Maps released this week reveal there is no risk from nitrates in two Pembrokeshire farming areas earmarked as nitrate vulnerable zones (NVZ).

Environment Agency Wales has published a series of maps for the water framework directive, and two of them, one for an area west of Pembroke and the other which stretches from Narberth to mid Wales, show the Environment Agency believe there is no nitrate risk in these regions.

NFU Cymru has now called on the Welsh Assembly to demonstrate the justification for introducing nitrate vulnerable zones in Wales.

President, Dai Davies, said: "Clearly, for large parts of the proposed designated areas, there is no evidence that nitrates are a problem."

Bangeston Farm, in St Petrox, falls within the proposed NVZ on the Castlemartin peninsula.

Martin Mathias, who farms the 340acre holding, said the latest evidence confirms the proposals are unwarranted.

Calculations show his farm income will fall by £30,000 a year if he is forced to cut his stocking rate to comply with NVZ requirements. This does not include the cost of slurry storage facilities or the expense of off-wintering stock on tack.

He says he has changed his system for the better by abandoning autumn tillages and there is less reliance on housing because his herd is spring calving. All the slurry is injected instead of being surface spread.

"Unless there is concrete evidence that pinpoints agriculture as being a pollutant then I struggle to see the sense in designated this area an NVZ,'' he said.