Dr Rémi Cardinael1,2,3, Dr Kevin Hoeffner4, Pr Claire Chenu3, Dr Tiphaine Chevallier2, Camille Béral5, Antoine Dewisme4, Dr Daniel Cluzeau4
1Cirad – UR AIDA, Montpellier, France, 2IRD – UMR Eco&Sols, Montpellier, France, 3AgroParisTech – UMR Ecosys, Thiverval-Grignon, France, 4Univ-Rennes – UMR Ecobio, Rennes, France, 5Agroof, Anduze, France
The aim of this study was to assess how soil organic C (SOC) stocks and earthworm communities were modified in agroforestry systems compared to treeless control plots, and within the agroforestry plots (tree rows vs alleys). We used a network of 13 silvoarable agroforestry sites in France along a North/South gradient. Total earthworm abundance and biomass were significantly higher in the tree rows than in the control plots, but were not modified in the alleys compared to the control plots. Earthworm species richness, Shannon index, and species evenness were significantly higher in the tree rows than in the alleys. Total abundance of epigeic, epi-anecic, strict anecic and endogeic was higher in the tree rows. Surprisingly, earthworm individual weight was significantly lower in the tree rows than in the alleys and in the control plots. SOC stocks were significantly higher in the tree rows compared to the control plots across all sites. Despite higher SOC stocks in the tree rows, the amount of available C per earthworm individual was lower compared to the control. The absence of disturbance (no tillage, no fertilizers, no pesticides) in the tree rows rather than increased SOC stocks therefore seems to be the main factor explaining the increased total abundance, biomass, and diversity of earthworms. The observed differences in earthworm communities between tree rows and alleys may lead to modified and spatially structured SOC dynamics within agroforestry plots.
Professor of Soil Science at AgroParisTech