Industrial hemp could be a valuable tool for UK agriculture, helping the transition to more sustainable practices and providing a new crop, according to a farming group.
To further explore the potential of hemp, five farmers are collaborating with researchers from Cranfield University and the British Hemp Alliance under an Innovative Farmers program run by the Soil Association.
They plan to conduct field trials on the farm to collect science-based data on the plant’s environmental benefits.
Long stigmatized because it belongs to the cannabis family (hemp varieties have a low THC content of Cannabis Stiva L and are not used in narcotics), hemp does not require any agrochemicals.
And there’s growing international evidence that it can increase biodiversity, fight pests, improve soils, and sequester carbon, researchers say.
It could also be a useful cover crop alternative to oilseed rape, which is becoming increasingly difficult to grow in the UK.
However, unlike many other countries, the UK still classifies industrial hemp as a ‘controlled drug’ and farmers wishing to grow the plant must apply for a license from the Home Office.
As a result, there are only about 20 licensed British breeders with a total area of only 2,000 hectares.
“With post-Brexit agricultural policies focused on delivering public goods like biodiversity and carbon sequestration, we need to look again at how we approach hemp in the UK,” said Nathaniel Loxley, Innovative Farmers project coordinator and co-founder of the UK Hemp Alliance.
“Hemp could be a very valuable tool in the UK farmers box, but the UK is currently lagging behind the curve internationally and there is a definite lack of data in the UK context,” says Loxley.
“We hope that by better understanding the benefits of hemp and gathering evidence, we can pave the way for more UK breeders.”
Industrial hemp is a versatile plant that is used in the manufacture of building materials, clothing textiles, animal litter and as a substitute for plastics.
Manufacturers from the construction, fashion and packaging industries are increasingly looking for ecological solutions in the system.
The UK has a long history of growing hemp, and during the reign of Henry VIII it was so important to the British Navy that it was illegal for landowners not to grow it.
Henry Ford even built a car made from hemp and powered by hemp, and the facility was used to remove pollutants after the Chernobyl nuclear disaster.
“More and more benefits of this incredibly versatile plant are being discovered again and again,” says Helen Aldis, program manager at Innovative Farmers.
“There is very real potential for UK farmers to use hemp to regenerate their land, deliver public goods and grow a new crop, so it is fantastic that Innovative Farmers can be part of it.
“It is critical that farmers and researchers work together on these hands-on farm trials so that we can discover the true environmental benefits of hemp and share that knowledge with more growers.”
Benefits for the environment
Much evidence about hemp’s environmental benefits is currently anecdotal or comes from a limited number of studies from the US and Europe, says Dr. Lynda Deeks, a Cranfield University researcher who did research on the plant.
“It has been shown to be beneficial for the environment below and above the ground, but it could potentially have other environmental benefits, and we need to understand that,” says Dr. Deeks.
One area the trial will explore is the potential of hemp for storing carbon. The plant has the potential to store carbon in the soil and through the use of its fibers in bio-composite materials, for example for the construction or automotive industries, says Dr. Deeks.
“Data from other studies have shown varying rates of carbon sequestration, which are likely to be related to soil types – so we need to know how this would apply in the UK context,” she says.
“The plant also has a strong tap root that could aid soil health by relieving compaction, improving drainage, and helping to aerate the soil.
“Ultimately, when the roots rot, the carbon should support a more resilient soil structure.”
Trial participant Nick Voase is at the forefront of hemp growing and product innovation in the UK with his company East Yorkshire Hemp.
He converted most of his farmland to growing the plant 15 years ago and currently has 450 acres for hemp.
Mr. Voase processes the harvest into fibers, animal litter, HempLogz (fire briquettes) and “Hempcrete” (for construction).
“Although we are not an organic farm, we grow hemp without pesticides, without seed treatment, nothing at all – it does well without it,” says Mr. Voase.
“There are currently no fungal diseases or insect pests that cause a lot of damage.”
“This makes it very useful for insects, and there is often a swallow cloud over the hemp at this time of year,” he said.
“I’m also interested in its carbon sequestration potential – if we turn hemp into hemp concrete, we may sequester that carbon for as long as the building is standing.”
Experimental breeder Camilla Hayselden-Ashby in Kent is growing hemp for the first time on her family’s 320 acre mixed farm. She plans to add hemp to the farm’s rotation.
“Once hemp is established, it has a very dense canopy of leaves so that it shades weeds – that attracted us as we have a problem with black grass,” says Ms. Hayselden-Ashby.
“Its roots also reach deep down, so that it absorbs nutrients from further down and makes them available for future plants.
“I hope that by producing data on the environmental benefits of hemp, we will encourage licensing easing.
“It is not a dangerous drug, it is a plant with great potential and farmers should be encouraged to grow it the same way they are encouraged to grow legumes to improve the soil.”
The farms involved in the Innovative Farmers Study are all licensed hemp farmers and have been selected to represent a large part of the diverse climatic, topographical and soil conditions in England.
They will grow industrial hemp on two plots, including a control plot, and test their soils for organic carbon, soil structure, soil biology and biomass nutrients. They will also conduct biodiversity surveys for butterflies, insects and birds.
Pre-sowing preparations to obtain baseline data are currently underway.