From 1945 to 1972 Iowa farmers remade their landscape in the image of an industrial model characterized by large-scale production, the substitution of capital for labor, strict cost accounting, specialization, and efficiency. Farm families were leaders in adopting new technology to solve their problems in the post World War II period, a contrast to the pre-war years when experts such as college educated professionals, journalists, and industry leaders advocated the application of industrial ideals to agriculture. Many farmers industrialized production because of a persistent postwar farm labor shortage and a cost-price squeeze in which the prices farmers paid for products increased faster than prices they received for commodities. They used pesticides, fertilizer, and feed additives to boost yields and livestock gains as well as altered crop rotations and traditional cycles of livestock production. They purchased, borrowed, or hired new machines, remodeled existing structures or built new ones. Iowa's landscape of the early 1970s was still dedicated to agriculture, but new agricultural production techniques resulted in changed land use patterns and work cycles that would have been unrecognizable to farmers who lived from 1900 to 1945. By 1972 pesticides, fertilizers, feed additives, hay balers, and combines were common on Iowa farms. While a minority of producers used combines for harvesting shelled corn and confinement feeding systems, the value of these practices for lowering unit costs and maximizing production was proven. Many new techniques that increased production simultaneously created problems. Farmers learned that success in controlling pest species allowed new pest species that were resistant to pesticides to thrive. Public concern over pesticide, fertilizer, feed additives, and manure runoff also led to government regulation that limited farmers' technological choices. Furthermore, as farmers invested more money in pesticides and fertilizer, they found that they needed expensive new harvesting and grain storage techniques to reduce harvest losses. The financial costs of field equipment, automated feeding systems, and storage facilities pressured farmers to increase production per acre and spread those costs over more acres. Farmers' technological choices kept many families in agriculture but compelled many more to leave.