DIVERSIFICATION Discover, every day, an analysis of our partner The Conversation. This Wednesday, agronomists unveil the ecological virtues of “pulses” more-sustainable-agri-food-system-728b9fd.jpg” alt=”Agriculture: Sowing legumes would promote a more sustainable agri-food system” />
Faced with the recurring instability of agricultural markets, encouraging the cultivation of legumes would reduce the dependence of our food systems on imports of vegetable proteins, such as soybeans, for example — Shutterstock
- Encouraging the cultivation of pulses would reduce the dependence of our food systems on imported plant proteins, according to our partner The Conversation.
- Pulses also represent an option for crop diversification in the territories and provide a series of ecological and socio-economic benefits.
- This analysis was conducted by Nicolas Guilpart , lecturer in agronomy at AgroParisTech (Paris-Saclay University), David Makowski, research director in agroecological statistics, Marie-Hélène Jeuffroy, research director in agronomy, Olivier Réchauchere, research engineer in agronomy, and Rémy Ballot, research engineer in agronomy (all four at the National Research Institute for Agriculture, Food and the Environment – INRAE).< /li>
The current explosion in the price of synthetic nitrogen fertilizers, linked to the that of gas, increases the production costs of most major crops such as wheat; or rapeseed. Europe is also globally deficient in vegetable proteins. Developing the cultivation of legumes, which do not require nitrogen fertilizers, therefore appears interesting.
Remember that the term leguminous refers, in agricultural systems, to two groups: forage legumes, used as whole plants in the diet of ruminants – alfalfa, clover, vetch… – and legumes to seeds (protein crops or pulses) whose seeds are harvested for animal or human consumption – soybeans, peas, beans, lentils, beans…
Legumes can be grown pure (a single species in the plot), in associated annual crops, or in multi-species and multi-annual meadows. They can be incorporated into rotations as the main crop, as an intermediate crop (planted between two main crops to provide services other than production) or as service plants, grown with a main crop to provide it with various benefits.
Facing instability recurrent feature of agricultural markets, encouraging the cultivation of legumes would reduce the dependence of our food systems on with regard to imports of vegetable proteins. Not to mention that legumes represent an option for the diversification of crops in the territories and provide a series of ecological and socio-economic benefits. It is still necessary that there is a potential for extending these crops, and that we know how to integrate them into cropping systems.
Less than; impact on the climate and the environment
Let's first look at the benefits associated with growing pulses. Thanks to; a symbiosis with bacteria at the level of their roots, these plants are able to use the nitrogen present in the atmosphere to ensure their growth and to synthesize their proteins.
< p>To grow, and produce fodder and seeds, they do not require synthetic nitrogen fertilizers (such as ammonium nitrate or urea), the use of which generates emissions of nitrous oxide (N₂O), a powerful gas greenhouse effect (GHG). Emissions which in France represent almost half of the those of the agricultural sector.
Alfalfa type « Flemish » – Jean Weber – INRA/Flickr CC BY 2.0
The production of these fertilizers, which is very costly in energy (and therefore economically), also induces CO2 emissions, and their use , when it is excessive, contributes to pollute the water with nitrates.
Some of the nitrogen that legumes take up from the atmosphere and leave in the soil via crop residues and the root system becomes available for subsequent crops in the rotation . This supply of nitrogen from legumes is useful in reducing the dependence of agricultural systems on nitrogen fertilizers, and is an essential source of nitrogen for organic farming systems.
Diversification, food autonomy, health
Pulses also contribute to the diversification of European arable farming systems, highly specialized in the production of cereals and oilseeds. This diversification brings agroecological benefits in terms of water quality. soil and biodiversity, while disrupting the life cycle of insect pests, main crop diseases and weeds.
Producing more pulses in Europe would also contribute to improve the food autonomy of our livestock: in 2021, the European Union thus imported 15 million tonnes (Mt) of soybeans and 16 Mt of meal to feed its livestock. But this substitution of imported proteins by locally grown legumes means reducing the areas cultivated with other crops, or transforming livestock systems to give more from place to place; grass and fodder legumes.
In our European diets, where animal proteins dominate, the rebalancing of consumption towards plants has health benefits; while reducing the surfaces devoted to the production of animal feed.
To develop the culture of legumes, it is necessary to work at; two scales: continental, to estimate the agroclimatic potential of the extension of legumes; and territory and cultivated field, to assess the potential and feasibility of development of these crops.
Agroclimatic potential of the European continent
Soybean cultivation in France – Nicolas Guilpart
To measure the agroclimatic potential of the extension of legumes, we looked at soybeans, the price of which has almost doubled. in two years while soybean areas have quadrupled; in twelve years on the European continent, to reach 5 million ha in 2016. Despite that, soy represents only 1.7% of cultivated areas. Imports, particularly from Brazil and Argentina, remain the majority (90%) of consumption on the continent.
The capacity from the European continent to becoming self-sufficient in soy should not be challenged with climate change. According to our models for estimating soybean yield in Europe, the continent could reach 50% self-sufficiency by 2020. 100% by 2050 if 4% at 11% of European cropland was devoted to soy.
Soybean yield projections in historical climate (A) and future climate (B). The future climate corresponds to; strong heating (RCP 8.5) – Suitable for from Guilpart N. et al, Nature food, article cited)
Such an expansion would contribute to reduce “imported deforestation” and at decrease from 4 to 17% nitrogen fertilizer use on the continent. Land use changes in Europe and beyond international relations generated by such an expansion must, however, be studied.
Thus, achieving 50% self-sufficiency would imply about 9 million additional ha of soybeans, or 15% of the wheat area. on the European continent. What would be the impact of such an increase on the production of other crops in Europe and around the world? The question is crucial, a fortiori in a context of instability. agricultural commodity prices.
Other legumes such as peas or fava beans have good agroclimatic potential. But the evaluation of this potential says nothing about the socio-economic conditions necessary for the concrete development of these crops, in particular their profitability. for farmers.
Feasibility; territorial
Faced with the many agronomic problems encountered by simplified crop successions in base of rapeseed and winter cereals which dominate on the Langrois plateau, in Côte d’Or, the actors of the territory have mobilized with one of our research teams to é study the feasibility a diversification of these successions, by introducing legumes.
In order for a common vision of the territory to emerge, integrating supply chains, farms and natural resources, new cropping systems integrating legumes have been developed. designed during participatory workshops. They served as a basis for discussion for stakeholders to define objectives concerning the place of legumes in their territory.
Cropping systems design workshop in Burgundy – Marie-Hélène Jeuffroy
4 contrasting scenarios have been elaborated and simulated, with areas devoted to legumes (peas, lentils, sainfoin, alfalfa) varying from 9 to 23% of surfaces, against 6% today in the territory. Diversification projects were then developed. launched on the territory; remains at assess sustainability changes and the conditions for their generalization.
The articulation of the two approaches that we have just presented makes it possible to identify the legume species and the most promising to their development, while supporting their integration into the the local scale.
Public policy issue
Finally, there remains the question of public policies to support and stimulate these transitions. The EU has dedicated important means in the 1970s and 80s to promote the cultivation of legumes. Protein crops have thus exceeded 700,000 ha in France in the 1990s, but for thirty years, their production has only decreased, the surface area dropping to 700,000 ha. 467,000 ha in 2000 then to 313,000 ha in 2020, which shows the value of strong and monitored public policies.
Since 1975, after the American embargo on soybeans, protein plans have followed one another. without the culture of protein crops becoming anchored in the landscapes. The directions taken with the 1992 CAP have contributed to to reduce surfaces, with more oriented support; towards cereals.
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This is a typical case of socio-technical lock-in, which explains the small surfaces of diversification crops: the whole system (research, varietal selection, seed production, collection and processing, agricultural advice) is organized and specialized around dominant cultures and tends to strengthen them to the detriment of diversification crops.
The sustainable establishment of legumes in the territories therefore also requires public policies encouraging all the actors concerned to engage in a coordinated way in a process of change.
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This article is produced by The Conversation and hosted by 20 Minutes.