Epsilon Archive for Student Projects

Abstract

Nitrogen has long been one of the limiting factors for boreal forest growth. To test N-fixation of specified niches in response to different levels of N fertilization and different environments, the study has been carried out in a boreal forest in northern Sweden. In this study, I used a 15N2 pulse labeling approach to quantify the nitrogen fixation rate of Scots pine (Pinus sylvestris) and birch (Betula spp.) leaves and roots in both field and common garden environments under different nitrogen fertilization treatments. In the common garden environment, I also added an extra water treatment for both species. In addition, I measured the nitrogen fixation rate of feather moss in the field environment. I found that the N-fixation rate of moss decreased as N fertilization treatment increased, while water treatment had no significant impact on tree seedling N-fixation rates. Comparing to field environments, N-fixation rates are more detectable in common garden environments.