The National Farmers' Union in Scotland is demanding action to ensure that declining EU aid is not wrongly spent on unproductive land and is warning that key targets on boosting the country's food and drink sector will be affected.
Farmers, particularly in the livestock sector, fear that reforms to the EU's Common Agricultural Policy could see many lose up to 50% in payments, with dire consequences for the industry and consumers with a loss of high-quality local produce.
The NFUS is lobbying the Scottish Government to demand CAP payments go to productive farms.
The sector admits a distinction between productive farms and "slipper farms" to distinguish between those who produce crops or livestock and others who simply own unproductive land, and the NFUS is pushing the Scottish Government to change the fomula to favour the producers.
CAP aid amounts to around £600 million a year but this is falling and moves to end "beef mountains and wine lakes" mean the emphasis has shifted to land ownership, not land use.
NFUS president Nigel Miller said working farmers who had used the government's online calculator for latest proposals were alarmed that this could see many losing up to 50% of their support.
He said: "It is clear from the many farmers who have now done their sums that the core implementation proposals for the CAP, as outlined in the Scottish Government's current consultation, fails to provide a viable support framework for a significant part of Scottish farming."
He added: "If unchanged, these proposals will exert a downward pressure on production across a number of key sectors."
Rural Affairs Secretary Richard Lochhead told MSPs: "We worked hard to ensure the new CAP would end slipper farming, and were pleased when the so-called Scottish clause was included in the CAP regulations."