## 3 Results  
### Evaluation of Control Simulations  
The model physics has previously been evaluated at Storflaket and Stordalen peat mire by [45, 58]. This is also summarised in Figure 1 for the \(Control\) simulation of \(PFT_{compete}\) which shows the simulated snow depth, soil temperature, and active layer compared with the observations. The model matches the soil temperature observations well but has a small warm bias in soil temperature during the winter. There is a general agreement between the observed and modelled snow depth. The mean simulated maximum summer thaw \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Name** & **C:N Ratio** & **Root Depth (m)** & **Treatment** & **Present/Future** \\ \hline \(CN_{high}Root_{25}\) & higher & 0.25 & \(C\) & both \\ \(CN_{high}Root_{25}\) & higher & 0.25 & \(NS\) & present \\ \(CN_{high}Root_{25}\) & higher & 0.25 & \(TF\) & present \\ \(CN_{high}Root_{25}\) & higher & 0.25 & \(NS-TF\) & present \\ \(CN_{high}Root_{60}\) & higher & 0.6 & \(C\) & both \\ \(CN_{low}Root_{60}\) & lower & 0.6 & \(C\) & both \\ \(CN_{low}Root_{60}\) & lower & 0.6 & \(NS\) & present \\ \(CN_{low}Root_{60}\) & lower & 0.6 & \(TF\) & present \\ \(CN_{low}Root_{60}\) & lower & 0.6 & \(NS-TF\) & present \\ \(CN_{low}Root_{90}\) & lower & 0.9 & \(C\) & both \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Table of simulations discussed in this paper. \(C\) represents the control simulation, \(NS\) represents fertiliser added near the surface; \(TF\) represents fertiliser added near the thaw-front; and \(NS-TF\) represents fertiliser added both near the surface and deeper in the soil. depth between 2006 and 2014 is 64 cm which falls well within the range of observational uncertainty at Storflaket. However, this is slightly deeper than the active layer at the experimental site described in [40]. \(CN_{high}Root_{25}\) and \(CN_{low}Root_{60}\) simulations (not shown) have some very minor differences in these physical variables mainly caused by differences in the canopy height and evapotranspiration. For example, the mean maximum summer thaw depth ranges from 60 cm for \(CN_{low}Root_{60}\) to 65 cm for \(CN_{high}Root_{25}\). The most realistic simulation of this specific field site is expected to be the \(PFT_{complete}\) simulation which allows both the shallow and deep-rooted vegetation to co-exist. The competition in \(PFT_{complete}\) means that \(CN_{low}Root_{60}\) covers about 40% of the grid cell and \(CN_{high}Root_{25}\) covers about 55% of the grid cell with the rest bare soil. This means that the \(PFT_{complete}\) simulation contains more of \(CN_{low}Root_{60}\) vegetation when compared with the observations (12% and 78% observed for \(CN_{low}Root_{60}\) and \(CN_{high}Root_{25}\), respectively, with no bare soil). In addition, there is _Sphagninum_ moss at the observation site, which is not currently represented in JULES. The \(CN_{low}Root_{60}\) and \(CN_{high}Root_{25}\) simulations, with only one type of vegetation present, have approximately 80% vegetation cover and 20% bare soil. The soil carbon profiles and the gross primary productivity (GPP) are shown in Figure 2 for the three different configurations, i.e., \(PFT_{complete}\), \(CN_{high}Root_{25}\), and \(CN_{low}Root_{60}\). The GPP is compared with the estimate from the FLUXNET2015 [61] dataset for Stordalen Mire and the soil carbon compared with the observational data used by [45]. The GPP for \(PFT_{complete}\) where both vegetation types are present compares well with these observations. This appears to be a combination of the lower GPP associated with \(CN_{high}Root_{25}\) and the higher GPP associated with \(CN_{low}Root_{60}\). The simulated amount of soil carbon in Figure 2 is too small and the profile of soil carbon is more representative of a mineral soil with some organic matter--high soil carbon at the surface decreasing with depth. However, Stordalen Mire has a peat soil, a representation of which is currently under development for JULES [62].