WHAT IS CROP ROTATION?

Based on an extract from ‘Practical Gardening and Food Production in Pictures’ – published in 1940

On any piece of ground that is used for growing edible plants it is important to adopt some kind of crop rotation. The effect of rotation is to obtain a better yield from your crops and to avoid diseases which will attack said crops if they are continuously grown on the same piece of land. Be aware that if you continue to grow the same or related edible plants in the same piece of ground then both soil borne pests as well as foliage pests will build up over time. This can only result in poorer crop yields in each subsequent year. That being said, onions are the only crop which can be grow on the same land year after year, provided that suitable fertilisers and manures are applied.

In practise, many gardeners follow a two year rotation. Half of their plot is taken up with potatoes while the remainder is used for other crops. In such a case the operation is to simply rotate the crops alternate years, but the best method is to use a three year crop rotation. Take a look at the following crop rotation diagram.

By using a rotation of crops, the same piece of land will not carry the same vegetables in successive years. For convenience, crops can be divided into three groups.

1. Peas and Beans
2. Cabbage, broccoli and other brassicas, turnips and Swedes.
3. Root crops

Note. Lettuce, spinach and other salad crops can be treated as intercrops, while leeks, onions and celery can be placed anywhere, but preferably in the area where the brassicas etc are being grown.

Regarding fertilisers and digging, each area will of course need to be treated differently. In this way only one section (Root crops) will need to be double-dug each year, reducing the amount of heavy work required.

For related articles click onto the following links:
CROP ROTATION
GREEN MANURES FOR AUTUMN SOWING
WHAT IS AN F1 HYBRID?