Nitrogen Status and Dynamics in German Forest Soils

作者：Stefan Fleck, Nadine Eickenscheidt, Bernd Ahrends, Jan Evers, Erik Grüneberg, Daniel Ziche, Juliane Höhle, Andreas Schmitz, Wendelin Weis, Paul Schmidt‐Walter, Henning Andreae, Nicole Wellbrock · 发表于：Ecological studies · 年份：2019 · DOI：10.1007/978-3-030-15734-0_5 · 被引用次数：30 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Peatlands and Wetlands Ecology

Increased deposition of reactive nitrogen (N) since pre-industrial times has dramatically altered the conditions for forest growth and decomposition of organic material in Germany. The second National Forest Soil Inventory (NFSI II, 2006–2008) shows the status of N accumulation in forest soils. A median N stock of 6.3 t ha –1 has been found in the soil profile down to a depth of maximum 90 cm, whereof 50% is stored in the upper 30 cm of the mineral soil. The high regional variability of N stocks is explained by forest type, parent material, soil acidity, annual mean temperature, and adjacent agricultural land use. C/N ratios of the top soil were on average higher (24.0) than those during NFSI I (22.4, 1989–1992), which may be seen as a first effect of slowly decreasing deposition rates. Observations on limed plots suggest that acidification inhibits soil biological activity and thereby reduces N-storage in the mineral soil. The median annual N balance for German forest soils between NFSI I and II varies between +2.9 and +7 kg ha –1 , depending on the harvest regime assumed. Negative N balances occurred mainly in mountain ranges like the Black Forest or the Rhenish Slate Mountains. N stocks in the upper 30 cm of the soil generally increased, while there are indications for losses of N from deeper soil layers, potentially linked to progressing acidification in these layers. Irrespective of existing measurement uncertainties, the findings indicate the vulnerability of forest N s...