2 Klarides Village Drive
Why do some gardeners recommend crop rotation?
|Crop rotation is a way to prevent or minimize pest infestations. The principle is to avoid putting plants from the same family in the same soil two plantings in a row. Rather, one rotates plants from three or four families through one section of the garden.|
This requires knowing which families your plants are in, and keeping some records.
Eliot Coleman has a nice list in Four Season Harvest that gives examples of some frequently grown plants and their families.
The reason to rotate crops is to keep the pests and diseases that affect the crop from building up in the soil and becoming worse each year until the crop is decimated. It takes time (usually) for the pests to find their favorite foods. It slows them down when the food is a moving target.
Beneficial organisms in the soil take time to find and eat bacteria that infect susceptible plants. Crop rotation gives healthy soil the time to balance out the population of microoorganisms.
Different crops take up different amounts of nutrients from the soil. In a well fed, healthy soil, this is not a big problem. But rotating plants evens out the uptake of nutrients, to an extent.
Some crops, like legumes, actually leave the soil more rich in certain nutrients which is beneficial to the crop that follows. Grains following legumes is a common rotational practice.