%0 Research article
%T Foliar nitrogen, phosphorus and potassium concentrations of Scots pine in drained mires in Finland
%A Moilanen, Mikko
%A Saarinen, Markku
%A Silfverberg, Klaus
%D 2010
%J Silva Fennica
%V 44
%N 4
%R doi:10.14214/sf.129
%U https://silvafennica.fi/article/129
%X An imbalanced nutrient status in Scots pine stands on drained mires is  primarily a consequence of excess nitrogen (N) in relation to mineral  nutrients such as phosphorus (P) and potassium (K). In this study, the  variation of foliar N, P, and K concentrations relative to some site and  environmental characteristics was examined. Foliar nutrient  concentrations were determined on needle samples collected from mires  representing different drainage ages, site types, geographical locations  and annual weather conditions. In the overall data (n = 971 samples in  333 stands) the foliar N concentration varied between 6.7 and 24.2 mg g<sup>-1</sup>, the P concentration between 0.83 and 2.32 mg g<sup>-1</sup>, and the K concentration between 2.22 and 6.23 mg g<sup>-1</sup>.  The original (pre-drainage) mire site type proved to be an important  factor in explaining the nutrient status of the trees: on originally  forested sites, the nutrient balance (N versus K;  N versus P) was mostly adequate, whereas on sparsely forested and  treeless sites, K deficiency was common. N deficiency was the most  common in forested ‘nitrogen-poor’ sites, while  P and K deficiencies were more common in originally treeless or sparsely  forested ‘nitrogen rich’ sites, where the nutrient imbalance was also  the greatest. Over the whole data, 29% of the cases were diagnosed to be  N-deficient, 51% P-deficient, and 25% K-deficient. The foliar N  concentration increased with increasing temperature sum. The foliar K  concentration decreased with increasing depth of the peat layer. On  former treeless or sparsely forested sites, foliar K decreased slightly  with increasing drainage age. In contrast, on thin-peated sites the  foliar P concentration increased with increasing drainage age. The  climate conditions (location), the original site type of the mire and  peat thickness should be taken into account when planning silvicultural  measures on mires drained for forestry.