Columbia subject headings:
Agricultural price supports--United States.
Agriculture and state--United States.
Farm income--United States.
Field crops--Economic aspects--United States.
Harvard subject headings:
Agricultural price supports--United States.
Agriculture and state--United States.
Farm income--United States
Field crops--Economic aspects--United States.
Princeton subject headings:
Agricultural price supports--United States.
Agriculture and state--United States.
Farm income--United States.
Field crops--Economic aspects--United States.