Straw is an agricultural byproduct consisting of the dry stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has a number of different uses, including fuel, livestock bedding and fodder, thatching and basket making.
Straw is usually gathered and stored in a straw bale, which is a bale, or bundle, of straw tightly bound with twine or wire. Straw bales may be square, rectangular, or round, and can be very large, depending on the type of baler used.
Varieties
The height of the straw varies according to the species and cultivated varieties. For example, certain types of wheat known as short cane have been selected precisely to prevent the risk of lodging. However, there are also treatments that limit the growth of the canes with the same purpose.
Collection
After having matured the cereal, comes the threshing season, during which the height of the cutting bar of the harvester-thresher is regulated, depending on whether you want to collect a maximum of straw or not, operation carried out by the harvester, which goes leaving the straw in the form of hozadas in the own field. Then, we must go with another machine that picks up the straw and press it into bales, bales, bales or rolls, which will be transported and stored later in the shelter of the weather. Finally, the part of the cane of scarce height that still remains on the ground after threshing is the so-called stubble.
In the past, the straw could be obtained after the threshing operation of the parvas (separation of the grain from the cereal cane) in a closed enclosure called era. For its conservation as food for animals it was stored in bales or bales in barns or sheds, or even silos, in more recent times.
Uses
Straw can be used both materially and energetically. Here, the use of straw can be traced back to the prehistoric stages of human history with the beginnings of agricultural use of cereals. The straw of various cereals, mainly wheat, rye, barley and triticale, is a by- product of the use of grain for nutrition and starch production. In Germany, about 23 million tons of wheat are produced every year on 3.2 million hectares, plus 11.5 million tons of barley on 2 million hectares, 2.8 million tons of rye on 550,000 hectares, 2.6 Million t of triticale on 380,000 ha and 1.2 million t of oats on 210,000 ha. About 21 million tonnes of cereal straw are produced each year, including 11 million tonnes of wheat, 6.5 million tonnes of barley, 2 million tonnes of rye, 1.3 million tonnes of oats and 1.2% Million tonnes of triticale straw (calculated on the basis of the grain-straw ratio). Of these, around 20-30% can be taken from the material cycle for energy or material use without damage to soil fertility, otherwise a supply of comparable organic substance to the cultivated areas is necessary to ensure a balanced humus balance.
Material use
Bedding and horticultural use
Most of the retracted straw is used as animal bedding for large livestock (cattle, horses and pigs) and is recycled back into the nutrient cycle after use. In the private sector, straw is used for the keeping of rabbits and other small animals: it can be used as an alternative to sawdust or shivesbe used. Barley straw has a much lighter color than straw from other cereals and absorbs bad moisture. For that reason, it is not as good as litter. The same applies to oat straw, which is also very soft and therefore mainly used as feed straw. Rye and wheat straw, on the other hand, are suitable for feeding as well as litter. Smaller amounts of straw are used in mushroom cultivation as a rearing substrate or in fruit production, especially in strawberries to underlay the fruits so that the fruits do not rest on the soil and pollute. In addition, it serves as cold protection.
Building and Insulation
A material use mainly of wheat straw represents its use as a building and insulating material. In the house construction of straw bale is established, which was practiced since about 1890 in the US and has experienced a renaissance since the 1980s, nowadays straw bales serve as a building material in North America, Europe and Asia. In carrying straw bale construction, the walls consist entirely of straw bales and the roof load is carried over the bales of straw. In the non-load-bearing construction, a wooden stand structure forms the framework and the interstices (compartments) are filled with straw. This type of construction corresponds largely to timber frame constructionor the traditional half-timbered house and is usually preferred in Germany, as straw bales have Building not yet approved here as a load-bearing building materials. Another way of insulation with straw represents Einblasstroh that can be used as cellulose. Furthermore, straw is used in the form of straw building boards for drywall purposes.
Straw is a good insulation material that has a WLG value of 046 in bale shape, as a blow-in insulation of 043. Professionally installed bales of straw are mold-resistant, categorized as a normal inflammable building material (B2) and, with settlement values of 2.3% in the component, are equal to other insulating materials. The bulk density of the bales is between 90 and 150 kg / m³.
In addition, there are numerous hybrid forms. So Straw was in earth building traditionally often mixed with clay used, it increases the strength and improves the thermal insulation. In addition, straw roofs used to be made in many regions.
Other material uses
Historically, the use of straw has been much more important for a number of products, but has been replaced by other materials. From woven straw shoes were made, the so-called straw shoes. Another use was woven baskets of plaited straw, which are still occasionally made today.
Also obsolete is the use as a drinking straw, although plastic drinking straws are not infrequently still referred to as straws. The packaging used to be straws to dampen shocks. Today, this function is mainly fulfilled by polystyrene and other plastics, although there are also new straw-based products as packaging filling material. Sometimes straw is also used for the production of paper. Also, targets for archery are made of straw.
In Japan, the living rooms and bedrooms are laid out with rice-straw mats called tatamis. In Europe, among other things, tatami are used as a basis for the practice of judo and other Japanese martial arts.
Around 1800, straw was used as weft material for the production of Marlingewebe.
For a long time straw was used in Europe as a bed straw or as a filling for mattresses. But as the long stalks broke quickly, the camp became hard and uncomfortable. Today, the natural product in straw mattresses is experiencing a minor renaissance: cleaned straw is pressed, surrounded by a fabric, quilted with yarn and often combined with layers of other natural materials such as natural rubber. The straw wiping was used as a field sign.
In addition to wood, especially fast-growing wood from short-rotation plantations, cereal straw is a potential supplier of lignocellulose as a raw material for use in biorefineries for the production of various platform chemicals. However, similar projects are still in the planning stage.
Energetic use
Combustion
According to the Kleinfeuerungsanlagenverordnung, straw is approved as a standard fuel for heating systems between 15 kW and 100 kW in Germany, so that it is permitted to burn in domestic appliances without a special permit. For facilities of z. 15 to 50 kW result from this regulation exhaust gas limit values (per m³ exhaust gas) of 0,15 g / m³ fine dust and 4 g / m³ carbon monoxide (CO), the use in heaters for single households is however little spread, since the plant technology in the Compared to other fuels (pellets, wood) is more expensive. In Denmark, the burning of straw for decentralized heat and power generation is already relatively widespread. In northern Germany, the first three straw thermal power plants in Germany are planned, each with a rated thermal output of 49.8 MW. It is to delineate it from the grain combustion, in which the grain is used for firing. The production of energy pellets from straw for incineration is isolated practice, however, most pellet heaters are only suitable for wood pellets.
The combustion characteristics of straw differ significantly from those of the fuel wood. Among other things, the ash contents are significantly higher, with simultaneously reduced ash melting point and higher dust emissions. In addition, the concentrations of nitrogen, sulfur and chlorine are less favorable for combustion. Especially in small plants compliance with the applicable emission limit values is associated with considerable additional expenses. It has a calorific value of 18.3 to 18.5 MJ / kg.
After burnt down entire rows of houses in many villages, were in the 18th century under Count Palatine Charles IV. Preventing a fire blaze serving strict instructions issued, in which the proper handling of straw and hay was regulated.
Liquid fuels
As a cellulosic raw material, straw is also suitable for producing biofuels that use cellulose as a starting material (for example, BtL fuel and other synthetic biofuels, cellulose-ethanol). These fuels are still largely in the development phase.
Biomethane
In 2012, the first plant in Zörbig (Saxony-Anhalt) was commissioned, which can produce biomethane from 20,000 tonnes of straw per year. The German Biomass Research Center in Leipzig estimates the potential in Germany at 8-13 million tons, in Eastern Europe at 240 million tons, with 8 million tons corresponding to 2.5 gigawatts or clearly the energy requirements of 4 million natural gas vehicles. Unlike the cultivation of energy cropsthe energetic use of straw does not cause competition for land for food production. Since the fermentation residues can be applied to the fields, no loss of nutrients occurs.
Current and historic uses of straw include:
Animal feed
Straw may be fed as part of the roughage component of the diet to cattle or horses that are on a near maintenance level of energy requirement. It has a low digestible energy and nutrient content (as opposed to hay, which is much more nutritious). The heat generated when microorganisms in a herbivore’s gut digest straw can be useful in maintaining body temperature in cold climates. Due to the risk of impaction and its poor nutrient profile, it should always be restricted to part of the diet. It may be fed as it is, or chopped into short lengths, known as chaff.
Basketry
Bee skeps and linen baskets are made from coiled and bound together continuous lengths of straw. The technique is known as lip work.
Bedding: humans or livestock
The straw-filled mattress, also known as a palliasse, is still used in many parts of the world.
It is commonly used as bedding for ruminants and horses. It may be used as bedding and food for small animals, but this often leads to injuries to mouth, nose and eyes as straw is quite sharp.
Biofuels
The use of straw as a carbon-neutral energy source is increasing rapidly, especially for biobutanol. Straw or hay briquettes are a biofuel substitute to coal.
Biogas
Straw, processed first as briquettes, has been fed into a biogas plant in Aarhus University, Denmark, in a test to see if higher gas yields could be attained.
Biomass
The use of straw in large-scale biomass power plants is becoming mainstream in the EU, with several facilities already online. The straw is either used directly in the form of bales, or densified into pellets which allows for the feedstock to be transported over longer distances. Finally, torrefaction of straw with pelletisation is gaining attention, because it increases the energy density of the resource, making it possible to transport it still further. This processing step also makes storage much easier, because torrefied straw pellets are hydrophobic. Torrefied straw in the form of pellets can be directly co-fired with coal or natural gas at very high rates and make use of the processing infrastructures at existing coal and gas plants. Because the torrefied straw pellets have superior structural, chemical and combustion properties to coal, they can replace all coal and turn a coal plant into an entirely biomass-fed power station. First generation pellets are limited to a co-firing rate of 15% in modern IGCC plants.
Construction material:
In many parts of the world, straw is used to bind clay and concrete. A mixture of clay and straw, known as cob, can be used as a building material. There are many recipes for making cob.
When baled, straw has moderate insulation characteristics (about R-1.5/inch according to Oak Ridge National Lab and Forest Product Lab testing). It can be used, alone or in a post-and-beam construction, to build straw bale houses. When bales are used to build or insulate buildings, the straw bales are commonly finished with earthen plaster. The plastered walls provide some thermal mass, compressive and ductile structural strength, and acceptable fire resistance as well as thermal resistance (insulation), somewhat in excess of North American building code. Straw is an abundant agricultural waste product, and requires little energy to bale and transport for construction. For these reasons, straw bale construction is gaining popularity as part of passive solar and other renewable energy projects.
Composite lumber: Wheat straw can be used as a fibrous filler combined with polymers to produce composite lumber.
Enviroboard can be made from straw.
Strawblocks
Crafts
Corn dollies
Straw marquetry
Straw painting
Straw plaiting
Scarecrows
Japanese Traditional Cat’s House
Erosion control
Straw bales are sometimes used for sediment control at construction sites. However, bales are often ineffective in protecting water quality and are maintenance-intensive. For these reasons the U.S. Environmental Protection Agency (EPA) and various state agencies recommend use of alternative sediment control practices where possible, such as silt fences, fiber rolls and geotextiles.
Burned area emergency response
Ground cover
In-stream check dams
Hats
There are several styles of straw hats that are made of woven straw.
Many thousands of women and children in England (primarily in the Luton district of Bedfordshire), and large numbers in the United States (mostly Massachusetts), were employed in plaiting straw for making hats. By the late 19th century, vast quantities of plaits were being imported to England from Canton in China, and in the United States most of the straw plait was imported.
A fiber analogous to straw is obtained from the plant Carludovica palmata, and is used to make Panama hats.
Traditional Japanese rain protection consisted of a straw hat and a mino cape.
Horticulture
Straw is used in cucumber houses and for mushroom growing.
In Japan, certain trees are wrapped with straw to protect them from the effects of a hard winter as well as to use them as a trap for parasite insects.
It is also used in ponds to reduce algae by changing the nutrient ratios in the water.
The soil under strawberries is covered with straw to protect the ripe berries from dirt, and straw is also used to cover the plants during winter to prevent the cold from killing them.
Straw also makes an excellent mulch.
Packaging
Straw is resistant to being crushed and therefore makes a good packing material. A company in France makes a straw mat sealed in thin plastic sheets.
Straw envelopes for wine bottles have become rarer, but are still to be found at some wine merchants.
Wheat straw is also used in compostable food packaging such as compostable plates. Packaging made from wheat straw can be certified compostable and will biodegrade in a commercial composting environment.
Paper
Straw can be pulped to make paper.
Rope
Rope made from straw was used by thatchers, in the packaging industry and even in iron foundries.
Shoes
Koreans wear jipsin, sandals made of straw.
In some parts of Germany like Black Forest and Hunsrück people wear straw shoes at home or at carnival.
Targets
Heavy gauge straw rope is coiled and sewn tightly together to make archery targets. This is no longer done entirely by hand, but is partially mechanised. Sometimes a paper or plastic target is set up in front of straw bales, which serve to support the target and provide a safe backdrop.
Thatching
Thatching uses straw, reed or similar materials to make a waterproof, lightweight roof with good insulation properties. Straw for this purpose (often wheat straw) is grown specially and harvested using a reaper-binder.
Expressions and phrases
See the straw in someone else’s eye ; expression that refers to the biblical parable of the straw and the beam (Luke 6: 41-42) in which Jesus reproaches the hypocrites for wanting to remove the straw from the eye of others, when in fact they do not see the beam in their own. It is used to indicate that, often, who judges or criticizes has the same faults (or even to a greater degree) than it censures in others.
For a take away those straws there ; it is said when the reason for a confrontation or discussion is insignificant or of little importance.
In a get me there those straws ; expression equivalent to in a jibe or in a pispás ; ‘quickly’.
In vulgar language used straw to refer to masturbation 1 male and female. Other variants are straw or straw.
In Latin America, especially in Venezuela and Costa Rica, the straw-speaking expression is often used to refer to the person who tells a lot of lies or talks about unimportant topics (trivialities). Speak no more straw is said to who in a conversation does not provide anything that is profitable.
In Mexico, the expression ” man of straw” is commonly used to refer to the name-borrowers, the figureheads, who lend themselves to doing business, usually shady, on behalf of others who remain anonymous.
In Colombia, Guatemala, Honduras and El Salvador the term straw is used to refer to lying. For example, only straws say, that in a good way it would be: only lies you say. The term pajero refers to who says straws or lies.
There is a fallacy very common in the language, called fallacy of the straw man.
In Argentina, Chile, Paraguay and Uruguay, it is used to express fatigue or laziness. “Going to the corner gives me straw.”
In Venezuela when someone has a share of responsibility in a shameful or unpleasant matter is said to have a tail.
Health and safety
Dried straw presents a fire hazard that can ignite easily if exposed to sparks or an open flame. It can also trigger allergic rhinitis in people who are hypersensitive to airborne allergens such as straw dust.
Research
In addition to its current and historic uses, straw is being investigated as a source of fine chemicals including alkaloids, flavonoids, lignins, phenols, and steroids.
Source from Wikipedia