Agriculture is the science, art, or occupation concerned with cultivating land, raising crops, feeding, breeding, and raising livestock; farming. It is a very ancient activity, with origins in prehistory, and it is now an indispensable and essential economic sector in the world's food.
It is estimated that agriculture has grown from about 8,000 to 10,000 years ago. Since then, all of the peoples living on Earth have recognized the value that cultivated plants have for human and domestics pets.
Some vegetables have become traditional in many countries, even some of them have become monocultures, and the most important source of income. Moreover, between the various agricultural products, some of the products distinguished for humans are cereals, wheat, corn, rye, rice, sugarcane, sugar beet, oil, vegetables and fruits. As for animal feed, it is important the feed based on soy beans, green maize and sorghum. On the other hand, not all agricultural food products have valuable, there are also numerous crops used to produce materials for industry such as rubber, oil seeds to make paints or synthetic chemical compounds, plants for producing fibers, etc.
Even though the distribution of agriculture is varied, the true value of it is appreciated when half of the world’s population is engaged in this activity.Thus, while in Africa and Asia over [pass the 60 percent of the population, in the United States and Canada it is barely a 5 percent. Meanwhile, in South America the population engaged in these tasks is almost a quarter; Western Europe accounts for about 7 percent; and the countries of the Russian Federation and encompassed in the former Soviet Union reaches 15 percent.
Types of agriculture
In the Neolithic, shifting cultivation was practiced (and still practice in some primitive villages), which consisted in leaving the land once their resources have been drained and then finding a new productive soils. Currently agriculture has evolved to an industrial character, where genetic engineering, chemical and mechanical technology play key roles.
Various types of agriculture are distinguished such as:
Extensive
Extensive farming is one in which simple tasks are performed, also, in which organic fertilizer are used, such as manure, quite irrespective of artificial fertilizers. It is a type of agriculture defensible from an ecological point of view, because the earth is not usually subject to pressure that print other activities, such as intensive or industrial agriculture.
Intensive or industrial
Intensive pr industrial agriculture is one in which complex work is done, and it depends entirely on artificial fertilizers for optimum development. The soils usually occur continuously, which implies the need to restore also continuously minerals and elements that were assimilated by plants; this means having to face long to various environmental problems arising not only the frequent use of chemicals, but also of the urgent need to ensure the crops against pests and diseases by pesticides, herbicides, etc., which may end finally introduced in the food chain.
Biological
Organic or biological farming was born to address the problems posed by intensive farming. It is an increasingly popular activity for consumers, respects the environment and health. This type of agriculture relies on natural methods to combat diseases and pests, and rejects the use of pesticides and synthetic fertilizers.
Parcelaria
Smallholding agriculture is limited to scattered and small areas. There are many regions in the world for its orographic features are dedicated to this type of agriculture. An example are the platforms or terraces Hispanic Andean and still exist in the Guatemalan highlands, where corn, beans and squash are grown; and coffee in the lower areas of the slopes.
Monoculture
Monoculture farming is an activity which is specialized in a single product. While subsistence farmers around the world tend to grow various vegetables, usually not so in the case of large commercial farms. Thus, many farms produce only coffee, tea, cereal, cocoa, or rubber. An example is the dependence of Thailand rice, which is one of the world's largest producers of this graminácea;or Sri Lanka, which depends entirely on the production of tea.
When a surface is dedicated to produce a single species, it often provide greater economic benefits, and simplified the land management, production and marketing. However, it may lead to the concentration of pest, which it is usually controlled, it sometimes can produce the devastation and loss of production. Crop diversity is an advantage against this problem, but is limited by the characteristics of soils, climate, and other economic factors.