Reduction of pesticide use can increase earthworm populations in wheat crops in a European temperate region

Céline Pélosi (1) , Lucile Toutous (1) , François Chiron (2) , Florence Dubs (3) , Mickael Hedde (4) , Audrey Muratet (5) , Jean-François Ponge (6) , Sandrine Salmon (6) , David Makowski (7)

1 PESSAC
2 CERSP - Conservation des espèces, Restauration et Suivi des Populations
3 Bioemco - Biogéochimie et écologie des milieux continentaux
4 PESSAC - Physicochimie et Ecotoxicologie des SolS d'Agrosystèmes Contaminés
5 ODBU - Observatoire départemental de la Biodiversité urbaine
6 MAOAC - Mécanismes adaptatifs : des organismes aux communautés
7 Agronomie

Agricultural intensification has led to reduced soil biodiversity in arable lands. The potential benefits from organic farming and from low-input cropping systems have not yet been precisely assessed. Earthworm, having important agro-ecological functions, may be affected by pesticide applications, especially those species living mainly in the surface soil layer. We used a five-year experimental database including conventional and organic cropping systems to establish simple relationships between the Treatment Frequency Index - a phytosanitary indicator of pesticide pressure - and the abundance of three important earthworm species. We found that insecticides have more negative influence on earthworm species than herbicides and fungicides, and that species living in the soil's surface layer were the most affected by pesticides. Density of these earthworm species could be multiplied by a factor 1.5-4 if the Treatment Frequency Index was halved, as is currently required by some European regulations. Our results thus demonstrate that a reduction in pesticide application would increase earthworm population density in agricultural fields.

Mots clés: Organic farming; Treatment Frequency Index; Earthworm density; Pesticides; Conventional cropping system

Domaines: Science des sols

Céline Pélosi, Lucile Toutous, François Chiron, Florence Dubs, Mickael Hedde, et al.. Reduction of pesticide use can increase earthworm populations in wheat crops in a European temperate region. Agriculture, Ecosystems & Environment, 2013, 181, pp.223-230. ⟨10.1016/j.agee.2013.10.003⟩. ⟨hal-00904152⟩