The number of school visits to farms has plummeted despite renewed interest from farmers wanting to attract more visitors onto their land.
In the past four years, numbers have dropped by 11 per cent, with 50,000 less pupils enjoying a trip to a farm, according to figures published by organisation Farms for Schools.
Warwickshire-based group Farming and Countryside Education has launched a series of training courses for farmers in a bid to encourage more schools to visit.
The initiative comes as the Government announced an outdoor manifesto, urging teachers to opt for more out of school trips.
Bill Graham, head of education at FACE, based at Stoneleigh Park, believes all pupils should be given a chance to visit a farm to learn about where their food comes from.
He said: "There has been a decline and it really follows the whole decline in visits out of school in general.
"Nationally it has been a real concern about the fact that children aren't getting out of the classroom and the reason for that lies with the great fear of litigation and enormous amount of paperwork.
"Farmers have been very active about this, they understand there is an issue here and we have been running training schemes for farms so they can get accreditation.
"We want schools to think if they go to farms they can actually feel assured that the person taking them knows their farm is safe."
Mr Graham said farm visits were also an important way of addressing concerns over the healthiness of children's diets, especially school meals.
"How can we actually teach them about the food they eat if they don't ever see where it is made and grown," he added.
Many farmers wanted to attract more schools on to farms, he said.
"The problem has not been the willingness of the farmers, a lot of them actually strongly believe that they ought to be connecting with the public and they actually want to have people on their farms.
"The supply is greater than the demand," he said.
According to Farms for Schools, 470,000 children visited farms in 2000. In 2004 this had dropped to 420,000.
Nina Hatch, who works for Birmingham City Council at Chapmans Hill School Farm in Romsley, said the farm was still seeing large numbers of pupils each year.
The 150-acre farm is one of two schools used by the local authority for school visits.
It welcomes 12,000 children every year and has been open to schools since 1972.
Ms Hatch said: "Our farm is very well established in having school visits. For many of the children, they have never come close to the countryside before, let alone to farm animals. Generally they live in a totally different environment and that in itself is important.
"The classic question they ask is if we have got different money, because it is like a foreign place. They say, 'what sort of money do you have here'."
Peter Melchett, policy director of the Soil Association, said visits to farms played a vital role in children's health.
"The Soil Association would like to see every primary school child visit a farm at least once and ideally a farm where they are producing a food so they can make that direct link," he said.