Results summary: we found little difference in yield between N rates from 140 to 260 kg/ha, indicating that the economically optimal rate for gross margin was around 140 kg/ha, or could have been even lower. The Yara N tester recommended no further N after the first two splits totalling 140 kg/ha, and has been proved right in this case.
This trial result is in keeping with other N rate trials in 2022, which found lower N optima than usual. This is thought to be because the mild, dry winter caused higher mineralisation and lower leaching than usual, leading to high soil residual N levels at the end of winter.