Key Points:
- Application rates of nitrogen (N) for perennial ryegrass are based on taking account of the soil mineral N level in late winter.
- Targets of 180 kg/ha of total N (soil mineral and applied) are giving the best results over 22 individual experiments on a range of soil types, with a range of soil mineral N values.
- On average growers can expect a 43% increase in seed yield through applying the correct amount of spring nitrogen.
- Changes in seed head numbers are the main causes of changes in seed yield from various N treatments.
- Application to the optimum N rate (approximately 140 kg applied N) resulted in a return of approximately $8 (net) for each $1 spent on N fertiliser.