As a result, her party's popularity has plummeted - a major challenge for Chris Hipkins, who is set to replace her as leader of the Labour Party and the country.
Farmers and rural voters say reforms by the Labour Party, meant to improve the environmental impact of farming, are costly and ineffective - and will make their products less competitive.
Scotty Bright is the Auckland representative of a farming lobby group called Groundswell.
He says a government proposal that farmers pay for methane emissions from their sheep and cows is among unworkable regulations.
"This emissions tax, you know, the 'fart tax' it's going to mean, like all these cattle here, it's going to be three hundred and thirty dollars per head. So on a farm like this, it's about a hundred and thirty, hundred and forty thousands a year extra tax farmers are going to have to find."
New Zealand farmers are some of the most efficient in the world.
They receive minimal subsidies but compete with top economies due to good practices, good farmland and a climate amenable to year-round agriculture.
Most New Zealanders live in urban areas, but farming is key to the economy in a country with five times as many sheep as people.
Ardern make the shock announcement on Thursday (January 19) that she was resigning, saying she had "no more in the tank".
Part of her burnout may also have been caused by rural New Zealanders falling out of love with her.
"I think the worst thing would be that the they didn't seem to listen to the farmers. It appeared that they (Labour) are in their own bubble and they didn't really know the facts of what the farmers deal with on a daily basis."
Ardern won over rural voters with her effective "go hard, go early" approach to lockdowns and sealing the border.
That allowed her to form the first single-party government since New Zealand adopted proportional voting in the 1990s.
But tractors and pickup trucks have descended on parliament in nationwide protests against Labour's reforms.
As that vote has now largely swung back, angered at Labour's efforts, which also include plans to reduce water pollution from fertilisers and animal waste, change the leases on high country ranches and overhaul water systems.
