| N rate (kg N ha−1) | Mean Plant N Concentration (%) | ||
| Parma | Ashton | Rupert | |
| 0 | 0.33c | 0.35b | 0.33c |
| 84 | 0.41bc | 0.39ab | 0.41bc |
| 168 | 0.65a | 0.45a | 0.65a |
| 252 | 0.49b | 0.35b | 0.49b |
| 336 | 0.70a | 0.45a | 0.70a |