2. Information relating to crop nitrogen requirement
Part 4 of the Regulations establishes a limit on the amount of nitrogen (from manufactured nitrogen fertiliser and crop available nitrogen from livestock manures) that can be applied to specified crops (see Leaflet 7). The N max limits for the specified crops are provided in Table 5 below, together with a range of permitted adjustments to the limits.
Part 6 of the Regulations establishes a closed period for manufactured nitrogen fertiliser, although applications are permitted to some crops which have a crop nitrogen requirement during this closed period (see Leaflet 9). These crops are listed in Table 6 together with their maximum permissible application rates.
Table 5: The N max limits
| Crop |
N max limit
(kg N/ha)
(note a) |
Standard crop yield (t/ha) |
| Wheat, autumn or early winter sown |
220 (notes b, c, d) |
8.0 |
| Wheat, spring sown |
180 (notes c, d) |
7.0 |
| Barley, winter |
180 (notes b, c) |
6.5 |
| Barley, spring |
150 (note c) |
5.5 |
| Oilseed rape, winter |
250 (notes e) |
3.5 |
| Sugar beet |
120 |
n/a |
| Potatoes |
270 |
n/a |
| Forage maize |
150 |
n/a |
| Field beans |
0 |
n/a |
| Peas |
0 |
n/a |
| Grass |
330 (note f) |
n/a |
Notes:
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An additional 80 kg N/ha is permitted to all crops grown in fields where the previous or current crop received an application of straw for mulching or paper sludge.
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An additional 20 kg N/ha is permitted on fields with a shallow soil type (not shallow soils over sandstone).
-
An additional 20 kg N/ha is permitted for every tonne that the expected yield exceeds the standard yield.
-
An additional 40 kg N/ha is permitted to milling wheat varieties.
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This consists of a maximum autumn application of 30 kg N/ha (allowed as an exemption to the closed period for manufactured nitrogen fertiliser) and a maximum spring application of 220 kg N/ha. The spring application can be increased by up to 30 kg N/ha for every half tonne that the expected yield exceeds the standard yield.
-
An additional 40 kg N/ha is permitted to grass that is cut at least 3 times in a year. From 1st January 2012, the N max rate for grass drops to 300 kg N/ha.
Table 6: Crops to which manufactured nitrogen fertiliser may be applied during the closed spreading period
| Crop |
Maximum nitrogen rate (kg/ha) |
| Oilseed rape, winter (note a) |
30 |
| Asparagus |
50 |
| Brassica (note b) |
100 |
| Bulb onions |
40 |
| Over-wintered salad onions |
40 |
| Parsley |
40 |
| Grass (notes a, c) |
80 |
Notes:
-
Nitrogen must not be applied to these crops after 31 October.
-
An additional 50 kg N/ha may be applied every four weeks during the closed spreading period up to the date of harvest.
-
A maximum of 40 kg N/ha may be applied at any one time.