Agriculture is the production of food and goods through farming. Agriculture
was the key development that led to the rise of human civilization, with the
husbandry of domesticated animals and plants (i.e. crops) creating food
surpluses that enabled the development of more densely populated and stratified
societies. The study of agriculture is known as agricultural science.
Agriculture is also observed in certain species of ant and termite.[1][2]
Agriculture encompasses a wide variety of specialties and techniques, including
ways to expand the lands suitable for plant raising, by digging water-channels
and other forms of irrigation. Cultivation of crops on arable land and the
pastoral herding of livestock on rangeland remain at the foundation of
agriculture. In the past century there has been increasing concern to identify
and quantify various forms of agriculture. In the developed world the range
usually extends between sustainable agriculture (e.g. permaculture or organic
agriculture) and intensive farming (e.g. industrial agriculture).
Modern agronomy, plant breeding, pesticides and fertilizers, and technological
improvements have sharply increased yields from cultivation, and at the same
time have caused widespread ecological damage and negative human health
effects.[3] Selective breeding and modern practices in animal husbandry such as
intensive pig farming (and similar practices applied to the chicken) have
similarly increased the output of meat, but have raised concerns about animal
cruelty and the health effects of the antibiotics, growth hormones, and other
chemicals commonly used in industrial meat production.[4]
The major agricultural products can be broadly grouped into foods, fibers,
fuels, and raw materials. In the 2000s, plants have been used to grow biofuels,
biopharmaceuticals, bioplastics,[5] and pharmaceuticals.[6] Specific foods
include cereals, vegetables, fruits, and meat. Fibers include cotton, wool,
hemp, silk and flax. Raw materials include lumber and bamboo. Other useful
materials are produced by plants, such as resins. Biofuels include methane from
biomass, ethanol, and biodiesel. Cut flowers, nursery plants, tropical fish and
birds for the pet trade are some of the ornamental products.
In 2007, about one third of the world's workers were employed in agriculture.
The services sector has overtaken agriculture as the economic sector employing
the most people worldwide.[7] Despite the size of its workforce, agricultural
production accounts for less than five percent of the gross world product (an
aggregate of all gross domestic products).