A seventh-generation has accused Labour of "actively trying to destroy" the sector following ' changes.
Tom Wright, who tends to his 200-year-old mixed farm in the Norfolk broads, warned the Chancellor's decisions last month will have repercussions for food prices and the environment.
He said: "Being 40, it's the first time in my lifetime I've known something like this. The Tories didn't care about farming but this is actively trying to destroy it. This is even worse."
The April 2026 start for the policy means farmers may not have time to make use of existing rules to skip inheritance tax by passing on an asset seven years before death.
Tom, who will join the farmers' rally in London next Tuesday, said: "It's one of those where it may not impact you at all but if the seven years doesn't work then that's the end of the farm which is not a nice thought for anybody.
"They say to plan for it but you can't plan for it. You can rush to do it now but it's still seven years. Someone could get hit by a bus. You can't plan for that.
"We're the most dangerous industry in the country, sadly, and we don't seem to have a lot of support."
Tom described Ms Reeves' Budget last month as a "kick in the mouth" after announcing that they are accelerating the end of direct payments.
He said: "Personally, I had hopes that they wouldn't lie as much as the Tories but they are lying more.
"Politically, there's no point in ever expecting anyone to help you. It's each for their own and you've got to get on with your business. Have as little paperwork to do with the Government because we're being done over again and again.
"They're very slippery. Ultimately we will survive, they're not going to win. They increasingly need to work with farmers for their carbon offsetting targets and that's not going to happen now. They've screwed it."
He warned food prices will begin to rise if farms disappear because of announcements in the Budget.
Tom said: "It's going to affect farming in the UK and it's going to affect our costs more so there's either going to be less of us.
"We're price takers at the end of the day. We can't put our prices up. We grow wheat and we sell it at the market value but if we start disappearing."