By Sarah Mukherjee
BBC Environment Correspondent
The UK government has to make a decision very soon on the future of an arcane farming subsidy called set-aside.
Set aside has become an important environmental tool
Although it sounds of little interest to the non-farming public, conservationists say it has, accidentally, become a powerful environmental tool - and stopping it could be devastating to some of our rarest wildlife.
On a blustery, misty Leicestershire day, Dr Alistair Leake, from the Game Conservancy Trust, shows me a strip of tussocky grass in a field, and explains this beetle bank is a natural insecticide system - and a benefit of set-aside.
Every winter, the beetles take cover; every summer they leave their home to go to eat greenfly in the fields. Dr Leake manages the Trust's 323-hectare (800 acre) estate in Loddington.
The farm is used to research new techniques that enhance food production and conservation.
But as pressure to use land, particularly for biofuels, increases, Dr Leake worries that the benefits of what farmers know as set-aside will be lost.
"Over the years we've been working with set aside, we've learned to manage it very well for the environment. But how do we keep those benefits if set-aside disappears?" he asks.
At this point, you may be scratching your head and asking yourself what on earth "set aside" is.
If you have spent time - despite the weather - in the countryside this year, you may have been struck by strips of scarlet poppies, and other wild flowers, alive with bees and butterflies. It's a big change from the fields of single crops that were so much a feature of the 1970s.
Conservationists say that, in no small part, this environmental success has come about because of payments farmers received from the 1990s to "set aside" their land, and take it out of production.
As the post-war reforms of farming and increased yields from intensive production found their way onto grocery shelves, much of the agricultural debate about farming was couched in terms of excess - too much food, too much land in production.
This year, poor harvests worldwide have sent the price of grain rocketing - anecdotal industry figures suggest wheat's gone up by as much as 50% in the last couple of months - and now farmers are itching to get that land back in production. The European Commission has signalled it, too, is keen to scrap the payment.
The system has been a boon for wildlife
People in the industry are now asking how are we going to do all the things we want to do - conservation, energy crops, food - with a finite amount of land.
Dave Turley, head of alternative crops at the Central Science Laboratory, says we need to think long-term about prioritising our needs - inevitably, wildlife could suffer to produce low-carbon crops that will help with the nation's energy goals.
"It's quite clear that in some cases we're going to have to accept there will be some environmental hits which we will have to accept because of the benefits," he says.
But organisations like the RSPB say the set-aside system has been a boon for wildlife. Highly endangered birds such as the stone curlew have prospered on set-aside land, which has also provided food for skylarks and cirl buntings. They ask what happens to the birds when the set-aside goes?
Paul Temple is an east Yorkshire farmer and vice-president of the National Farmers' Union. He says he never tires of the view from his farm on the Yorkshire Wolds.
On the day I went to see him, with a pale yellow sun seeping through the clouds, you could see the Humber Bridge on one side, the North Sea on the other.
As he walked his fields he showed me the stubble he'll leave over the winter to provide food and shelter for wildlife. It's not part of a set-aside scheme, but there will be an environmental benefit.
Fields of single crops were much more common before set aside
As he points out, recent reforms of the Common Agricultural Policy mean farmers are now paid to look after the environment, reducing the need for the incidental set-aside benefits:
"Farmers care passionately about this environment - this wonderful landscape looks like it is because of farmers, and we've become much more sophisticated about the way we manage farmland for the environment." he says.
"Half of farm land is in some sort of environmental scheme. We're managing it specifically for wildlife, and not incidentally as part of set-aside."
There are some who say with good land management, conservation and crop production are not mutually exclusive.
But if the government - and the main opposition parties - agree that a good environment can be a justification in itself for farming, conservationists argue that politicians need to find a way to carry on the accidental good work that set-aside has achieved.