## 3 Results  
Greenhouse gas exchange (Figure 2), soil climate simulations (Figure 3) and crop biomass simulations (Figure 4) were generally in agreement with measurements through most of the modelled timeframe. For GPP, there was a good correlation \(\rho\) between simulated and measured data, though MAE was poor, RMSE was fair, and the model pBias% underestimated and scored poor. For NEE, there was a good \(\rho\) correlation between simulated and measured data, though MAE was poor, RMSE was fair, and the model scored good overall, with a small pBias% underestimate. For Reco, there was a good \(\rho\) correlation between simulated and measured data, though MAE was poor, RMSE was good, but model pBias% underestimated and scored poor (Table 5). For soil temperature there was a correlation \(\rho\) score of excellent, MAE was excellent, RMSE was excellent and pBias% scored fair, and showed that the model overestimated compared to measured data. Soil water (WFPS) at 5 cm scored \"good\" \(\rho\) for [PERSON]'s correlation, MAE was excellent, and RMSE was also excellent, while there was a small, but good underestimation for pBias%. For WFPS at 20 cm there was a poor \(\rho\) correlation, whereas MAE was excellent and RMSE was excellent, whilst there was only a small pBias% underestimation, which scored excellent (Table 5). The DNDC model simulated seasonal patterns of GHG exchange (Figure 2) and soil climate (Figure 3) well. Seasonally, GHG's tended to be close to 0 between October and April, although in the evaluation year eddy covariance did not show the simulated uptick in ecosystem respiration and NEE (Figure 2b,c) until six weeks later in mid-June, and DNDC did not pick up on this and also did not pick up on wintertime ecosystem respiration (Figure 2c). Soil temperature at 5 cm (Figure 3a) was very similar to measured data, although WFPS at 5 cm (Figure 3b) showed less accuracy in January and May, and in the 20 cm layer DNDC overestimated in May 2018 and underestimated between December 2018 and May 2019 (Figure 3c). Biomass (DM kg/ha\({}^{-1}\)) simulation were compared with measured cuts using an independent sample \(t\)-test. Measured DM (mean = 3117, sd = 915) was compared to simulated DM (mean = 4517, sd = 926) and there was a significant difference between the two \(t\) (8) = \(-\)2.4, \(p\) < 0.05. \begin{table}
\begin{tabular}{l c c c c} \hline
**Evaluation Method** & **Poor** & **Fair** & **Good** & **Excellent** \\ \hline Spearman’s rank correlation (\(\rho\)) & 0.30 & 0.50 & 0.70 & 1.00 \\ MAE & 4.0+ & 3.0–3.9 & 2.0–2.9 & 1.0–1.9 \\ RMSE & \(\geq\)40 & 20–39 & 10–19 & 0–10 \\ pBias\% & \(>\)20\% & 15–20\% & 11–15\% & \(<\)10\% \\ \hline \end{tabular}
\end{table} 
Table 4: Model evaluation based on classifications as per [27; 31; 34]. Overall scores are calculated as the mean performance of variables across all four metrics. \begin{table}
\begin{tabular}{c c c c c c} \hline  & \(\rho\) & **MAE** & **RMSE** & **pBias\%** & **Mean Score** \\ \hline GPP (kg C ha\({}^{-1}\)) & 0.80 (\(p\) \(<\) 0.001) & 21.3 & 35.1 & \(-\)20.7\% & Fair \\ NEE (kg C ha\({}^{-1}\)) & 0.72 (\(p\) \(<\) 0.001) & 16.6 & 26.7 & \(-\)14.2\% & Fair \\ Reco (kg C ha\({}^{-1}\)) & 0.85 (\(p\) \(<\) 0.001) & 10.9 & 14.2 & \(-\)22.8\% & Fair \\ \hline Soil Temp (\({}^{\circ}\)C) & 1.00 (\(p\) \(<\) 0.001) & 0.1 & 1.2 & 18.2\% & Excellent \\ WFPS (cm\({}^{3}\)/cm\({}^{3}\)) 5 cm & 0.73 (\(p\) \(<\) 0.001) & 0.1 & 0.1 & \(-\)11.2\% & Excellent \\ WFPS (cm\({}^{3}\)/cm\({}^{3}\)) 20 cm & 0.25 (\(p\) \(<\) 0.001) & 0.1 & 0.1 & \(-\)5.0\% & Good \\ \hline \end{tabular}
\end{table} 
Table 5: Evaluation results for simulated versus measured GHG exchange and soil microclimate. The ‘Mean score’ column represents the overall assessment when all four measures are accounted for.