Planned changes to Natural Resources Wales' Ammonia Screening Guidance will have damaging consequences for farms, NFU Cymru has warned.
The guidance provides farmers advice on how NRW expects assessments from developments that emit ammonia to be carried out for permit and planning applications.
In the NRW consultation, that closed earlier this week, the regulator proposed sweeping new changes, including application of the guidance to all developments emitting ammonia.
Previously, the guidance was applied to intensive farming operations, as well as the requirement to prove ‘no harm’ to ammonia sensitive species outside designated sites such as SSSIs.
NFU Cymru said the proposals would result in more developments being brought into the screening process with requirements to undertake 'detailed and costly assessments' of the potential impact of ammonia and nitrogen.
The union added more developments would be blocked where stringent tests of ‘no harm’ could not be met.
The proposals were also likely to have 'detrimental consequences' on farmers wishing to develop, diversify or improve their environmental performance, it said.
NFU Cymru Deputy President Aled Jones said: “NRW’s proposed approach is likely to put constraints and limitations on farm development, threatening future viability at what is a critical time for the industry.
"We are disappointed that NRW has failed to publish the costs and benefits of its proposed approach, despite the fact that the Regulators’ Code clearly states that, before changing policies, regulators should consider the impact on business.
“Perversely the proposals, as they stand, will work directly against NRW’s own objectives of improving the environment."
Mr Jones said the proposals were likely to place 'further barriers' to new farm infrastructure projects on farms: "This is unacceptable and we have urged NRW to look again at its proposals."
NFU Cymru said it was also disappointed that the consultation focused exclusively on livestock production, and 'did nothing' to address ammonia sources from other non-agricultural sectors.
Mr Jones said: “Policies should facilitate, and not hinder, the development of farm businesses to enable them to continue to deliver their key role producing food for our nation.”