| Tree species have an impact on soil properties and nutrient cycling in forest ecosystems (Legout et al., 2016; Staelens et al., 2012). Several studies have investigated the nitrate (NO$_3$) dynamics in soil and compared tree species (Lovett et al., 2004; Andrianarisoa et al., 2010). However, most studies investigate only potential net nitrification (PNN), which does not show the real dynamics in the soil. In this study we have investigated gross N dynamics in a common garden experiment in Denmark.
The aim of the study was to understand how gross dynamics of NO$_3$ processes differ in soil with different tree species. Soil from plots with Norway spruce (\textit{Picea abies}) and beech (\textit{Fagus sylvatica}) was sampled. \textsuperscript{15}N isotopes were used to trace the activities in the soil and numerical modelling to calculate gross rates. Nitrous oxide (N$_2$O) losses from the incubated soils were also measured.
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The preliminary results show low NO$_3$ concentration in \textit{Picea} soil, while a steady nitrification and consumption of NO$_3$, which indicates a small NO$_3$ pool with fast turnover. In \textit{Fagus} soil the NO$_3$ concentration is much higher, which could be explained by the low NO$_3$ consumption rates, leading to a build-up of NO$_3$ in the soil. The N$_2$O fluxes from \textit{Fagus} soil are also higher, indicating larger N losses. These results show the significance of tree species and suggest what long-term effects it could have on the soil N retention.
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Andrianarisoa, K. S., Zeller, B., Poly, F., Siegenfuhr, H., Bienaim\'{e}, S., Ranger, J., and Dambrine, E.: Control of Nitrification by Tree Species in a Common-Garden Experiment, Ecosystems, 13, 1171-1187, 10.1007/s10021-010-9390-x, 2010.\\\\
Legout, A., van der Heijden, G., Jaffrain, J., Boudot, J.-P., and Ranger, J.: Tree species effects on solution chemistry and major element fluxes: A case study in the Morvan (Breuil, France), For. Ecol. Manage., 378, 244-258, http://dx.doi.org/10.1016/j.foreco.2016.07.003, 2016.\\\\
Lovett, G. M., Weathers, K. C., Arthur, M. A., and Schultz, J. C.: Nitrogen cycling in a northern hardwood forest: Do species matter?, Biogeochemistry, 67, 289-308, 10.1023/B:BIOG.0000015786.65466.f5, 2004.\\\\
Staelens, J., R\"{u}tting, T., Huygens, D., de Schrijver, A., M\"{u}ller, C., Verheyen, K., and Boeckx, P.: In situ gross nitrogen transformations differ between temperate deciduous and coniferous forest soils, Biogeochemistry, 108, 259-277, 10.1007/s10533-011-9598-7, 2012. |