Les pratiques culturales : couvert hivernal sur les sols agricoles en France
En hiver, les sols nus peuvent être soumis à des phénomènes de dégradations physiques (semelle de labour, tassement, ruissellement et érosion), de perturbations de la biodiversité qu’ils hébergent, d’accélération du déstockage de carbone et de lessivage des reliquats d’azote. Le maintien d’un couvert végétal en hiver, comme le non labour ou le semis direct, permettent de limiter ces inconvénients ; il s’agit de fait d’une pratique culturale favorable à l’environnement. Elle favorise toutefois le tassement du sol, la prolifération de mauvaises herbes et des insectes ravageurs, impliquant un recours éventuel aux pesticides
In winter, bare soils can undergo physical degradation (compacted layer, compaction, runoff and erosion), disruption of hosted biodiversity, accelerated carbon loss and nitrogen leaching. Maintaining winter vegetation cover, such as through no-till or direct sowing, helps limit these drawbacks; in fact this represents an environmentally favorable farming practice. However, it can promote soil compaction, weed proliferation and pest insects, potentially requiring pesticide use.
- Major crops sown without prior tillageTillage effectsTillage significantly affects soils: physical degradation (compacted layer, compaction, runoff and erosion), disruption of biodiversity, accelerated carbon loss and nitrate leaching.No-till techniques• No-till techniques include both simplified cultivation techniques with shallow soil disturbance and direct sowing without any soil cultivation. These conservation techniques contribute to environmental protection and more sustainable agricultural production. They enable: • protecting soils from erosion by maintaining quasi-permanent vegetation cover; • reducing input use and associated pollution; • preserving soil biological activity. • However, biological tillage, replacing physical tillage, may take several years to become effective. In the first years of implementing a no-till farming approach, weed management can become more challenging. Adjusting crop rotations helps manage this.No-till area trends• In 2017, 47% of major crop areas in France were managed without prior tillage. These areas more than doubled since 2001 (21%). Overall, no-till techniques continue expanding across all major crops. Tillage remains more prevalent on spring crops than autumn crops. • Direct sowing increased 4 percentage points between 2011 (2%) and 2017 (6%).
- Major crop soils left bare in winterMajor crop areaIn 2017, agricultural operators cultivated over 13 million hectares in major crops (cereals, oilseeds, protein crops, potatoes, industrial crops including fallow land), representing 46% of utilized agricultural land.Winter preceding cropsOne-third of these major crops are sown in spring, of which 61% benefited from a preceding winter crop. These may include catch crops (nitrogen traps) (44% cruciferous), harvested intermediate crops, energy-use intermediate crops or crop residues.Bare winter soil trendsIn 2017, 14% of spring crop parcels remained bare in winter compared to 17% in 2014 and 20% in 2011. This mainly affects southern France (except the Provence-Alpes-Côte d'Azur region).
Further reading
- Service de la donnée et des études statistiques : Sols et sous-solsnotre-environnement.gouv.fr
Les sols se situent au cœur des grands enjeux environnementaux, comme la disponibilité en eau de qualité, la préservation de la biodiversité, la sécurité alimentaire ou la lutte contre le changement climatique, et ne se renouvellent que très lentement.
- Ministère de l’Agriculture et de l’Alimentationnotre-environnement.gouv.fr
En France, le ministère de l’Agriculture et de l'Alimentation est l’administration chargée de la politique agricole, halieutique, alimentaire et forestière.
