A ban on autumn muck-spreading is being reviewed by ministers as part of efforts to prevent a slump in food production sparked by a global shortage of fertiliser.

Farmers have called on the Government to change the rules over fears that soaring gas prices could lead to some food shortages and hit their profits. 

The National Farmers Union said farmers should be able to use manure as an organic alternative to artificial fertiliser, for which gas is a key ingredient, as it becomes more scarce. 

The cost of fertiliser, essential for growing crops and grass for livestock, has quadrupled in the past year in some instances following sanctions on Russia. 

The NFU’s wide-ranging proposals were shared with the Department for Environment, Food and Rural Affairs (Defra) last week and discussions are ongoing.

They also asked for gas supplies to be “preserved, protected and prioritised” for food production if food security was at risk. 

Farmers are not permitted to spread manure on their fields in the autumn. Doing so would help them build healthier soils ahead of planting next year’s crops, they claim. 

Defra expects to publish new guidance on the so-called farming rules for water, including muck-spreading, this spring.

The Environment Agency has previously said the rules were designed to prevent water pollution from agriculture, and the practice could be harmful. 

Mark Topliff, a lead analyst at Agriculture and Horticulture Development Board, an arms-length body of Defra that works with farmers, said: “The cost of inputs has been increasing for a few months before the Ukraine crisis, so what that has done is continued that trend and increased the price of those key inputs like fertiliser. 

“Fertiliser is a big one for farms, one of their main costs. If you bought fertiliser in October, November last year, and if you applied the same amount this year as you did last year, you’d find that your costs have increased by up to £200 per hectare, which is significant.”

Mr Topliff said farmers were trying to reduce the amount of industrial fertiliser they can apply to their crops this year to cut costs. 

“They’re looking at whether they can use 60pc they’ve bought [for] this year and save 40pc for next year and be able to top that up and prices will hopefully be a bit lower,” he added. 

Using less fertiliser would mean lower wheat yield, however. He added that organic alternatives, such as livestock manure, “could certainly have some influence” in winter time.