Crop rotation is the practice of moving different crops on the same land. If this process was not done, harmful organisms and other pests would spread when the crop is prepared for raising. Crop rotation also helps stop the loss of water in soil nutrients.
A normal way to do crop rotation is to mix green manure and other organic matter in with the soil. This adds nitrogen and other nutrients that plants need to grow. When this is added, it can help different crops be able to grow at the same time in the same space.
It was used in New Zealand during the 1920's and onwards, as an efficient way of farming.