Norfolk four-course system
The Norfolk four-course system is a method of agriculture that involves crop rotation. Unlike earlier methods such as the three-field system, the Norfolk system is marked by an absence of a fallow year. Instead, four different crops are grown in each year of a four-year cycle: wheat, turnips, barley, and clover or ryegrass.
This system was developed in the early 16th century in the region of Waasland, and was popularized in the 18th century by British agriculturist Charles Townshend. The sequence of four crops, included a fodder crop and a grazing crop, allowing livestock to be bred year-round. The Norfolk four-course system was a key development in the British Agricultural Revolution.