In the early agricultural period in the United States, land and labor represented about 85 percent of all resources used, farms tended to be small, farmers had limited skill and experience in managing their farms. Each farmer produced food for himself and his family. Capital inputs represented about 15 percent of the total. About 5 decades ago a big change began in U.S. agriculture. The combined programs in research and education of the USDA and the Land-Grant Colleges resulted in discoveries of improved varieties of seeds and livestock, hybrid seed, fertilizer, new machinery, chemicals for diseases, and weed and insect control. The educational program provided modern agricultural information to farmers through extension workers. With changes in technology U.S. agriculture has grown more efficient, farms are more highly capitalized, mechanized and productive. Large quantities of capital are required to substitute for land and labor. One farmer can produce enough food to feed himself and in 1966 thirty nine and a half persons. Changing technology in agriculture has affected size of farms, number of farms, capital requirements and management.