Hemp, grown under license mostly in Canada, is the most publicized “new” crop in North America. Until very recently the prohibition against drug forms of the plant prevented consideration of cultivation of fiber and oilseed cultivars in Canada. However, in the last 10 years three key developments occurred: (1) much-publicized recent advances in the legal cultivation of hemp in western Europe, especially for new value-added products; (2) enterprising farmers and farm groups became convinced of the agricultural potential of hemp in Canada, and obtained permits to conduct experimental cultivation; and (3) lobby groups convinced the government of Canada that narcotic forms of the hemp plant are distinct and distinguishable from fiber and oilseed forms. In March 1998, new regulations (under the Controlled Drugs and Substances Act) were provided to allow the commercial development of a hemp industry in Canada, and since then more than a thousand licenses have been issued. Hectares licensed for cultivation for 1998–2001 were respectively, 2,500, 14,200, 5,487, and 1,355, the decreasing trend due to a glut of seed produced in 1999 and pessimism over new potential regulations barring exports to the US. Information on the commercial potential of hemp in Canada is in Blade (1998), Marcus (1998), and Pinfold Consulting (1998). In the US, a substantial trade in hemp products has developed, based on imports of hemp fiber, grain, and oil. The American agricultural community has observed this, and has had success at the state level in persuading legislators of the advisability of experimental hemp cultivation as a means of evaluating the wisdom of re-establishing American hemp production. However, because of opposition by the federal government, to date there has only been a small experimental plot in Hawaii. Information on the commercial potential of hemp in the US is presented in the following.
Fig. 3. Photograph of Cannabis sativa. Left, staminate (“male”) plant in flower; right, pistillate (“female”) plant in flower. Fig. 4. United States National Institute of Health, University of Mississippi marijuana plantation site, showing variation in plant size. A tall fiber-type of hemp plant is shown at left, and a short narcotic variety (identified as “Panama Gold”) at right.
μ-Opioid receptor agonists (opioids) (e.g., morphine, heroin, hydrocodone, oxycodone, opium, kratom) α2δ subunit-containing voltage-dependent calcium channels blockers (gabapentinoids) (e.g., gabapentin, pregabalin, phenibut) AMPA receptor antagonists (e.g., perampanel) CB1 receptor agonists (cannabinoids) (e.g., THC, cannabis) Dopamine receptor agonists (e.g., levodopa) Dopamine releasing agents (e.g., amphetamine, methamphetamine, MDMA, mephedrone) Dopamine reuptake inhibitors (e.g., cocaine, methylphenidate) GABAA receptor positive allosteric modulators (e.g., barbiturates, benzodiazepines, carbamates, ethanol (alcohol) (alcoholic drink), inhalants, nonbenzodiazepines, quinazolinones) GHB (sodium oxybate) and analogues Glucocorticoids (corticosteroids) (e.g., dexamethasone, prednisone) nACh receptor agonists (e.g., nicotine, tobacco, arecoline, areca nut) Nitric oxide prodrugs (e.g., alkyl nitrites (poppers)) NMDA receptor antagonists (e.g., DXM, ketamine, methoxetamine, nitrous oxide, phencyclidine, inhalants) Orexin receptor antagonists (e.g., suvorexant)
In Japan, hemp was historically used as paper and a fiber crop. There is archaeological evidence cannabis was used for clothing and the seeds were eaten in Japan back to the Jōmon period (10,000 to 300 BC). Many Kimono designs portray hemp, or asa (Japanese: 麻), as a beautiful plant. In 1948, marijuana was restricted as a narcotic drug. The ban on marijuana imposed by the United States authorities was alien to Japanese culture, as the drug had never been widely used in Japan before. Though these laws against marijuana are some of the world's strictest, allowing five years imprisonment for possession of the drug, they exempt hemp growers, whose crop is used to make robes for Buddhist monks and loincloths for Sumo wrestlers. Because marijuana use in Japan has doubled in the past decade, these exemptions have recently been called into question.
The most valid claims to environmental friendliness of hemp are with respect to agricultural biocides (pesticides, fungicides, herbicides). Cannabis sativa is known to be exceptionally resistant to pests (Fig. 51), although, the degree of immunity to attacking organisms has been greatly exaggerated, with several insects and fungi specializing on hemp. Despite this, use of pesticides and fungicides on hemp is usually unnecessary, although introduction of hemp to regions should be expected to generate local problems. Cannabis sativa is also relatively resistant to weeds, and so usually requires relatively little herbicide. Fields intended for hemp use are still frequently normally cleared of weeds using herbicides, but so long as hemp is thickly seeded (as is always done when hemp is grown for fiber), the rapidly developing young plants normally shade out competing weeds.