## 3 Results
### N Fluxes and Cumulative Emissions  
During the oxic incubation phase, only N\({}_{2}\)O and NO fluxes were measured as N\({}_{2}\) fluxes were below the detection limit (Figure 2a,b). N\({}_{2}\)O fluxes from litter treatments were higher than 3.7 \(\mu\)g N kg\({}^{-1}\) h\({}^{-1}\) for the first measurements on 1 DAO and declined to <1 \(\mu\)g N kg\({}^{-1}\) h\({}^{-1}\) until 5 DAO. N\({}_{2}\)O fluxes from litter-amended soils were in tendency higher than N\({}_{2}\)O fluxes from Control. Initial NO fluxes were -0.08 \(\mu\)g N kg\({}^{-1}\) h\({}^{-1}\) in Control and Root, and -0.06 \(\mu\)g N kg\({}^{-1}\) h\({}^{-1}\) in leaves and straw. In Leaf, a second NO \begin{table}
\begin{tabular}{c c c c c c c} \hline  & \multicolumn{2}{c}{**Total CO\({}_{2}\)**} & \multicolumn{2}{c}{**SOM-Derived CO\({}_{2}\)**} & \multicolumn{2}{c}{**Litter-Derived CO\({}_{2}\)**} & \multicolumn{2}{c}{**Priming Effect**} \\  & **(mg C kg\({}^{-1}\) dry soil)** & **(mg C kg\({}^{-1}\) dry soil)** & **(mg C kg\({}^{-1}\) dry soil)** & **(mg C kg\({}^{-1}\) dry soil)** & **(mg C kg\({}^{-1}\) dry soil)** \\ \hline Control & 359.5 \(\pm\) 13.2 & d & 359.5 \(\pm\) 13.2 & c & - & - \\ Maize Leaves & 1266.0 \(\pm\) 118.8 & a & 654.8 \(\pm\) 83.5 & a & 597.5 \(\pm\) 33.9 & a & 288.2 \(\pm\) 76.2 & a \\ Maize Roots & 749.8 \(\pm\) 68.1 & c & 504.9 \(\pm\) 10.7 & b & 281.6 \(\pm\) 17.6 & c & 130.0 \(\pm\) 12.0 & b \\ Maize Straw & 970.8 \(\pm\) 34.3 & b & 561.9 \(\pm\) 26.9 & b & 449.7 \(\pm\) 21.1 & b & 178.4 \(\pm\) 21.5 & b \\ \hline \end{tabular} Values represent means (n = 5, for Control n = 4) \(\pm\) standard deviation. Different letters in the same column indicate a significant difference.  
\end{table} 
Table 4: Cumulative SOM and litter-derived CO\({}_{2}\) emissions, and priming effect. Figure 1: (**a**) Litter-derived CO\({}_{2}\) fluxes, (**b**) SOM-derived CO\({}_{2}\) fluxes, and (**c**) cumulative priming effect (means and standard deviation for n = 5, n = 4 for Control, when not visible, error bars are smaller than the symbols). peak was detected on 5 DAO. NO fluxes in Control were in tendency higher than in all litter treatments until 14 DAO, while NO flux declined fastest in Straw, where fluxes were smaller than in all other treatments after 3 DAO. The ratio of NO/N\({}_{2}\)O was highest in Control directly after onset of incubation with maximum values of 0.47 (Supplementary Figure S5). In Root and Leaf, it reached maximum values of 0.2 and 0.1 on 5 and 6 DAO. In Straw, highest measured values were 0.1 on 2 DAO. With onset of the anoxic phase, NO/N\({}_{2}\)O decreased to 0.015 in all treatments. During the oxic phase, cumulative N\({}_{2}\)O emissions from litter-amended soil were higher than from Control (\(p<0.05\), Table 5). Cumulative emissions in Straw were higher than in Root and similar to Leaf. Cumulative NO emissions were highest in Control and lowest in Straw, and NO/N\({}_{2}\)O ratio was significantly higher in Control than in litter-amended treatments. NO emissions strongly decreased with decreasing litter C:N ratio (adj; R\({}^{2}\) = 0.86, \(p<0.001\)) and increased with increasing N mineralization (adj; R\({}^{2}\) = 0.57, \(p<0.001\)) confirming that litter quality affected nitrification-derived NO emissions during the oxic incubation phase. Figure 2: (**a**,**b**) N\({}_{2}\)O, and NO fluxes during oxic incubation period (0–47 DAO). (**c**–**e**) N\({}_{2}\)O, N\({}_{2}\), and NO fluxes during anoxic incubation (47–55 DAO) of maize litter on grassland soil (means and standard deviation for n = 5, n = 4 for Control, when not visible, error bars are smaller than the symbols).