Decomposition of litter mixtures induces non-additive effects on soil priming across a riparian land use gradient

Buchanan Serra-Willow, Sauvadet Marie, Isaac Marney E.. 2024. Decomposition of litter mixtures induces non-additive effects on soil priming across a riparian land use gradient. Soil Biology and Biochemistry, 190:109285, 8 p.

Résumé : While litter traits have been used for decades to predict decomposition rates through the Leaf Economics Spectrum (LES) acquisitive to conservative trait lens, litter trait and litter mixture effects on soil carbon (C) priming effects (PE) is less known. To assess whether the LES can predict soil C PE during the decomposition of litter mixtures from complex ecosystems, a 99-day incubation experiment was conducted. The experiment involved soil and leaf litter from three Canadian riparian land uses (grasslands, deciduous agroforests, and coniferous agroforests), incubated as single plant species, and as plant species mixtures in their natural proportions. Natural abundance δ13C-isotopic analysis was used to assess the proportion of CO2 derived from leaf litter versus soil C mineralization at initial (0–21 days, stage I) and later (22–99 days, stage II) stages of decomposition. Single species positions on the LES mirrored litter-C mineralization dynamics, yet PE emissions remained harder to predict with LES traits. Nonetheless, higher PE emissions relative to litter-C mineralization were observed with litter from LES species expressing conservative traits compared to LES species expressing acquisitive traits. Leaf litter mixtures from both agroforests, expressing high leaf litter trait functional dissimilarity, resulted in synergistic, non-additive effects on soil PE. These findings contribute to our understanding of the effects of leaf litter functional traits and trait mixing on soil PE, highlighting that mixed-species litter decomposition can lead to non-additive effects on soil C dynamics in forested riparian ecosystems.

Mots-clés Agrovoc : litière végétale, litière forestière, cycle du carbone, conservation des sols, dégradation, carbone organique du sol, utilisation des terres

Mots-clés géographiques Agrovoc : Canada

Mots-clés libres : 13C Natural abundance, Decomposition, Priming effect, Litter mixtures, Agroforestry, Leaf functional traits, C mineralization, Leaf economics spectrum

Classification Agris : P34 - Biologie du sol
P33 - Chimie et physique du sol

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

Agences de financement hors UE : Agriculture and Agri-Food Canada

Auteurs et affiliations

• Buchanan Serra-Willow, University of Toronto Scarborough (CAN)
• Sauvadet Marie, CIRAD-PERSYST-UMR Eco&Sols (FRA) ORCID: 0000-0002-7520-8565
• Isaac Marney E., University of Toronto Scarborough (CAN) - auteur correspondant

Source : Cirad-Agritrop (https://agritrop.cirad.fr/607720/)

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