Agriculture involving domestication of plants and animals was developed around 12,000 years ago although earlier people began altering communities of flora and fauna for their own benefit through other means such as fire-stick farming prior to that.[1][2]Agriculture has undergone significant developments since the time of the earliest cultivation. The Fertile Crescent of Western Asia,Egypt and India were sites of the earliest planned sowing and harvesting of plants that had previously been gathered in the wild. Independent development of agriculture occurred in northern and southern China, Africa's Sahel, New Guinea, parts of India and several regions of the Americas.[3] Agricultural techniques such as irrigation, crop rotation, the application of fertilizers were developed soon after the Neolithic Revolution but have made significant strides in the past 200 years. The Haber-Bosch method for synthesizing ammonium nitrate represented a major breakthrough and allowed crop yields to overcome previous constraints.
In the past century, agriculture in the developed nations, and to a lesser extent in the developing world, has been characterized by enhanced productivity, the replacement of human labor by synthetic fertilizers and pesticides, selective breeding, and mechanization. The recent history of agriculture has been closely tied with a range of political issues including water pollution, biofuels, genetically modified organisms, tariffs, and farm subsidies. In recent years, there has been a backlash against the external environmental effectsof mechanized agriculture, and increasing support for the organic movement and sustainable agriculture.
Origins[edit]
Scholars have developed a number of hypotheses to explain the historical origins of agriculture. The transition from hunter-gatherer to agricultural societies, based on evidence from south west Asia and China, indicates an antecedent period of intensification and increasing sedentism known as the Natufian in south West Asia and the Early Chinese Neolithic in China. Current models indicate that a range of food resources was being used more intensively. Wild stands that had been harvested previously started to be planted. Evidence is also now emerging that the crops grown initially were wild and not domesticated.[4]Crops such as emmer and einkorn wheat do not appear to have become domesticated until well into the Neolithic and 'ancient cultivated rice' (Oryza sativa) took 3000 years to become domesticated.
Localised climate change is the favoured explanation for the origins of agriculture in the Levant. The fact that farming was 'invented' at least three times elsewhere, suggests that social reasons may have been instrumental. When major climate change took place after the last ice age (c. 11,000 BC), much of the earth became subject to long dry seasons.[5] These conditions favoured annual plants which die off in the long dry season, leaving a dormant seed or tuber. These plants tended to put more energy into producing seeds than into woody growth. An abundance of readily storable wild grains and pulses enabled hunter-gatherers in some areas to form the first settled villages at this time.
The Oasis hypothesis was proposed by Raphael Pumpelly in 1908, and popularized by Vere Gordon Childe who summarized the hypothesis in his book Man Makes Himself[6]This hypothesis maintains that as the climate got drier, communities contracted to oases where they were forced into close association with animals which were then domesticated together with planting of seeds. The hypothesis has little contemporary support[citation needed], as the climate data for the time does not support the hypothesis.
The Hilly Flanks hypothesis, proposed by Robert Braidwood in 1948, suggests that agriculture began in the hilly flanks of the Taurus and Zagros Mountains, and that it developed from intensive focused grain gathering in the region.[7]
The Feasting model by Brian Hayden[8] suggests that agriculture was driven by ostentatious displays of power, such as throwing feasts to exert dominance. This required assembling large quantities of food which drove agricultural technology.
The Demographic theories were proposed by Carl Sauer[9] and adapted by Lewis Binford[10] and Kent Flannery. They describe an increasingly sedentary population, expanding up to the carrying capacity of the local environment, and requiring more food than can be gathered. Various social and economic factors help drive the need for food.
The evolutionary/intentionality hypothesis, advanced by scholars including David Rindos,[11] is the idea that agriculture is a co-evolutionary adaptation of plants and humans. Starting with domestication by protection of wild plants, followed specialization of location and then domestication.
The Levantine Primacy Model was developed in the 1980s by Ofer Bar-Yosef and his collaborators. This provides a cultural ecology explanation, based on the idea that some areas were better favoured with domesticable plants and animals than others.[12]
The domestication hypothesis put forth by Daniel Quinn and others states that first humans stayed in particular areas, giving up their nomadic ways, then developed agriculture and animal domestication.
Another hypothesis is that humans were prevented from staying in one place for much of their history, due to the risk of attacks from other tribes.[13]
The Innovation and Specialisation Model was put forward recently by Rupert Gerritsen, in Australia and the Origins of Agriculture (2008). This hypothesis considers the question in terms of economic development and treats agriculture as a form of specialisation arising from two factors, higher population densities and innovation in areas of higher net natural productivity, and long-term advantageous information acquisition at nodal points in communication in long range scale-free networks.
Development of agriculture[edit]
Main article: Neolithic Revolution
Identifying the exact origin of agriculture remains problematic because the transition from hunter-gatherer societies began thousands of years before the invention of writing.
Anthropological and archaeological evidence from sites across Southwest Asia and North Africa indicate use of wild grain (e.g., from the c. 20,000 BCE site of Ohalo II in Israel, many Natufian sites in the Levant and from sites along the Nile in the 10th millennium BCE). There is even evidence of planned cultivation and trait selection: grains of rye with domestic traits have been recovered from Epi-Palaeolithic(10,000+ BCE) contexts at Abu Hureyra in Syria, but this appears to be a localised phenomenon resulting from cultivation of stands of wild rye, rather than a definitive step towards domestication.
Previously, archaeobotanists/paleoethnobotanists had traced the selection and cultivation of specific food plant characteristics in search of the origins of agriculture. One notable example is the semi-tough rachis (and larger seeds) traced to just after the Younger Dryas (about 9500 BCE) in the early Holocene in the Levant region of the Fertile Crescent. However, studies have demonstrated monophyleticcharacteristics attained without any human intervention, implying that what some may perceive as domestication among rachis could have occurred quite naturally.[14] In fact, the timescale insisted upon for rachis domestication (approx. 3,000 years) coincidentally has been demonstrated to directly coincide with the statistically generated timeframe numerically modeled that would be required for monophyly to be reached if a population were simply abandoned and left to only natural demands, implying that if any sort of human intervention had occurred at all then the timescale insisted upon should be considerably shorter (than 3,000 years).[14]
It was not until after 9500 BCE that the eight so-called founder crops of agriculture appear: first emmer and einkorn wheat, then hulled barley, peas, lentils, bitter vetch, chick peasand flax. These eight crops occur more or less simultaneously on PPNB sites in the Levant, although the consensus is that wheat was the first to be grown and harvested on a significant scale.
At around the same time (9400 BCE), another study argues, parthenocarpic fig trees appear to have been domesticated.[15] The simplicity associated with cutting branches off fig trees and replanting them alongside wild cereals owes to the basis of this argument.[16]
By 7000 BCE, sowing and harvesting reached Mesopotamia, and there, in the fertile soil just north of the Persian Gulf, Sumerians systematized it and scaled it up. By 8000 BCE farming was entrenched on the banks of the Nile River. About this time, agriculture was developed independently in the Far East, probably in China, with rice rather than wheat as the primary crop. Maize was first domesticated, probably from teosinte, in the Americas around 3000-2700 BCE, though there is some archaeological evidence of a much older development. The potato, the tomato, the pepper, squash, several varieties of bean, and several other plants were also developed in the New World, as was quite extensiveterracing of steep hillsides in much of Andean South America. Agriculture was also independently developed on the island of New Guinea.[17]
Recent discoveries in Europe, such as Cyprus and mainland Greece has shown that farming started early in south east Europe. In Franchthi Cave in Greece there are no certain gathering of plant foods attested before ca. 11,000 BCE, although large numbers of seeds of the Boraginaceae family may come from plants gathered to furnish soft bedding or for the dye which their roots may have supplied. First appearing at ca. 11,000 BCE are lentils, vetch, pistachios, and almonds. Then ca. 10,500 BCE appear a few very rare seeds of wild oats and wild barley. Neither wild oats nor wild barley become at all common until ca. 7000 BCE[18][19] in Cyprus. The oldest agricultural settlement ever found on a Mediterranean island has been discovered in Klimonas. between 9100 and 8600 BCE organized communities were farming and they build half-buried mud brick communal buildings, 10 meters in diameter and surrounded by dwellings, that must have been used to store the village's harvests. Remains of carbonized seeds of local plants and grains introduced from the Levantine coasts (including emmer, one of the first Middle Eastern wheats) have also been found in Klimonas.[20]
There is evidence of emmer and einkorn wheat, barley, sheep, goats and pigs that suggest a food producing economy in Greece and the Aegean by 7000 BCE.[21] Archaeological evidence from various sites on the Iberian peninsula suggest the domestication of plants and animals between 6000 and 4500 BCE.[21] Céide Fields in Ireland, consisting of extensive tracts of land enclosed by stone walls, date to 3500 BCE and are the oldest known field systems in the world.[22][23] The horse was domesticated in the Pontic steppearound 4000 BCE.[24]
In China, rice and millet were domesticated by 8000 BCE, followed by the beans mung, soy and azuki. In the Sahel region of Africa local rice and sorghum were domestic by 5000 BCE. Local crops were domesticated independently in West Africa[citation needed] and possibly in Ethiopia. In New Guinea, ancient Papuan peoples are thought to have begun practicing agriculture around 7000 BCE. They began domesticating sugarcane and root crops. Pigs may also have been domesticated around this time. By 3000 BCE, Papuan agriculture was characterized by water control for irrigation.[25][page needed] Evidence of the presence of wheat and some legumes in the 6th millennium BCE have been found in the Indus Valley. Oranges were cultivated in the same millennium. The crops grown in the valley around 4000 BCE were typically wheat, peas, sesame seed, barley, dates andmangoes. By 3500 BCE cotton growing and cotton textiles were quite advanced in the valley. By 3000 BCE farming of rice had started. Other monsoon crops of importance of the time was cane sugar. By 2500 BCE, rice was an important component of the staple diet in Mohenjodaro near the Arabian Sea. By this time the Indians had large cities with well-stocked granaries. Three regions of the Americas independently domesticated corn, squashes, potato and sunflowers.
Regional history[edit]
Sumer[edit]
See also: Neolithic Revolution
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By the Bronze Age, wild food contributed a nutritionally insignificant component to the usual diet. If the operative definition of agricultureincludes large scale intensive cultivation of land, mono-cropping, organized irrigation, and use of a specialized labour force, the title "inventors of agriculture" would fall to the Sumerians, starting c. 5500 BCE. Intensive farming allows a much greater density of population than can be supported by hunting and gathering, and allows for the accumulation of excess product for off-season use, or to sell/barter. The ability of farmers to feed large numbers of people whose activities have nothing to do with agriculture was the crucial factor in the rise of standing armies. Sumerian agriculture supported a substantial territorial expansion which along with internecine conflict between cities, made them the first empire builders. Not long after, the Egyptians, powered by farming in the fertile Nile valley, achieved a population density from which enough warriors could be drawn for a territorial expansion more than tripling the Sumerian empire in area.[citation needed]
In Sumer, barley was the primary crop; wheat, flax, dates, apples, plums, and grapes were grown as well. Mesopotamian agriculture was both supported and limited by flooding from the Tigris and Euphrates rivers, as floods came in late spring or early summer from snow melting from the Anatolian mountains. The timing of the flooding, along with salt deposits in the soil, made farming in Mesopotamia difficult. Sheep and goats were domesticated, kept mainly for meat and milk, butter and cheese being made from the latter. Ur, a large town that covered about 50 acres (20 hectares), had 10,000 animals kept in sheepfolds and stables and 3,000 slaughtered every year. The city's population of 6,000 included a labour force of 2,500, cultivating 3,000 acres (12 km²) of land. The labour force contained storehouse recorders, work foremen, overseers, and harvest supervisors to supplement labourers. Agricultural produce was given to temple personnel, important people in the community, and small farmers.[citation needed]
The land was plowed by teams of oxen pulling light unwheeled plows and grain was harvested with sickles in the spring. Wagons had solid wheels covered by leather tires kept in position by copper nails and were drawn by oxen and the Syrian onager (now extinct). Animals were harnessed by collars, yokes, and headstalls. They were controlled by reins, and a ring through the nose or upper lip and a strap under the jaw. As many as four animals could pull a wagon at one time. The horse was domesticated in Ukraine around 4000 BCE, and was in use by the Sumerians around 2000 BCE.[citation needed]
Ancient Egypt[edit]
Main article: Ancient Egyptian agriculture
Indus civilization[edit]
Main article: Agriculture in India
Wheat, barley, and jujube were domesticated in the Indian subcontinent by 9000 BCE; Domestication of sheep and goat soon followed.[27] Barley and wheat cultivation—along with the domestication of cattle, primarily sheep and goat—continued in Mehrgarh culture by 8000-6000 BCE.[28][29] This period also saw the first domestication of the elephant.[27]Agro pastoralism in India included threshing, planting crops in rows—either of two or of six—and storing grain in granaries.[29][30] By the 5th millennium BCE agricultural communities became widespread in Kashmir.[29] Archaeological evidence indicates that rice was a part of the Indian diet by 8000 BCE.[31][unreliable source?] The Encyclopædia Britannica—on the subject of the first certain cultivated rice—holds that:[32] A number of cultures have evidence of early rice cultivation, including China, India, and the civilizations of Southeast Asia.
Irrigation was developed in the Indus Valley Civilization by around 4500 BCE.[33] The size and prosperity of the Indus civilization grew as a result of this innovation, which eventually led to more planned settlements making use of drainage and sewers.[33] Archeological evidence of an animal-drawn plough dates back to 2500 BCE in the Indus Valley Civilization.[34]
Ancient China[edit]
Further information: Agriculture in China and Agriculture (Chinese mythology)
Records from the Warring States (481 BC-221 BCE), Qin Dynasty (221 BC-207 BCE), and Han Dynasty (202 BC-220 CE) provide a picture of early Chinese agriculture which included a nationwide granary system, and widespread use of sericulture. An important early Chinese book on agriculture is the Chimin Yaoshu of 535 CE, written by Jia Sixia.[35] Jia's writing style was straightforward and lucid relative to the elaborate and allusive writing typical of the time. Jia's book was also very long, with over one hundred thousand written Chinese characters, and it quoted many other Chinese books that were written previously, but no longer survive.[36] The contents of Jia's 6th century book include sections on land preparation, seeding, cultivation, orchard management, forestry, and animal husbandry. The book also includes peripherally related content covering trade and culinary uses for crops.[37] The work and the style in which it was written proved influential on later Chinese agronomists, such as Wang Zhen and his groundbreaking Nong Shu of 1313 CE.[36]
For agricultural purposes, the Chinese had innovated the hydraulic-powered trip hammer by the 1st century BC.[38] Although it found other purposes, its main function to pound, decorticate, and polish grain that otherwise would have been done manually. The Chinese also began using the square-pallet chain pump by the 1st century CE, powered by a waterwheel or oxen pulling an on a system of mechanical wheels.[39] Although the chain pump found use in public works of providing water for urban and palatial pipe systems,[40] it was used largely to lift water from a lower to higher elevation in filling irrigation canals and channels for farmland.[41]
Roman Empire[edit]
Further information: Agriculture in ancient Greece and Roman agriculture
In classical antiquity, Roman agriculture built from techniques pioneered by the Sumerians, transmitted to them by subsequent cultures, with a specific emphasis on the cultivation of crops for trade and export. Romans laid the groundwork for the manorial economic system, involving serfdom, which flourished in the Middle Ages. The farm sizes in Rome can be divided into three categories. Small farms were from 18-88 iugera (one iugerum is equal to about 0.65 acre). Medium-sized farms were from 80-500 iugera (singular iugerum). Large estates (called latifundia) were over 500 iugera.[42]
The Romans had four systems of farm management: direct work by owner and his family; slaves doing work under supervision of slave managers; tenant farming or sharecropping in which the owner and a tenant divide up a farm’s produce; and situations in which a farm was leased to a tenant.[42] There was a great deal of commerce between the provinces of the empire, all the regions of the empire became interdependent with one another, some provinces specialized in the production of grain, others in wine and others in olive oil, depending on the soil type.
Mesoamerica[edit]
Main article: Agriculture in Mesoamerica
In Mesoamerica, wild teosinte was transformed through human selection into the ancestor of modern maize, more than 6,000 years ago. It gradually spread across North America and was the major crop of Native Americans at the time of European exploration.[43] Other Mesoamerican crops include hundreds of varieties of squash and beans. Cocoa was also a major crop in domesticated Mexico and Central America. The turkey, one of the most important meat birds, was probably domesticated in Mexico or the U.S. Southwest.
In Mesoamerica, the Aztecs were active farmers and had an agriculturally focused economy. The land around Lake Texcoco was fertile, but not large enough to produce the amount of food needed for the population of their expanding empire. The Aztecs developed irrigation systems, formed terraced hillsides, and fertilized their soil. However, their greatest agricultural technique was the chinampas, or artificial islands, also known as "floating gardens". These were used to make the swampy areas around the lake suitable for farming. To make chinampas, canals were dug through the marshy islands and shores, then mud was heaped on huge mats made of woven reeds. The mats were anchored by tying them to posts driven into the lake bed and then planting trees at their corners that took root and secured the artificial islands permanently. The Aztecs grew corn, squash, vegetables, and flowers on chinampas.
South America[edit]
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See also: Incan agriculture
In the Andes region of South America the major crop was the potato, domesticated approximately 7,000–10,000 years ago.[44][45][46] Many varieties of beans were domesticated in South America, as well as coca, which is still a major crop to this day. Animals were also domesticated, including llamas, alpacas, and guinea pigs.
The Pre-Columbian Andean civilizations were predominantly agricultural societies. These civilizations took advantage of the difficult terrain, facing challenges from the narrow mountain valleys and coastal desert regions by developing terrace agriculture and sophisticated irrigationnetworks. Many sites of terrace farms can now be observed as anden. The adaptation of earlier agricultural technologies of the Wari andMoche allowed the Incas to organize the production of diverse crops in coastal, mountainous, and jungle environments. The strong centralized government of the Sapa Inca allowed for the redistribution of food to other regions where it was not normally accessible or less abundant. This redistribution and storage was in part made possible by the Inca road system.
North America[edit]
Main articles: Eastern Agricultural Complex, Agriculture in the prehistoric Southwest and Agriculture on the prehistoric Great Plains
The indigenous people of the Eastern U.S. appear to have domesticated numerous crops. Sunflowers, tobacco,[47] varieties of squash andChenopodium, as well as crops no longer grown, including marshelder and little barley, were domesticated.[48][49] Other wild foods may have undergone some selective cultivation, including wild rice and maple sugar. The most common varieties of strawberry were domesticated from Eastern North America.[50] Two major crops, pecans and Concord grapes, were utilized extensively in prehistoric times but do not appear to have been domesticated until the 19th century.[51][52]
The natives in what is now California and the Pacific Northwest practiced various forms of forest gardening and fire-stick farming in the forests, grasslands, mixed woodlands, and wetlands, ensuring that desired food and medicine plants continued to be available. The natives controlled fire on a regional scale to create a low-intensity fire ecology which prevented larger, catastrophic fires and sustained a low-density agriculturein loose rotation; a sort of "wild" permaculture.[53][54][55][56]
Australia[edit]
From the time British colonization of Australia began in 1788, Indigenous Australians were characterised as being nomadic hunter-gathererswho did not engage in agriculture or other forms of food production, despite some evidence to the contrary. Rhys Jones, however, proposed in 1969 that Indigenous Australians engaged in systematic burning as a way of enhancing natural productivity, what has been termed fire-stick farming.[57] In the 1970s and 1980s archaeological research in south west Victoria established that the Gunditjmara and other groups had developed sophisticated eel farming and fish trapping systems over a period of nearly 5,000 years.[58] Professor Harry Lourandos suggested in the 1980s that there was evidence of 'intensification' in progress across Australia,[59] a process that appeared to have in progress over the preceding 5,000 years. These concepts have led Bill Gammage to argue that in effect the whole continent was a managed landscape.[2]
It is now being argued that in two regions of Australia, the central west coast and eastern central Australia, forms of early agriculture were being practiced, whereby plants were being sown or planted on a large scale and the yield being stored or preserved in significant amounts.[2]:281–304[60] It also appears that the people in these regions were living in permanent settlements of significant size (over 200 residents, possibly up to 1,000), in dwellings large enough to house 10 or more people, and they exhibited high degrees of sedentism. The Nhanda and Amangu of the central west coast grew yams (Dioscorea hastifolia), while various groups in eastern central Australia (the Corners Region) planted and harvested bush onions (yaua - Cyperus bulbosus), native millet (cooly, tindil - Panicum decompositum) and a sporocarp, ngardu (Marsillea drumondii).
Middle Ages and early modern period[edit]
Population continued to increase along with land use. From 100 BC to 1600 AD, methane emissions rose an average of 31 million tons per year. This average annual rise is almost as high as the United States produced annually in 2012. Methane gas was produced primarily by domesticating animals and the growing of rice.[61]
Arab world[edit]
Main article: Arab Agricultural Revolution
From the 8th century, the medieval Islamic world underwent a transformation in agricultural practice which has been described by some as the "Arab Agricultural Revolution". This transformation was driven by a number of factors including the diffusion of many crops and plants along Muslim trade routes, the spread of more advanced farming techniques, and an agricultural-economic system which promoted increased yields and efficiency. The shift in agricultural practice led to significant changes in economy, population distribution, vegetation cover, agricultural production, population levels, urban growth, the distribution of the labour force, cooking and diet, clothing, and numerous other aspects of life in the Islamic world.[62][63]
Muslim traders covered an expansive area of the Old World, and these trade routes enabled the diffusion of many crops, plants and farming techniques across the Islamic world, as well as the adaptation of crops, plants and techniques from beyond the Islamic world.[63] Historian Andrew Watson has argued that this diffusion introduced a number of crops of major importance to Europe by way of Al-Andalus, along with the techniques for their cultivation. Important crops involved in this transfer included sugar cane, rice, and cotton. A number of additional fruit trees, nut trees, and vegetables were also transferred.
Agricultural technologies that were widely adopted during this period included intensive irrigation systems, crop rotation systems, and use of agricultural manuals. A sophisticated system of irrigation made use of norias, water mills, water raising machines, dams and reservoirs. Some irrigation infrastructure and technology was continued from Roman times, and some introduced by Muslims.
Europe[edit]
The Middle Ages saw significant improvements in the agricultural techniques and technology. During this time period, monasteries spread throughout Europe and became important centers for the collection of knowledge related to agriculture and forestry. The manorial system, which existed under different names throughout Europe and Asia, allowed large landowners significant control over both their land and its laborers, in the form of peasants or serfs.[64] During the medieval period, the Arab world was critical in the exchange of crops and technology between the European, Asia and African continents. Besides transporting numerous crops, they introduced the concept of summer irrigation to Europe and developed the beginnings of the plantation system of sugarcane growing through the use of slaves for intensive cultivation.[65] Population continued to increase along with land use. From 100 BC to 1600 AD, methane emissions rose an average of 31 million tons per year. This average annual rise is almost as high as the United States produced annually in 2012. Methane gas was produced primarily by domesticating animals and growing rice.[66]
By 900 AD in Europe, developments in iron smelting allowed for increased production, leading to developments in the production of agricultural implements such as ploughs, hand tools and horse shoes. The plough was significantly improved, developing into themouldboard plough, capable of turning over the heavy, wet soils of northern Europe. This led to the clearing of forests in that area and a significant increase in agricultural production, which in turn led to an increase in population.[67] A similar plough, which may have developed independently, was also found in China as early as the 9th century.[68] At the same time, farmers in Europe moved from a two field crop rotation to a three field crop rotation in which one field of three was left fallow every year. This resulted in increased productivity and nutrition, as the change in rotations led to different crops being planted, including legumes such as peas, lentils and beans. Inventions such as improved horse harnesses and the whippletree also changed methods of cultivation.[67] Watermills were initially developed by the Romans, but were improved throughout the Middle Ages, along with windmills, and used to grind grains into flour, cut wood and process flax and wool, among other uses.[69]
Crops included wheat, rye, barley and oats. Peas, beans, and vetches became common from the 13th century onward as a fodder crop for animals and also for their nitrogen-fixation fertilizing properties. Crop yields peaked in the 13th century, and stayed more or less steady until the 18th century.[70] Though the limitations of medieval farming were once thought to have provided a ceiling for the population growth in the Middle Ages, recent studies[71][72] have shown that the technology of medieval agriculture was always sufficient for the needs of the people under normal circumstances, and that it was only during exceptionally harsh times, such as the terrible weather of 1315–17, that the needs of the population could not be met.[73]
Columbian exchange[edit]
After 1492, a global exchange of previously local crops and livestock breeds occurred. Key crops involved in this exchange included maize, potatoes, sweet potatoes and manioc traveling from the New World to the Old, and several varieties of wheat, barley, rice and turnips going from the Old World to the New. There were very few livestock species in the New World, with horses, cattle, sheep and goats being completely unknown before their arrival with Old World settlers. Crops moving in both directions across the Atlantic Ocean caused population growth around the world, and had a lasting effect on many cultures.[74] Maize and cassava were introduced from Brazil into Africa by Portuguese traders in the 16th century.[75] They are now important staple foods, replacing native African crops.[76]
After its introduction from South America to Spain in the late 1500s, the potato became an important staple crop throughout Europe by the late 1700s. The potato allowed farmers to produce more food, and initially added variety to the European diet. The nutrition boost caused by increased potato consumption resulted in lower disease rates, higher birth rates and lower mortality rates, causing a population boom throughout the British Empire, the US and Europe.[77] The introduction of the potato also brought about the first intensive use of fertilizer, in the form of guano imported to Europe from Peru, and the first artificial pesticide, in the form of an arsenic compound used to fight Colorado potato beetles. Before the adoption of the potato as a major crop, the dependence on grain caused repetitive regional and national famines when the crops failed: 17 major famines in England alone between 1523 and 1623. Although initially almost eliminating the danger of famine, the resulting dependence on the potato eventually caused theEuropean Potato Failure, a disastrous crop failure from disease resulting in widespread famine, and the death of over one million people in Ireland alone.[78]
Modern agriculture[edit]
British agricultural revolution[edit]
Main article: British Agricultural Revolution
Use of primitive agricultural techniques was the historical standard. The vast majority of the world population engaged in subsistence agriculture and yields remained low. Between the 16th century and the mid-19th century, Great Britain saw a massive increase in agricultural productivity and net output. New agricultural practices like enclosure,mechanization, four-field crop rotation and selective breeding enabled an unprecedented population growth, freeing up a significant percentage of the workforce, and thereby helped drive the Industrial Revolution. By the early 19th century, agricultural practices, particularly careful selection of hardy strains and cultivars, had so improved that yield per land unit was many times that seen in the Middle Ages and before. It is estimated that the productivity of wheat went up from about 19 bushels per acre in 1720 to 21–22 bushels by the middle of the century and finally stabilised at around 30 bushels by 1840.[79]
The Agricultural Revolution was a major turning point in history. The population of England in 1750 reached the level of 5.7 million, just as it had done in the past in around 1350 and again in 1650. This time, instead of a Malthusian catastrophe occurring from plague or famine, the population growth remained sustained.
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One of the keys to the British Agricultural Revolution was the development of ways of keeping and improving the arable land in Great Britain to counteract the loss of the soil's plant nutrients in cropping a given area. Higher yielding land was added to higher yielding crops with more yield/acre. Farm workers using more productive tools and machinery produced more crops with fewer workers. The Agricultural Revolution picked up speed as the Industrial Revolution and the advances in chemistry produced the scientific knowledge, wealth and technology for a more systematic development of commercial fertilizers and new and more productive agricultural machinery.
Advice on more productive techniques for farming began to appear in England in the mid-17th century, from writers such as Samuel Hartlib, Walter Blith and others.[80] The main problem in sustaining agriculture in one place for a long time was the depletion of nutrients, most importantly nitrogen levels, in the soil. To allow the soil to regenerate, productive land was often let fallow and in some places crop rotation was used. A four-field rotation was popularised by the British agriculturist Charles Townshend in the 18th century. The system (wheat, turnips, barley and clover), opened up a fodder crop and grazing crop allowing livestock to be bred year-round. The use of turnip was especially important as the legume roots were an important source of nutrients for the soil.
Another catalyst for improvement came from the Enclosure movement. Prior to the 18th century, agriculture across Europe used the feudal open field system with subsistence farmers cropping strips of land in fields held in common and splitting up the produce; this was very inefficient and reduced incentive to improve the productivity. Many farms began to be enclosed by Yeomen who improved the use of their land. This process accelerated in the 15th and 16th centuries with special acts of Parliament to expedite the legal process. This culminated in the General Enclosure Actof 1801, which sanctioned large-scale land reform.
The mechanisation and rationalisation of agriculture was another important factor. Robert Bakewell and Thomas Coke introduced selective breeding, and initiated a process of inbreeding to maximise desirable traits from the mid 18th century, such as the New Leicester sheep.
Machines were invented to improve the efficiency of various agricultural operation, such as Jethro Tull's seed drill of 1701 that mechanised seeding at the correct depth and spacing and Andrew Meikle's threshing machine of 1784. Ploughs were steadily improved, from Joseph Foljambe's Rotherham iron plough in 1730[81] to James Small's improved "Scots Plough" metal in 1763. In 1789 Ransomes, Sims & Jefferies was producing 86 plough models for different soils.[82] Traction machines also began to replace horsepower on the farms in the 19th century.
The scientific investigation of fertilization began at the Rothamsted Experimental Station in 1843 by John Bennet Lawes. He investigated the impact of inorganic and organic fertilizers on crop yield and founded one of the first artificial fertilizer manufacturing factories in 1842. Fertilizer, in the shape of sodium nitrate deposits in Chile, was imported to Britain by John Thomas North as well as guano (birds droppings). The first commercial process for fertilizer production was the obtaining of phosphate from the dissolution of coprolites in sulphuric acid.[83]
The repeal of the Corn Laws in 1846 that removed tariffs on food imports, and the development of steamships and railways, which revolutionised the transportation of food, allowed a truly global market for food to emerge. This reduced volatility in food prices as scarcity in one area could be offset by cheap imports from another area.
The work of Charles Darwin and Gregor Mendel created the scientific foundation for plant breeding that led to its explosive impact over the past 150 years.[84] Firms, such asGartons Agricultural Plant Breeders began to market hybrid crops in the 1890s.
20th century[edit]
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Dan Albone constructed the first commercially successful gasoline-powered general purpose tractor in 1901, and the 1923 International Harvester Farmall tractor marked a major point in the replacement of draft animals (particularly horses) with machines. Since that time, self-propelled mechanical harvesters (combines), planters, transplanters and other equipment have been developed, further revolutionizing agriculture.[85] These inventions allowed farming tasks to be done with a speed and on a scale previously impossible, leading modern farms to output much greater volumes of high-quality produce per land unit.[86]
The Haber-Bosch method for synthesizing ammonium nitrate represented a major breakthrough and allowed crop yields to overcome previous constraints. It was first patented by German chemist Fritz Haber. In 1910 Carl Bosch, while working for German chemical companyBASF, successfully commercialized the process and secured further patents. In the years after World War II, the use of synthetic fertilizer increased rapidly, in sync with the increasing world population.[87]
In the past century agriculture has been characterized by increased productivity, the substitution of synthetic fertilizers and pesticides for labor, water pollution, and farm subsidies. In recent years there has been a backlash against the external environmental effects of conventional agriculture, resulting in the organic movement.[88] Famines continued to sweep the globe through the 20th century. Through the effects of climactic events, government policy, war and crop failure, millions of people died in each of at least ten famines between the 1920s and the 1990s.[89]
Other applications of scientific research since 1950 in agriculture include gene manipulation, Hydroponics, and the development of economically viable biofuels such as Ethanol.
Green Revolution[edit]
Main article: Green Revolution
The Green Revolution refers to a series of research, development, and technology transfer initiatives, occurring between the 1940s and the late 1970s, that increased agriculture production around the world, beginning most markedly in the late 1960s.[90] The initiatives, led byNorman Borlaug, the "Father of the Green Revolution" credited with saving over a billion people from starvation, involved the development of high-yielding varieties of cereal grains, expansion of irrigation infrastructure, modernization of management techniques, distribution of hybridized seeds, synthetic fertilizers, and pesticides to farmers.
Synthetic nitrogen, along with mined rock phosphate, pesticides and mechanization, have greatly increased crop yields in the early 20th century. Increased supply of grains has led to cheaper livestock as well. Further, global yield increases were experienced later in the 20th century when high-yield varieties of common staple grains such as rice, wheat, and corn were introduced as a part of the Green Revolution. The Green Revolution exported the technologies (including pesticides and synthetic nitrogen) of the developed world to the developing world.Thomas Malthus famously predicted that the Earth would not be able to support its growing population, but technologies such as the Green Revolution have allowed the world to produce a surplus of food.[91]
Although the Green Revolution significantly increased rice yields in Asia, yield increases have not occurred in the past 15–20 years.[92] The genetic "yield potential" has increased for wheat, but the yield potential for rice has not increased since 1966, and the yield potential for maize has "barely increased in 35 years".[92] It takes a decade or two for herbicide-resistant weeds to emerge, and insects become resistant to insecticides within about a decade.[92]Crop rotation helps to prevent resistances.[92]
Organic farming[edit]
Main article: History of organic farming
Though the intensive farming practices pioneered and extended in recent history generally led to increased outputs, they have also led to the destruction of farmland, most notably in the dust bowl area of the United States following World War I. As global population increased, agriculture continued to replace natural ecosystems with monoculture crops. Activists such as Sir Albert Howard began the organic movement as a reaction to the widely used intensive agriculture practices. In recent years, growing awareness has led to increased interest in such areas of agriculture as organic farming, permaculture, heirloom plants and biodiversity, the growth of the Slow Food movement, and an ongoing discussion surrounding the potential for sustainable agriculture.
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