Thousands of farmers missed out on government funding after online applications for a £233m green scheme for the whole of England closed down in under six hours.
Farming and environmental groups condemned the race to secure the sustainable farming incentive (SFI) funding, with some comparing it to a "frantic" online scramble to secure Glastonbury or Oasis gig tickets.
The post-Brexit scheme, which replaced EU subsidies with payments for farmers to look after nature and provide "public goods", opened at 10:00 BST on Tuesday but had run out of budget by 15:48 BST.
The government said farmers had responded "in force" to the scheme and there would be further funding opportunities for 2027.
The National Farmers' Union is calling for the government to explain why the scheme opened and closed so quickly, with so many farmers left out of pocket.
NFU vice-president Robyn Munt said: "The rapid uptake of the scheme comes as no surprise. We have made the demand clear to Defra for some time."
When the scheme was suddenly closed without notice last year, there were concerns that some farmers might turn their backs on environmental work if they could not access the payments and demand for Tuesday's scheme was expected to be high.
Cambridgeshire arable farmer Martin Lines, who leads the NFFN, said: "This entire SFI system, with windows opening and closing within a few hours, isn't fit for purpose."
The Department for Environment, Food and Rural Affairs (Defra) said it would provide further information on future opportunities for funding applications in 2027 "soon".