The history of agriculture dates back thousands of years, and its development has been driven and defined by greatly different climates, cultures, and technologies. However, all farming generally relies on techniques to expand and maintain the lands suitable for raising domesticated species. For plants, this usually requires some form of irrigation, although there are methods of dryland farming; pastoral herding on rangeland is still the most common means of raising livestock. In the developed world, industrial agriculture based on large-scale monoculture has become the dominant system of modern farming, although there is growing support for sustainable agriculture (e.g. permaculture or organic agriculture).
Modern agronomy, plant breeding, pesticides and fertilizers, and technological improvements have sharply increased yields from cultivation, but at the same time have caused widespread ecological damage and negative human health effects. Selective breeding and modern practices in animal husbandry such as intensive pig farming 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.
The major agricultural products can be broadly grouped into foods, fibers, fuels, and raw materials. In the 21st century, plants have been used to grow biofuels, biopharmaceuticals, bioplastics, and pharmaceuticals. 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, 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. 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).
3.1 Ancient origins
3.2 Middle Ages
3.3 Modern era
4 Crop production systems
4.1 Crop statistics
5 Livestock production systems
6 Production practices
7 Processing, distribution, and marketing
8 Crop alteration and biotechnology
8.1 Genetic engineering
8.2 Herbicide-tolerant GMO crops
8.3 Insect-resistant GMO crops
8.4 Costs and benefits of GMOs
9 Modern agriculture
10 Food safety, labeling and regulation
11 Environmental impact
11.1 Livestock issues
11.2 Land transformation and degradation
11.5 Climate change
12 International economics and agriculture
13 List of countries by agricultural output
14 Energy and agriculture
14.1 Mitigation of effects of petroleum shortages
14.2 Electrical energy efficiency on farms
16 See also
19 External links
 EtymologyThe word agriculture is the English adaptation of Latin agricultūra, from ager, "a field", and cultūra, "cultivation" in the strict sense of "tillage of the soil". Thus, a literal reading of the word yields "tillage of a field / of fields".