The survey of UK producers found that 38 per cent think that remaining in the EU is the right decision for the industry.
However nearly one in four (28 per cent) don’t know whether farming would be better off if the country voted to leave the union next week.
The survey of more than 2,300 farmers, carried out by the National Farm Research Unit on behalf of agricultural analysts Map of Agriculture, found that farmers who wanted to remain in the EU were concerned that Brexit would create uncertainty around trade and subsidies.
Meanwhile the 36 per cent who planned to vote out said they were frustrated by the EU, and felt that British agriculture would be better off without regulations being decided in Brussels.
Farmers who run smaller businesses were more likely to favour leaving the union, the survey discovered, while those who manage larger farmers favoured remaining.
The survey’s results were announced at the start of a heated debate which took place between industry leaders, farmers and politicians at the country’s largest arable event.
Conservative MEP David Campbell Bannerman told the debate that farm subsidies would be maintained at their current levels in the event of Brexit.
Trade deals would be agreed to ensure farmers could continue trading with Europe, he added.
But former Defra minister Jim Paice urged farmers to think long-term about their decision at the polls, and not to be seduced by promises the Leave campaign was making.
“The idea that the money not being paid to the EU will still compensate farmers is madness,” he told the packed conference room.
“Farmers cannot depend on future governments to keep the pledges [the Leave campaign] are making.”
Sir Jim said UK farmers needed the lobbying support of European farmers, as without it they would be left alone by British government which did not prioritise agriculture.
“There’s a lot wrong with Europe, but we won’t put it right from the outside,” he added. “We need to be part of the debate.”
NFU president Meurig Raymond said it was unrealistic to expect a ‘clean divorce’ from the EU if the country voted to leave, and said trade would take a massive hit.
“We can’t negotiate with other countries,” he said. “We would be thrown to a free market and would be so uncompetitive it would destroy UK farming.”
• Speaking earlier in the week Peter Kendall, former English NFU president and a member of the ‘Farmers for In’ campaign, criticised the Vote Leave group for “taking farmers for fools”.
It had claimed current funding for farmers could be maintained if Britain left the EU, despite warnings from economic experts that leaving would blow a £40 billion hole in the nation’s finances.
“Farmers are practical people and have to do basic sums on a daily basis; we know that the magical money tree doesn’t exist”.