## 3 Results and Discussion
### Soil
#### 3.1.5 Nitrate  
Mean soil nitrate contents for each tillage type, nitrogen dose, and soil depth are presented in Table 8, and ANOVA results are reported in Table 6. Table 8 shows that  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Nitrogen** **(kg N ha\({}^{-1}\))** & **Tillage/Depth** **(cm)** & **0-5** & **5-10** & **10-20** & **20-40** & **40-60** & **Mean** & **Mean** \\ \hline \multirow{2}{*}{20} & NT & 17.8 (5.1) & 9.1 (0.4) & 7.1 (0.4) & 9.6 (0.9) & 13.6 (0.9) & 11.4 (3.5) & 8.7 (3.0) A \\  & CT & 5.0 (0.8) & 6.6 (1.0) & 5.5 (0.9) & 8.0 (0.8) & 5.0 (1.1) & 6.0 (1.6) & \\ \hline \multirow{2}{*}{40} & NT & 19.6 (3.6) & 10.1 (1.8) & 12.1 (2.5) & 9.8 (0.3) & 5.0 (0.9) & 11.3 (3.7) & 8.3 (4.1) A \\  & CT & 6.0 (0.8) & 5.2 (0.8) & 4.0 (0.7) & 5.1 (0.6) & 6.0 (0.7) & 5.3 (1.2) & 8.3 (4.1) A \\ \hline \multirow{2}{*}{60} & NT & 7.4 (0.9) & 11.1 (1.7) & 10.6 (0.6) & 9.6 (1.0) & 7.1 (1.0) & 9.2 (1.7) & \multirow{2}{*}{8.0 (2.0) A} \\  & CT & 5.0 (0.9) & 7.5 (0.8) & 8.1 (0.5) & 6.6 (0.6) & 6.8 (0.6) & 6.8 (1.1) & \\ \hline \multirow{2}{*}{Mean} & NT & 14.9 (5.1) & 10.1 (1.6) & 9.9 (2.8) & 9.7 (0.9) & 8.6 (1.3) & 10.6 (3.3) & \\  & CT & 5.3 (0.9) & 6.4 (1.3) & 5.9 (1.7) & 6.6 (1.6) & 5.9 (1.3) & 6.0 (1.4) & \\ \hline \multirow{2}{*}{Mean} & Mean & 10.1 (5.1) & 8.3 (2.8) & 7.9 (3.1) & 8.1 (1.8) & 7.3 (1.3) & 8.3 (3.1) \\ \hline \end{tabular}
\end{table}
Table 7: Ammonium content (mg kg\({}^{-1}\)) measured at the end of the experiment for each nitrogen dose (kg N ha\({}^{-1}\)), tillage type, and soil depth (cm). Means (_n_ = 3) with standard deviations followed by the same letter are not statistically different at the 0.05 significance level according to [PERSON]’s post hoc test. NT= no tillage, CT= conventional tillage.  
nirate contents for each nitrogen dose are higher under conventional conditions than under no-tillage conditions.  
ANOVA (Table 6) revealed highly significant differences for the three factors: F value = 50.10 and \(p\)-value = 0.019 for tillage type, F value = 30.74 and \(p\)-value \(<\) 0.001 for nitrogen dose, and F value = 11.81 and \(p\)-value \(<\) 0.001 for soil depth. Mean values were higher for CT (13.8 mg kg\({}^{-1}\)) than NT (11.6 mg kg\({}^{-1}\)). [PERSON]'s post hoc test showed that the three nitrogen doses significantly differed, with mean values of 8.4, 13.9, and 15.8 mg kg\({}^{-1}\) corresponding to 20, 40, and 60 kg N ha\({}^{-1}\), respectively. Regarding soil depth, three groups were identified: 10-20 cm, with a mean value of 14.6 mg kg\({}^{-1}\); 5-10, 20-40, and 40-60 cm, which did not significantly differ, with mean values of 13.6, 12.5, and 13.1 mg kg\({}^{-1}\), respectively; and 0-5 cm, with a mean value of 9.9 mg kg\({}^{-1}\). All interactions, except tillage type x nitrogen dose, were statistically significant.  
The levels of total nitrogen and ammonium in NT were higher than in CT, contrary to nitrate content, which can be explained by the use of excess nitrogen fertilizers or by the use of plant protection products. In addition, nitrate content for each nitrogen treatment was higher under CT than NT, although nitrate has higher mobility than ammonium, which could be impacted by leaching.