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  Wikipedia: Agriculture

Wikipedia: Agriculture
Agriculture
From Wikipedia, the free encyclopedia.

Agriculture is the process of producing food, feed, and fiber by cultivation of certain plants and the raising of domesticated animals. Agriculture is also known as farming.

Overview

Agriculture includes both subsistence agriculture, which is producing enough food to meet the needs of the farmer and family, but no more) and also (almost universally in the "developed" nations and increasingly so in other areas) the production of financial income from cultivation of the land or commercial raising of animals (animal husbandry). Agriculture is the practice -- the study of these disciplines is called agricultural science.

Increasingly, besides food for humans and animal feeds, agriculture produces goods such as cut flowers, ornamental and nursery plants, fertilizers, animal hides, leather, industrial chemicals (starch, ethanol, and plastics), fibers (cotton, wool, hemp, and flax), fuels (methane, biodiesel, biomass), and both legal and illegal drugs (biopharmaceuticals, marijuana, opium, cocaine). Genetically engineered plants and animals produce specialty drugs.

In the Western world, use of improved genetics, better management of soil nutrients, and improved weed control have greatly increased yields per acre. At the same time, use of mechanization has decreased labor requirements, releasing most of the populace from intense agricultural labor. The developing world is behind by Western measures of productivity, because of unavailability of the education, capital and technology base needed to sustain these advances, and usually ecoregion with less optimal climates and soils.

Animal husbandry means breeding and raising animals for meat or to harvest animal products (like milk, eggs, or wool) on a continual basis.

In recent years, some aspects of industrial intensive agriculture have been the subject of increasing discussion. The widening sphere of influence held by large seed and chemical companies and meat packers has been a source of concern both within the farming community and for the general public. 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. Some argue 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.

Increasing consumer awareness of agricultural issues has led to the rise of community supported agriculture, local food movement, Slow food, and commercial organic farming, though these yet remain fledgling industries.

History

Determining the origin of agriculture is problematic since it pre-dates the invention of writing. Some authorities insist localized farming took place more than 10,000 years ago while others believe the earliest systematic plantings/harvestings took place no more than 7,000 years ago. The practice of agriculture is often used to distinguish the neolithic period from earlier parts of the stone age. The first crops that humans domesticated included wheat and barley. It is clear that farming was invented at least twice, probably more often: once in the Fertile Crescent (some say by the Natufian culture, others say by the Sumerians), once in East Asia, and probably once in Central America. Most likely, there was a gradual transition from a hunter-gatherer economy to an agricultural one, via a lengthy period when some crops were deliberately planted, and other foods were gathered from the wild. The reasons for the earliest introduction of farming may have included climate change. Farming allows a much greater density of population than can be supported by hunting and gathering.

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 populations needs.
  • Food quality: Ensuring that the food supply is of a consistent and known quality.

  • Conservation
  • Environmental impact
  • Economic stability

Methods

Crops

World production of major crops in 2002

In millions of metric tons, based on USDA estimates:

Maize 624
Wheat 570
Rice 381.1
Cotton 96.5

Note: There are two units of measure used for rice. Paddy rice is a measure of the tonnage of rice in its as-harvested state. Milled rice is a measure of the tonnage of rice after it is processed to remove the husk and, sometimes, polish the kernel.

Crop improvement

Domestication of plants is made in order to increase yield, disease resistance, drought tolerance, ease of 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. Extensive radiation mutagenesis efforts (i.e. primative 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 tonnes per hectare (40 bushels per acre) in 1900 to about 9.4 t/ha (150 bushels per acre) in 2001, primarily due to improvements in genetics. 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. Higher yields are due to improvements in genetics, as well as use of intensive farming techniques (use of fertilizers, chemical pest control, growth control to avoid lodging).

[Conversion note: 1 bushel (q) of wheat = 60 pounds (lb) ≈ 27.215 kg. 1 bushel of corn = 56 pounds ≈ 25.401 kg]

Very recently, genetic engineering has begun to be employed 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. 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 : List of domesticated plants, List of vegetables, List of herbs, List of fruit, List of domesticated animals

Environmental problems

  • Nitrogen surplus in rivers and lakes.
  • Detrimental effects of herbicides, fungicides, insecticides, and other biocides.
  • Conversion of natural ecosystems of all types into arable land.
  • Erosion
  • Weeds - Feral Plants and Animals

See also

External links

nds:Landwertschap simple:Agriculture zh-cn:农业 zh-tw:農業

  

From Wikipedia, the free encyclopedia. 
Modified by Geona