Columbia subject headings:
Agricultural pollution--Great Britain--History--20th century.
Agriculture and state--Great Britain--History--20th century.
Land use, Rural--Government policy--Great Britain--History--20th century.
Harvard subject headings:
Agricultural pollution--Great Britain--History--20th century.
Agriculture and state--Great Britain--History--20th century.
Land use, Rural--Government policy--Great Britain--History--20th century.
Princeton subject headings:
Agricultural pollution--Great Britain--History--20th century.
Agriculture and state--Great Britain--History--20th century.
Land use, Rural--Government policy--Great Britain--History--20th century.