To what extent are greenhouse-gas emissions offset by trees in a Sahelian silvopastoral system?

Agbohessou Yélognissè Frédi, Delon Claire, Mougin Eric, Grippa Manuela, Tagesson Torbern, Diedhiou Moussa, Ba Seydina, Ngom Daouda, Vezy Rémi, Ndiaye Ousmane, Assouma Mohamed Habibou, Diawara Mamadou Oumar, Roupsard Olivier. 2023. To what extent are greenhouse-gas emissions offset by trees in a Sahelian silvopastoral system?. Agricultural and Forest Meteorology, 343:109780, 14 p.

Résumé : To assess the extent to which trees in a semi-arid silvopastoral system (SPS) can offset the greenhouse-gas (GHG) emissions of the system's livestock, this study used two process-based models (STEP-GENDEC-N2O and DynACof) to simulate 9 years of agricultural activity and resulting emissions in a SPS that has been operating in sahelian Senegal. STEP-GENDEC-N2O simulated soil N2O and CO2 fluxes, plus growth of the herbaceous layer, while DynACof focused on the tree layer. Outputs from the models included simulated time series of vegetative growth, water fluxes, and emissions. This output was validated through the use of published data, and measurements that were made at the SPS. Overall, the outputs from STEP-GENDEC-N2O agreed well with validation data for water fluxes, soil N, soil C, herbaceous biomass, and N2O emissions. Good agreement was also found between the measured fluxes of the SPS ecosystem, and the simulated values that were generated by combining STEP-GENDEC-N2O's simulations (of the herbaceous layer's heterotrophic respiration, autotrophic respiration, and gross primary productivity (GPP)) with DynACof's simulations of the tree layer's autotrophic respiration and GPP. Among the insights gained from the simulations was that in this SPS's sandy soils, nitrification was the dominant process that leads to N2O emissions. Our results show that the trees, at their current density (81 ha−1) offset 18 % to 41 % of the GHG emissions from livestock. With further development, the model set-up can be used for estimating the GHG offset at other tree densities, and will be useful for guiding future policies regarding climate-change adaptation and mitigation in the management of the Sahel's SPSs.

Mots-clés Agrovoc : modèle de simulation, séquestration du carbone, changement climatique, agroforesterie, gaz à effet de serre, système sylvopastoral, évaluation de l'impact, atténuation des effets du changement climatique, cycle du carbone, matière organique du sol

Mots-clés géographiques Agrovoc : Sénégal, Sahel

Mots-clés libres : Silvopastoral systems, Greenhouse gas emissions, Livestock, Trees, Process-based model

Classification Agris : P40 - Météorologie et climatologie
F08 - Systèmes et modes de culture
L01 - Élevage - Considérations générales

Champ stratégique Cirad : CTS 6 (2019-) - Changement climatique

Agences de financement européennes : European Commission

Agences de financement hors UE : Svenska Forskningsrådet Formas, Swedish National Space Agency, H2020 Marie Skłodowska-Curie Actions

Programme de financement européen : H2020

Projets sur financement : (EU) Sequestration and Green-house Gas Emissions in (Agro) Sylvopastoral Ecosystems in the Sahelian CILSS States, (EU) Development Smart Innovation through Research in Agriculture

Auteurs et affiliations

• Agbohessou Yélognissè Frédi, CIRAD-PERSYST-UMR Eco&Sols (FRA)
• Delon Claire, Université Toulouse III Paul Sabatier (FRA) - auteur correspondant
• Mougin Eric, GET (FRA)
• Grippa Manuela, Université de Toulouse (FRA)
• Tagesson Torbern, Lund University (SWE)
• Diedhiou Moussa, CIRAD-PERSYST-UMR Eco&Sols (FRA)
• Ba Seydina, ISRA (SEN)
• Ngom Daouda, UCAD (SEN)
• Vezy Rémi, CIRAD-BIOS-UMR AMAP (FRA) ORCID: 0000-0002-0808-1461
• Ndiaye Ousmane, ISRA (SEN)
• Assouma Mohamed Habibou, CIRAD-ES-UMR SELMET (BFA) ORCID: 0000-0002-8163-0340
• Diawara Mamadou Oumar, USTTB (MLI)
• Roupsard Olivier, CIRAD-PERSYST-UMR Eco&Sols (SEN) ORCID: 0000-0002-1319-142X

Source : Cirad-Agritrop (https://agritrop.cirad.fr/608568/)

Métriques

[ Page générée et mise en cache le 2024-12-02 ]