Potato and root vegetable growers are increasingly being urged to use unproductive field headlands to deliver significant environmental enhancements, including protecting valuable soil and water resources, by sowing a wildlife-friendly headland mix.

At this year’s Syngenta Potato Science Live event in Dundee, its field technical specialist, Dr Max Newbert, said that the company’s ‘Operation pollinator’ research it undertakes in conjunction with ASDA, had demonstrated clear improvements in soil protection and structure on areas sown using a ‘green’ headland mix alongside crops.

The specially created seed mix – developed by seed specialists, Kings – incorporates vetches, clover, phacelia and radish. Sown in the spring to achieve fast growth, trials have shown it could generate 36 tonnes/ha of green organic matter over the summer, including capturing 106 kg N/ha, that would help improve soil structure and fertility.

This cover crop also helps trap and retain soil movement in the field, whilst the rooting acts to stabilise the soil surface and protect from damage by tractors and irrigation equipment through the crop’s growing operations.

Reporting the latest findings of 2018 monitoring on green headlands, independent ecologist, Paul Lee, assessed more than 36,000 invertebrates collected from sweep netting on six farms on just two occasions over the summer. Some margins contained up to 55 different species, including high numbers of beneficial predatory insects.

Identifying 199 different insect species overall, it was the beetles and bugs that dominated the mixtures, he reported. “But a number of insect groups that had suffered in successive cool wet summers, did particularly well in the warm dry conditions, particularly the flies and bee species,” he added.

Dr Newbert said there were few, if any, aphids caught from the headland areas in any of the samplings. “Given that aphids quickly lose the capability to transfer non-persistent viruses, the green headland areas could potentially act as a barrier to reduce disease spread into potato and vegetable crops,” he argued.

His studies showed that, where the headland mix was grown around carrot fields, there was a 70% reduction in visible virus effects, compared to those with no margin – albeit with a relatively low level in all the crop and a low risk year.

“The green headland had a significantly higher biomass of insect life and whilst the crop received the same insecticide programme, it did demonstrate the potential for this IPM approach to give results over and above the conventional programme, for carrots and potatoes.”

Belinda Bailey, Syngenta’s sustainable farming manager, highlighted that potato and root vegetable headlands were typically left uncropped to aid management and harvesting of the field area. However, these bare soil areas are potentially exposed to soil erosion or damage by headland-turning of heavy machinery and have little or no ecological value.

“Our ‘Green Headland Mix’ demonstrated a practical and viable technique to both protect the soil structure and provide a valuable feeding and habitat resource for invertebrates and other farmland biodiversity,” she said.

“We are now really keen for more growers to get involved and to see how it can be integrated more extensively throughout farm rotations and situations, as well as to explore new agronomic aspects of the green headland potential.”

The mix is available to growers now at a Syngenta subsidised cost of £35 per ha pack (subject to availability).

Dr Chris Brown, ASDA’s senior director of sustainable sourcing, said the project demonstrated good stewardship of farmland. “This initiative highlights the efforts of UK growers to work towards increasing biodiversity and protecting resources.

“Planting up green headlands is a genuinely sustainable solution. It can offer a simple, cost effective and time efficient option to make better use of a hitherto unused area of land, that will improve the environment and to protect soil and water.”

Fife in bloom

With around 80 ha of potatoes – including pre-pack production for IPL-ASDA – Scottish growers, Alex and Robbie Brewster, have integrated the green headland mix around potato fields to enhance soil conditioning and provide a vibrant flowering food source for the farm’s biodiversity.

“We look to grow green manures wherever possible in the rotation, to build soil nutrients and structure,” reported Alex Brewster. “There’s a real benefit to following crops, especially on headlands which can otherwise be compacted and hard to work.”

The brothers farm around 400 ha at Kirkton Farm, Culross, near Dunfermline, growing cereals, beans, oilseed rape and potatoes, including on-farm processed certified cereal seed.

Alex said the ‘green’ mix was extremely easy to establish. It was shallow drilled in May, into warm soils around two weeks after potato planting. “We wouldn’t otherwise be cropping the headland, so it makes sense to plant something beneficial for the soil and biodiversity,” he pointed out.

Phacelia, which is part of the mix, is particularly good at hosting beneficial predators, which he believes has significantly reduced aphid numbers and the risk of virus in the farm’s seed crops.

“The later flowering plants looked incredible and were especially attractive for butterflies, which we saw in huge numbers last year with the dry summer. It’s also providing another valuable pollen and nectar source for bees on the farm,” he added.

Bees buzz back

Some solitary bee species have been increasing in both number and range across the UK over the past decade, benefitting from the trend to warmer temperatures.

“Last year’s record temperatures and prolonged dry conditions were particularly favourable for some solitary bees and we have seen the numbers increase accordingly,” pointed out ecologist, Mr Lee.

Solitary bees are typically far more efficient as pollinators, compared to honey bees. The hairy bodies of some species can transfer dry pollen between flowers more effectively. Studies have indicated that, as a pollinator, a solitary bee is three times more effective than a honey bee, and typically visits in excess of 100 x more flowers a day.

The solitary squat furrow bee, classified as nationally scarce but doing well and expanding its range in recent years, was one of the exciting finds on the Suffolk farm of the Geoffrey Mayhew Farms, based at Pond Farm, near Erwarton, Ipswich – winners of the Syngenta Operation Pollinator Green Headlands Biodiversity Award 2018.

Geoff Mayhew said: “Environmentally it delivers a real positive boost for the farm and, since we are growing the mix on previously uncropped headland, there is no loss in productivity from then field. It’s also a great attraction for visitors to the farm.”