Legumes to save crops, it works!

Legumes to save crops, it works!

Legumes to save crops, it works!

The cultivation of legumes really works, anywhere in the world, whatever the crop: yields have improved by an average of 20%. 48% in Africa. Details by Mathilde Fontez, editor-in-chief of the magazine Epsilon.

franceinfo: An international study today demonstrates the effectiveness in boosting the yields of a type of crop, the cultivation of legumes, beans and peas?

Matilde Fontez: Beans, peas, but also lentils, clover, alfalfa, broad beans. This category of plants has a particular power, which we have known for a long time, even if biologists have not yet been able to fully unravel its mysteries: they store nitrogen from the air, to deposit it in the soil, through their roots. They are therefore fertilizers for the soil since nitrogen is what is consumed by most crops. Basically, legumes are a natural fertilizer.

Where did the idea of ​​growing them to restore the nitrogen level in the soil come from?

This is the idea yes. And it is already widely practiced: crop rotation with legumes is recognized as a key strategy for sustainable agriculture, namely organic crops. The beans are planted to better grow corn or wheat later.

But there, a study demonstrates for the first time the effectiveness of the technique on a large scale. The researchers, an international team, collected field studies in 53 countries. They have accumulated 12,000 observations on yield, nearly 500 experiments, between 1959 and 2020. And what they find is that the increase in yield is quite remarkable: legumes increase yields, at a constant surface, by an average of 20%.

So does it work?

It works yes. Everywhere. For all crops, be it corn, rice, wheat, beets. And the researchers detail the variations. For example, the increase in yield is less strong on soils where chemical fertilizers, nitrogen fertilizers are used. This was expected: when the soil is enriched with nitrogen, inevitably, the contribution of legumes, in proportion, is lower.

But their use is still beneficial for performance. And it is a surprise: for the researchers it is probably the effect of crop rotation on the ecosystem of the field: legumes interrupt the pathological cycles, prevent the proliferation of parasites and pathogens. And on low-yielding soils: organically grown soils, or African soils, the increase there is impressive. It reaches 43% in Africa.

In their conclusion, the researchers bluntly state that “legume-based rotations offer a critical path to improving global agricultural production. “ While this may initially reduce the main crop area, the yield gains quickly compensate for this loss. A real sustainable solution then …

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