Legumes are plants whose fruit is a pod. Most of these plants have bacteria on their roots which fix atmospheric nitrogen, which means nitrogen fertilizers are not necessary for their cultivation. In addition, choosing to add legumes in a cropping system improves soil fertility and reduces fertilizer inputs including on the following crops. This reduction in the use of nitrogen fertilizers results in a reduction of greenhouse gas emissions.
Legumes are particularly rich in protein (20 to 40% in dry seeds, depending on the species), fibre and micronutrients. Their amino acid profile is complementary to that of cereals, and cereal-legume food associations have been the basis of food for civilisations for thousands of years.
There are thousands of legume species in the world and a wide diversity of uses: the pods or seeds harvested fresh or dried on one side (peas, beans, faba beans, haricot grains, lentils, chick peas, lupins, green beans, green peas …) and forage or grassland legumes on the other (alfalfa, vetch, clover, sainfoin …). Soy, also very rich in oil, is essentially used in the form of soya meals for animal feed. Pulses refer only to dried legumes not rich in oil.
In the twentieth century, legumes were less and less cultivated and less and less consumed, due to an increase of meat consumption and the development of soya and corn for animal feed. During the first half of the 21st century, legumes had an important role to play, on the one hand, for the nutritional transition which tends towards a rebalance of protein intake from animal and plant origin; and, on the other hand, for a re-strengthening of the autonomy of livestock systems and the resilience of the territories with a greater diversity of cultivated legumes.
Their agro-environmental assets and their nutritional properties should therefore lead to a resurgence of legumes as an essential pillar of the diversification of cropping systems and diets, in order to improve the health of humans and ecosystems.
References to explore
De Ron, A.M., Sparvoli, F., Pueyo, J.J. and Bazile, D., 2017. Editorial: Protein crops: food and feed for the future. Frontiers in plant science, 8, p.105. doi: 10.3389/fpls.2017.00105
FAO. 2016 was declared as the International Year of Pulses by the United Nations.
Murphy-Bokern, D., Stoddard, F. L., Watson, C. A. 2017. Legumes in cropping systems. CABI editions. ISBN : 9781780644981. doi: 10.1079/9781780644981.0018