Nitrogen saturation induced during winter by experimental NH4NO3 addition to a forested catchment.
To investigate the potential risk of 'nitrogen saturation' in Scandinavian boreal forests, the authors are experimentally adding 30-50 kg N ha(-1) year(-1) as NH4NO3 in precipitation to an entire 0.52-ha 80-year-old spruce forested catchment at Gårdsjön, near Gothenburg on the Swedish west coast. NO3 concentrations in runoff increased from 0 to about 7 microeq liter(-1) (maximum pulse of 43 microeq liter(-1)). The increase occurred in winter; during the April-October growing season, NO3 concentrations were very low. The speed of the response suggests that these forests are already close to saturation.
Hultberg
H
H
Swedish Environmental Research Institute (IVL), Department of Ecology and Environmental Research, Box 47086,40258 Gothenburg, Sweden.
Dise
N B
NB
Wright
R F
RF
Andersson
I
I
Nyström
U
U