four-course crop rotation
four-course system

Norfolk four-course crop rotation: Fodder crops, particularly turnips and clover, replaced leaving the land fallow.

It was to be replaced by the four-course system of crop rotation, devised in England in 1730 by Charles Townshend, 2nd Viscount Townshend or "Turnip" Townshend during the British Agricultural Revolution, as he was called by early detractors.