%0 Research note
%T Respiration in a forest soil 27 years after fertilization with different doses of urea
%A Nohrstedt, Hans-Örjan
%A Börjesson, Gunnar
%D 1998
%J Silva Fennica
%V 32
%N 4
%R doi:10.14214/sf.679
%U https://silvafennica.fi/article/679
%X A number of previous studies have shown that N fertilization often  reduces respiration in forest soils. However, the durability of this  effect has not been fully explored. In this study, the response of soil  respiration to a single fertilization with urea, applied 27 years  earlier, was examined in a field experiment located in a stand of Pinus  sylvestris in central Sweden. The doses that had been added were 120,  240 and 600 kg N ha–1. Samples were taken from the humus layer and the  upper 7.5 cm of the mineral soil. Sieved samples were incubated in the  laboratory. No effect of the previous fertilization on soil respiration  was found, thus indicating that the reduction shown in earlier studies  is not persistent. There was a tendency that the highest N dose had  caused a higher N concentration and a lower C/N-ratio in the humus layer  and a higher C concentration in the mineral soil.