Willow strips deliver beetle bank return

28 April 2000

Willow strips deliver beetle bank return

Growers reluctant to install beetle banks or buffer strips for fear of losing money-earning area might care to examine a West Country research project. Andrew Swallow reports

WHAT has all the environmental benefit of a beetle bank or buffer strip and still gives a gross margin of £440/ha (£178/acre)?

The answer is a willow beetle bank, judging by the results of a recently completed three-year project at IACR-Long Ashton.

Project co-ordinator Vic Jordan believes that income could be the financial incentive to persuade growers to adopt beetle banks more widely in commercial crops.

"But establishment costs are high, so some form of grant would probably be needed initially," he says (see panel).

The main cost is the willow rods planted at 16,000/ha (6475/acre) in rows 70cm (28in) apart and 30cm (12in) in-row. Spring plantings throw one or two shoots in the first summer which are cut back in autumn to promote six or more the following spring.

Pre-planting glyphosate is used to clean the strip, and a residual herbicide is needed in the first autumn. "But once the canopy has formed willow is very competitive so weeds do not become a problem."

Despite the dense canopy, species diversity is at least as good as in grass beetle banks.

"It may look inert underneath, but the leaves fall and are recycled, providing an insect habitat," says Dr Jordan.

Pest in crops between the strips never reached spray threshold levels. "We cant say there was a link, but it suggests there were sufficient predators about."

An adapted forage harvester harvests the willows every three years, yielding about 36t/ha (14.5t/acre) of dry matter. Winter harvesting avoids a labour clash with other arable work.

In theory the woodchip is worth £45/t. "Markets are the big problem," says Dr Jordan. "Basically you are selling woodchip and need to be within 15km of an end user, or transport becomes excessive."

Typically willow strips would be cropped for 25 years, by which time substantially better clones should make re-planting economic. &#42

&#8226 More Arable on page 67.

Willows can boost the benefits of installing beetle banks banks, say Long Ashton researchers Vic Jordan (left) and Alex Nicholls.

WILLOWBEETLEBANKS

&#8226 Income from eco-feature.

&#8226 £2000/ha to establish 25 year strip.

&#8226 £50 to harvest 36t/ha of DM.

&#8226 Value £45/t? = £440/ha GM.

Funding plans

MAFF and the Forestry Commission aim to invest £29m in an Energy Crops Scheme over the next six years under a Rural Development Plan, according to a Biomass Farmer & User report. Proposals suggest short rotation coppice planted on AAPS land would be eligible for £1000/ha (£400/acre), and livestock ground suitable for arable coppicing would attract £1600/ha (£650/acre). A minimum 3ha (7 acres) would have to be planted and proof of a market within 25 miles provided. Further information from MAFF (www.maff.gov.uk). Click on Farming, then Crops – renewable raw materials.