The new NVZ rules do not expressly rule out setting pigs on rented land against the whole farm average for livestock nitrogen. But unlike the previous NVZ guidelines, new guidance from Defra does not specifically make provision for setting outdoor pigs against the whole farm average.

This being the case, NPA, NFU and BPEX have jointly written to Defra to seek clarification. There is now an element of doubt in producers’ minds, they say, so it would be helpful if the issue is addressed — so producers can be clear where they stand.

They point out that outdoor pig production probably now accounts for around 40 percent of the English sow herd, having developed in response to consumer demand for higher animal welfare.

And they explain to Defra that outdoor pigs are an important break crop in arable rotations, helping control plant pests and diseases and so reducing the need for pesticides and manufactured fertilisers.

A typical cycle is for pigs to remain on one site for two years, before the land returns to arable cropping. Often it is several years before the pigs return to the same site, and within the rotation the whole farm average for livestock manure is not a problem.

Earlier Defra guidance has recognised short term agreements of less than two years between principal and temporary land occupiers as allowing the whole farm average for livestock nitrogen to be considered as part of the principal’s farm.

It is important that Defra continues to accommodate the outdoor pig sector, which is so highly valued by its customer base, say NPA, NFU and BPEX.

“We are principally concerned to get the outcomes of environmental management right in a relevant and proportionate fashion. If we fail to get this right it could well lead to significant detrimental impacts on an already fragile industry, which in turn could run counter to the direction of travel in respect of animal welfare.

“In total the area of land occupied by outdoor sows will be a little in excess of 6,000 hectares (15,000 acres), so a relatively small, but none the less important, fraction of the total designated area.

“Without outdoor production, the United Kingdom pig industry would be severely reduced and lose significant volume putting the sustainability of both the farms and the whole supply chain at risk.“