Beziehungen zwischen Stickstoff-Mineralisation und Stickstoff-Ernährungszustand der Fichte im südostbayerischen Flyschgebiet

The relations between Nitrogen-mineralization in the soil and Nitrogen-concentration in the needles of the Norway spruce were investigated at twelve site units on Teisenberg (south-eastern Bavarian Flysch-area). It was found that, although the yield of investigated forest stands was equal, spruce growing on soils enriched with NH ₄ ⁺ -N contained more Nitrogen and thus were fed better than those growing on soils with vast NO ₃ ^- -accumulation. This can be explained by the symbiosis of the spruce roots with NH ₄ ⁺ -mineralizing mycorrhiza fungi on one hand, and by the considerable ablation of nitrate on account of high rainfall in the northern border area of the alps. Generally it was found that the difference of biomass between stands of sundry yield is so big that N-levels are no suitable bases for comparison of nutritive state between various site units.