The deep history of human experience links food production to ecological realities. From the origins of humans roughly 300,000 years ago, the agricultural era is a mere 10,000 years old; the emergence of America agriculture, initially based on European practices, is even shorter- less than 400 years old. Since domestication of crops and animals made human societies based on settled agriculture possible, ecological processes largely dictated agricultural practices. Opportunities for trade, observation along with trial and error and technological innovation led to the rise of American farming practices.
The ecological constraints of agricultural systems played an important role in the productivity of the land until access to external inputs and promotion by commercial interests altered the landscape. For example, guano --a source of nitrogen-became commercially available in 1853 in New York City and quickly was adopted by those who could afford it. Emphasis was placed on productivity and profit, not the land or the disruption of ecological systems. In fact, the westward migration of the US population in the 19th century was in part driven by abandonment of "tired" lands in the east as settlers sought new and more productive soils in Ohio, Indiana, and the Midwestern grasslands and prairies.
American agriculture evolved with little formalized public support until the latter half of the 1800s. During the Lincoln presidency, two important steps were taken. Both the US Department of Agriculture and the land-grant college system (through passage of the Morrill Act) were created by the Federal government in 1862 The Hatch Act, creating the agricultural experiment station system, was passed in 1887; from these steps more formal public support of education and research emerged. Nevertheless, agricultural science and related economic studies stood apart from the development of the field of ecology and so ecology rarely informed a more holistic and systematic approach to agricultural research.
The modern perception of an agriculture/environment "tradeoff" is a relatively recent development. It is in part a product of the rise in ecological and environmental sciences research, and the realization by many that we live on "spaceship" Earth-a place of limited, not limitless, resources. It is also a product of the industrialization of food (and feed) production and of the dramatic increase in global human populations since the nineteenth century. The American population has grown significantly in two hundred years: from 7,239,000 in 1810 to just over 308 million in 2010. In this time the world population has grown 7-fold: from 1 to 7 billion. Thus, keeping this population fed inexpensively and exporting food and feed to the rest of the world have been major objectives of American agriculture. Only with the passage of environmental legislation such as the Clean Water Act of 1972 and Endangered Species Act of 1973 has the successful increase in food production made the environmental and ecosystems challenges caused by agriculture to become clearer. Reducing the environmental impact of modern agriculture has therefore become an important research initiative for States and the federal government, thus motivating researchers to explore ecological solutions to pressing environmental problems.
Farmers nevertheless live, whether they fight it or flow with it, within an ecological imperative, even in the modern era. We know and accept that farmers must disrupt ecological systems to produce food efficiently, but we are also learning that they must not disrupt these systems too much or productivity will go down. In our paper, we aim to put this ecological imperative in historical, contemporary, and prospective contexts. Our prospective view will focus on examples of where contemporary ecological research and the associated opportunities for improvements in agriculture are beginning to yield an exciting future. Therefore, the adoption of an ecological paradigm for agriculture should more strongly influence the mind-sets of agricultural researchers and those whose policies direct public funding to their support.