Former DAERA chief scientific adviser and ex-CEO of AFBI, Dr Sinclair Mayne, has raised concerns that some measures proposed by the department as part of a revised Nutrients Action Programme (NAP) do not come with “appropriate supporting scientific evidence”.

Dr Mayne, in his capacity as scientific adviser to AgriSearch, has identified three particular areas of concern within the DAERA proposals.

The first relates to new nitrogen (N) fertiliser limits for grassland which, under the current regulations, are set at 272kg N/ha for dairy farms and 222kg N/ha for non-dairy.

Under the DAERA proposals, grazing land on a dairy farm would be limited to 180kg N (5.5 bags of CAN / acre), while in silage swards, allowance would have to be made for slurry.

Dairy and intensive beef farms would be limited to 182kg N/ha on grass silage swards, with high-input dairy at 242kg N/ha.

In practice, it would mean that most dairy and intensive beef farms, typically cutting three times per year, would see the amount of CAN they are allowed to apply annually on silage swards drop from 8.25 bags / acre to 5.5 bags / acre.

The reduction is much more severe for non-dairy. Typical beef and sheep farms cutting silage twice per year, would have to work within an N fertiliser limit on silage swards that reduces from 6.75 bags / acre to only 2.5 bags / acre. Grazing land would be limited to just under 4 bags / acre.

According to DAERA, the new limits are in line with the UK fertiliser manual, RB209 and follow on from “trials by AFBI”. However, Dr Mayne points out that no data are presented to support the changes and that the RB209 recommendations were evaluated in previous reviews of the NAP, but rejected because they don’t take account of local grass growing conditions.

He warns that cutting fertiliser N will lead to unintended consequences – silage yields will be down, forcing farmers to feed more concentrate to make up the deficit, thereby adding more problem phosphorus (P) into the overall farming system.

Derogation

The second issue he raises relates to how the Department has arrived at new N limits for derogated farmers. These farmers (around 420) are allowed to operate at up to 250 kg manure N/ha/year, rather than the normal 170kg limit, but must meet a number of conditions, including the submission of a fertiliser plan to DAERA.

Under the latest NAP proposals, because these farms have more slurry, the Department has proposed lower N limits on their silage swards. On a derogated farm with dairy or intensive beef, they would be restricted to 4.5 bags / acre. A high yielding dairy herd, cutting up to four times per year, would be limited to just over 6 bags / acre.

Target

The final issue relates to the potential for DAERA to select out some areas for a “focused set of measures” where ultimately, farms could end up being forced to reduce livestock numbers.

In his summary, the AgriSearch scientific adviser points out there is no information in the NAP consultation on the measurements to be undertaken, nor any recognition of the fact it can take a considerable period of time before improvements in water quality can be seen.