Alberta Bog Net Nitrogen Mineralization, 2013-2015

Alberta bogs are subject to periodic wildfire. Although these bogs have persisted under low atmospheric nitrogen deposition (less than 2 kg N/ha/yr), nitrogen deposition in northern Alberta is increasing due to ongoing oil sands development. This study examined how time since fire and experimental N deposition affects nitrogen mineralization in near-surface bog peat. Net nitrogen mineralization (ammonification, nitrification, dissolved organic N production) was quantified using the buried bag technique in 5 Alberta bogs differing in time since fire. At each site, 24 2.4 _ 4.8 m plots were established, with 6 replicate plots receiving one of four N addition treatments: controls (receiving no water or N), H2O controls (receiving water, but no N; 0 kg N ha-1 yr-1), and 10 and 20 kg N ha-1 yr-1, applied as NH4NO3 dissolved in 15 L of H2O and applied via backpack sprayer eight times during each summer field season. We established plots and began N additions in 2011 at the Utikuma Bog site and in 2013 for the other four sites. This study is published as: Stuart JEM, Wieder RK, Vile MA (2018) Net Nitrogen Mineralization in Alberta Bog Peat is Insensitive to Experimentally Increased Nitrogen Deposition and Time Since Wildfire. Biogeochemistry, in press.