It's a tricky problem – how do you make money from barren fields which have rejected all efforts to grow viable cereals or vegetables? The answer for a growing number of East Anglian farmers is a towering energy crop which seems to thrive in low-yielding soil.

Eastern Daily Press: David Sargent with his crop of Miscanthus. Picture: ANTONY KELLYDavid Sargent with his crop of Miscanthus. Picture: ANTONY KELLY (Image: Archant Norfolk 2015)

Miscanthus, also known as "elephant grass", is a perennial bamboo-like plant which can rise with rampant vigour to heights of 15ft.

Grown from rhizomes, it only needs to be planted once, it will be productive for more than 20 years, and it is harvested in a season that doesn't conflict with other crops.

That, allied to a low-maintenance character which needs no fertilisers, chemicals or annual soil cultivation once established, leaves farmers able to concentrate resources elsewhere, potentially raising the overall efficiency and profitability of their rotation.

Norfolk arable farmers and Gressingham Duck producers David and Christopher Sargent, have been successfully growing miscanthus for five years on land at Morningthorpe near Long Stratton, which previously failed to yield.

They grow 32 acres of it within the farm's 2,000-acre arable rotation.

David Sargent said: "One particular field has historically been called the 'barren field'. It never grew anything except rabbits.

"But then we found out about this miscanthus stuff and it grew like mad. That one field produced 124 bales last year. It did 74.4 tonnes from 5.05ha, and it produced a gross margin of £755 per hectare after costs.

"That is £755 a hectare from a worthless field.

"Unlike maize, you don't have to drill it every year. Once its established, it does not have to be sprayed or fertilised - all we have to do is to cut it. We get a contractor in as it has to go through a forage harvester. Then you bale it up and it has to leave your farm below 16pc (moisture), but the advantage is you harvest it in March or April, which is when you are not using your machinery for anything else. That was the attraction for us."

The current crop has no virtually weeds underneath the tall canopy. There are deer tracks, but no plant damage, and Mr Sargent said the foliage provides cover for wildlife including roe deer, pheasants and other birds.

Energy supply chain

The miscanthus at Friars Farm was initially established and maintained by International Energy Crops, but the farm's current supply contract is with Lincolnshire-based firm Terravesta.

The bales are turned into pellets at a mill in Cambridgeshire which then go to Drax Power Station in North Yorkshire, to be burnt for energy generation.

Alex Robinson, Terravesta's business development manager, said: "There has been a study that there is 350,000 hectares of unproductive land on farms that could be used for perennial energy crops, without affecting commercial food crops.

"Every farmer has problem fields or marginal land - and 'marginal' land is very subjective. It could be an odd-shaped field or unproductive land. So we are saying put these fields into an energy crop that you only have to plant once, and you can get a fixed contract for ten years."

A government grant which the Sargents used to help with their establishment costs is no longer available, but Mr Robinson said that had been offset by a reduction in the initial outlay.

"There is a bit of a capital cost up-front, but we have brought the prices of planting right down to about £1,000 per hectare," he said. "We are quite happy that grant has gone, because we want the crop to stand on its own two feet. Everyone can see the potential of it, particularly at the moment with the cereals prices so low."

A farm walk will take place at 10.30am on October 29 to show farmers the miscanthus crops growing at Friars Farm in Morningthorpe, For bookings, see www.terravesta.com, email helenh@terravesta.com or call 01522 731873.