Nutritional status of Norway spruce needles and fine roots in relation to the supply of nutrients in the soil

For two contrasting sites in the Balck Forest, mineral contents in the needles and fine roots (Ø < 2 mm) of Norway spruce (Picea abies [L.] Karst.) are compared to the nutrient supply in the soil. The Schluchsee stand stocking on a granite podzol is well supplied with N, P, and K whereas Mg is critical. In contrast, the poorly growing spruce trees on a sandstone pseudogley-brown-earth (town forest of Villingen) is characterized by a low nutrition with N, P, K, and Mg. The nutritional status of the two stands can largely be explained by a different nutrient supply in the soil as reflected in microbial turnover, ion exchange properties, and soil solution chemistry. However, only with the knowledge of the differences in site management history the present nutrient cycling becomes fully legible. For the supply of cation nutrients also disequilibria between outer and inner parts of soil aggregates (K) as well as an antagonistic impairment by Al-ions (Mg, Ca) are important. As a consequence of tightly closed nutrient cycles, nutrient supply is highest in the forest floor. Therefore, fine roots on both sites reveal an extremely shallow growth pattern. A direct impact of Al in the soil solution, on the other hand, is to be excluded. Site-dependent strategies are discussed in order to improve nutrient supply and ecosystem stability. © 1992 Verlag Paul Parey.