Why crop rotation is important
11:08 (GMT+2), Wed, Wednesday, February 15, 2012
The idea of crop rotation – growing different crops on the same land each year – can be difficult to understand. After all, if you’ve been growing maize and only just managing to feed your family, why reduce the amount of maize you plant (which is what crop rotation requires) and plant something else? But here’s the secret: crop rotation will increase your maize yield and give you a surplus to sell.
A farmer who follows the Foundations for Farming system can feed his family off a quarter of a hectare (50m x 50m). This means more land left over to grow other food or cash crops. Which crops should you grow? The best combination is grain, legumes and cash crops.
Crop rotation has the following benefits:
How to do it
- It makes your soil more fertile, as legumes such as beans and groundnuts fix nitrogen in the soil.
- You use less chemical fertiliser, because the nitrogen is fixed naturally in the soil.
- It helps to control weeds, diseases and pests by breaking their life cycles.
- It reduces the risk of crop failure in case of drought or disease.
Divide your land into three equal sections and rotate these according to one of the following plans (see diagram).
Section 1: grain
Section 2: cash crop
Section 3: legume
Section 1: legume
Section 2: grain
Section 3: cash crop
Section 1: cash crop
Section 2: legume
Section 3: grain
Sections 1 and 2: grain.
Section 3: legume.
Section 1: legume.
Sections 2 and 3: grain.
Sections 1 and 3: grain.
Section 2: legume.
About conservation farming
- Grains – maize, sorghum, millet.
- Legumes (cash or food crops) – soya bean, cowpea, groundnut, field bean or combinations of these.
- Cash crops (non-legumes) – cotton, sunflower, sesame.
Conservation agriculture increases the amount of food you can grow off the same land. It’s completely different to normal farming methods. It involves disturbing the soil as little as possible (no ploughing), using mulch cover, never burning, rotating crops, and managing the land carefully. Foundations for Farming founder Brian Oldreive used it in Zimbabwe, and achieved a 20-year average of 9t/ha of maize and a maximum of 13,95t/ha.
All life needs nitrogen to live. But pure nitrogen in the atmosphere can’t be used by plants or animals. It must be changed or “fixed” chemically. Legumes such as lucerne and soya beans help to do this in the soil. When the plant dies, the fixed nitrogen is released and becomes available to other plants.•FW
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