The nitrogen excretion figure for a dairy cow, used to calculate stocking rate, is to be increased later this year, the Irish Farmers Journal understands.

It has been a long touted move, as the latest published data suggests the figure of 85kg N/ha is no longer accurate. There will not be a huge increase, but it is believed the new figure will be in the region of 89kg to 90kg N/ha.

In documents seen by this newspaper, the Department has set an estimated timescale of autumn of this year for the amendment, which is likely to apply from next year.

The Department, along with the Department of Housing, will also publish a consultation document on the next nitrates action programme (NAP) around the same time.

Further stakeholder consultation will take place throughout 2021, with a view to having the next NAP approved by the European Commission and ready for implementation in January 2022.

Stocking rates

Increasing the organic nitrogen excretion figure from 85kg to 89kg or 90kg per cow will have the effect of bringing more dairy farmers into the nitrates derogation zone.

The limit for organic nitrogen per hectare without derogation is 170kg/ha. At 85kg organic nitrogen per cow, this is a stocking rate of two cows per hectare.

At 90kg organic nitrogen per cow, the maximum stocking rate without a derogation drops to 1.89 cows/ha.

Farmers who go over the 170kg/ha organic N limit can either export slurry off their holding to bring them back under the limit or apply for a derogation.

The average dairy farm is stocked at 172kg organic nitrogen per hectare, so it would be expected that more farmers would apply for derogation after this change is made.

Changes

A small number of farmers at the upper end of the organic nitrogen per hectare limit, which is 250kg/ha, will also be affected by these changes.

Speaking earlier this year on the topic, senior Department official Jack Nolan said: “If you're a dairy farmer, for 2021 you should be looking at your system and saying 'can I cope with reduced fertiliser use, reduced nitrogen and can I cope if the dairy cow changes to 89 kilos', because that's what's coming very shortly."

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