The primary sector is concerned with the extraction of raw materials. It includes fishing, farming and mining.
Primary industry is a larger sector in
developing countries; for instance,
animal husbandry is more common in countries in
Africa than in
 Mining in 19th-century
South Wales provides a case study of how an economy can come to rely on one form of activity.
developed countries primary industry has become 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
combine harvesters pick the corn, and spray systems distribute large amounts of
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.
Developed countries are allowed to maintain and develop their primary industries even further due to the excess wealth. For instance, European Union
agricultural subsidies provide buffers for the fluctuating inflation rates and prices of agricultural
produce. This allows developed countries to be able to export their agricultural products at extraordinarily low prices. This makes them extremely competitive against those of poor or underdeveloped countries that maintain free market policies and low or non-existent tariffs to counter them.
 Such differences also come about due to more efficient production in developed economies, given farm machinery, better information available to farmers, and often larger scale.