Modern agriculture depends heavily on engineering and technology and on the biological and physical sciences. Irrigation, drainage, conservation, and sanitary engineering—each of which is important in successful farming—are some of the fields requiring the specialized knowledge of agricultural engineers. Agricultural chemistry deals with other vital farming concerns, such as the application of fertilizer, insecticides (see Pest Control), and fungicides, soil makeup, analysis of agricultural products, and nutritional needs of farm animals. Plant breeding and genetics contribute immeasurably to farm productivity.
Genetics has also made a science of livestock breeding. Hydroponics, a method of soilless gardening in which
plants are grown in chemical nutrient solutions, may help meet the need for greater food production as the world’s
population increases. 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.
Mechanization, the outstanding characteristic of late 19th- and 20th-century agriculture, has eased much of the backbreaking toil(involving enormous physical effort) of the farmer. More significantly, mechanization has enormously increased farm efficiency (desired result without using much effort) and productivity (rate of production). Animals including horses, oxen, llamas, alpacas, and dogs, however, are still used to cultivate fields, harvest crops, and transport farm products to markets in many parts of the world.
Airplanes and helicopters are employed in agriculture for seeding, spraying operations for insect and disease control, transporting perishable products, and fighting forest fires. Increasingly satellites are being used to monitor crop yields. 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.
Over the 10,000 years since agriculture began to be developed, peoples everywhere have discovered the food value of wild plants and animals, and domesticated and bred them. The most important crops are cereals such as wheat, rice, barley, corn, and rye; sugarcane and sugar beets; meat animals such as sheep, cattle, goats, and pigs or swine; poultry such as chickens, ducks, and turkeys; animal products such as milk, cheese, and eggs; and nuts and oils. Fruits, vegetables, and olives are also major foods for people. Feed grains for animals include soybeans, field corn, and sorghum. Agricultural income is also derived from nonfood crops such as rubber, fiber plants, tobacco, and oil seeds used in synthetic chemical compounds, as well as animals raised for pelts(animal skin).
Conditions that determine what is raised in an area include climate, water supply and waterworks, terrain, and ecology. In 2003, 44 percent of the world’s labor force was employed in agriculture. The distribution ranged from 66 percent of the economically active population in sub-Saharan Africa (mali, Ethiopia, Zimbabwe etc) to less than 3 percent in the United States and Canada. In Asia and the Pacific the figure was 60 percent; in Latin America and the Caribbean, 19 percent; and in Europe, 9 percent. Farm size varies widely from region to region. In the early
2000s the average for Canadian farms was about 273 hectares (about 675 acres) per farm; for farms in the United States, 180 hectares (440 acres). By contrast, the average size of a single land holding in India was 2 hectares (about 5 acres).
Size also depends on the purpose of the farm. Commercial farming, or production for cash, usually takes place on large holdings. The latifundia of Latin America are large, privately owned estates worked by tenant labor. Single-crop
plantations produce tea, rubber, and cocoa. Wheat farms are most efficient when they comprise thousands of hectares and can be worked by teams of people and machines. Australian sheep stations and other livestock farms must be large to provide grazing for thousands of animals. Individual subsistence(condition of managing to stay alive) farms or small-family mixed-farm operations are decreasing in number in developed countries but are still numerous in the developing countries of Africa and Asia. Nomadic herders range over large areas in sub-Saharan Africa, Afghanistan, and Lapland (region largely within the arctic circle, extending across the northern parts of Norway,Sweden, finland and the Kola peninsula of Russia.) ; and herding is a major part of agriculture in such areas as Mongolia. Much of the foreign exchange earned by a country may be derived from a single agricultural commodity; for example, Sri Lanka depends on tea, Denmark specializes in dairy products, Australia in wool, and New Zealand and Argentina in meat products. In the United States, wheat, corn, and soybeans have become major foreign exchange commodities in recent decades.
The importance of an individual country as an exporter of agricultural products depends on many variables. Among them is the possibility that the country is too little developed industrially to produce manufactured goods in sufficient quantity or technical sophistication (advance technical development). Such agricultural exporters include Ghana, with cocoa, and Myanmar (formerly Burma), with rice. However, a developed country may produce surpluses that are not needed by its own population; this is the case with the United States, Canada, and some other countries. Because nations depend on agriculture not only for food but for national income and raw materials for industry as well, trade in agriculture is a constant international concern. It is regulated by the World Trade Organization.
The Food and Agriculture Organization of the United Nations (FAO) (to eliminate hunger on world scale main headquarter is Rome, Italy) directs much attention to agricultural trade and policies. According to the FAO, world agricultural production, stimulated by improving technology, grew steadily from the 1960s to the 1990s. Per capita food production saw sustained growth in Latin America, the Caribbean, Asia, and the Pacific areas (surrounding pacific ocean), and limited growth in the Near East ( middle east) and North Africa. The only region not to experience growth during the 1980s and 1990s was sub-Saharan Africa, which suffered from climatic conditions that
made agriculture difficult. Although agricultural growth began to taper off in the year 2000, it continued to outpace world population growth.