Four-field system | definition of Four-field system by Medical dictionary
crop rotation (redirected from Four-field system)
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crop rotation the growing of CROPS (3) in a regular sequence over a number of seasons so as not to exhaust the soil. A simple example of a rotation is root crop, oats, leguminous plants and wheat. Some or all of the leguminious crop is often ploughed back into the soil as it is of particular importance in returning nitrogen to the soil from the atmosphere through the nitrogen-fixing bacteria (see NITROGEN FIXATION in the root nodules.