Unlocking the potential of hemp
Hemp by-products can be used for everything from building materials to food supplements. But while it grows well here, we lack the infrastructure to take full advantage of the plant's potential for farm incomes and job creation, writes Barry Caslin
There has been a recent surge of interest in hemp production globally. Industrial hemp can be legally grown in Ireland under licence from the Department of Health for a range of uses, including for fibre, food and feed. The varieties of hemp permitted are listed in the EU's 'Common Catalogue of Varieties of Agricultural Plant Species'.
Industrial Hemp is pretty much the same as cannabis, but without the narcotic effects and the active ingredient - tetrahydrocannabinol (THC) - does not exceed 0.2pc in industrial plants.
The hemp industry has been slow to take off in Ireland due largely to a lack of processing infrastructure.
With the recent renewed interest in hemp worldwide, it is important to look at the barriers faced by farmers and then look at how we can unlock the potential of hemp growing as an alternative farm enterprise.
The first research on hemp at Oak Park (then An Foras Taluntais) began in 1960. The main objective was to produce hemp fibre for textile production.
The experiments found that French monoecious varieties were well adapted to the Irish climate and grew well.
They also showed that Irish-grown hemp was suitable for spinning and that paper of satisfactory quality could be produced.
But with low-cost mineral-based plastic fibres freely available, commercial development was not possible and the research was terminated.
Work resumed at Oak Park (now Teagasc) in 1997, with two objectives: to establish the yield potential of newly-available varieties and to examine the potential of the crop for fibre-board production.
The results showed that high yields of stem material (10-14t/ha) could be produced, that seed rates (and input costs) could be reduced where fibre quality was not a priority, and that whole chopped hemp stems could be used in the manufacture of medium- density fibre board.
The focus of more recent research was on optimising the agronomy of the crop particularly in relation to nutrient requirements.
In summary, this research has shown that hemp can be grown successfully in Ireland, that high stem yields of adequate quality material can be attained, and that difficulties in the harvesting of the crop can be overcome.
Recently, several new factors have increased the desirability of establishing a hemp industry in Ireland.
* A growing need for new environmentally-friendly rural enterprises;
* A requirement for additional biomass to meet bio-energy targets;
* A need for tillage break crops and for replacements for high-energy insulation and composite reinforcement products.
Markets for hemp products
For a viable operation, markets are needed for three hemp products: hurds, fibre and fines.
Hurds comprise over 60pc of the plant output. Three markets for this product could be pursued: animal bedding, energy use and lightweight concrete. Clean dust-free hemp hurds are highly absorbent and are marketed successfully as horse or poultry bedding in the UK.
Hurds have a heating value only slightly lower than wood, and their combustion properties are generally favourable. Two energy uses for hurds could be explored. In the short term, supply to a power station (just beginning to substitute biomass to replace, for example, peat).
In the medium term, briquette production for use as domestic fuel for open fires and hand-fed stoves could be developed. Hemp hurds mixed into concrete give a light-weight product with a high insulating value and a much reduced carbon footprint.
This use has been developing rapidly in the UK, and could be grown here as the building sector recovers. Everybody is aiming to be carbon neutral these days and hempcrete fits the bill because all the carbon dioxide used by the hemp plant during photosynthesis is locked away.
Hemp fibre use in woven fabric is likely to remain small and requires a high-quality fibre whose production may not be feasible.
Instead, it could be marketed as an environmentally acceptable replacement for insulation materials such as fossil produced glass-fibre, rock wool and polystyrene, and for fibre-glass in composite reinforcement applications.
A high-quality biodegradable bioplastic can also be produced from the fibre. Hemp fibre is being used in the automotive sector for the manufacture of recyclable door panels and other parts. Hempcrete, a breathable mix of shiv and lime, is used as an energy- efficient building material that can be sprayed on to a wooden frame. Hemp fines have combustion properties similar to hurds. One of the main advantages of hempcrete is that is not at all flammable. Fuel briquettes from fines could be produced and marketed.
Processing hemp for fibre
Processing facilities will be required to process hemp straw each year. An industrial hemp decortication plant would be needed to separate the crop into its two main components - shivs or hurds (60-70pc) and fibre (20-25pc); the remainder (10-15pc) consists of fines and dust from the process and is also marketable as a biofuel.
A decortication plant would also include facilities to remove dust from the hurds and to produce fuel briquettes from fines and hurds. The fibre could be sold for insulation and bio-composite reinforcement, bioplastics to replace fossil fuel-derived equivalents and the fines as a by-product could be used as fuel.
Hemp (cannabis sativa) is believed to contain up to 400 compounds, including cannabinoids, terpenoids and flavonoids. Their content depends upon the plant genetics, growth conditions, time of harvest and drying conditions. (The cultivation of cannabis sativa was banned in the early 20th century due to the principal intoxicant cannabinoid ∆9-tetrahydrocannabinol (THC).
Industrial hemp has naturally low THC levels, which has led to a worldwide demand for hemp derived cannabidiol (CBD). CBD is one of 108 cannabinoids identified in the hemp and cannabis sativa plant. CBD interacts with our bodies' endocannabinoid systems and according to the World Health Organisation, preclinical research and clinical studies have shown that CBD may have health benefits.
The industry standard method of extraction of cannabinoids is by using solvents or supercritical CO2 extraction, but due to these methods not being used with hemp in the EU to a significant degree prior to 1997, they are considered a novel food and therefore, you cannot sell CBD extracted with these methods in the EU unless you obtain a novel food licence.
You are permitted to sell CBD oil extracted simply by pressing, e.g. cold pressing. Hemp oil obtained by cold-pressing the seeds or other parts of the hemp plant does not require authorisation. This is because hemp oil was consumed in the EU to a significant degree before 1997.
Hemp oil's beneficial properties
In crushing seed varieties such as finola, you can produce a hemp oil. Its mix of omega 3, 6 and 9 fatty acids is supposed to be closest to what occurs naturally in the body. Hempseed offers a unique nutritional package, in terms of dietary oil, protein, vitamins and minerals. The increased cultural and environmental shift towards eating less meat will be a driver for hemp-based food.
The construction of a hemp decortications plant would make possible the establishment of a bio-refinery type industry in Ireland that would utilise a renewable native raw material to make a number of environmentally favourable energy and other industrial products.
It would provide valuable rural employment in production, transport and processing, and would provide farmers with a new business opportunity and a valuable break crop.
Decorticators are commonly used in the European, American, Canadian and Chinese hemp industry, but due to the economies of scale, this basic technology for the development of the hemp industry is not yet available in Ireland.
Barry Caslin is a Teagasc Energy & Rural Development specialist. Email: firstname.lastname@example.org
For Stories Like This and More
Download the Free Farming Independent App