## Materials and Methods
### Calculations and Statistical Analysis  
Conversion of \(\delta^{15}\)N into \({}^{15}\)N atom% was performed with Equation (1):  
\[{}^{15}\text{N atom }\%=[(\delta^{15}\text{N}/1000)^{*}0.3665]+0.3665 \tag{1}\]  
where \(\delta^{15}\)N is the isotopic signature expressed as \"delta\" notation and 0.3665 (%) is the \({}^{15}\)N natural abundance in the standard (N\({}_{2}\) air).  
Net rates, gross production, and gross consumption were calculated with the following equations (Equations (2)-(4)) [70]:  
\[\text{Nr}=(\text{C}_{\text{t24}}-\text{C}_{\text{t0}})/\text{t} \tag{2}\]  
\[Gp=Nr^{*}\left[\text{log }(\text{APE}_{\text{t0}}/\text{APE}_{\text{t24}})/ \text{log}(\text{C}_{\text{t24}}/\text{C}_{\text{t0}})\right] \tag{3}\]  
\[Gc=Gp-Nr \tag{4}\]  
where \(Nr\), \(Gp\), and \(Gr\) are net rates, gross production, and gross consumption (mg NO\({}_{3}\)\({}^{-}\) or NH\({}_{4}\)+-N kg\({}^{-1}\) day\({}^{-1}\) dm), respectively. C is the concentration of NH\({}_{4}\)+-N or NO\({}_{3}\)\({}^{-}\)-N in mg kg\({}^{-1}\), APE is the atom% excess of \({}^{15}\)N, calculated as atom% \({}^{15}\)N measured is the sample-\({}^{15}\)N natural abundance (0.3665%), t\({}_{0}\) and t\({}_{24}\) are the initial and final extraction points, t is the time intercurred in the incubation (1 day). Nr (Equation (2)) indicates the temporal net variation of the target pool size with incubation time and does not allow the discrimination between production and consumption processes. By relating Nr with the dilution of the introduced \({}^{15}\)N pool with newly produced NH\({}_{4}\)+-N or NO\({}_{3}\)\({}^{-}\)-N at natural abundance by ammonification and nitrification processes, gross production rates can be calculated (Equation (3)). Finally, it is possible to calculate the rate of consumption by subtracting Nr from the Gp (Equation (4)).  
Gaseous N\({}_{2}\)O-N and CO\({}_{2}\)-C fluxes were calculated on soil mass basis by considering the linear increase in headspace concentration over the incubation period according to [71]. The ideal gas law was used to convert ppm of N\({}_{2}\)O and CO\({}_{2}\) in ppm, to N and C mass. The conversion factor of ppm to \(\upmu\)m\({}^{3}\) was calculated according to Equation (5):  
\[\text{Cf}=(\text{P*Mwc*1000})/(\text{R*T}) \tag{5}\]where Cf is the conversion factor (ppm to \(\mathrm{\SIUnitSymbolMicro g}\) m\({}^{3}\)); P is the air pressure (in kPa); Mwc is the molar mass of N or C; R is the gas constant (8.314); T is the incubation air temperature (K) [71].  
Then, the flux on the mass basis was calculated according to Equation (6):  
\[\mathrm{Fmass}=[\Delta(\mathrm{ppm}\,\mathrm{*}\,\mathrm{Cf})/\Delta\mathrm{t} )^{\mathrm{*}}\mathrm{Hs}]/(\mathrm{Vo}^{\mathrm{*}}\mathrm{Db}) \tag{6}\]  
where Fmass is the linear gas efflux in the incubation container on soil mass basis (mg N\({}_{2}\)O-N or CO\({}_{2}\)-C g\({}^{-1}\) soil h\({}^{-1}\)); Ppm is the concentration measured with the GC in ppm; Cf, conversion factor calculated from Equation (5); \(\Delta\)t is the incubation time (hours); \(\Delta\) (ppm * CF) is the change in gas concentration during the incubation period; Hs is the headspace of the container (m\({}^{3}\)); Db is the soil bulk density (g cm\({}^{-3}\)); Vo is the volume of the microcosm (cm\({}^{3}\)) [71].  
To evaluate significant differences between the treatments, ANOVA and multi-comparison Tukey HSD tests were performed at \(p\) < 0.05. Normality and homoscedasticity were tested before running ANOVA using [PERSON] and Bartlett's tests. If data were not normally distributed, data were ln transformed to meet ANOVA assumptions. If normality was not reached, the non-parametric Kruskal Wallis test was applied. All statistical analysis was performed using R studio version 1.3.335. The following R packages have been employed for data analysis and figure building in this paper: \"_ggplot2_\" [72], \"_Agricolae_\" [73].