Hemp
   Hemp is a commonly used term for varieties of the Cannabis plant and its products, which include fiber, oil, and seed. In many countries regulatory limits for concentrations of psychoactive drug compounds (THC) in hemp encourages the use of strains of the plant which are bred for low tetrahydrocannabinol (THC) content or otherwise have the THC removed. Hemp is refined into products like hemp seed foods, hemp oil, wax, resin, rope, cloth, pulp, and fuel.
 
History
    Hemp is one of the earliest domesticated plants known. It has been cultivated by many civilizations for over 12,000 years.
 
Yield
    Hemp is one of the faster growing biomasses known,producing up to 25 tonnes of dry matter per hectare per year. A typical average yield in large scale modern agriculture is about 2.5–3.5 t/ac (air dry stem yields of dry, retted stalks per acre at 12% moisture). Approximately one tonne of bast fiber and 2–3 tonnes of core material can be decorticated from 3–4 tonnes of good quality, dry retted straw.
 
Environmental impact
    Hemp is considered by a 1998 study in Environmental Economics to be environmentally friendly due to a decrease of land use and other environmental impacts, indicating a possible decrease of ecological footprint in a US context compared to typical benchmarks. A 2010 study, however, that compared the production ofpaper specifically from hemp and eucalyptus concluded that "industrial hemp presents higher environmental impacts than eucalyptus paper"; however, the article also highlights that "there is scope for improving industrial hemp paper production". Hemp is also claimed to require few pesticides and no herbicides, and it has been called a carbon negative raw material. Results indicate that high yield of hemp may require high total nutrient levels (field plus fertilizer nutrients) similar to a high yielding wheat crop.
 
Cultivars
    Cannabis sativa L. subsp. sativa var. sativa is the variety grown for industrial use, while C. sativa subsp. indica generally has poor fiber quality and is primarily used for recreational and medicinal purposes. The major difference between the two types of plants is the appearance and the amount of Δ9-tetrahydrocannabinol (THC) secreted in a resinous mixture by epidermal hairs called glandular trichomes, although they can also be distinguished genetically. Oilseed and fiber varieties of Cannabis approved for industrial hemp production produce only minute amounts of this psychoactive drug, not enough for any physical or psychological effects. Typically, hemp contains below 0.3% THC, while cultivars of Cannabis grown for recreational use can contain anywhere from 2% to over 20%.
 
Sources
    The world leading producer of hemp is China with smaller production in Europe, Chile and North Korea. While more hemp is exported to the United States than to any other country, the United States Government does not consistently distinguish betweenmarijuana and the non-psychoactive Cannabis used for industrial and commercial purposes.
 
Uses
    Hemp is used for a wide variety of purposes including the manufacture of cordage of varying tensile strength, durable clothing and nutritional products. The bast fibers can be used in 100% hemp products, but are commonly blended with other organic fibers such as flax, cotton or silk, for apparel and furnishings, most commonly at a 55%/45% hemp/cotton blend. The inner two fibers of hemp are more woody and are more often used in non-woven items and other industrial applications, such as mulch, animal bedding and litter. The oil from the fruits ("seeds") oxidizes (commonly, though inaccurately, called "drying") to become solid on exposure to air, similar to linseed oil, and is sometimes used in the manufacture of oil-based paints, in creams as a moisturizing agent, for cooking, and in plastics. Hemp seeds have been used in bird seed mix as well. A survey in 2003 showed that more than 95% of hemp seed sold in the EU was used in animal and bird feed. Hempseed is also used as a fishing bait.
   In modern times hemp is used for industrial purposes including paper, textiles, clothing, biodegradable plastics, construction (as withHempcrete and insulation), body products, health food and bio-fuel.
 
Fiber
   Hemp fiber was widely used throughout history. Items ranging from rope, to fabrics, to industrial materials were made from hemp fiber. Hemp was often used to make sail canvas, and the word canvas derives from cannabis. Today, a modest hemp fabric industry exists, and hemp fibers can be used in clothing.Pure hemp has a texture similar to linen.
 
Cordage
   Hemp rope was used in the age of sailing ships, though the rope had to be protected by tarring, since hemp rope has a propensity for breaking from rot, as the capillary effect of the rope-woven fibers tended to hold liquid at the interior, while seeming dry from the outside. Tarring was a labor-intensive process, and earned sailors the nickname "Jack Tar". Hemp rope was phased out when Manila, which does not require tarring, became widely available. Manila is sometimes referred to as Manila hemp, but is not related to hemp; it is abacá, a species of banana.
 
Water and soil purification
   Hemp can be used as a "mop crop" to clear impurities out of wastewater, such as sewage effluent, excessive phosphorus from chicken litter, or other unwanted substances or chemicals. Eco-technologist Dr. Keith Bolton from Southern Cross University in Lismore, New South Wales, Australia, is a leading researcher in this area. Hemp is being used to clean contaminants at the Chernobyl nuclear disaster site. This is known as phytoremediation- the process by the cleaning radiation as well as a variety of other toxins from the soil, water, and air.
----From Wikipedia, the free encyclopedia