Bayreuther Institut für Terrestrische Ökosystemforschung
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Effect of stem runoff and stem-runoff-affected soil on the turnover of nitrogen in beech stands - soil chemistry


From 01/1995 to 12/1997

Principal Investigator: Egbert Matzner
Staff: Shih-Chieh Chang
Grant: 0339476 B Vorhersage und Erklärung des Verhaltens und der Belastbarkeit von Ökosystemen unter veränderten Umweltbedingungen

To investigate the role of stemflow in the biogeochemistry of a beech (Fagus sylvatica L.) forest the input of elements to the soil by stemflow and canopy drip, the output with seepage, and soil process in the proximal stem area and distal stem area were characterized in a 130-year-old beech forest in Steigerwald (north Bavaria, Germany). The proximal stem area was defined as a cylinder around stem with a soil surface area of 1 m2 and 60 cm depth. The chemical properties of stemflow, canopy drip and soil solutions from different depths and distances were analyzed continuously since summer 1995 to autumn 1997. Water fluxes through the soil were calculated with the simulation tool HYDRUS-2D using measured matrixpotentials for calibration. The nitrification and N-mineralization rates in the proximal and distal stem area were determined by in situ incubations. With the exception of proton flux, less than 10% of the total element fluxes with throughfall (canopy drip plus stemflow) reached the soil via stemflow while stemflow contributed 7 % of the water input. The volume-weighted proton and K concentration of stemflow were higher than the concentrations of canopy drip. On the contrary, the Ca, Mg and P concentrations in stemflow were lower as compared to canopy drip. Distance from stem was correlated with the soil solution chemistry. Potassium concentration decreased with stem distance, but the Mg, Na and NO3 concentrations increased. The seepage water flux through the proximal stem area contributed ca. 10% of the total seepage (434 mm/yr) of the site. Seepage fluxes proximal to the stems for the elements K and DOC amounted to 16 and 14% of total seepate while for Mg, Ca and Na only 5-7% were found. The incubation studies revealed a significant relation between nitrification rate and water content in the forest floor. The nitrification rate of forest floor material in the proximal stem area was significantly higher than it in the distal stem area. Our results confirm the concept of a microhabitat around beech stems influencing element fluxes and nutrient availability in beech ecosystems.
(final report 1998)

List of publications of this Project

Chang, S-C; Matzner, E: Soil nitrogen turnover in proximal and distal stem areas of European beech trees, Plant and Soil, 218, 117-125 (2000) -- Details
Chang, S-C; Matzner, E: The effect of beech stemflow on spatial patterns of soil solution chemistry and seepage fluxes in a mixed beech/oak stand, Hydrological Processes, 14, 135-144 (2000) -- Details
Chang, S-C: The effect of stemflow on element fluxes and soil nitrogen transformations in a mixed beech/oak stand in the Steigerwald, Germany in Bayreuther Institut für Terrestrische Ökosystemforschung (BITÖK): Bayreuther Forum Ökologie, Selbstverlag, 72, 1-107 (1999) -- Details
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