Crop rotation is a system of growing different crops on the same piece of land each season, in sequences. The system prevents the buildup of pests and diseases on the land.
It enables the farmer to get rid of weeds cheaply and yet effectively, by alternating natural weed suppressors like sweet potatoes with other crops. Different crops make different demands on the soil.
Leguminous crops like beans and ground nuts enable the soil to have its reserves replenished by adding nitrogen to it.
Growing the same crop on the same piece of land continuously exhausts the soil. Soil structure is improved at different levels when deep rooted crops are alternated with crops that have shallow roots.
Rotation can be carried out according to the crop family, their ability to improve the soil or their feeding habits. Crop families include Solenaceace (fruit crops such as tomato), Cucurbitaceae (Pumpkin family such as melon) Leguminosae (Pod crops such as beans), Malvaceae ( Okra and cotton), Cruciferae (Cabbage family such as beet), Lilaceae (bulb family such as onion), Graminacae ( cereals such as maize), Compositae ( sunflower) and Convolvulaceae (sweet potato).
The farmer can also rotate crops according to their feeding habits. Heavy feeders like cabbage can be alternated with light feeders like sweet potatoes.
The farmer can also be guided by the crop’s ability to improve soil. For instance, root or tuber crops such as sweet-potato can be alternated with short rooted crops like cabbages or onions. Nitrogen fixing crops like beans, can also be alternated with long rooted crops such as eggplants.
Grain crops like maize can also be alternated with cover crops such as sweet potatoes.
