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Agriculture

2007 Schools Wikipedia Selection. Related subjects: Food and agriculture

   Agriculture (a term which encompasses farming) is the process of
   producing food, feed, fibre and other goods by the systematic raising
   of plants and animals.

   Agri is from Latin ager, meaning "a field", and culture is from Latin
   cultura, meaning "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. In modern usage, the word Agriculture covers all activities
   essential to food/feed/fibre 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 closely linked to
   human history, and agricultural developments have been crucial factors
   in social change, including the specialization of human activity.

   42% of the world's laborers are employed in agriculture, making it by
   far the most common occupation. However, agricultural production
   accounts for less than 5% of the Gross World Product (an aggregate of
   all Gross Domestic Products).
   A farmer in Germany working the land in the traditional way, with horse
   and plough.
   Enlarge
   A farmer in Germany working the land in the traditional way, with horse
   and plough.

Overview

   Tea plantation in Java, Indonesia.
   Enlarge
   Tea plantation in Java, Indonesia.
   Farming with a tractor in Sweden.
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   Farming with a tractor in Sweden.

          "Oh Farmers, Pray That Your Summers Be Wet And Your Winters
          Clear." - Virgil

   Farming refers to a wide range agricultural production work, covering a
   large spectrum of operation scales (acerage, output, etc), practices,
   and commercial inclination. At one end of this spectrum, the
   subsistence farmer 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 of the spectrum is commercial intensive agriculture,
   including industrial agriculture. Such farming involves large fields
   and/or numbers of animals, large resource inputs (pesticides, and
   fertilizers, etc.), and a high level of mechanization. These operations
   generally attempt to maximize financial income from produce or
   livestock.

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

   The 20th Century saw massive changes in agricultural practice,
   particularly in agricultural chemistry. Agricultural chemistry includes
   the application of chemical fertilizer, chemical insecticides (see Pest
   control), and chemical fungicides, soil makeup, analysis of
   agricultural products, and nutritional needs of farm animals. Beginning
   in the Western world, the green revolution spread many of these changes
   to farms throughout the world, with varying success.

   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 in an extended growing area.
   Genetic engineering of plants has proven controversial, particularly in
   the case of herbicide-resistant plants.

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

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

   Animals, including horses, mules, oxen, camels, llamas, alpacas, and
   dogs, are often used to cultivate fields, harvest crops and transport
   farm products to markets. Animal husbandry means breeding and raising
   animals for meat or to harvest animal products (like milk, eggs, or
   wool) on a continual basis. Mechanization has enormously increased farm
   efficiency and productivity in Western agriculture (see Agricultural
   machinery).

   Airplanes, helicopters, trucks and tractors are used in Western
   agriculture for seeding, spraying operations for insect and disease
   control, 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.
   Farming, ploughing rice paddy, in Indonesia.
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   Farming, ploughing rice paddy, in Indonesia.

   According to the National Academy of Engineering in the US,
   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. Today, due to advances
   in agricultural technology , a single farmer can feed over 130 people .
   This comes at a cost, however. A large energy input, often from fossil
   fuel, are required to maintain such high levels of output.

   In recent years, some aspects of intensive industrial agriculture have
   been the subject of increasing discussion. 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 because of the disastrous effect
   that intensive agriculture has on the environment. In the US, for
   example, fertilizer has been running off into the Mississippi for years
   and has caused a dead spot in the Gulf of Mexico, where the Mississippi
   empties. Intensive agriculture also depletes the fertility of the land
   over time, potentially leading to Desertification.
   A Field
   Enlarge
   A Field

   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 favour of the seed companies, allowing
   them to dictate terms and conditions previously unheard of. The Indian
   activist and scientiest Vandana Shiva argues that these companies are
   guilty of biopiracy.

   Soil conservation and nutrient management have been important concerns
   since the 1950s, with the best farmers taking a stewardship role with
   the land they operate. However, increasing contamination of waterways
   and wetlands by nutrients like nitrogen and phosphorus are of concern
   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.

History

   Ancient Egyptian farmer
   Enlarge
   Ancient Egyptian farmer

Ancient Origins

   Developed independently by geographically distant populations, evidence
   suggests that agriculture first appeared in Southwest Asia, in the
   Fertile Crescent area of Mesopotamia. Around 9,500 B.C., farmers first
   began to select and cultivate food plants with specific
   characteristics. Though there is evidence of earlier use of wild
   cereals, it wasn't until after 9,500 B.C. 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 B.C., sowing and harvesting reached Egypt. By 6000 B.C.,
   farming was entrenched on the banks of the Nile River. About this time,
   agriculture was developed independently in the Far East, with rice,
   rather than wheat, the primary crop. By 5000 B.C., Sumerians had
   developed core agricultural techniques including large scale intensive
   cultivation of land, mono-cropping, organized irrigation, and use of a
   specialized labour force.

   Evidence suggests that Maize was first domesticated in the Americas
   around 3000-2700 B.C. The potato, the tomato, the pepper, squash,
   several varieties of bean, and several other plants were also developed
   in the New World, as was extensive terracing of steep hillsides in much
   of Andean South America.

   Roman agriculture built on techniques pioneered by the Sumerians, with
   a specific emphasis on the cultivation of crops for trade and export.
   Sumerian Harvester's sickle, 3000 BCE. Baked clay. Field Museum.
   Enlarge
   Sumerian Harvester's sickle, 3000 BCE. Baked clay. Field Museum.

Agriculture in the Middle Ages

   During the Middle Ages, Muslim farmers in North Africa and the Near
   East developed and disseminated agricultural technologies including
   irrigation systems based on hydraulic and hydrostatic principles, the
   use of machines such as norias, and the use of water raising machines,
   dams, and reservoirs. Muslims also wrote location-specific Farming
   manuals, and were instrumental in the wider adoption of crops including
   sugar cane, rice, citrus fruit, apricots, cotton, artichokes,
   aubergines, and saffron. Muslims also brought lemons, oranges, cotton,
   almonds, figs and sub-tropical crops such as bananas to Spain.

Renaissance to Present Day

   A tractor ploughing an alfalfa field
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   A tractor ploughing an alfalfa field

   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, tobacco, and coffee.

   By the early 1800s, 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. 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.

Crops

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.
   Top agricultural products, by crop types
   (million metric tons) 2004 data
   Cereals                             2,264
   Vegetables and melons                 866
   Roots and Tubers                      715
   Milk                                  619
   Fruit                                 503
   Meat                                  259
   Oilcrops                              133
   Fish (2001 estimate)                  130
   Eggs                                   63
   Pulses                                 60
   Vegetable Fibre                        30
   Source:
   Food and Agriculture Organization (FAO)

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

Crop improvement

   Tractor and wagon
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   Tractor and wagon
   An agricultural scientist records corn growth
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   An agricultural scientist records corn growth
   Netting protecting wine grapes from birds
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   Netting protecting wine grapes from birds

   Domestication of plants is done in order to increase yield, improve
   disease resistance and drought tolerance, ease harvest and to improve
   the taste and nutritional value and many other characteristics.
   Centuries of careful selection and breeding have had enormous effects
   on the characteristics of crop plants. Plant breeders use greenhouses
   and other techniques to get as many as three generations of plants per
   year so that they can make improvements all the more quickly.

   Plant selection and breeding in the 1920s and '30s improved pasture
   (grasses and clover) in New Zealand. Extensive radiation 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 (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 use or non-use 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]

   In industrialized agriculture, crop "improvement" has often reduced
   nutritional and other qualities of food plants to serve the interests
   of producers. After mechanical tomato-harvesters were developed in the
   early 1960s, agricultural scientists bred tomatoes that were harder and
   less nutritious (Friedland and Barton 1975). In fact, a major
   longitudinal study of nutrient levels in numerous vegetables showed
   significant declines in the last 50 years; garden vegetables in the
   U.S. today contain on average 38 percent less vitamin B2 and 15 percent
   less vitamin C (Davis and Riordan 2004).

   Very recently, genetic engineering has begun to be employed in some
   parts of the world to speed up the selection and breeding process. The
   most widely used modification is a herbicide resistance gene that
   allows plants to tolerate exposure to glyphosate, which is used to
   control weeds in the crop. A less frequently used but more
   controversial modification causes the plant to produce a toxin to
   reduce damage from insects (c.f. Starlink).

   There are specialty producers who raise less common types of livestock
   or plants.

   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,

Environmental problems

   Severe soil erosion in a wheat field near Washington State University,
   US (c.2005)
   Enlarge
   Severe soil erosion in a wheat field near Washington State University,
   US (c.2005)

   Agriculture may often cause environmental problems because it changes
   natural environments and produces harmful by-products. Some of the
   negative effects are:
     * 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-gasing from
       animal waste contributing to air pollution
     * Weeds - feral plants and animals
     * Odour from agricultural waste
     * Soil salination

   Agriculture is cited as a significant adverse impact to biodiversity in
   many nations' Biodiversity Action Plans, due to reduction of forests
   and other habitats when new lands are converted to farming. Some
   critics also include agriculture as a cause of current global climate
   change.

Policy

   Agricultural policy focuses on the goals and methods of agricultural
   production. At the policy level, common goals of agriculture include:
     * Food safety: Ensuring that the food supply is free of
       contamination.
     * Food security: Ensuring that the food supply meets the population's
       needs.
     * Food quality: Ensuring that the food supply is of a consistent and
       known quality.

     * Conservation
     * Environmental impact
     * Economic stability

   Satellite image of circular crop fields characteristic of center pivot
   irrigation in Haskell County, Kansas in late June 2001. Healthy,
   growing crops are green. Corn would be growing into leafy stalks by
   then. Sorghum, which resembles corn, grows more slowly and would be
   much smaller and therefore, possibly paler. Wheat is a brilliant gold
   as harvest occurs in June. Fields of brown have been recently harvested
   and plowed under or lie fallow for the year.
   Enlarge
   Satellite image of circular crop fields characteristic of centre pivot
   irrigation in Haskell County, Kansas in late June 2001. Healthy,
   growing crops are green. Corn would be growing into leafy stalks by
   then. Sorghum, which resembles corn, grows more slowly and would be
   much smaller and therefore, possibly paler. Wheat is a brilliant gold
   as harvest occurs in June. Fields of brown have been recently harvested
   and plowed under or lie fallow for the year.
   Retrieved from " http://en.wikipedia.org/wiki/Agriculture"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
