Agriculture (from ''Agri'' Latin for ''ager'' ("a field"), and ''culture'', from the Latin ''cultura'' "cultivation" in the strict sense of "tillage of the soil". A literal reading of the English word yields ''"tillage of the soil of a field"''.) is the production of food, feed, fiber and other goods by the systematic raising of domesticated plants and animals. In modern usage, the word ''agriculture'' covers all activities essential to food/feed/fiber production, including all techniques for raising and "processing" livestock. Agriculture is also short for the study of the practice of agriculture — more formally known as agricultural science.

The history of agriculture is a central element of human history, as agricultural progress has been a crucial factor in worldwide socio-economic change. Wealth-building and militaristic specializations rarely seen in hunter-gatherer cultures are commonplace in agricultural and agro-industrial societies—when farmers became capable of producing food beyond the needs of their own families, others in the tribe/nation/empire were freed to devote themselves to projects other than food acquisition.

As of 2006, an estimated 36 percent of the world's workers are employed in agricultureInternational Labour Organization Key Indicators of the Labour Market 2007 , chapter 4 p. 6 (down from 42% in 1996), making it by far the most common occupation. However, the relative significance of farming has dropped steadily since the beginning of industrialization, and in 2006 – for the first time in history – the services sector overtook agriculture as the economic sector employing the most people worldwide. Also, agricultural production accounts for less than five percent of the gross world product (an aggregate of all gross domestic products).

Overview

Subsistence farming, who farms a small area with limited resource inputs, and produces only enough food to meet the needs of his/her family. At the other end is commercial intensive agriculture, including industrial agriculture. Such farming involves large fields and/or numbers of animals, large resource inputs (pesticides, fertilizers, etc.), and a high level of mechanization. These operations generally attempt to maximize financial income from grain, produce, or livestock.

Modern agriculture extends well beyond the traditional production of food for humans and animal feeds. Other agricultural production goods include timber, fertilizers, animal hides, leather, industrial chemicals (starch, sugar, alcohols and resins), fibers (cotton, wool, hemp, silk and flax), fuels (methane from biomass, ethanol, biodiesel), cut flowers, ornamental and nursery plants, tropical fish and birds for the pet trade, and both legal and illegal drugs (biopharmaceuticals, tobacco, marijuana, opium, cocaine).

The twentieth century saw massive changes in agricultural practice, particularly in agricultural chemistry and in mechanization. Agricultural chemistry includes the application of chemical fertilizer, chemical insecticides (see pest control), and chemical fungicides, analysis of soil makeup and nutritional needs of farm animals.

Up to and including the 1970s, surface runoff of fertilizer and pesticides was a growing, uncontrolled problem. Starting roughly in 1980, many Western nations, prodded by dozens of environmental action groups, began to implement effective controls on farming-related pollution, and this green revolution spread many of the benefits of agricultural chemistry to farms throughout the world, without the extreme pollution that originally accompanied them. Between 1950 and 1984, as the green revolution transformed agriculture around the globe, world grain production increased by 250%.Can We Feed the World Without Industrial Agriculture?
Mechanization has also enormously increased farm efficiency and productivity in most regions of the world, due especially to the tractor and various "gins" (short for "engine") like the cotton gin, semi-automatic balers and threshers and, above all, the combine (see agricultural machinery).

Other recent changes in agriculture include hydroponics, plant breeding, hybridization, gene manipulation, better management of soil nutrients, and improved weed control. Genetic engineering has yielded crops which have capabilities beyond those of naturally occurring plants, such as higher yields and disease resistance. Modified seeds germinate faster, and thus can be grown on an accelerated schedule. Genetic engineering of plants has proven controversial, particularly in the case of herbicide-resistant plants.

Engineers may develop plants for irrigation, drainage, conservation and sanitary engineering, particularly important in normally arid areas which rely upon constant irrigation, and on large scale farms.

The processing, packing and marketing of agricultural products are closely related activities also influenced by science. Methods of quick-freezing and dehydration have increased the markets for many farm products (see food preservation and meat packing industry).

Animals, including horses, mules, oxen, camels, llamas, alpacas, and dogs, are often used to help cultivate fields, harvest crops, wrangle other animals, and transport farm products to buyers. Animal husbandry not only refers to the breeding and raising of animals for meat or to harvest animal products (like milk, eggs, or wool) on a continual basis, but also to the breeding and care of species for work and companionship.

Airplanes, helicopters, trucks, tractors, and combines are used in Western (and, increasingly, Eastern) agriculture for seeding, spraying operations for insect and disease control, harvesting, aerial topdressing and transporting perishable products. Radio and television disseminate vital weather reports and other information such as market reports that concern farmers. Computers have become an essential tool for farm management.

According to the National Academy of Engineering in the United States, agricultural mechanization is one of the 20 greatest engineering achievements of the 20th century. Early in the century, it took one American farmer to produce food for 2.5 people. By 1999, due to advances in agricultural technology, a single farmer could feed over 130 people.

In recent years, some aspects of intensive industrial agriculture have been the subject of increasing debate. The widening sphere of influence held by large seed and chemical companies, meat packers and food processors has been a source of concern both within the farming community and for the general public. Another issue is the type of feed given to some animals that can cause bovine spongiform encephalopathy in cattle. There has also been concern over the effect of intensive agriculture on the environment.

The patent protection given to companies that develop new types of seed using genetic engineering has allowed seed to be licensed to farmers in much the same way that computer software is licensed to users. This has changed the balance of power in favor of the seed companies, allowing them to dictate terms and conditions previously unheard of. The Indian activist and scientist Vandana Shiva argues that these companies are guilty of biopiracy.

Soil conservation and nutrient management have been important concerns since the 1950s, with the most advanced farmers taking a stewardship role with the land they use. However, increasing contamination of waterways and wetlands by nutrients like nitrogen and phosphorus are concerns that can only be addressed by "enlightenment" of farmers and/or far stricter law enforcement in many countries.

Increasing consumer awareness of agricultural issues has led to the rise of community-supported agriculture, local food movement, "Slow Food", and commercial organic farming.

Ancient origins

Developed independently by geographically distant populations, systematic agriculture first appeared in Southwest Asia in the Fertile Crescent, particularly in modern-day Iraq and Syria/Israel. Around 9500 BC, proto-farmers began to select and cultivate food plants with desired characteristics. Though there is evidence of earlier sporadic use of wild cereals, it was not until after 9500 BC that the eight so-called founder crops of agriculture appear: first emmer and einkorn wheat, then hulled barley, peas, lentils, bitter vetch, chick peas and flax.

By 7000 BC, small-scale agriculture reached Egypt. From 9000 BC the Indian subcontinent saw farming of wheat and barley, as attested by archaeological excavation at Mehrgarh in Balochistan. By 6000 BC, mid-scale farming was entrenched on the banks of the Nile. About this time, agriculture was developed independently in the Far East, with rice, rather than wheat, as the primary crop. Chinese and Indonesian farmers went on to domesticate mung, soy, azuki and taro. To complement these new sources of carbohydrates, highly organized net fishing of rivers, lakes and ocean shores in these areas brought in great volumes of essential protein. Collectively, these new methods of farming and fishing inaugurated a human population boom dwarfing all previous expansions, and is one that continues today.

By 5000 BC, the Sumerians had developed core agricultural techniques including large scale intensive cultivation of land, mono-cropping, organized irrigation, and use of a specialized labour force, particularly along the waterway now known as the Shatt al-Arab, from its Persian Gulf delta to the confluence of the Tigris and Euphrates. Domestication of wild aurochs and mouflon into cattle and sheep, respectively, ushered in the large-scale use of animals for food/fiber and as beasts of burden. The shepherd joined the farmer as an essential provider for sedentary and semi-nomadic societies.

Maize, manioc, and arrowroot were first domesticated in the Americas as far back as 5200 BC. http://www.ucalgary.ca/news/feb2007/early-farming/ The potato, tomato, pepper, squash, several varieties of bean, Canna, tobacco and several other plants were also developed in the New World, as was extensive terracing of steep hillsides in much of Andean South America.

In later years, the Greeks and Romans built on techniques pioneered by the Sumerians but made few fundamentally new advances. The Greeks and Macedonians struggled with very poor soils, yet managed to become dominant societies for years. The Romans were noted for an emphasis on the cultivation of crops for trade.

Renaissance to present day

The invention of a three field system of crop rotation during the Middle Ages, and the importation of the Chinese-invented moldboard plow, vastly improved agricultural efficiency.

After 1492, a global exchange of previously local crops and livestock breeds occurred. Key crops involved in this exchange included the tomato, maize, potato, cocoa and tobacco going from the New World to the Old, and several varieties of wheat, spice and coffee going from the Old World to the New. The most important animal exportations from the Old World to the New were those of the horse and dog (dogs were already present in the pre-Columbian Americas but not in the numbers and breeds suited to farm work). Although not usually food animals, the horse (including donkeys and ponies) and dog quickly filled essential production roles on western hemisphere farms.

By the early 1800s, agricultural techniques, implements, seed stocks and cultivars had so improved that yield per land unit was many times that seen in the Middle Ages. With the rapid rise of mechanization in the late 19th and 20th centuries, particularly in the form of the tractor, farming tasks could be done with a speed and on a scale previously impossible. These advances have led to efficiencies enabling certain modern farms in the United States, Argentina, Israel, Germany, and a few other nations to output volumes of high quality produce per land unit at what may be the practical limit.

In 2005, the agricultural output of China was the largest in the world, accounting for almost one-sixth world share followed by the EU, India and the USA, according to the International Monetary Fund.

World production of major crops in 2004

Specific crops are cultivated in distinct growing regions throughout the world. In millions of metric tons, based on FAO estimates.

! colspan=2\|Top agricultural products, by crop types (million metric tons) 2004 data \|- \| Cereals \|\| align="right" \| 2,263 \|- \| Vegetables and melons \|\| align="right" \| 866 \|- \| Roots and Tubers \|\| align="right" \| 715 \|- \| Milk \|\| align="right" \| 619 \|- \| Fruit \|\| align="right" \| 503 \|- \| Meat \|\| align="right" \| 259 \|- \| Oilcrops \|\| align="right" \| 133 \|- \| Fish (2001 estimate) \|\| align="right" \| 130 \|- \| Eggs \|\| align="right" \| 63 \|- \| Pulses \|\| align="right" \| 60 \|- \| Vegetable Fiber \|\| align="right" \| 30 \|- \|colspan=2\|''Source: Food and Agriculture Organization (FAO)''

! colspan=2\|Top agricultural products, by individual crops (million metric tons) 2004 data \|- \| Sugar Cane \|\| align="right" \| 1,324 \|- \| Maize \|\| align="right" \| 721 \|- \| Wheat \|\| align="right" \| 627 \|- \| Rice \|\| align="right" \| 605 \|- \| Potatoes \|\| align="right" \| 328 \|- \| Sugar Beet \|\| align="right" \| 249 \|- \| Soybean \|\| align="right" \| 204 \|- \| Oil Palm Fruit \|\| align="right" \| 162 \|- \| Barley \|\| align="right" \| 154 \|- \| Tomato \|\| align="right" \| 120 \|- \|colspan=2\|''Source: Food and Agriculture Organization (FAO)''

Crop alteration

Domestication of plants has, over the centuries increased yield, improved disease resistance and drought tolerance, eased harvest and improved the taste and nutritional value of crop plants. Careful selection and breeding have had enormous effects on the characteristics of crop plants. Plant breeders use greenhouses (known as glasshouses or hothouses in some areas) and other techniques to get as many as three generations of plants per year towards the continued effort of improvement.
Plant selection and breeding in the 1920s and 1930s improved pasture (grasses and clover) in New Zealand. Extensive X-ray an ultraviolet induced mutagenesis efforts (i.e. primitive genetic engineering) during the 1950s produced the modern commercial varieties of grains such as wheat, corn and barley.

For example, average yields of corn (maize) in the USA have increased from around 2.5 tons per hectare (t/ha) (40 bushels per acre) in 1900 to about 9.4 t/ha (150 bushels per acre) in 2001. Similarly, worldwide average wheat yields have increased from less than 1 t/ha in 1900 to more than 2.5 t/ha in 1990. South American average wheat yields are around 2 t/ha, African under 1 t/ha, Egypt and Arabia up to 3.5 to 4 t/ha with irrigation. In contrast, the average wheat yield in countries such as France is over 8 t/ha. Variation in yields are due mainly to variation in climate, genetics, and the level of intensive farming techniques (use of fertilizers, chemical pest control, growth control to avoid lodging).Conversion note: 1 bushel of wheat = 60 pounds (lb) ≈ 27.215 kg. 1 bushel of corn = 56 pounds ≈ 25.401 kg

After mechanical tomato-harvesters were developed in the early 1960s, agricultural scientists bred tomatoes that were more resistant to mechanical handling. These varieties have been criticized as being harder and having poor texture.
More recently, genetic engineering has begun to be employed in large parts of the world to speed up the selection and breeding process. One widely used modification is a herbicide resistance gene that allows plants to tolerate exposure to glyphosate, a non-systemic (i.e kills all plants) chemical used to control weeds in a crop such as oilseed rape. Normally, expensive systemic herbicides would have to be applied to kill the weeds without harming the crop. Relatively cheap and safe glyphosate may be applied to the modified crops, efficiently killing weeds without harming the resistant crop. Another modification causes the plant to produce a toxin to reduce damage from insects (c.f. Starlink). This, in contrast, requires fewer insecticides to be applied to the crop.

Aquaculture, the farming of fish, shrimp, and algae, is closely associated with agriculture.

Apiculture, the culture of bees, traditionally for honey—increasingly for crop pollination.

:''See also'' : botany, List of domesticated plants, List of vegetables, List of herbs, List of fruit

Environmental impact

Agriculture may often cause environmental problems because it changes natural environments and produces harmful by-products. Some of the negative effects are:

Loss of biodiversity

Surplus of nitrogen and phosphorus in rivers and lakes

Detrimental effects of herbicides, fungicides, insecticides, and other biocides

Conversion of natural ecosystems of all types into arable land

Consolidation of diverse biomass into a few species

Soil erosion

Depletion of minerals in the soil

Particulate matter, including ammonia and ammonium off-gassing from animal waste contributing to air pollution

Weed Science - feral plants and animals

Odor from agricultural waste

Soil salination

According to the United Nations, the livestock sector (primarily cows, chickens, and pigs) emerges as one of the top two or three most significant contributors to our most serious environmental problems, at every scale from local to global. Livestock production occupies 70% of all land used for agriculture, or 30% of the land surface of the planet.Food and Agricultural Organization of the U.N. retrieved 27 jun 2007It is one of the largest sources of greenhouse gases—responsible for 18% of the world’s greenhouse gas emissions as measured in CO₂ equivalents. By comparison, all transportation emits 13.5% of the CO₂. It produces 65% of human-related nitrous oxide (which has 296 times the global warming potential of CO₂) and 37% of all human-induced methane (which is 23 times as warming as CO₂). It also generates 64% of the ammonia, which contributes to acid rain and acidification of ecosystems.Livestock’s long shadow: Environmental issues and options

Conventional hybridization for higher yield, Genetic Engineering and the resulting loss of Biodiversity, a threat to Food Security

In agriculture and animal husbandry, green revolution popularized the use of conventional hybridization to increase yield many folds by creating "high-yielding varieties". Often the handful of breeds of plants and animals hybridized originated in developed countries and were further hybridized with local verities, in the rest of the developing world, to create high yield strains resistant to local climate and diseases. Local governments and industry since have been pushing hybridization with such zeal that several of the wild and indigenous breeds evolved locally over thousands of years having high resistance to local extremes in climate and immunity to diseases etc. have already become extinct or are in grave danger of becoming so in the near future. Due to complete disuse because of un-profitability and uncontrolled intentional, compounded with unintentional cross pollination and crossbreeding (genetic pollution) formerly huge gene pools of various wild and indigenous breeds have collapsed causing widespread genetic erosion and genetic pollution resulting in great loss in genetic diversity and biodiversity as a whole.“Genetic Pollution: The Great Genetic Scandal” ; Devinder Sharma can be contacted at: 7 Triveni Apartments, A-6 Paschim Vihar, New Delhi-110 063, India. Email: dsharma@ndf.vsnl.net.in. CENTRE FOR ALTERNATIVE AGRICULTURAL MEDIA (CAAM)., http://www.infochangeindia.org/features43.jsp

A Genetically Modified Organism (GMO) is an organism whose genetic material has been altered using the genetic engineering techniques generally known as recombinant DNA technology. Genetic Engineering today has become another serious and alarming cause of genetic pollution because artificially created and genetically engineered plants and animals in laboratories, which could never have evolved in nature even with conventional hybridization, can live and breed on their own and what is even more alarming interbreed with naturally evolved wild varieties. Genetically Modified (GM) crops today have become a common source for genetic pollution, not only of wild varieties but also of other domesticated varieties derived from relatively natural hybridization.THE YEAR IN IDEAS: A TO Z.; Genetic Pollution By MICHAEL POLLAN, The New York Times, December 9, 2001Dangerous Liaisons? When Cultivated Plants Mate with Their Wild Relatives by Norman C. Ellstrand; The Johns Hopkins University Press, 2003; 268 pp. hardcover , $ 65; ISBN 0-8018-7405-X. Book Reviewed in: Hybrids abounding; Nature Biotechnology 22, 29 - 30 (2004) doi:10.1038/nbt0104-29; Reviewed by: Steven H Strauss & Stephen P DiFazio.“Genetic pollution: Uncontrolled spread of genetic information (frequently referring to transgenes) into the genomes of organisms in which such genes are not present in nature.” Zaid, A. et al. 1999. Glossary of biotechnology and genetic engineering. FAO Research and Technology Paper No. 7. ISBN 92-5-104369-8“Genetic pollution: Uncontrolled escape of genetic information (frequently referring to products of genetic engineering) into the genomes of organisms in the environment where those genes never existed before.” Searchable Biotechnology Dictionary. University of Minnesota. http://iufro-archive.boku.ac.at/silvavoc/glossary/6_0en.html“Genetic pollution: Living organisms can also be defined as pollutants, when a non-indigenous species (plant or animal) enters a habitat and modifies the existing equilibrium among the organisms of the affected ecosystem (sea, lake, river). Non-indigenous, including transgenic species (GMOs), may bring about a particular version of pollution in the vegetal kingdom: so-called genetic pollution. This term refers to the uncontrolled diffusion of genes (or transgenes) into genomes of plants of the same type or even unrelated species where such genes are not present in nature. For example, a grass modified to resist herbicides could pollinate conventional grass many miles away, creating weeds immune to the most widely used weed-killer, with obvious consequences for crops. Genetic pollution is at the basis of the debate on the use of GMOs in agriculture.” The many facets of pollution; Bologna University web site for Science Communication. The Webweavers: Last modified Tue, 20 Jul 2005

It is being said that genetic erosion coupled with genetic pollution is destroying that needed unique genetic base thereby creating an unforeseen hidden crisis which will result in a severe threat to our food security for the future when diverse genetic material will cease to exist to be able to further improve or hybridize weakening food crops and livestock against more resistant diseases and climatic changes.“Genetic Pollution: The Great Genetic Scandal” Devinder Sharma can be contacted at: 7 Triveni Apartments, A-6 Paschim Vihar, New Delhi-110 063, India. Email: dsharma@ndf.vsnl.net.in. CENTRE FOR ALTERNATIVE AGRICULTURAL MEDIA (CAAM). http://www.infochangeindia.org/features43.jsp

Agriculture Safety and Health

Agriculture ranks among the most hazardous industries. Farmers are at high risk for fatal and nonfatal injuries, work-related lung diseases, noise-induced hearing loss, skin diseases, and certain cancers associated with chemical use and prolonged sun exposure. Farming is one of the few industries in which the families (who often share the work and live on the premises) are also at risk for injuries, illness, and death.

In an average year, 516 workers die doing farm work in the U.S. (1992-2005). Of these deaths, 101 are caused by tractor overturns.

Every day, about 243 agricultural workers suffer lost-work-time injuries, and about 5% of these result in permanent impairment.

Young Workers

Agriculture is the most dangerous industry for young workers, accounting for 42% of all work-related fatalities of young workers between 1992 and 2000. Unlike other industries, half the young victims in agriculture were under age 15. NIOSH 2003. Unpublished analyses of the 1992–2000 Census of Fatal Occupational Injuries Special Research Files provided to NIOSH by the Bureau of Labor Statistics (includes more detailed data than the research file, but excludes data from New York City). Morgantown, WV: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Division of Safety Research, Surveillance and Field Investigations Branch, Special Studies Section. Unpublished database.

For young agricultural workers aged 15–17, the risk of fatal injury is four times the risk for young workers in other workplaces BLS 2000. Report on the youth labor force. Washington, DC: U.S. Department of Labor, Bureau of Labor Statistics, pp. 58–67. Agricultural work exposes young workers to safety hazards such as machinery, confined spaces, work at elevations, and work around livestock.

An estimated 1.26 million children and adolescents under 20 years of age resided on farms in 2004, with about 699,000 of these youth performing work on the farms. In addition to the youth who live on farms, an additional 337,000 children and adolescents were hired to work on U.S. farms in 2004.

On average, 103 children are killed annually on farms (1990-1996). Approximately 40 percent of these deaths were work-related.

In 2004, an estimated 27,600 children and adolescents were injured on farms; 8,100 of these injuries were due to farm work.

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