%0 Research article
%T Nutrient loading of Norway spruce seedlings hastens bud burst and enhances root growth after outplanting
%A Luoranen, Jaana
%A Rikala, Risto
%D 2011
%J Silva Fennica
%V 45
%N 3
%R doi:10.14214/sf.105
%U https://silvafennica.fi/article/105
%X We studied the effects of late season nutrient loading (NLOAD) on the  timing of bud burst, growth and changes in nitrogen (N) concentrations  in the first growing season after seedlings were outplanted.  Two-year-old Norway spruce (Picea abies (L.) Karst.) seedlings with  three foliar nitrogen concentration levels (NLOAD levels 11.3, 22.5 and  27.5 g N kg<sup>-1</sup> for L, M- and H-seedlings, respectively) were  examined in the following three experiments: root growth capacity test  (RGC), rooting experiment in the field and soil fertility experiment  (‘rich’ or ‘poor’ soil) in the field. Bud burst in RGC was monitored  daily and foliar N concentration (field experiments), height and root  growth (rooting experiment) at monthly intervals. With respect to the  RGC test, no differences in root growth were observed among the three  NLOAD levels, but buds of H-seedlings burst 2–6 days earlier than  others. In the rooting experiment, nutrient loading increased height and  root growth but did not affect the timing of height growth. In the soil  fertility experiment, foliar N of H- and M-seedlings decreased rapidly,  but the decline was slower in rich soil. Current-year needles had more N  in seedlings growing in rich soil and the N concentration declined  until height growth ceased whereafter it increased until autumn.  Improved growth from nutrient loading seems to last only for the first  season after planting and the greatest benefits are enjoyed by seedlings  planted in poor soils.