| Nitrogen dose (mg∙dm−3) | Variable observed | Maximum production |
| 113.33 | Height of plants | 81.67 cm |
| 162.00 | Number of leaves | 176.27 leaves pot−1 |
| 186.00 | Chlorophyll index | 68.19 |
| 190.00 | Number of head | 17.52 units pot−1 |
| 174.40 | Dry mass of shoot | 28.08 g pot−1 |
| 177.02 | Dry mass of root | 25.98 g pot−1 |