Large swathes of prime arable land in eastern England could be forced back into grassland, if the UK is to meet tough new EU conditions on water quality, rural consultants ADAS has warned.

New research has shown that, even with improved farming practices, the level of nitrates leaching is leading to excessively high pollution that only a change of land use will address.

“Diffuse nitrate pollution puts a big question mark over the future compatibility of UK food production and public water supplies,” said ADAS consultant Roger Bradley.

The need for water quality improvements was set out in the EU’s Water Framework Directive, he explained.

While this set no specific limit for nitrate levels in all water, the “working assumption” was that this would be set at 50mg/litre – the same level as in the Nitrates Directive.

“This would limit nitrogen leaching from arable land to a maximum of 26kg/ha,” he said.

“The problem is, no arable crops achieve this – for example, winter cereals produce 50kg/ha of nitrogen and even sugar beet has 30kg/ha.”

The situation was worst in the east, as it did not rain very much and so the nitrogen was not as diluted as in the west.

According to Prof Bradley, as much as half the cultivated land in East Anglia would have to be put into grassland or woodland by 2015 to meet the new EU limits.

“That’s just a crude guesstimate based on the assumption that levels of leaching will have to be halved, but the implication is clear – there are big changes ahead.”

But NFU head of policy services Andrew Clark described the report as “a bit of a scare story”.

“While the Water Framework Directive seeks to achieve ‘good ecological status’, it also provides certain ‘get-outs’ where this leads to disproportionate costs.

We would argue strongly that substantial land use change is disproportionate.”

Dr Clark added that the NFU would be pressing Brussels for more flexibility in defining “good” water quality, and not just simply apply the 50mg/litre standard of the Nitrates Directive across the board.

East Anglian arable farmer Steve Bumstead also attacked the ADAS report, saying it was ironic that an organisation that in the 1970s and 1980s was urging farmers to step up their nitrogen applications was now advocating the widespread abandonment of cereal production in one of the most productive and efficient parts of the country.

philip.clarke@rbi.co.uk