Mr Day from the NFU said the news of the inheritance tax had left its members “devastated”.
“Farmers aren’t earning a lot of money because commodity prices are so low,” he said.
“Inflation is so high… this is an additional tax now that we’ve suddenly got to go and find the money for at a time when agriculture is at its lowest ebb.”
The government said most estates claiming Agricultural and Business Property Reliefs will be “unaffected” by the changes.
“The latest data shows that 40% of Agricultural Property Relief – worth £219m – was directed to just 117 estates,” A HM Treasury spokesperson said.
“The money raised will go towards public services we all rely on every day instead.
“We’re investing billions of pounds in sustainable food production and nature’s recovery, slashing costs for food producers to export to the EU and have appointed former NFU president Baroness Minette Batters to advise on reforms to boost farmers’ profits.”