Root distribution and properties of a young alley-cropping system: effects on soil carbon storage and microbial activity

Siegwart Lorène, Jourdan Christophe, Piton Gabin, Sugihara Soh, Van Den Meersche Karel, Bertrand Isabelle. 2023. Root distribution and properties of a young alley-cropping system: effects on soil carbon storage and microbial activity. Plant and Soil, 482 (1-2) : 601-625.

Résumé : Purpose: In agroforestry systems, the root distributions and properties of the annual and perennial vegetation are poorly known, although they are recognized for fostering soil carbon (C) stocks through annual root-derived C inputs and by altering microbial activity. This study aimed to evaluate the potential contribution of roots from the understory vegetation strip (UVS) and the crop to top- and subsoil C stocks (0–100 cm) to a 3-year-old agroforestry system of the alley-cropping type. Methods: Root biomass, chemical composition, functional traits and anatomical structure were assessed in parallel to a characterization of soil physicochemical and microbiological properties, including enzymatic activity, at different depths and locations perpendicular to the tree line. Results: The root biomass and properties were heterogeneous in the young alley-cropping system due to the presence of different plant communities and the heterogeneity of the soil mineral N content according to the location perpendicular to the tree line. The soil microbiological properties and organic C stocks did not vary horizontally at this stage of agroforestry but should be monitored through multiple-time samples to confirm a differentiation in subsequent years suggested by the tight link between root stoichiometry and microbial extracellular enzymatic activities that we found. Conclusions: Altogether, our results suggested that increasing the root biomass in topsoil in agroforestry systems positively contributes to increasing soil organic C stocks, but in deeper soil layers, an increase in litter inputs with a high C:N ratio might accentuate microbial N limitations and limit soil C storage.

Mots-clés Agrovoc : agroforesterie, système racinaire, microbiologie, propriété physicochimique du sol, activité enzymatique, teneur en éléments minéraux, légume racine, caractéristiques du sol, stockage, séquestration du carbone, structure chimique, systèmes agroforestiers, enracinement, charbon actif

Mots-clés libres : Agroforestry, Soil organic carbon stocks, Root functional traits, Root-derived carbon inputs, Soil enzymatic stoichiometry

Classification Agris : P33 - Chimie et physique du sol
P34 - Biologie du sol
F08 - Systèmes et modes de culture

Champ stratégique Cirad : CTS 2 (2019-) - Transitions agroécologiques

Agences de financement hors UE : Total Foundation, Agropolis Fondation, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

Projets sur financement : (FRA) Dynamics of Soil Carbon Sequestration in Tropical and Temperate Agricultural systems

Auteurs et affiliations

• Siegwart Lorène, CIRAD-PERSYST-UMR Eco&Sols (FRA)
• Jourdan Christophe, CIRAD-PERSYST-UMR Eco&Sols (FRA) ORCID: 0000-0001-9857-3269
• Piton Gabin, Université de Montpellier (FRA)
• Sugihara Soh, University of Tokyo (JPN)
• Van Den Meersche Karel, CIRAD-PERSYST-UMR Eco&Sols (FRA) ORCID: 0000-0002-0866-7657
• Bertrand Isabelle, INRAE (FRA)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/604642/)

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