The primary sector of the economy is the sector of an economy making direct use of natural resources. This includes agriculture, forestry and fishing, mining, and extraction of oil and gas. This is contrasted with the secondary sector, producing manufactured and other processed goods, and the tertiary sector, producing services. The primary sector is usually most important in less developed countries, and typically less important in industrial countries.
The manufacturing industries that aggregate, pack, package, purify or process the raw materials close to the primary producers are normally considered part of this sector, especially if the raw material is unsuitable for sale or difficult to transport long distances.
Primary industry is a larger sector in developing countries; for instance, animal husbandry is more common in Africa than in Japan. Mining in 19th century South Wales is a case study of how an economy can come to rely on one form of business.
Canada is unusual among developed countries in the importance of the primary sector, with the logging and oil industries being two of Canada's most important. However, in recent years, the number of terminal exchanges have heavily reduced Canada's primary industry, making them rely more on quaternary industry.
In developed countries primary industry becomes more technologically advanced, for instance the mechanization of farming as opposed to hand picking and planting. In more developed economies additional capital is invested in primary means of production. As an example, in the United States corn belt, combine harvesters pick the corn, and spray systems distribute large amounts of insecticides, herbicides and fungicides, producing a higher yield than is possible using less capital-intensive techniques. These technological advances and investment allow the primary sector to require less workforce and, this way, developed countries tend to have a smaller percentage of their workforce involved in primary activities, instead having a higher percentage involved in the secondary and tertiary sectors.