By Anna Hill
BBC Farming Today
Farmers are increasingly using a novel way to a fertilise their crops - human waste.
Human fertiliser costs a fifth of its conventional counterpart
The cost of conventional fertiliser - which is closely linked to the price of oil - has shot up over the past year.
But many landowners are turning to a ready supply of treated human sewage from water companies who are no longer allowed to dump it at sea.
And it seems farmers are taking as much as they can get - supply is up by as much as 25% in the past few months.
Severn Trent Water, which supplies sewage to farmers, reports that it is unable to keep up with demand.
Jonathan Barrett, who farms 4,500 acres at the Kirby Cane estate in Norfolk, says human fertiliser costs just a fifth of the price of its conventional counterpart.
But he admits receiving a few complaints from people living near his fields about the smell.
"We're making an effort to turn it into the soil," he says.
"If we do get complaints we come and turn the soil again to incorporate it that bit more."
Human sewage is allowed to be spread on grassland and crops - it cannot be used on salads, fruit and root crops.
Tony Martindale, recycling manager at Seven Trent Water, which supplies 600,000 tonnes of sludge to farmers every year, says there has been a 25% increase in demand over previous years.
He says every effort is made to ensure there is no danger to human health, insisting that 99% of the pathogens are killed in the treatment process.
The sludge is also tested in laboratories to make sure there are no heavy metals in it and there are no cases of people being affected by the practice, Mr Martindale adds.
He adds that they do their best to address concerns about the smell.
"There are a few problems with odour but we do try to minimise that," he says.
"We always take the wind direction into account."