In developed countries the primary sector has become more technologically advanced, enabling for example the mechanization of farming, as compared with lower-tech methods[a] in poorer countries.[6] More developed economies may invest additional capital in primary means of production: for example, in the United States corn belt, combine harvesters pick the corn, and sprayers spray 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 employ a smaller workforce, so 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.[7]
^Kjeldsen-Kragh, Søren (2007). The Role of Agriculture in Economic Development: The Lessons of History. Copenhagen Business School Press DK. p. 73. ISBN978-87-630-0194-6.