial, Bs = spodic, Bv = cambic horizon, Cv = weathering zone; see AG Bodenkunde 1982)
Fig. 3. Molar concentration ratios of H, A1, NH 4, NO 3 and SO 4 with CI in the mineral soil input (mean values of summer and winter, respectively).
Table 4. Physical parameters of the typic Dystrochrept derived from granite at the Hohe Matzen site
Fig. 4. Molar concentration ratios of H, AI, NH4, NO 3 and SO4 with CI in the soil solution from 25 cm depth (mean values of summer and winter, respectively).
Table 5. Correlation coefficients between cation and anion concentrations in soil solution of the mineral soil (mean values for the period August 1988 to October 1990. *** =p < 0.001, * =p < 0.05)
Fig. 5. Alkalinity in seepage output at 70 cm mineral soil depth for the period August 1988 to July 1990, calculated with and without NO3-concentrations.
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