The New Age of Hemp
Marijuana, or psychotropic hemp, (Cannabis sativa L.) is widely known as a "recreational" drug but few appreciate the other uses and value of this plant, which has been cultivated since the time of ancient civilizations. Remnants of hemp fabric date back to 8,000 BC and, more recently, naval powers such as Spain and Great Britain depended on hemp for ropes and sails. Grown for its naturally long and soft fibres and for its seed oil, industrial hemp was one of the world's largest agricultural crops and, up until the late C19th, was the most traded commodity. And yet in the early decades of this century the importance of hemp had been sidelined by the mechanization of cotton production. Drug prohibition laws, which do not discriminate between low and high narcotic varieties of hemp, also contributed to its decline as cultivation of any kind of hemp was made illegal in many developed countries. By the early 1990s, hemp production was confined to 290,000ha in China, the Ukraine and parts of Eastern Europe.
Hungary and Romania in Eastern Europe and China remain the largest growers of hemp and exporters of hemp products: hemp cordage, paper, rugs and textiles. But, during the 1990s, recognition of the qualities of hemp as a fibre has led to a worldwide resurgence in interest in the crop and subsidies have helped to develop a burgeoning industry in many countries. Much of the current research and commercial development programmes for hemp focus on its potential for paper manufacture but markets are emerging for it use as an insulation filler material, for composting mediums, animal litter and, in France, a market has been pioneered for building materials that utilize the stem core. The strength and manufacturing qualities of hemp have also been recognized for its use in high matrix composites and injection moulded thermoplastics.
European experience has shown that hemp is less prone to pests and disease than many other crops and grows well without the use of chemicals. Hemp is normally dioecious (male plants provide the fibre and female plants the seeds) but monecious varieties are now available. The potential for illegal drug production of marijuana has also been restricted through the selection of Cannabis sativa L. with low levels of narcotic tetrahydrocannabinol (THC). In Industrial Hemp the THC level is less than 0.3%, too low to produce any pyschotropic effect, compared with 3-10% in narcotic hemp. France is now the main source of viable low-thc hempseed although seed breeders in the Netherlands are also developing new strains of low-thc varieties. Licenses to grow industrial hemp for commercial production have now been granted in much of Europe, Canada and in the state of Victoria in Australia. In April this year, industrial hemp was reclassified from a noxious weed to an oilseed crop in the US state of North Dakota and other states in the US are currently considering industrial hemp legislation or research.
In the developing countries, Industrial Hemp is grown in Egypt and Thailand and large stands of naturalized Cannabis are grown in India for use in cordage, textiles and seed oil. Chile, once a major producer of hemp for the Spanish Conquistadors, continues to grow hemp on a limited basis for seed oil production: the seed is more nutritious (25% protein) and more easily digestible than soybean and contains more essential fatty acids than any other source.
Many landraces and cultivars of hemp have been grown around the world depending on the hemp products required and "varieties" can be divided into four basic categories: fibre hemp, seed hemp, mixed hemp (fibre and seed) and drug Cannabis. The success of hemp in tropical countries depends on the origin of hemp seed. Much of it is currently selected for growing in temperate regions but Hemp-Agro International, a private company located in Nicaragua and Canada, has successfully developed a tropical variety 'Zolguanica '95', which was introduced in 1995. It was genetically created in conjunction with Ukranian and Chinese seed stock and 4,000 acres of this variety is planted in Nicaragua with two crops grown per year.