One third of farmers have changed their crop plans in the past four months, with 90% of them blaming fertiliser costs, the results of a survey of 525 crop farmers by the National Farmers' Union (NFU) showed.
"Costs are rising rapidly on farms across the country," NFU President Minette Batters said. "It's already having an impact on the food that we are producing as a nation as well as leading to a crisis of confidence among Britain's farmers."
Britain is facing its worst inflation in 40 years, pushing up prices of everything from food to furniture and contributing to a wave of worker strikes across industries where unions are arguing for better pay.
"The survey also indicates that farmers are beginning to switch from growing milling wheat for bread to feed wheat for animals, because it has a lower fertiliser requirement," the NFU said. "These rising costs are denting farmers' confidence to invest."
The conflict in Ukraine has worsened inflation, spurring an increase in oil and gas prices and translating to higher prices at fuel pumps.
Soaring costs have been a headache for British farmers for several months now, with many being forced to stop planting crops such as cucumbers, aubergines and tomatoes after a surge in natural gas prices.
Batters said more government investment and support was crucial in helping farmers tackle spiralling costs, noting fertiliser prices had doubled alongside increases in feed and fuel prices.
A separate NFU survey of 610 dairy farmers showed 7% of them believe they could stop producing milk by 2024, which could remove 840 producers from the industry.
(Reporting by Sachin Ravikumar; Editing by Hugh Lawson)