Mr Lochhead raised concerns over an end to direct support to farmers
The UK government's vision on agriculture reforms would be a "disaster" for Scotland if brought in, the SNP annual conference has heard.
Environment Secretary Richard Lochhead said Labour's plans for the European Common Agricultural Policy would cut support for farmers.
And he reiterated that Scotland should have decision-making powers on fishing.
Mr Lochhead also urged delegates in Inverness to "step up the food revolution" to support Scots produce.
He referred to a recent, independent report on the UK government's plans for agriculture policy, adding: "A vision they are trying to sell to Europe envisages an end to direct support for our farmers to help save the UK Treasury cash.
"If implemented, the UK government vision would be a disaster for Scottish agriculture."
Mr Lochhead said the Scottish government would continue to make protecting fish stocks a priority - and demanded decision-making be returned to Scotland, which he said had 70% of the UK quota.
Recounting a recent visit he made to the European agriculture and fisheries council, Mr Lochhead told delegates: "The UK minister had to leave early. Did he offer the seat to the Scottish fisheries minister?
"No, wait for it, on orders from Downing Street, he instructed one of his civil servants to take the vacant seat.
"So we had two civil servants at the top table, neither of whom would be able to point to Peterhead, Lerwick, Kirkwall, Stornoway, Eyemouth or any other fishing port on a map."
The environment secretary went on to say that Forestry Commission Scotland would be ramping up its contribution to renewable energy, by developing more wind farms on its land, through partnerships with energy companies.
And he announced a summit to make every Scottish tourist attraction into a showcase for the best of Scotland's food and drink, declaring: "Let's step up the food revolution and take advantage of producing the best food and drink in the world."