A precision approach to planting a fast-growing energy crop was essential to long-term profitability, farmers were told at a Norfolk demonstration.

Demand for elephant grass or miscanthus has been growing rapidly as an industrial feedstock, particularly for co-firing in electricity production.

'This is a green crop. It is good for biodiversity and will help to keep the lights on,' said Steve Bacon, general manager of International Energy Crops.

With about 10,000 acres of miscanthus in the ground in England, Mr Bacon said that there was the demand from power stations including Ely and Drax in Yorkshire. Several farmers in eastern England and especially Norfolk have put down small areas of miscanthus.

At Horsford, near Norwich, RG Carter's Drayton Farms have planted miscanthus. It has a total of about 30 hectares including a significant block on reclaimed quarry land near Holt, said farm manager Richard Mace.

Although the miscanthus rhizomes were planted in late March, after four weeks without rain, the crop has made rapid growth once the 13-week late spring drought ended.

Andy Lee, who is head of agronomy for Shropshire-based IEC, said that the key to obtaining sustainable yields over at least 20 years was good establishment, protection from rabbits and hares and weed control. The aim was to achieve yields of about 20 tonnes per hectare, which could deliver net returns of more than �1,000 ha. At 10t yield, net returns would be about �465 ha and 15t some �735 ha. The existing single farm payment was on top.

It was a big investment to establish the crop, typically about �2,100 hectare but 50pc grant aid from Natural England was available, also to help with the cost of rabbit fencing. 'Rabbits love miscanthus especially in year one,' he added.

Mr Lee said that the yields, especially with some early established crops, had been very variable because of 'gappy' and uneven emergence. And given that the crop might be in production for 20 years, it was essential to use precision-planting techniques.

The demonstration crop had been planted on March 28 – three days later than at Holt. 'We did something different this year and used larger rhizomes which have a bigger battery life if you like.

'We didn't expect to be quite as dry but possibly by default, that gave us an extra few weeks before the rhizome died,' said Mr Lee. By consolidating the soil after planting, it squeezed out the air and 'sealed in' the moisture and ensured even emergence.

But, he stressed, the crop was frost sensitive, which is hardly surprising given its tropical origins. 'We've actually had the worst year for miscanthus apart from the dryness at planting. Some crops in Shropshire and Yorkshire have had three 'burnings with frost.'

However, it can be quite hardy and it has survived Polish winters of minus 28C and our coldest winter for 100 years. 'It is very suited to our climate. Obviously, we get lower yields than in Italy or Georgia in the USA, where they enjoy hot sweaty tropical weather,' said Mr Lee.

Once established, it was harvested between January and April when it was eight to 10ft high and possibly in May on heavier soils. In Shropshire, they started cutting on January 28 and it was left in the field until baled in April.

'This is another advantage because it can spread the workload,' said Mr Lee. And once the crop has been pelleted and delivered to a power station, it was typically included at a rate of between 10 and a maximum 20pc of the total feedstock.

Mr Bacon said that proposed pelleting plants, one in Shropshire and another in Swaffham, would be a further boost. 'We take Hesston bales and pellet them to reduce the carbon footprint of transport. The real reason – a bale is an agricultural farm product but a pellet is a fuel product and that it is the format that the buyers require.'

He suggested that in Norfolk and Suffolk, a plant producing 20,000 tonnes of pellets, would require about 1,000 acres of miscanthus.

Mr Lee said that the crop, worth potentially �65 tonne, was suitable for most soil types. 'Good, proper establishment is absolutely vital; but don't expect 20 tonnes per hectare if it is just thrown into a rubbish bit of land. The ground needs to be prepared properly to get a crop which makes a profit.'

It have further appeal if farmers had problems with emerging blackgrass resistance, said Mr Bacon. 'We've got miscanthus crops after 22 years still producing the right level and showing no signs of dropping off. And in Europe, they're got crops growing after 30 years.

'The one thing that I'd say about miscanthus, it is not the most exciting crop in the world. And your yield almost irrespective of the weather will be 10pc either way. Once you hit your 15, 18, 20 tonnes per hectare, that's what you're going to get.

'The future does look bright. We've already got crops planted and we're looking to double the area next year. But what really sells miscanthus is when farmers look over their neighbour's fence,' he added.

Details - www.energycrops.com