International System of Units
The International System of Units is the modern form of the metric system, and is the most widely used system of measurement. It comprises a coherent system of units of measurement built on seven base units, the system establishes a set of twenty prefixes to the unit names and unit symbols that may be used when specifying multiples and fractions of the units. The system was published in 1960 as the result of an initiative began in 1948. It is based on the system of units rather than any variant of the centimetre-gram-second system. The motivation for the development of the SI was the diversity of units that had sprung up within the CGS systems, the International System of Units has been adopted by most developed countries, the adoption has not been universal in all English-speaking countries. The metric system was first implemented during the French Revolution with just the metre and kilogram as standards of length, in the 1830s Carl Friedrich Gauss laid the foundations for a coherent system based on length and time.
In the 1860s a group working under the auspices of the British Association for the Advancement of Science formulated the requirement for a coherent system of units with base units and derived units. Meanwhile, in 1875, the Treaty of the Metre passed responsibility for verification of the kilogram, in 1921, the Treaty was extended to include all physical quantities including electrical units originally defined in 1893. The units associated with these quantities were the metre, second, kelvin, in 1971, a seventh base quantity, amount of substance represented by the mole, was added to the definition of SI. On 11 July 1792, the proposed the names metre, are and grave for the units of length, capacity. The committee proposed that multiples and submultiples of these units were to be denoted by decimal-based prefixes such as centi for a hundredth, on 10 December 1799, the law by which the metric system was to be definitively adopted in France was passed. Prior to this, the strength of the magnetic field had only been described in relative terms.
The technique used by Gauss was to equate the torque induced on a magnet of known mass by the earth’s magnetic field with the torque induced on an equivalent system under gravity. The resultant calculations enabled him to assign dimensions based on mass, length, a French-inspired initiative for international cooperation in metrology led to the signing in 1875 of the Metre Convention. Initially the convention only covered standards for the metre and the kilogram, one of each was selected at random to become the International prototype metre and International prototype kilogram that replaced the mètre des Archives and kilogramme des Archives respectively. Each member state was entitled to one of each of the prototypes to serve as the national prototype for that country. Initially its prime purpose was a periodic recalibration of national prototype metres. The official language of the Metre Convention is French and the version of all official documents published by or on behalf of the CGPM is the French-language version
The open-field system was the prevalent agricultural system in much of Europe during the Middle Ages and lasted into the 20th century in parts of western Europe, Russia and Turkey. Under the open-field system, each manor or village had two or three fields, usually several hundred acres each, which were divided into many narrow strips of land. The strips or selions were cultivated by individuals or peasant families, the holdings of a manor included woodland and pasture areas for common usage and fields belonging to the lord of the manor and the church. The farmers customarily lived in houses in a nucleated village with a much larger manor house. The open-field system necessitated co-operation among the inhabitants of the manor, the Lord of the Manor, his officials, and a Manorial court administered the manor and exercised jurisdiction over the peasantry. The Lord levied rents and required the peasantry to work on his personal lands, in medieval times, little land was owned outright. Instead the lord had rights given to him by the king, lords demanded rents, often ruinous, and labour from the tenants, but the tenants had firm user rights to cropland and common land and those rights were passed down from generation to generation. A medieval lord could not evict a tenant nor hire labour to him without legal cause.
Most tenants likewise were not free without penalty to depart the manor for other locations or occupations, the rise of capitalism and the concept of land as a commodity to be bought and sold led to the demise of the open-field system. The open-field system was replaced over several centuries by private ownership of land. France and other northern European countries had similar to England. Some elements of the system were practised by early settlers in the New England region of the United States. The most visible characteristic of the system was that the arable land belonging to a manor was divided into many long narrow furlongs for cultivation. The fields of cultivated land were unfenced, hence the name open-field system, each tenant of the manor cultivated several strips of land scattered around the manor. The village of Elton, Cambridgeshire is representative of a medieval manor in England. The manor, whose Lord was an abbot from a monastery, had 13 hides of arable land of six virgates each.
The acreage of a hide and virgate varied, but at Elton a hide was 144 acres, the total of arable land amounted to 1,872 acres. The abbots demesne land consisted of three hides plus 16 acres of meadow and 3 acres of pasture, the remainder of the land was cultivated by 113 tenants who lived in a village on the manor
Livestock are domesticated animals raised in an agricultural setting to produce commodities such as food and labor. The term is used to refer solely to those raised for food. In recent years, some organizations have raised livestock to promote the survival of rare breeds, animal husbandry practices have varied widely across cultures and time periods. Originally, livestock were not confined by fences or enclosures, but these practices have largely shifted to intensive animal farming and these practices increase yield of the various commercial outputs, but have led to increased concerns about animal welfare and environmental impact. Livestock production continues to play an economic and cultural role in numerous rural communities. Livestock as a word was first used between 1650 and 1660, as a merger between the live and stock. Older English sources, such as the King James Version of the Bible, the word cattle is derived from Old North French catel, which meant all kinds of movable personal property, including livestock, which was differentiated from immovable real estate.
In English, sometimes smaller livestock such as chickens and pigs were referred to as small cattle, the modern meaning of cattle, without a modifier, usually refers to domesticated bovines, but sometimes livestock refers only to this subgroup. Legal definition United States federal legislation sometimes more narrowly defines the term to make specified agricultural commodities either eligible or ineligible for a program or activity, for example, the Livestock Mandatory Reporting Act of 1999 defines livestock only as cattle and sheep. Animal-rearing originated during the transition to settled farming communities from hunter-gatherer lifestyles. Animals are domesticated when their breeding and living conditions are controlled by humans, over time, the collective behaviour and physiology of livestock have changed radically. Many modern farm animals are unsuited to life in the wild, dogs were domesticated in East Asia about 15,000 years ago. Goats and sheep were domesticated around 8000 BC in Asia, swine or pigs were domesticated by 7000 BC in the Middle East and China.
The earliest evidence of horse domestication dates to around 4000 BC, the term livestock is nebulous and may be defined narrowly or broadly. Broadly, livestock refers to any breed or population of animal kept by humans for a useful and this can mean domestic animals, semidomestic animals, or captive wild animals. Semidomesticated refers to animals which are only lightly domesticated or of disputed status and these populations may be in the process of domestication. Some people may use the term livestock to refer to only used for red meat. Livestock are used by humans for a variety of purposes, many of which have an economic value, Livestock products include, Meat A useful form of dietary protein and energy, meat is the edible tissue of the animal carcass
Troy weight is a system of units of mass customarily used for precious metals and gemstones. One troy ounce equals 31.1034768 grams exactly, there are only 12 troy ounces per troy pound, rather than the 16 ounces per pound found in the more common avoirdupois system. However, the pound has 7000 grains whereas the troy pound has only 5760 grains. Both systems use the same grain defined by the international yard, therefore the troy ounce is 480 grains, compared with the avoirdupois ounce, which is 437.5 grains. So the troy ounce is about 10% heavier than the avoirdupois ounce, although troy ounces are still used to weigh gold and gemstones, troy weight is no longer used in most other applications. One troy ounce of gold is denoted with the ISO4217 currency code XAU, troy weight probably takes its name from the French market town of Troyes in France where English merchants traded at least as early as the early 9th century. The name troy is first attested in 1390, describing the weight of a platter, the word troni refers to markets.
Watson finds the dialect word troi, meaning a balance in Wrights Dialect Dictionary, troy weight referred to the tower system, the earliest reference to the modern troy weights is in 1414. Many aspects of the weight system were indirectly derived from the Roman monetary system. The Romans used bronze bars of varying weights as currency, an aes grave weighed 1 pound. One twelfth of an aes grave was called an uncia, or in English an ounce, before the adoption of the metric system, many systems of troy weights were in use in various parts of Europe, among them Holland troy, Paris troy, etc. Their values varied from one another by up to several percentage points, troy weights were first used in England in the 15th century, and were made official for gold and silver in 1527. The British Imperial system of weights and measures was established in 1824, the troy ounce in use today is essentially the same as the British Imperial troy ounce, adopted as an official weight standard for United States coinage by Act of Congress on May 19,1828.
The British Imperial troy ounce was based on, and virtually identical with, the pre-1824 British troy ounce, the English troy ounce was officially adopted for coinage in 1527. Troy ounces have been used in England since about 1400, before that, various sorts of troy ounces were in use on the continent. The troy ounce and grain were part of the apothecaries system and this was long used in medicine, but has now been largely replaced by the metric system. The only troy weight in widespread use today is the British Imperial troy ounce, both are currently based on a grain of 0.06479891 gram, with 480 grains to a troy ounce. The British Empire abolished the 12-ounce troy pound in the 19th century, the origin of the troy weight system is unknown
A paddy field is a flooded parcel of arable land used for growing semiaquatic rice. Paddy cultivation should not be confused with cultivation of deep water rice, Paddy fields are the typical feature of rice farming in east and southeast Asia. Fields can be built into steep hillsides as terraces and adjacent to depressed or steeply sloped features such as rivers or marshes and they can require a great deal of labor and materials to create, and need large quantities of water for irrigation. Oxen and water buffalo, adapted for life in wetlands, are important working animals used extensively in paddy field farming, during the 20th century, paddy-field farming became the dominant form of growing rice. Hill tribes of Thailand still cultivate dry-soil varieties called upland rice, Paddy fields are a major source of atmospheric methane and have been estimated to contribute in the range of 50 to 100 million tonnes of the gas per annum. Studies have shown that this can be reduced while boosting crop yield by draining the paddies to allow the soil to aerate to interrupt methane production.
Studies have shown the variability in assessment of methane emission using local and global factors, the word paddy is derived from the Malay word padi, rice plant. Archaeologists generally accept that wet-field cultivation originated in China, the earliest paddy field found, dates to 4330 BC, based on carbon dating of grains of rice and soil organic matter found at the Chaodun site in Kunshan County. At Caoxieshan, a site of the Neolithic Majiabang culture, archaeologists excavated paddy fields, some archaeologists claim that Caoxieshan may date to 4000–3000 BC. There is archaeological evidence, that unhusked rice was stored for the military and for burial with the deceased, there are ten archaeologically excavated rice paddy fields in Korea. The two oldest are the Okhyun and Yaumdong sites, found in Ulsan, dating to the early Mumun pottery period, Paddy field farming goes back thousands of years in Korea. Ancient paddy fields have been unearthed in Korea by institutes such as Kyungnam University Museum of Masan.
They excavated paddy field features at the Geumcheon-ni Site near Miryang, the paddy field feature was found next to a pit-house that is dated to the latter part of the Early Mumun Pottery Period. KUM has conducted excavations, that have revealed similarly dated paddy field features, at Yaeum-dong and Okhyeon, the earliest Mumun features were usually located in low-lying narrow gullies, that were naturally swampy and fed by the local stream system. Mumun Period rice farmers used all of the elements that are present in todays paddy fields, such as terracing, canals and we can grasp some paddy-field farming techniques of the Middle Mumun, from the well-preserved wooden tools excavated from archaeological rice fields at the Majeon-ni Site. However, iron tools for farming were not introduced until sometime after 200 BC. The spatial scale of paddy-fields increased, with the use of iron tools. The first paddy fields in Japan date to the Early Yayoi period, the Early Yayoi has been re-dated, and it appears that wet-field agriculture developed at about the same time as in the Korean peninsula
Animal husbandry is the management and care of farm animals by human beings, in which genetic qualities and behavior, considered to be advantageous to humans, are further developed. The term can refer to the practice of breeding and raising livestock to promote desirable traits in animals for utility, pleasure. Animal husbandry has been practiced for thousands of years since the first domestication of animals, selective breeding for desired traits was first established as a scientific practice by Robert Bakewell during the British Agricultural Revolution in the 18th century. One of his most important breeding programs was with sheep, using native stock, he was able to quickly select for large, yet fine-boned sheep, with long, lustrous wool. The Lincoln Longwool was improved by Bakewell and in turn the Lincoln was used to develop the subsequent breed, named the New Leicester and it was hornless and had a square, meaty body with straight top lines. These sheep were exported widely and have contributed to modern breeds.
Under his influence, English farmers began to breed cattle for use primarily as beef for consumption -, long-horned heifers were crossed with the Westmoreland bull to eventually create the Dishley Longhorn. Over the following decades, farm animals increased dramatically in size, in 1700, the average weight of a bull sold for slaughter was 370 pounds. By 1786, that weight had more than doubled to 840 pounds, in more modern times herds are tended on horses, all-terrain vehicles, four-wheel drive vehicles, and helicopters, depending on the terrain and livestock concerned. Today, herd managers often oversee thousands of animals and many staff, farms and ranches may employ breeders, herd health specialists and milkers to help care for the animals. Techniques such as artificial insemination and embryo transfer are used today, not only as methods to guarantee that females breed regularly. This may be done by transplanting embryos from high-quality females into lower-quality surrogate mothers - freeing up the higher-quality mother to be reimpregnated and this practice vastly increases the number of offspring which may be produced by a small selection of the best quality parent animals.
On one hand, this improves the ability of the animals to feed to meat, milk, or fiber more efficiently. On the other, it decreases genetic diversity, increasing the severity of disease outbreaks among other risks. The semi-natural, unfertilized pastures formed by traditional methods in Europe, were managed and maintained by the grazing and mowing of livestock. Animal agriculture is responsible for 20%-33% of all fresh water consumption in the world today, livestock or livestock feed occupies 1/3 of the earth’s ice-free land. Animal agriculture is the cause of species extinction, ocean dead zones, water pollution. Animal agriculture contributes to species extinction in many ways, the widespread use of pesticides and chemical fertilizers used in the production of feed crops often interferes with the reproductive systems of animals and poison waterways
Veld, spelled veldt, is a type of wide open rural landscape in Southern Africa. Particularly, it is an area covered in grass or low scrub, especially in the countries of South Africa, Swaziland, Botswana. A certain sub-tropical woodland ecoregion of Southern Africa has been defined as the Bushveld by the World Wide Fund for Nature. Trees are found only in a few places—frost and grazing animals allow grass to grow, the word veld comes from the Afrikaans word for field. The etymological origin is older Dutch veldt, a spelling that the Dutch abandoned in favour of veld during the 19th century, decades before the first Afrikaans dictionary. Subsequent addition of the t in the spelling veldt seems to have been mainly an English confusion with the already obsolete Dutch usage. Precipitation mostly occurs in the months in the form of high-energy thunderstorms. Temperature is closely related to elevation, in general, the mean July temperatures range between 45 °F in the Lesotho Highlands and 60 °F in the Lowveld.
January temperatures range between 65 °F and 80 °F, in Zimbabwe the precipitation averages around 30 to 35 inches on the Highveld, dropping to less than 15 inches in the lowest areas of the Lowveld. Temperatures are slightly higher than in South Africa, over the entire veld and annual average rainfall variations of up to 40 percent are common. Damaging drought affects at least half the area about once every three or four years, it reduces plant and animal biomass to sustainable levels again, everywhere the average number of hours of annual sunshine varies from 60 to 80 percent of the total amount possible. Veld can be compared to the Australian terms outback or the bush, to the prairie of North America, to the pampas lowlands of South America. Someone from Yorkshire might equate wandering across the moors to walking through the veld, by extension, the veld can be compared to the boondocks or those places beyond the black stump in Australia. There is a sense in which it refers in essence to unimproved land and these areas are referred to as fields.
The word is appropriate for land that is heavily forested, mountainous. The simplest explanation will be to say the word veld means natural vegetation, excluding vegetation like swamps and it does include mountains with vegetation but not deserts or mountains without natural vegetation. Whereas mountainous peaks and thick forests do not really fit in with the term veld, the word Renosterveld, rhinoceros-field, is now used to differentiate one of the major vegetation types of the Cape Floristic Region. A carefully husbanded sports field on which the game of Rugby is played in the middle of such as Cape Town or Johannesburg is referred to as a rugbyveld in the Afrikaans language
Arable land is, according to one definition, land capable of being ploughed and used to grow crops. In Britain, it was contrasted with pasturable lands such as heaths which could be used for sheep-rearing. A quite different kind of definition is used by various agencies concerned with agriculture, the abandoned land resulting from shifting cultivation is not included in this category. Data for ‘Arable land’ are not meant to indicate the amount of land that is potentially cultivable, a briefer definition appearing in the Eurostat glossary similarly refers to actual, rather than potential use, land worked regularly, generally under a system of crop rotation. According to Food and Agriculture Organization of the United Nations the worlds Arable land amounted to 1,407 M ha, out of a total 4,924 M ha land used for agriculture, as for year 2013. Agricultural land that is not arable according to the FAO definition above includes, Permanent crop - land that produces crops from woody vegetation, other non-arable land includes land unsuitable for any agricultural use.
Although such limitations may preclude cultivation, and some will in some cases preclude any agricultural use, for example, US NRCS statistics indicate that about 59 percent of US non-federal pasture and unforested rangeland is unsuitable for cultivation, yet such land has value for grazing of livestock. Similar examples can be found in many rangeland areas elsewhere, land incapable of being cultivated for production of crops can sometimes be converted to arable land. New arable land makes more food, and can reduce starvation and this outcome makes a country more self-sufficient and politically independent, because food importation is reduced. This process is extremely expensive. An alternative is the Seawater Greenhouse which desalinates water through evaporation and condensation using solar energy as the energy input. This technology is optimized to grow crops on land close to the sea. The people covered the islands with a layer of seaweed. Israel, The construction of desalination plants along Israels coast allowed agriculture in areas that were formerly desert.
The desalination plants, which remove the salt from water, have created a new source of water for farming, drinking. Slash and burn agriculture uses nutrients in wood ash, but these expire within a few years, terra preta, fertile tropical soils created by adding charcoal. Some examples of fertile land being turned into infertile land are. Rainforest deforestation, The fertile tropical forests are converted into infertile desert land, for example, Madagascars central highland plateau has become virtually totally barren, as a result of slash-and-burn deforestation, an element of shifting cultivation practiced by many natives
In geography, a plain is a flat, sweeping landmass that generally does not change much in elevation. Plains occur as lowlands along the bottoms of valleys or on the doorsteps of mountains, as coastal plains, and as plateaus or uplands. In a valley, a plain is enclosed on two sides but in other cases a plain may be delineated by a complete or partial ring of hills, where a geological region contains more than one plain, they may be connected by a pass. Coastal plains would mostly rise from sea level until they run into elevated features such as mountains or plateaus, plains are one of the major landforms on earth, where they are present on all continents, and would cover more than one-third of the world’s land area. Plains may have formed from flowing lava, deposited by water, wind, or formed by erosion by these agents from hills. Plains would generally be under the grassland, savannah or tundra biomes, in a few instances and rainforests can be plains. Structural plains are relatively undisturbed horizontal surfaces of the Earth and they are structurally depressed areas of the world that make up some of the most extensive natural lowlands on the Earths surface.
Erosional plains have been leveled by various agents of such as running water, rivers and glacier which wear out the rugged surface. Plain resulting from the action of these agents of denudation are called peneplains while plains formed from wind action are called pediplains, depositional plains formed by the deposition of materials brought by various agents of transportation such as rivers, wind and glaciers. Their fertility and economic relevance depend greatly on the types of sediments that are laid down, flood plain, adjacent to a stream, lake or wetland that experiences occasional or periodic flooding. Scroll plain, a plain through which a river meanders with a low gradient. Lacustrine plain, a plain that originally formed in a lacustrine environment, lava plain, formed by sheets of flowing lava. Glacial plains, formed by the movement of glaciers under the force of gravity, sandar consist mainly of stratified gravel and sand. Till plain, a plain of glacial till that forms when a sheet of ice becomes detached from the body of a glacier.
Till plains are composed of unsorted material of all sizes, abyssal plain, a flat or very gently sloping area of the deep ocean basin. Planitia, the Latin word for plain, is used in the naming of plains on extraterrestrial objects, such as Hellas Planitia on Mars or Sedna Planitia on Venus