ARCHIVE: Fertiliser Manual (RB209)

Ryegrass Grown for Seed

  SNS Index
  0 1 2 3 4 5 6
Nitrogen (N)
- Light sand soils 160 110 60 0-40 0 0 0
- All other mineral soils   160 110 60 0-40 0 0
- Organic soils       60 0-40 0 0
- Peaty soils           0-40
Phosphate (P2O5) 90 60 30 0 0 0 0
Potash (K2O) 150 120 90 (2-)
60 (2+)
0 0 0 0


Nitrogen rates are for crops where there is a low risk of crop lodging either due to field characteristics or use of a growth regulator. A lower nitrogen rate will be appropriate for crops with a higher risk of lodging. Higher rates may be needed in the second cropping year or where amenity varieties are grown.

Where the recommended rate is 100 kg N/ha or more, apply 40 kg N/ha in early-mid March and the balance of the application in early April. Where the requirement is less than 100 kg N/ha, apply the whole application in early April.

Where a crop of Italian ryegrass seed is to be grown following a silage crop, apply 60 kg N/ha immediately following the silage crop

Phosphate and potash

The amounts of phosphate and potash shown at target Index 2 are needed to replace the offtakes and maintain the soil at the target Index. Crops grown on soil at Index 0 and 1 would be expected to respond to the extra amounts of phosphate, potash and magnesium shown in the table below. Also over a number of years, these extra amounts of fertiliser will help to raise the Index level of most soils, except light sands.

Phosphate and potash can be applied at any convenient time except at Index 0 and 1 when the dressing should be applied in the spring of the harvest year.

Don’t forget to:

make allowance for nutrients applied in organic manures (see Section 2)

ensure the phosphate and potash offtake is balanced by application on Index 2 soils and check that the soil is maintained at Index 2 by soil sampling every 3 – 5 years

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