Untersuchungen über die jahreszeitliche und jahrweise Fluktuation der Nährelementkonzentrationen in den Nadeln eines jüngeren Fichtenbestandes

Abstract

Summary Of the youngest annual set of needles taken from a spruce thicket the N, P, K, Mg, Ca and Mn content was measured every month over a period of six years. From the measured curves representing the mean seasonal movement of the nutrient were derived. In the individual years there are in part considerable deviations of the measured every month from the mean values. These deviations are conditioned mainly by wheather. In the middle of the vegetation period (July) a depression phase is observed in the levels of N, P, K and Mg. In future more attention should be attached to this depression phase in nutrition diagnoses. Due to the fluctuations of the nutrient level diagnosis of the nutritive condition becomes very difficult, if are taken from foliar analyses by one-time sampling. In order to improve the possibility of interpretation the following measures are recommended: permanent observation on index stands growing on typical sites and compilation of tables containing the values of the mean seasonal movement of nutrient level.