Crop rotation is the practice of growing a series of different types of crops in the same area in sequential season, meaning, that the succeeding crop belongs to a different family than the previous one
The importance of practice crop rotation
- It helps control weeds, pests and diseases hence reduce reliance on agro- chemicals. Planting the same crop season after season encourages certain weeds, insects, nematodes and diseases. Planting different crops breaks their life cycle and prevents them from multiplying.
- It increases soil fertility I: Legumes fix nitrogen in the soil. This nitrogen can be used by other crops such as maize. The result is higher, more stable yields, without the need to apply expensive inorganic fertilizers.
- It increases soil fertility II: Different crops have different nutrient requirements. Changing crops annually reduces the chance of particular soil deficiencies developing hence reduce the use of fertilizers.
- It functions as biological pumps as different crops are rooting at different soil depths hence are capable to explore the different soil layers for nutrients
- It improves the soil structure and reduces erosion: Some crops have strong, deep roots which can break up hardpans, and tap moisture from deep in the soil. Others have many fine, shallow roots which form many tiny holes so that air and water can get into the soil.
- May also replace ploughing the soil
How to plan a crop rotation
1. Make a list of the crops you want to grow
2. Know the family where your crops belong to make sure that you plant on the next cropping season a crop that belongs to a different family to the previous one;
3. Sweet potato
3. Draft the map of the entire farm showing the different fields
4. Take under consideration the season conditions, crop duration and following points:
- Grow legumes before grains or cereals
- Pests such as root-knot nematodes are a big problem in intensive vegetable production such as tomato (and other Solanaceae). Crop rotation pattern recommended entails a rotation in sequence with brassicas then cassava/cereals/ Allium and then back to tomatoes
- The brassica family also has soil-borne problems, and should always be shifted around in the fields. Brassicas clean the field from potato/tomato problems, so are very good crops to grow before a potato or tomato crop.
- Heavy feeding plants as Brassicas and Solanaceae families should be planted (and fed by good organic material) before less demanding plants.The less demanding plants can then benefit from left over manure from the heavy feeders.