fibre is obtained from the bast of the plant
L. It grows easily - to a height of 4 m without agrochemicals
and captures large quantities of carbon. Production of
is restricted in some countries, where the plant is confused
with marijuana. Optimum yield of
fibre is more than 2 tonnes per ha, while average yields are
around 650 kg.
Long, strong and durable,
fibres are about 70% cellulose and contain low levels of lignin
(around 8-10%). The fibre diameter ranges from 16 to 50 microns.
fibre conducts heat, dyes well, resists mildew, blocks
ultraviolet light and has natural anti-bacterial properties.
Shorter, woody core fibres ("tow") contain higher levels of
To achieve an optimum hemp yield, twice as much nutrient must be
available to the crop as will finally be removed from the soil
at harvest. A hemp field produces a very large bulk of
vegetative material in a short vegetative period. The nitrogen
uptake is most intensive the first 6 to 8 weeks, while potassium
and in particular phosphorous are needed more during flowering
and seed formation. Industrial hemp requires 105 to 130 lbs/acre
(120 to 150 kg/ha) nitrogen, 45 to 70 lbs/acre (50 to 80 kg/ha)
phosphate and 52 to 70 lbs/acre (60 to 80 kg/ha) potash. Hemp
prefers a mild climate, humid atmosphere, and a rainfall of at
least 25-30 inches per year. Good soil moisture is required for
seed germination and until the young plants are well
Hemp has been used for centuries to make rope, canvas and paper.
Long hemp fibres can be spun and woven to make crisp, linen-like
fabric used in clothing, home furnishing textiles and floor
coverings. In China, hemp is de-gummed for processing on flax or
cotton machinery. Blending with cotton, linen, silk and wool
gives hemp a softer feel, while adding resistance and durability
to the product.
In Europe, hemp fibres are used mainly in the special paper
industry. Hemp fibres are also used to reinforce moulded
thermoplastics in the automobile industry. The short core fibres
go into insulation products, fibreboard and erosion control
mats, while the fibrous core can be blended with lime to make
strong, lightweight concrete.
The world hemp production map and available statistics on ramie
is given below: