Key Points
- The optimum closing date for a mid season flowering cultivar (similar to Nui) was 2 October (in a Methven environment) in a year that had favourable December rainfall.
- Seed yields declined rapidly with closing dates that were later than the optimum.
- Earlier closing (12 and 22 September) had lower seed yields, between 15 and 21% (equal to 440 and 660 kg/ha).
- The biological optimum and economic optimum closing date was the same day.
- In drier than average years the optimum closing date for dryland growers in Methven is likely to be earlier than the optimum date predicted in this trial.