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Fueling the energy transition with fossil (not quite) stranded assets
No full textInternational audienceThe energy transition is associated with many problems, not least the high requirement for raw materials to build the infrastructure needed to supply electricity from renewable sources. In addition, climate policies push out some fossil fuel power generation capacity, generating stranded assets. However, these decommissioned structures constitute a stock of scrap, from which raw materials can be recovered and recycled to build the new infrastructure for renewable energy. In this paper, we investigate whether such a recycling process could, first, contain the rise in the price of virgin minerals and second, ease the stranded assets phenomenon. To do so, we use a stylized dynamic model, featuring the brown capital decommissioning rate as a control variable: it reduces the brown stock available for energy production but also increases the scrap that offers recycling potential. We study the effect of such recycling on decommissioning and extraction strategies. We also show that the ability to recycle reduces the cost of getting rid of fossil fuels, thus bringing forward their phase-out
Property versus possession, ten years on: assessing the lexical impact of the 2015 JOIE debate
No full textInternational audienceThis Comment assesses the legacy of the 2015 JOIE debate, critiquing the economic conflation of de jure 'property' and de facto 'possession'. Citation analysis confirms the debate's sustained intellectual footprint, but this did not translate into the lexical shift advocated by its proponents. A text-mining analysis of 58 economics journals finds negligible adoption of the specific term 'possession'. A broader test for a conceptual basket of related de facto terms also fails to find robust evidence; a fragile signal in one dataset, not replicated in a second. We conclude that no significant, profession-wide lexical adoption occurred.</div
Spatial and temporal assessment of soil microbial respiration at microscale using proximal hyperspectral imaging
No full textInternational audienceThe study aimed to test the usefulness of the Hyperspectral imaging (HSI) in the visible and near infrared (VNIR) to address temporal and spatial variations in surface soil microbial respiration during an incubation. We hypothesized that VNIR HSI could show the heterogeneity and different evolutions of soil respiration between thermal stress and control conditions. Two mesocosms (≈1500 cm 2 ) were incubated 28 days under controlled conditions. Prior to incubation, one mesocosm was heat-stressed (stress), while the other was not (control). HS images of mesocosms (pixel resolution 0.18 × 0.36 mm) were acquired at several incubation dates. To calibrate respiration measurement of pixels, 56 standard samples were built and used as a calibration subterfuge to represent all conditions that would occur at the mesocosm surface in terms of straw cover, soil moisture, incubation date and consequences of initial thermal stress. Images of standard samples were acquired at the same dates than mesocosm images, just after CO 2 emitted by each standard sample (i.e. respiration) was measured. Partial least squares (PLS) regression was used to establish a cumulative respiration model based on the average spectra of each standard samples at each incubation date. The calibration and validation yielded R 2 = 0.88 and 0.85, respectively. The prediction model of respiration was applied on each pixel of the mesocosms and yielded prediction maps. The maps showed hotspots of respiration around plant residues surrounded by large areas of low respiration. The approach did not only contrast pieces of straw versus the soil matrix, but also hotspots with different evolutions. The effect of thermal stress on soil respiration patterns was not noticeable on mesocosms but was noted on standard samples with high straw cover. Further development of VNIR HSI at proximal scale should be encouraged to investigate the spatio-temporal processes of biological activity after a disturbance
DiaPhen_DataViz: Shiny R app for envirotyping and plant phenotyping data visualization and management
No full textDiaPhen platformInternational audienceDiaPhen_DataViz is a web-based application designed to support real-time data querying, pre-processing, and visualization of phenotyping and envirotyping data. The application is implemented in the R programming language and is developed using the Shiny framework. It is partially hosted on the SK8 project infrastructure and integrates with the INRAE OpenSILEX-PHIS information system, enabling advanced data management in compliance with FAIR principles.DiaPhen_DataViz est une application web conçue pour prendre en charge l’interrogation, le prétraitement et la visualisation en temps réel de données de phénotypage et d’envirotypage. L’application est implémentée en langage R et développée à l’aide du framework Shiny. Elle est partiellement hébergée sur l’infrastructure du projet SK8 et s’intègre au système d’information OpenSILEX-PHIS d’INRAE, permettant une gestion avancée des données conforme aux principes FAIR
Evaluation of upland rice variety mixtures in the Madagascar highlands
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616353/)International audienceContext or problem Madagascar heavily depends on rice for caloric intake, especially through irrigated farming. In the Vakinankaratra region, rainfed upland rice farming is an important complement but faces challenges such as poor soil fertility and vulnerability to pathogens like Pyricularia oryzae. Objective or research question To address these challenges, we evaluated extended elite lines upland rice varietal mixtures adapted to local conditions, focusing on yield performance, stability, and food security. Methods Four upland rice varieties: Chhomrong Dhan, FOFIFA 172, FOFIFA 173, and FOFIFA 180, well-suited to Madagascar's high-altitude climatic conditions and resistant to Pyricularia oryzae, were evaluated in three experiments conducted in the highlands of Madagascar between 2013 and 2017. The experimental design assessed all variety combinations, considering two treatment factors: 'mixture type' (ranging from pure stands to mixtures of all four varieties) and 'varietal composition' (15 modalities representing different varietal combinations). The analysis included the identification of the best-performing varietal compositions using a mixed-effects linear regression model and land equivalent ratio calculations. Results The analysis revealed that grain yield did not significantly differ among various mixture types, while varietal composition within mixtures had a highly significant effect. No mixture combination yielded more than the best varieties in pure stand although some matched their performance. Three combinations showed a significantly improved land equivalent ratio. Varieties differed in competitive abilities and trait plasticity. Conclusions Contrary to literature suggesting that increased diversity through varietal mixtures enhances production, the study found that the number of varieties in mixtures (mixture type) did not have significant effects. However, it appears possible to identify specific mixture combinations with strong mixing abilities. Implications This study evaluated mixtures of elite rice varieties that are currently available to farmers, under optimal fertility management. In these conditions, varietal mixtures did not demonstrate clear advantages over pure stands. However, results may differ under low-fertility conditions more representative of farmers' fields, or when using a broader genetic diversity. These scenarios warrant further investigation. In such contexts, varietal mixtures could complement other diversification strategies aimed at enhancing the resilience of agricultural systems, particularly in vulnerable regions such as the Madagascar Highlands
Diversité dans les systèmes pastoraux : perceptions et pratiques de gestion d’éleveurs ovins du sud de France
No full textInternational audienceContext: In a context of global change and increasing pressure on pastoral livestock systems, managing animal diversity is a central challenge for the sustainability of small-population flocks. The three local sheep breeds studied here, all endangered, represent an essential genetic and cultural heritage in Southern France. Objective: This article aims to analyse how breeders perceive, define, and manage diversity within their flocks, by examining the interplay between selection criteria, herd management practices, and conceptions of rusticity and animal behaviour. Methods: The study draws on an ethnographic approach combining 17 semi-structured interviews, and field observations with breeders involved in the conservation and valorisation of these local breeds. Qualitative analysis was used to identify the criteria mobilised in diversity management and to explore their articulation with breeders’ trajectories and farming conditions. Results: The selection of breeding animals is based on a combination of zootechnical criteria (conformation, breed standard), ecological criteria (adaptation to the environment, behaviour, rusticity), and personal criteria (attachments, individual preferences). The relative importance of these criteria varies according to breeders’ professional trajectories, environmental contexts, and socio-economic constraints. The analysis also highlights the central role of rusticity, understood as a dynamic quality shaped by management practices. Furthermore, day-to-day management practices (lambing periods, feeding strategies, mobility, flock organisation) also contribute to structuring diversity. Conclusions: The study offers an integrated interpretation of animal diversity that links local ecological knowledge, perceptions of animals, and herd management practices. It shows that diversity results from a co-construction between breeders, animals, and their environment, and underscores the importance of recognising these knowledge systems and practices in policies aimed at conserving local breeds.Contexto: En un contexto de cambios globales y presión creciente sobre la ganadería pastoral, la gestión de la diversidad animal representa un reto central para la sostenibilidad de los sistemas con pocos efectivos. Las tres razas ovinas locales estudiadas, todas ellas amenazadas, constituyen un patrimonio genético y cultural esencial en el sur de Francia. Objetivo: Este artículo tiene el objetivo de analizar cómo los ganaderos perciben, definen y gestionan la diversidad de sus rebaños, combinando criterios de selección, prácticas de manejo y concepciones de la rusticidad y del comportamiento animal. Métodos: El estudio se basa en un enfoque etnográfico que combina observaciones de terreno con 17 entrevistas semidirectivas a ganaderos comprometidos en la conservación y la valoración de estas razas locales. Los datos fueron analizados cualitativamente para identificar los criterios adoptados en la gestión de la diversidad y su articulación con las trayectorias de los ganaderos y las condiciones de cría. Resultados: La selección de los reproductores se basa en una combinación de criterios zootécnicos (conformación, estándar de la raza), ecológicos (adaptación al medio, comportamiento, rusticidad) y personales (vínculos, preferencias individuales). Estos criterios se jerarquizan según la historia profesional, el contexto medioambiental y las limitaciones socioeconómicas de los ganaderos. El análisis pone también en evidencia el rol central de la rusticidad, considerada como un constructo dinámico moldeado por las prácticas de conducción. Finalmente, las prácticas de gestión cotidianas (estacionalidad de las pariciones, alimentación, movilidad, organización del rebaño) también contribuyen a estructurar la diversidad. Conclusiones: El estudio propone una lectura integrada de la diversidad animal que combina saberes ecológicos locales, percepciones de los animales y prácticas de manejo. Muestra que la diversidad resulta de una construcción conjunta entre los ganaderos, los animales y el entorno, y destaca la importancia de reconocer estos saberes y prácticas en las políticas de conservación de las razas locales.Contexte : Dans un contexte de changements globaux et de pressions croissantes sur l’élevage pastoral, la gestion de la diversité animale représente un enjeu central pour la durabilité des systèmes à petits effectifs. Les trois races ovines locales étudiées, toutes menacées, constituent un patrimoine génétique et culturel essentiel dans le sud de la France. Objectif : Cet article vise à analyser comment les éleveurs perçoivent, définissent et gèrent la diversité au sein de leurs troupeaux, en articulant critères de sélection, pratiques de conduite et conceptions de la rusticité et des comportements animaux. Méthodes : L’étude repose sur une approche ethnographique combinant 17 entretiens semi-directifs et des observations de terrain auprès d’éleveurs engagés dans la conservation et la valorisation de ces races locales. Les données ont été analysées qualitativement afin d’identifier les critères mobilisés dans la gestion de la diversité et leur articulation aux trajectoires des éleveurs et aux conditions d’élevage. Résultats : La sélection des reproducteurs repose sur une combinaison de critères zootechniques (conformation, standard de la race), écologiques (adaptation au milieu, comportements, rusticité) et personnels (attachements, préférences individuelles). Ces critères se hiérarchisent selon l’histoire professionnelle, le contexte environnemental et les contraintes socio-économiques des éleveurs. L’analyse met également en évidence le rôle central de la rusticité, considérée comme un construit dynamique façonné par les pratiques de conduite. Enfin, les pratiques de gestion (agnelages, alimentation, mobilité, organisation du troupeau) contribuent elles aussi à structurer la diversité au quotidien. Conclusions : L’étude propose une lecture intégrée de la diversité animale articulant savoirs écologiques locaux, perceptions des animaux et pratiques de conduite. Elle montre que la diversité résulte d’une co-construction entre les éleveurs, les animaux et le milieu, et souligne l’importance de reconnaître ces savoirs et pratiques dans les politiques de conservation des races locales
Vacuum pyrolysis of olive pomace for biochar production: Enhancing carbon stability and soil nutrient supply
No full textInternational audienceOlive pomace (OP), a significant agro-industrial byproduct in Mediterranean countries, poses considerable disposal challenges and offers potential as a feedstock for engineered biochar production. Conventional pyrolysis of OP has been widely studied and often yields biochar with limited aromaticity and variable nutrient content. However, no prior work has explored the potential of vacuum pyrolysis for this residue. Addressing this research gap, this study investigates the use of vacuum pyrolysis (500 °C, 15–20 kPa, 2 h) to transform OP into a stable and nutrient-rich biochar. The process yielded 30.9 wt.% biochar with 68.7 % fixed carbon, representing an improvement of 20 % in carbon retention compared with atmospheric pyrolysis. Elemental ratios (H/C = 0.03 and O/C = 0.18) confirmed high aromaticity and long-term stability, while mineral enrichment underscored high agronomic value. The biochar displayed a cation exchange capacity of 56.2 cmolc/kg and 79 % porosity, properties favorable for nutrient cycling, and soil remediation. The carbon sequestration potential was estimated at 2.6 tCO₂eq per ton of biochar applied and heavy metals were below international thresholds, ensuring environmental safety. Beyond material characterization, the work highlights engineering advantages, including reduced inert gas requirements and a reusable syngas fraction (64.6 wt.%) that can offset energy costs. However, as the study was conducted at a single pressure level, the specific contribution of vacuum conditions requires further confirmation through multi-pressure trials. Such results position vacuum pyrolysis as a promising technology for waste valorization, carbon management, and climate-smart agriculture, while future research should address field validation, contaminant screening, and life-cycle performance
Context dependency of tree diversity effects on standardized substrates decomposition: Role of tree functional composition, mycorrhizal type and climatic conditions
No full textInternational audienceTree diversity influences litter decomposition both directly, through changes in litter quality and composition, and indirectly, by altering the local decomposition environment (LDE). However, the role of the LDE in shaping litter decomposition rates remains less explored than the direct effects. A standardized decomposition experiment using cellulose and wood substrates was conducted over the course of a year across seven tree diversity experiments in Europe and North America to explore how tree diversity, through its influence on the LDE, impacts decomposition rates. Tree functional diversity enhanced the decomposition rate of high‐quality substrate (cellulose) but had no effect on the decomposition rate of low‐quality substrate (wood). The impact of LDE was context‐dependent, with decomposition rates being highest under favourable climatic conditions, such as moderate temperatures and high precipitation. Contrary to the common assumption that litter decomposes faster in broadleaved and arbuscular (AM)‐dominated stands, our findings show that decomposition was faster in mixtures containing coniferous species and ectomycorrhizal (EM)‐associated trees, suggesting that LDE plays a larger role than initially thought. Synthesis . This study highlights the crucial role of LDE in shaping decomposition rates. While tree functional diversity generally enhances decomposition under favourable climatic conditions, LDE played a more significant role than previously recognized in EM stands, suggesting that faster decomposition rates in AM stands are primarily due to litter quality. These findings emphasize the context‐dependent nature of decomposition and the importance of considering LDE in understanding how tree diversity influences decomposition processes
Impact of wheat-legume mix intercrops on wheat epidemics by modelling
No full textInternational audienceHighlights: • Simulated intercropping decrease disease intensity and improve protectiveness while canopy indicators predict such effects. • Pea intercropped with wheat decreased disease intensity compared with faba bean. • Nitrogen fertilization increased disease intensity. • This study stressed the critical lack of experimental data on disease in intercropping.Abstract: Context : Intercropping is a promising strategy for integrated disease management and agroecological transition, although experimental and modelling studies are scarce.Objectives: This study aims to understand and quantify the impact of non-host species choice and nitrogen (N) fertilization on disease epidemics in the context of intercropping.Methods: We collected existing experimental data on LAI based on a literature survey of non-diseased wheat intercropped with different non-host legume species (pea and faba bean) and N fertilization treatments. Based on a foliar epidemic model for intercropping, we simulated epidemics directly on these experimental data of LAI. The model is parameterized for two wheat fungal diseases: Septoria tritici blotch, a rain-borne disease, and wheat leaf rust, an air-borne disease.Results: Our results indicate that intercropping can decrease disease intensity and improve protectiveness for both diseases. Effect depends however on species choice as pea intercropped with wheat leads to lower disease intensity and better intercropping protectiveness compared with faba bean, whereas N fertilization increased disease intensity. We also found that crop indicators describing wheat leaf area index (LAI) can predict disease intensity, whereas indicators describing companion LAI can better predict intercropping protectiveness.Conclusions: Intercropping can significantly reduce fungal epidemics on wheat, and intercropping management practices can be optimized for effective disease management in wheat-legume intercrops. The dilution effect is more related to disease intensity, while the barrier effect is more related to intercropping protectiveness.Implications: These findings pave the way for identifying field indicators to predict epidemics. However, this study also stressed the critical lack of experimental data on disease in intercropping
RECHARGE, a model of potential recharge of aquifers applied to mainland France
No full textInternational audienceCalculating aquifer recharge provides a means of estimating the renewable fraction of groundwater resources, which is often difficult to quantify. This paper introduces the RECHARGE method, developed to calculate potential groundwater recharge from precipitation infiltration, and its application across mainland France over an extended historical period.The method relies on a simple soil water budget approach to estimate effective precipitation, using meteorological data and a spatial parameter that accounts for land cover and allows the seasonal variability of evapotranspiration to be reflected. An effective precipitation infiltration ratio (EPIR) is then derived for catchments with homogeneous geological lithology, based on linear regressions involving the baseflow index and a GIS-derived parameter. Given the low interannual variability of the baseflow index, the EPIR is assumed to remain constant over time and is subsequently used to convert effective precipitation into potential recharge at the scale of all groundwater bodies in mainland France.To validate this approach, annual effective precipitation estimates were compared for 556 selected catchments, both with observed annual river flows and with outputs from the physically based SURFEX model. The calculated potential recharge was also evaluated at both annual and seasonal scales for the entire French territory, using SURFEX as a reference. Results demonstrate that the RECHARGE model can effectively estimate annual and seasonal potential aquifer recharge. It is suitable for large-scale applications without requiring detailed knowledge of aquifer properties. Future improvements are envisioned, particularly to enhance monthlyscale accuracy in mountainous regions.</p