[hal-04321742] The interplay between microbial communities and soil properties
In recent years, there has been considerable progress in determining the soil properties that influence the structure of the soil microbiome. By contrast, the effects of microorganisms on their soil habitat have received less attention with most previous studies focusing on microbial contributions to soil carbon and nitrogen dynamics. However, soil microorganisms are not only involved in nutrient cycling and organic matter transformations but also alter the soil habitat through various biochemical and biophysical mechanisms. Such microbially mediated modifications of soil properties can have local impacts on microbiome assembly with pronounced ecological ramifications. In this Review, we describe the processes by which microorganisms modify the soil environment, considering soil physics, hydrology and chemistry. We explore how microorganism-soil interactions can generate feedback loops and discuss how microbially mediated modifications of soil properties can serve as an alternative avenue for the management and manipulation of microbiomes to combat soil threats and global change.
email@example.com (Laurent Philippot) 04 Dec 2023
[hal-04321684] Assessing the Potential Ecotoxicological Risk of Different Organic Amendments Used in Agriculture: Approach Using Acute Toxicity Tests on Plants and Earthworms
In Europe, spreading organic wastes to fertilize soils is an alternative commonly used instead of chemical fertilizers. Through their contributions of nutrients and organic matter, these wastes promote plant growth and thus agricultural production. However, these organic amendments can also contain mineral and organic pollutants requiring chemical and ecotoxicological analyses to guarantee their harmlessness on soil and its organisms during spreading. The purpose of this study was to assess the potential toxicity of three organic amendments from diferent sources (sewage sludge, dairy cow manure, dairy cow slurry) by performing chemical analyses and acute toxicity tests on three types of organism: earthworms, plants, soil microbial communities. Chemical analysis revealed a higher content of certain pharmaceuticals, polycyclic aromatic hydrocarbons and metals in sewage sludge in comparison with the two other types of organic wastes. The ecotoxicological assessment showed a dose-dependent efect on soil organisms for the three organic amendments with higher toxic efects during the exposure tests with a soil amended with dairy cow slurry. However, at realistic spreading doses (10 and 20 g kg−1 dry weight of organic amendments) on a representative exposed soil, organic amendment did not show any toxicity in the three organisms studied and had positive efects such as increased earthworm biomass, increased plant root growth and earthworm behavior showing attraction for organic amendment. On the contrary, exposure assays carried out on a limited substrate like sandy soil showed increased toxicity of organic amendments on plant germination and root growth. Overall,bthe ecotoxicological analysis revealed greater toxicity for soil organisms during the amendment of cow slurry, contrary to the chemical analysis which showed the potential high risk of spreading sewage sludge due to the presence of a higher quantity of pollutants. The analysis of the chemical composition and use of acute toxicity tests is the frst essential step for assessing the ecotoxicological risk of spreading organic amendments on soil organisms. In addition to standard tests, the study suggests using a representative soil in acute toxicity tests to avoid overestimating the toxic efects of these organic amendments.
firstname.lastname@example.org (Olivier Roques) 04 Dec 2023
[hal-04314568] Recycling wastes to mitigate trace elements contamination in plants: a new horizon for urban agriculture in polluted soils
Urban agriculture development often faces the problem of soil pollution. Soil engineering consisting in the addition over polluted soils of a top layer made of recycled wastes is a promising solution. This study was co-constructed with urban farmers and aimed at testing in situ the feasibility of growing vegetables safe for consumption in substrates consisting of organic and inorganic waste, directly overlaying soil polluted by trace elements (TE). Two plants were tested: radishes and tomatoes. Three substrates were tested: 1) sheep manure mixed with composted ramial chipped wood (SHW); 2) biowaste compost mixed with mushroom compost and ramial chipped wood (BMW); and 3) deep excavated subsoils mixed with green waste compost (EXC). Only radishes grown in EXC presented levels of TE below the threshold values. For all the other cases, cadmium levels were above the threshold values. This result concerning plant contamination by TE is consistent with a contamination of SHW and BMW substrates by the polluted soil underneath. EXC contained lower TE content, suggesting that mineral materials limited the transfer from the polluted soil towards the substrate overlay. We concluded that adding a combination of mineral and organic waste on top of polluted soils may better mitigate vegetables contamination than adding only organic waste. However, this result was not observed for all tested vegetables. More research is needed to evaluate the best substrate candidate and its adequate thickness, to study its physico-chemical evolution over a longer period of time and to test a larger panel of vegetables.
email@example.com (Anne Barbillon) 29 Nov 2023
[hal-04312284] Microbioterre : référencer des indicateurs de microbiologie des sols et les intégrer dans l’analyse de terre de routine, pour améliorer la gestion des apports de matières organiques au champ
La transition agroécologique des systèmes en grandes cultures nécessite d’optimiser les pratiques permettant à la fois i) de stocker du carbone dans le sol sur le long terme et ii) d’augmenter la fourniture de nutriments aux cultures. Les outils de diagnostic en laboratoire manquent encore pour que les agriculteurs puissent évaluer la capacité du sol à assurer ces deux fonctions afin de les optimiser. Microbioterre vise à référencer des indicateurs analytiques de microbiologie des sols en lien avec les cycles du carbone et de l’azote (« bioindicateurs »), les plus matures scientifiquement et techniquement. L’objectif est de pouvoir les utiliser en routine comme des outils de pilotage de pratiques culturales. Le projet a évalué comment ces bioindicateurs répondent à différents modes de gestion des matières organiques en grandes cultures et en polyculture-élevage à partir de mesures dans des essais de moyenne-longue durée dans des systèmes de production diversifiés, et d’analyses bibliographiques. Les relations entre ces indicateurs et, d’une part les fonctions des sols et, d’autre part les pratiques culturales étudiées, ont aussi été explicitées. Un guide pratique sur ces bioindicateurs et leur interprétation pour le diagnostic est proposé à destination des conseillers agricoles et agriculteurs ainsi que différents modules de formation.
firstname.lastname@example.org (Perrin Anne-Sophie) 28 Nov 2023
[hal-04307935] Soil Carbon Sequestration: Much More Than a Climate Solution
email@example.com (Budiman Minasny) 26 Nov 2023
[hal-04302997] Modeling the Impact of Proportion, Sowing Date, and Architectural Traits of a Companion Crop on Foliar Fungal Pathogens of Wheat in Crop Mixtures
Diversification of cropping systems is a lever for the management of epidemics. However, most research to date has focused on cultivar mixtures, especially for cereals, even though crop mixtures can also improve disease management. To investigate the benefits of crop mixtures, we studied the effect of different crop mixture characteristics (i.e., companion proportion, sowing date, and traits) on the protective effect of the mixture. We developed a SEIR (Susceptible, Exposed, Infectious, Removed) model of two damaging wheat diseases ( Zymoseptoria tritici and Puccinia triticina), which were applied to different canopy components, ascribable to wheat and a theoretical companion crop. We used the model to study the sensitivity of disease intensity to the following parameters: wheat-versus-companion proportion, companion sowing date and growth, and architectural traits. For both pathogens, the companion proportion had the strongest effect, with 25% of companion reducing disease severity by 50%. However, changing companion growth and architectural traits also significantly improved the protective effect. The effect of companion characteristics was consistent across different weather conditions. After decomposing the dilution and barrier effects, the model suggested that the barrier effect is maximized for an intermediate proportion of companion crop. Our study thus supports crop mixtures as a promising strategy to improve disease management. Future studies should identify real species and determine the combination of host and companion traits to maximize the protective effect of the mixture.
firstname.lastname@example.org (Sébastien Levionnois) 23 Nov 2023
[hal-04300094] Four-component net radiometers to quantify albedo and heat fluxes in conservation agriculture
email@example.com (Souleymane Diop) 22 Nov 2023
[hal-04300057] River ecosystem metabolism and carbon biogeochemistry in a changing world
River networks represent the largest biogeochemical nexus between the continents, ocean and atmosphere. Our current understanding of the role of rivers in the global carbon cycle remains limited, which makes it difficult to predict how global change may alter the timing and spatial distribution of riverine carbon sequestration and greenhouse gas emissions. Here we review the state of river ecosystem metabolism research and synthesize the current best available estimates of river ecosystem metabolism. We quantify the organic and inorganic carbon flux from land to global rivers and show that their net ecosystem production and carbon dioxide emissions shift the organic to inorganic carbon balance en route from land to the coastal ocean. Furthermore, we discuss how global change may affect river ecosystem metabolism and related carbon fluxes and identify research directions that can help to develop better predictions of the effects of global change on riverine ecosystem processes. We argue that a global river observing system will play a key role in understanding river networks and their future evolution in the context of the global carbon budget.
firstname.lastname@example.org (Tom Battin) 22 Nov 2023
[hal-04300044] Accurate evaluation of the Birch effect requires continuous CO2 measurements and relevant controls
The influence of dry-wet cycles (DWC) on soil organic carbon (SOC) decomposition is still debated given the somehow controversial results observed in the literature. The objective of this study was to evaluate the effects of DWC on SOC mineralization relative to various moisture controls in 7 treatments from two long-term French field experiments presenting contrasted SOC concentrations. A laboratory incubation was conducted for 97 days to quantify CO2 emissions upon four soil moisture scenarios: continuously wet scenario at pF 1.5 (WET), continuously moderate wet scenario at pF 2.5 (MWET), continuously dry scenario at pF 4.2 (DRY) and dry-wet cycles (DWC) between pF 1.5 and 4.2. Each cycle contained two phases, 10 days of drying phase, followed by 7 days of moist phase after rewetting. The drying phase consisted of adding silica gel to the incubation jars to absorb water in the soil and then gradually drying the soil. We also calculated the SOC mineralization that would correspond to the average water content in DWC (mean_DWC). Our results showed that across all treatments the daily carbon mineralization rate increased with soil moisture (WET > MWET > DRY). In DWC scenario, mineralization rates fluctuated with the changes in soil moisture. As soils dried, daily mineralization rates decreased and the subsequent soil rewetting, to pF 1.5, caused a rapid mineralization flush or "Birch effect". However, these flushes did not compensate for the low mineralization rates in the drying phase as the cumulative mineralization was not higher in the DWC scenario compared to the mean_DWC which was the scenario with equivalent water content as the DWC. We also observed that not accounting the CO2 emissions in the drying phase, could lead to an overestimation of the effect of DWC. We recommend to measure continuously the soil respiration during dry-wet experiments and to compare the CO2 emitted in DWC with a control that has a water content equivalent to the average water content in DWC. In addition, we questioned the importance of the effect of DWC on overall soil respiration.
email@example.com (Tchodjowiè P.I. Kpemoua) 22 Nov 2023
[hal-04300031] Supply costs, energy use, and GHG emissions of biomass from marginal lands in Brittany, France
Growing energy crops on marginal lands is an option to increase current bioresources while avoiding the food vs fuel dilemma. Yet, little is known about the extent and characteristics of marginal lands, and about how growing energy crops on such lands will impacts productivity, supply chains, and the environment. This study combined a geographic information system, a crop growth model, life cycle assessment, and a logistics model to (i) quantify and map marginal lands (ii) estimate the yields of miscanthus grown thereon (iii) assess the impact on supply chain and the environment of miscanthus from marginal lands in Brittany. Three miscanthus harvest forms (chips, bundles, and bales) and three logistics scenarios (no storage, one storage point, and two storage points) were studied. It showed that 57544 ha of marginal lands are available in Brittany and that rooting (55%) and salinity (34%) were the dominant marginality factors of these lands. Miscanthus yields on these lands varied from 0 to 21 t DM ha-1 y-1, depending on marginality constraints. Despite the low energy use (311-604 MJ t-1 DM) and GHG emissions (6-19 kg CO2-eq t-1 DM), the delivery costs were too high (81-108 euro t-1 DM). Bales were the cheapest and most environmental-friendly biomass form, as was the logistics configuration with no storage point. Sourcing biomass from marginal lands offers a solution for sustainable biofuel production in Brittany. However, economic incentives are needed to encourage production on marginal lands given the high delivery costs of biomass.
firstname.lastname@example.org (Sylvestre Njakou Djomo) 22 Nov 2023
[hal-04300015] Estimating ecosystem evaporation and transpiration using a soil moisture coupled two-source energy balance model across FLUXNET sites
The two-source energy balance model coupled with soil moisture (TSEB-SM) was evaluated against observations from a global set of 57 eddy covariance (EC) sites, part of the FLUXNET2015 dataset. In addition, modeled soil evaporation (E) and transpiration (T) were compared with the values obtained from the Transpiration Estimation Algorithm (TEA) and underlying water use efficiency (uWUE) approaches. The TSEB-SM model framework using near-surface soil moisture improved the agreement to EC-observed sensible and latent heat fluxes, reducing mean absolute percentage error (MAPE) by about 30% and root mean square error (RMSE) by about 44 W/m2 across all sites. The results show that the advantage of the TSEB-SM model, with respect to the original TSEB, becomes more evident as the ratio of actual to potential evapotranspiration (AET/PET) decreases. The E and T produced by TSEB-SM has better correlation with the results of uWUE partitioning than TSEB, especially under low soil water content condition. Likewise, TSEB-SM is superior to TSEB in simulating T when compared with sap flow measurements derived from the SAPFLUXNET database. These results imply that the development and appli-cation of TSEB-SM has made significant advances in modeling surface water fluxes, even though uncertainties remain. The approach used in TSEB-SM, driving the model with an extensive remotely sensed parameter set, gives valuable information on water use and provides an alternative to Global Climate Models where complex interactions of ecosystems are parametrized. Thus, TSEB-SM provides a unique insight into the flow of energy and the role of surface fluxes in the global water cycle.
email@example.com (Kejia Xue) 22 Nov 2023
[hal-04296774] Editorial trend: adverse outcome pathway (AOP) and computational strategy — towards new perspectives in ecotoxicology
The adverse outcome pathway (AOP) has been conceptualized in 2010 as an analytical construct to describe a sequential chain of causal links between key events, from a molecular initiating event leading to an adverse outcome (AO), considering several levels of biological organization. An AOP aims to identify and organize available knowledge about toxic effects of chemicals and drugs, either in ecotoxicology or toxicology, and it can be helpful in both basic and applied research and serve as a decision-making tool in support of regulatory risk assessment. The AOP concept has evolved since its introduction, and recent research in toxicology, based on integrative systems biology and artificial intelligence, gave it a new dimension. This innovative in silico strategy can help to decipher mechanisms of action and AOP and offers new perspectives in AOP development. However, to date, this strategy has not yet been applied to ecotoxicology. In this context, the main objective of this short article is to discuss the relevance and feasibility of transferring this strategy to ecotoxicology. One of the challenges to be discussed is the level of organisation that is relevant to address for the AO (population/community). This strategy also offers many advantages that could be fruitful in ecotoxicology and overcome the lack of time, such as the rapid identification of data available at a time t, or the identification of “data gaps”. Finally, this article proposes a step forward with suggested priority topics in ecotoxicology that could benefit from this strategy.
firstname.lastname@example.org (Damien Baudiffier) 20 Nov 2023
[hal-04283669] Using Machine-Learning Algorithms to Predict Soil Organic Carbon Content from Combined Remote Sensing Imagery and Laboratory Vis-NIR Spectral Datasets
Understanding spatial and temporal variability in soil organic carbon (SOC) content helps simultaneously assess soil fertility and several parameters that are strongly associated with it, such as structural stability, nutrient cycling, biological activity, and soil aeration. Therefore, it appears necessary to monitor SOC regularly and investigate rapid, non-destructive, and cost-effective approaches for doing so, such as proximal and remote sensing. To increase the accuracy of predictions of SOC content, this study evaluated combining remote sensing time series with laboratory spectral measurements using machine and deep-learning algorithms. Partial least squares (PLS) regression, random forest (RF), and deep neural network (DNN) models were developed using Sentinel-2 (S2) time series of 58 sampling points of bare soil and according to three approaches. In the first approach, only S2 bands were used to calibrate and compare the performance of the models. In the second, S2 indices, Sentinel-1 (S1) indices, and S1 soil moisture were added separately during model calibration to evaluate their effects individually and then together. In the third, we added the laboratory indices incrementally and tested their influence on model accuracy. Using only S2 bands, the DNN model outperformed the PLS and RF models (ratio of performance to the interquartile distance RPIQ = 0.79, 1.36 and 1.67, respectively). Additional information improved performances only for model calibration, with S1 soil moisture yielding the most stable improvement among three iterations. Including equivalent indices of the S2 indices calculated using soil spectra obtained under laboratory conditions improved prediction of SOC, and the use of only two indices achieved good validation performances for the RF and DNN models (mean RPIQ = 2.01 and 1.77, respectively).
email@example.com (Hayfa Zayani) 14 Nov 2023
[hal-04279293] Genome editing and acknowledgment of public awareness
When announcements by molecular biologists and the biotechnology sector are received negatively by the general public or policy makers, the fault is generally ascribed to a general ignorance of science. This short commentary argues that, on the contrary, the problem may be that an influential portion of the public is actually too well informed to accept blindly what they are told. This awareness does not come from scholarly publications or the media, but more likely from a series of influential books and magazine articles that for the last 3 decades have promulgated a view of molecular biology that diverges strongly from what is generally presented. The actual level of public awareness needs to be taken into account to develop an optimal communication strategy for the discipline.
firstname.lastname@example.org (Philippe Baveye) 10 Nov 2023
[hal-04266868] Impact of a large-scale replacement of maize by soybean on water deficit in Europe
email@example.com (Ronny Lauerwald) 31 Oct 2023
[hal-04233219] Temperature extremes of 2022 reduced carbon uptake by forests in Europe
Abstract The year 2022 saw record breaking temperatures in Europe during both summer and fall. Similar to the recent 2018 drought, close to 30% (3.0 million km 2 ) of the European continent was under severe summer drought. In 2022, the drought was located in central and southeastern Europe, contrasting the Northern-centered 2018 drought. We show, using multiple sets of observations, a reduction of net biospheric carbon uptake in summer (56-62 TgC) over the drought area. Specific sites in France even showed a widespread summertime carbon release by forests, additional to wildfires. Partial compensation (32%) for the decreased carbon uptake due to drought was offered by a warm autumn with prolonged biospheric carbon uptake. The severity of this second drought event in 5 years suggests drought-induced reduced carbon uptake to no longer be exceptional, and important to factor into Europe’s developing plans for net-zero greenhouse gas emissions that rely on carbon uptake by forests.
firstname.lastname@example.org (Auke van der Woude) 31 Oct 2023
[hal-04241644] Heterologous Expression and Biochemical Characterization of a New Chloroperoxidase Isolated from the Deep-Sea Hydrothermal Vent Black Yeast Hortaea werneckii UBOCC-A-208029
The initiation of this study relies on a targeted genome-mining approach to highlight the presence of a putative vanadium-dependent haloperoxidase-encoding gene in the deep-sea hydrothermal vent fungus Hortaea werneckii UBOCC-A-208029. To date, only three fungal vanadium-dependent haloperoxidases have been described, one from the terrestrial species Curvularia inaequalis, one from the fungal plant pathogen Botrytis cinerea , and one from a marine derived isolate identified as Alternaria didymospora . In this study, we describe a new vanadium chloroperoxidase from the black yeast H. werneckii , successfully cloned and overexpressed in a bacterial host, which possesses higher affinity for bromide (K m = 26 µM) than chloride (K m = 237 mM). The enzyme was biochemically characterized, and we have evaluated its potential for biocatalysis by determining its stability and tolerance in organic solvents. We also describe its potential three-dimensional structure by building a model using the AlphaFold 2 artificial intelligence tool. This model shows some conservation of the 3D structure of the active site compared to the vanadium chloroperoxidase from C. inaequalis but it also highlights some differences in the active site entrance and the volume of the active site pocket, underlining its originality.
email@example.com (Bastien Cochereau) 13 Oct 2023
[hal-04238993] Expected yield and economic improvements of a yam seed system in West Africa using agro-physiological modelling
Yam is a major tropical root crop and a staple food for millions of people in West Africa. The model used in this study shows that promoting the use of improved seed tubers would help increase yields and profitability for farmers. This could lead to improved food security, increased income and higher standards of living. Additionally, the model serves as a useful decision‐support tool for farmers and technicians to choose, depending on the species, the optimum seed‐tuber weight and planting date. This study provides agronomic arguments to justify investments in the improvement of yam planting materials in West Africa. Summary Yam ( Dioscorea spp.) is a major tropical root crop, grown mainly in West Africa using traditional extensive techniques. Farmers typically reuse seed tubers by setting aside up to 30% of their production for the next season, leading to high planting material variability that affects yields. Several initiatives aim to promote the use of improved seed tubers. However, to help their adoption, it is necessary to quantify the agronomic and economic advantages. To address this, a model for individual plant growth and development was developed based on six experiments in Benin from 2007 to 2009. This model simulates the combined effect of emergence (through photoperiod and temperature) and seed‐tuber weight on yam plant growth and development. Its predictions were highly correlated with observed plant tuber yield ( R 2 > 0.83). Results highlight the crucial role of key processes such as seed‐tuber physiological age and photoperiod sensitivity. The study shows that for the traditional planting dates, the use of improved planting material could lead to a yield increase of 22%–27% and a gain in profitability of 30% and 40% for Dioscorea alata and Dioscorea rotundata , respectively. The model proved to be a useful decision‐support tool for choosing an optimum seed‐tuber weight, depending on the species and the planting date. This study validates investments in yam seed systems in West Africa. However, beyond seed size and health, other factors such as dormancy, storage time and their management need to be considered to address emergence heterogeneity and its impact on yield.
firstname.lastname@example.org (Denis Cornet) 12 Oct 2023
[hal-04238611] Pluridisciplinarité et interdisciplinarité au cœur de l’expertise scientifique collective INRAE et Ifremer sur les effets des produits phytopharmaceutiques sur la biodiversité et les services écosystémiques
Une expertise scientifique collective menée conjointement par INRAE et l’Ifremer dans le cadre du plan Écophyto 2 + a mobilisé, pendant 2 ans, un panel pluridisciplinaire francophone de 46 experts scientifiques. Ce travail, basé sur l’analyse de plus de 4 000 références bibliographiques, a mis en évidence que les produits phytopharmaceutiques contaminent tous les milieux, majoritairement les zones agricoles, qu’ils sont responsables, par des effets directs et indirects, du déclin de certains groupes taxonomiques tels que les invertébrés terrestres et aquatiques et les oiseaux, et que la combinaison de différents leviers peut réduire cette contamination et les effets associés. La robustesse des conclusions de cette étude justifie l’intérêt d’approches combinant des disciplines variées dans le domaine des sciences de l’environnement mais aussi des sciences humaines et sociales.
email@example.com (Wilfried Sanchez) 12 Oct 2023
[hal-04236772] Comment développer un suivi de la biodiversité des sols français en s’appuyant sur le Réseau de Mesures de la Qualité des Sols (RMQS) ?
Pour répondre au besoin de connaissances sur la biodiversité des sols, nous explorons la possibilité d’adosser un suivi de la biodiversité des sols au Réseau de Mesures de la Qualité des Sols (RMQS). Ce couplage a pour objectif de bénéficier du caractère opérationnel du RMQS et de croiser les informations sur la biodiversité avec les données déjà disponibles sur les sols. Des mesures de biodiversité sont d’ailleurs déjà effectuées sur les sites du RMQS. Un groupe de travail incluant des experts nationaux a conçu un questionnaire pour évaluer la compatibilité du plan d’échantillonnage du RMQS avec la surveillance de la biodiversité des sols et définir les caractéristiques de ce nouveau suivi (taxons et fonctions à suivre, protocoles, besoins matériels, humains et financiers). Ces mêmes experts ont ensuite répondu au questionnaire et les informations collectées ont été complétées lors d’entretiens individuels. Les avancées du projet ont été validées en réunions plénières. Au sortir de ces réflexions, il a été conclu que le plan d’échantillonnage du RMQS (maille de 16 km x 16 km, site d’étude de 400 m2, ré-échantillonnage de chaque site tous les 15 ans) convenait à un suivi de la biodiversité des sols. Cependant, les experts écologues ont mis en avant la nécessité d’effectuer l’échantillonnage de la mésofaune et de la macrofaune au printemps. Ils recommandent cinq protocoles qui permettent de suivre les micro-organismes, la microfaune, la mésofaune et la macrofaune du sol. Une mesure de la flore a aussi été intégrée avec le suivi de la banque de graines. Trois fonctions (macroporosité du sol due à l’activité des vers de terre, activités enzymatiques et dégradation de la matière organique) seraient également mesurées. Si le RMQS-Biodiversité est mis en place de manière pérenne et déployé sur les 2240 sites métropolitains, il devrait permettre de documenter de manière robuste la biogéographie des organismes du sol, de décrypter leurs liens avec les pratiques agricoles et possiblement la découverte de nouvelles espèces. Une réflexion complémentaire devra être engagée pour les sites ultra-marins.
firstname.lastname@example.org (Camille Imbert) 11 Oct 2023
[hal-04231800] Challenges of accounting nitrous oxide emissions from agricultural crop residues
Abstract Crop residues are important inputs of carbon (C) and nitrogen (N) to soils and thus directly and indirectly affect nitrous oxide (N2O) emissions. As the current inventory methodology considers N inputs by crop residues as the sole determining factor for N2O emissions, it fails to consider other underlying factors and processes. There is compelling evidence that emissions vary greatly between residues with different biochemical and physical characteristics, with the concentrations of mineralizable N and decomposable C in the residue biomass both enhancing the soil N2O production potential. High concentrations of these components are associated with immature residues (e.g., cover crops, grass, legumes, and vegetables) as opposed to mature residues (e.g., straw). A more accurate estimation of the short‐term (months) effects of the crop residues on N2O could involve distinguishing mature and immature crop residues with distinctly different emission factors. The medium‐term (years) and long‐term (decades) effects relate to the effects of residue management on soil N fertility and soil physical and chemical properties, considering that these are affected by local climatic and soil conditions as well as land use and management. More targeted mitigation efforts for N 2 O emissions, after addition of crop residues to the soil, are urgently needed and require an improved methodology for emission accounting. This work needs to be underpinned by research to (1) develop and validate N 2 O emission factors for mature and immature crop residues, (2) assess emissions from belowground residues of terminated crops, (3) improve activity data on management of different residue types, in particular immature residues, and (4) evaluate long‐term effects of residue addition on N2O emissions.
email@example.com (Jørgen E Olesen) 11 Oct 2023
[hal-04232608] Monitoring of carbon-water fluxes at Eurasian meteorological stations using random forest and remote sensing
Simulating the carbon-water fluxes at more widely distributed meteorological stations based on the sparsely and unevenly distributed eddy covariance flux stations is needed to accurately understand the carbon-water cycle of terrestrial ecosystems. We established a new framework consisting of machine learning, determination coefficient (R 2), Euclidean distance, and remote sensing (RS), to simulate the daily net ecosystem carbon dioxide exchange (NEE) and water flux (WF) of the Eurasian meteorological stations using a random forest model or/and RS. The daily NEE and WF datasets with RS-based information (NEE-RS and WF-RS) for 3774 and 4427 meteorological stations during 2002-2020 were produced, respectively. And the daily NEE and WF datasets without RS-based information (NEE-WRS and WF-WRS) for 4667 and 6763 meteorological stations during 1983-2018 were generated, respectively. For each meteorological station, the carbon-water fluxes meet accuracy requirements and have quasi-observational properties. These four carbon-water flux datasets have great potential to improve the assessments of the ecosystem carbon-water dynamics.
firstname.lastname@example.org (Mingjuan Xie) 09 Oct 2023
[hal-04224631] Detection and attribution of an anomaly in terrestrial photosynthesis in Europe during the COVID-19 lockdown
Carbon dioxide (CO2) uptake by plant photosynthesis, referred to as gross primary production (GPP) at the ecosystem level, is sensitive to environmental factors, including pollutant exposure, pollutant uptake, and changes in the scattering of solar shortwave irradiance (SWin) − the energy source for photosynthesis. The spring lockdown due to COVID-19 resulted in improved air quality and atmospheric transparency, providing a unique opportunity to assess the impact of air pollutants on terrestrial ecosystem functioning. However, detecting these effects can be challenging as GPP is influenced by other meteorological drivers and management practices. Based on data collected from 44 European ecosystem-scale CO2 flux monitoring stations, we observed significant changes in spring GPP at 34 sites during 2020 compared to 2015-2019. Among these, 14 sites showed an increase in GPP associated with higher SW in , 10 sites had lower GPP linked to atmospheric and soil dryness, and seven sites were subjected to management practices. The remaining three sites exhibited varying dynamics, with one experiencing colder and rainier weather resulting in lower GPP, and two showing higher GPP associated with earlier spring melts. Analysis using the regional atmospheric chemical transport model (LOTOS-EUROS) indicated that the ozone (O3) concentration remained relatively unchanged at the research sites, making it unlikely that O3 exposure was the dominant factor driving the primary production anomaly. In contrast, SW in increased by 9.4 % at 36 sites, suggesting enhanced GPP possibly due to reduced aerosol optical depth and cloudiness. Our findings indicate that air pollution and cloudiness may weaken the terrestrial carbon sink by up to 16 %. Accurate and continuous ground-based observations are crucial for detecting and attributing subtle changes in terrestrial ecosystem functioning in response to environmental and anthropogenic drivers.
email@example.com (Angela Che Ing Tang) 02 Oct 2023
[hal-03831829] The older, the better: Ageing improves the efficiency of biochar-compost mixture to alleviate drought stress in plant and soil
Due to increased drought frequency following climate change, practices improving water use efficiency and reducing water-stress are needed. The efficiency of organic amendments to improve plant growth conditions under drought is poorly known. Our aim was to investigate if organic amendments can attenuate plant water-stress due to their effect on the plant-soil system and if this effect may increase upon ageing. To this end we determined plant and soil responses to water shortage and organic amendments added to soil. We compared fresh biochar/compost mixtures to similar amendments after ageing in soil.Results indicated that amendment application induced few plant physiological responses under water-stress. The re-duction of leaf gas exchange under watershortage was alleviated when plants were grown with biochar and compost amendments: stomatal conductance was least reduced with aged mixture aged mixture (-79 % compared to -87 % in control), similarly to transpiration (-69 % in control and not affected with aged mixture). Belowground biomass production (0.25 times) and nodules formation (6.5 times) were enhanced under water-stress by amendment addition. This effect was improved when grown on soil containing the aged as compared to fresh amendments. Plants grown with aged mixtures also showed reduced leaf proline concentrations (two to five times) compared to fresh mixtures indicating stress reduction. Soil enzyme activities were less affected by water-stress in soil with aged amendments. We conclude that the application of biochar-compost mixtures may be a solution to reduce the effect of water-stress to plants. Our findings revealed that this beneficial effect is expected to increase with aged mixtures, leading to a better water-stress resistance over time. However, while being beneficial for plant growth under water-stress, the use of amendments may not be suited to increase water use efficiency.
firstname.lastname@example.org (Charlotte Védère) 29 Sep 2023
[insu-04220866] Histoire de trois concepts du sol mal maîtrisés : le pH du sol, les cations échangeables et la capacité d'échange cationique
Cet article retrace à grands traits l’évolution des connaissances scientifiques sur les acides, les bases, les cations et les anions, depuis la première tentative d’explication de la nature des acides et des bases (1675) jusqu’à leurs ultimes définitions (1925). Parallèlement, l’évolution des connaissances sur les cations échangeables et la capacité d’échange des sols est racontée depuis 1840 jusqu’à nos jours avec, en contrepoint, la représentation qu’ont les agronomes et les pédologues, principalement français, de ces différents concepts. Enfin, l’histoire de l’intérêt du chaulage, pratiqué depuis l’antiquité romaine, est racontée telle que l’apprécient les agronomes depuis le début du XVIIe siècle. Ces histoires parallèles mettent en lumière le décalage important entre les acquis scientifiques et les écrits de nombreux agronomes et pédologues de 1925 à 2000: les cations sont dits « basiques », la capacité d’échange cationique est supposée « constante » et le pH du sol est censé dépendre du « taux de saturation » de la capacité d’échange par les cations basiques, ces derniers chassant les H+ « échangeables ». En France, à partir de 1995, des agronomes ont mené de nombreuses actions pour corriger ces idées fausses présentes même chez les chercheurs en Science du sol. Cette correction de la représentation des cations échangeables et de la capacité d’échange a des conséquences de plusieurs types. Tout d’abord, le pH du sol apparaît contrôlé par l’état des sites à charges variables sur une large gamme de pH. Ensuite, l’agronome peut enfin expliquer les effets du chaulage, connus depuis si longtemps: la hausse du pH et celle de la CEC effective sont étroitement corrélées. Et c’est l’augmentation de la CEC effective, pas celle du pH, qui explique l’amélioration de l’affinité pour l’eau et de la stabilité structurale du sol. Enfin, le mécanisme à la base de cette amélioration est dû à la nature polaire des molécules d’eau et aux forces de Coulomb entre molécules de charges opposées.
email@example.com (Jean-Luc Julien) 28 Sep 2023
[hal-04215019] An online downscaling method to simulate high resolution atmospheric concentrations of pesticides with the 3D Chemistry-Transport Model CHIMERE: application and evaluation
High resolution databases on atmospheric concentrations of pesticides are necessary in order to perform epidemiological studies but there is currently no modeling method to provide high resolution mapping of pesticides concentrations over a whole region. In this study, we propose an online downscaling method for CHIMERE to perform simulations at a sub-kilometer resolution. The main idea of this downscaling approach is to redistribute or interpolate some information simulated on the coarse grid to simulate the transport over a finer subgrid. The performance of the downscaling is analyzed by comparing the CHIMERE nested simulation results at 0.02° and CHIMERE simulation results downscaled from 0.1° to 0.02°. By applying this method to S-metolachlor, we diagnosed an error generated by the downscaling of a few percents on both background and hotspot concentrations. The method was used to simulate concentrations over France at a resolution of 0.004° with a limited increase of the computational time. Based on these simulations, we estimated that around 3 000 inhabitants were exposed to concentrations of S-metolachlor above 10 ng/m from April 15th to May 15th 2014.
firstname.lastname@example.org (Florian Couvidat) 26 Sep 2023
[hal-04214764] Assessing the chronic toxicity of spreading organic amendments on agricultural soil: Tests on earthworms and plants
Recycling organic wastes on agricultural soils improves the soil quality, but the environmental and health impact of these organic amendments closely depends on their origins, their bio-physicochemical characteristics and the considered organisms potentially affected. The aim of this study was to assess the potential chronic ecotoxicity of spreading organic amendments on agricultural soils. To do this, we characterized three different organic amendments: sewage sludge from an urban wastewater treatment plant, cow manure and liquid dairy manure. Their chronic ecotoxicity was studied through assays exposing earthworms of the species Eisenia fetida and two plants: Medicago sativa and Sinapis alba. Of the three amendments, the sewage sludge presented the highest concentrations of micropollutants and a considerable fraction of available and biodegradable organic matter. The cow manure and liquid dairy manure had lower chemical contamination and similar characteristics with lower biodegradable fractions of their organic matter. No chronic phytotoxicity was evidenced: on the contrary, particularly with sewage sludge, the germination rate and aerial and root biomass of the two plants increased. Considering earthworms, their biomass increased considerably during the reproduction assays in soil amended with sewage sludge, which contained the more bioavailable organic matter. Nonetheless, the earthworms presented an inhibition close to 78% of the production of juveniles when exposed to sewage sludge exceeding 20 g. kg-1 DW (that means 2 times the agronomic dose). This reprotoxic effect was also observed in the presence of liquid dairy manure, but not with cow manure. At the end of the assays, the glycogen and protein reserves in earthworms exposed to sewage sludge were inferior to that of control earthworms, respectively around 50% and 30%. For the earthworms exposed to liquid dairy manure, protein and lipid reserves increased. In the case of liquid dairy manure, this reprotoxic effect did not appear to be linked to the presence of micropollutants. In conclusion, our results confirm the need to use several ecotoxicity assays at different biological levels and with different biological models to assess the ecotoxic impacts of soil amendments. Indeed, although certain organic wastes present a strong nutritional potential for both plants and earthworms, a not inconsiderable risk was apparent for the reproduction of the latter. An integrated ecotoxicity criterion that takes into account a weighted sum of the different results would guide the utilization of organic amendments while ensuring the good health of agricultural ecosystems.
email@example.com (Olivier Roques) 22 Sep 2023
[hal-04131832] Elemental stoichiometry and Rock-Eval® thermal stability of organic matter in French topsoils
Abstract. The quality and quantity of soil organic matter (SOM) are key elements that impact soil health and climate regulation by soils. The Rock-Eval® thermal analysis technique is becoming more commonly used, as it represents a powerful method for SOM characterization by providing insights into bulk SOM chemistry and thermal stability. In this study, we applied this technique on a large soil sample set from the first campaign (2000–2009) of the French Soil Quality Monitoring Network (RMQS – Réseau de mesures de la qualité des sols). Based on our analyses of ca. 2000 composite surface (0–30 cm) samples collected across mainland France, we observed a significant impact of land cover on both the SOM thermal stability and elemental stoichiometry. Cropland soils had a lower mean hydrogen index value (a proxy for the SOM H/C ratio) and a higher thermal stability than grasslands and forests. Regarding the oxygen index (a proxy for the SOM O/C ratio), we observed significant differences among the values for croplands, grasslands, and forests. Positive correlations of the temperature parameters with the clay content and pH highlight the protective effect of clay on organic matter as well as the impact of pH on microorganisms' mineralization activity. Surprisingly, we found weak effects of climatic parameters on the thermal stability and stoichiometry of SOM. Our data suggest that topsoil SOM is on average more oxidized and biogeochemically stable in croplands. More generally, the high number and even distribution of data across the whole French territory allow one to build a national interpretative reference for these indicators in surface soils.
firstname.lastname@example.org (Amicie Delahaie) 13 Sep 2023
[hal-04205172] Inland water greenhouse gas budgets for RECCAP2: 2 Regionalization and homogenization of estimates following the RECCAP2 framework
Inland waters are important sources of the greenhouse gasses (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to the atmosphere. In the framework of the 2nd phase of the REgional Carbon Cycle Assessment and Processes (RECCAP-2) initiative, we synthesize existing estimates of GHG emissions from streams, rivers, lakes and reservoirs, and homogenize them with regard to underlying global maps of water surface area distribution and the effects of seasonal ice cover. We then produce regionalized estimates of GHG emissions over 10 extensive land regions. According to our synthesis, inland water GHG emissions have a global warming potential of an equivalent emission of 13.6 (10.0-20.3) and 8.3 (5.8-12.7) Pg CO2-eq. yr-1 at a 20 and 100 year horizon (GWP20 and GWP100), respectively. Contributions of CO2 dominate GWP100, with rivers being the largest emitter. For GWP20, lakes and rivers are equally important emitters, and the warming potential of CH4 is more important than that of CO2. Contributions from N2O are about two orders of magnitude lower. Normalized to the area of RECCAP-2 regions, S-America and SE-Asia show the highest emission rates, dominated by riverine CO2 emissions.
email@example.com (Ronny Lauerwald) 12 Sep 2023
[hal-04205167] Inland water greenhouse gas budgets for RECCAP2: 1. State-of-the-art of global scale assessments
Inland waters are important sources of the greenhouse gasses (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to the atmosphere. In the framework of the 2nd phase of the REgional Carbon Cycle Assessment and Processes (RECCAP-2) initiative, we review the state of the art in estimating inland water GHG budgets at global scale, which has substantially advanced since the first phase of RECCAP nearly ten years ago. The development of increasingly sophisticated upscaling techniques, including statistical prediction and process based models, allows for spatially explicit estimates which are needed for regionalized assessments of continental GHG budgets such as those established for RECCAP. A few recent estimates also resolve the seasonal and/or interannual variability in inland water GHG emissions. Nonetheless, the global-scale assessment of inland water emissions remains challenging because of limited spatial and temporal coverage of observations and persisting uncertainties in the abundance and distribution of inland water surface areas. To decrease these uncertainties, more empirical work on the contributions of hot-spots and hot-moments to overall inland water GHG emissions is particularly needed.
firstname.lastname@example.org (Ronny Lauerwald) 12 Sep 2023
[hal-04083391] Main conclusions and perspectives from the collective scientific assessment of the effects of plant protection products on biodiversity and ecosystem services along the land–sea continuum in France and French overseas territories
Preservation of biodiversity and ecosystem services is critical for sustainable development and human well-being. However, an unprecedented erosion of biodiversity is observed and the use of plant protection products (PPP) has been identified as one of its main causes. In this context, at the request of the French Ministries responsible for the Environment, for Agriculture and for Research, a panel of 46 scientific experts ran a nearly 2-year-long (2020-2022) collective scientific assessment (CSA) of international scientific knowledge relating to the impacts of PPP on biodiversity and ecosystem services. The scope of this CSA covered the terrestrial, atmospheric, freshwater, and marine environments (with the exception of groundwater) in their continuity from the site of PPP application to the ocean, in France and French overseas territories, based on international knowledge produced on or transposable to this type of context (climate, PPP used, biodiversity present, etc.). Here, we provide a brief summary of the CSA's main conclusions, which were drawn from about 4500 international publications. Our analysis finds that PPP contaminate all environmental matrices, including biota, and cause direct and indirect ecotoxicological effects that unequivocally contribute to the decline of certain biological groups and alter certain ecosystem functions and services. Levers for action to limit PPP-driven pollution and effects on environmental compartments include local measures from plot to landscape scales and regulatory improvements. However, there are still significant gaps in knowledge regarding environmental contamination by PPPs and its effect on biodiversity and ecosystem functions and services. Perspectives and research needs are proposed to address these gaps.
email@example.com (Stéphane Pesce) 08 Sep 2023
[hal-04193745] Potential impacts of climate change on the productivity and soil carbon stocks of managed grasslands
Rain-fed pastoral systems are tightly connected to meteorological conditions. It is, therefore, likely that climate change, including changing atmospheric CO2 concentration, temperature, precipitation and patterns of climate extremes, will greatly affect pastoral systems. However, exact impacts on the productivity and carbon dynamics of these systems are still poorly understood, particularly over longtime scales. The present study assesses the potential effects of future climatic conditions on productivity and soil organic carbon (SOC) stocks of mowed and rotationally grazed grasslands in France. We used the CenW ecosystem model to simulate carbon, water, and nitrogen cycles in response to changes in environmental drivers and management practices. We first evaluated model responses to individual changes in each key meteorological variable to get better insights into the role and importance of each individual variable. Then, we used 3 sets of meteorological variables corresponding to 3 Representative Concentration Pathways (RCP 2.6, RCP 4.5 and RCP 8.5) for long-term model runs from 1975 to 2100. Finally, we used the same three RCPs to analyze the responses of modelled grasslands to extreme climate events. We found that increasing temperature slightly increased grasslands productivities but strongly reduced SOC stocks. A reduction in precipitation led to reductions of biomass and milk production but increased SOC. Conversely, doubling CO2 concentration strongly increased biomass and milk production and marginally reduced SOC. These SOC trends were unexpected. They arose because both increasing precipitation and CO2 increased photosynthetic carbon gain, but they had an even greater effect on the proportion of biomass that could be grazed. The amount of carbon remaining on site and able to contribute to SOC formation was actually reduced under both higher precipitation and CO2. The simulations under the three RCPs indicated that grassland productivity was increased, but that required higher N fertilizer application rates and also led to substantial SOC losses. We thus conclude that, while milk productivity may continue at current rates under climate change, or even increase slightly, there could be some soil C losses over the 21st century. In addition, under the highest-emission scenario, the increasing importance of extreme climate conditions (heat waves and droughts) might render conditions at our site in some years as unsuitable for milk production. It highlights the importance of tailoring farming practices to achieve the dual goals of maintaining agricultural production while safeguarding soil C stocks.
firstname.lastname@example.org (Nicolas J.B. Puche) 04 Sep 2023
[hal-04189398] Sentinel-2 satellite images for monitoring cattle slurry and digestate spreading on emerging wheat crop: a field spectroscopy experiment
This study is aimed to evaluate the utility of Sentinel-2 imagery for monitoring exogenous organic matter (EOM) applied on winter wheat crop, using two spatial scales: proximal and satellite. From proximal sensing, multi-temporal spectral field measurements were taken on experimental fields consisting of three treatments (cattle slurry, liquid and raw digestates) and a control throughout 46 days. From Sentinel-2 satellites, images were analysed before and after EOM application. For both sensing scales, EOM and vegetation indices were used. On any scale of observation, the digestates spread on emerging wheat were easily detectable in late winter, in contrast to spring spreading events which were hindered by the developed vegetation. The agglomerative hierarchical clustering from the EOM indices divided by EVI achieved to discriminate digestates at early and medium stages of vegetation growth. Our findings did not apply for cattle slurry, presumably because of both lower organic and dry matter contents. HIGHLIGHTS • Digestates spread on emerging wheat are detectable in late winter. • Developed vegetation constrains the detection of spring spreading events. • Spectral measurements did not separate the field with cattle slurry and the control. • The visible to near infrared bands are the most impacted after digestate spreading.
email@example.com (Maxence Dodin) 28 Aug 2023
[hal-04183952] High fertilizing value but potentially high volatilization of urine based fertilizers
Human urine contains nutrients that are mainly not recycled in agriculture. It can be collected through source separation and treated to produce "urine-based fertilizers" with various nutrient contents and physiochemical characteristics. We measured ammonia (NH3) volatilization after the application of several urine-based fertilizers under controlled conditions and of stored urine under field conditions. The nitrogen-use efficiency of four urine-based fertilizers (stored urine from a university, stored urine from a festival, fermented urine and nitrified concentrated urine) was compared under on-farm conditions with ammonium nitrate and bovine slurry in a specific experiment. Stored urine was also compared with ammonium nitrate and seven other organic fertilizers in different experiments under on-farm conditions. Nitrous oxide emissions after the application of two urine-based fertilizers were also measured. NH3 volatilization from stored urine was high (up to 34% of the total nitrogen under on-farm conditions) compared with the other urine-based fertilizers and ammonium nitrate. Urine-based fertilizers were characterized by a nitrogen fertilizer replacement value (NFRV) greater than 70% and higher than that of all other organic fertilizers used in the experiments (but not significantly different). These differences were mainly explained by the mineral nitrogen content of the fertilizers. The mean NFRV of stored urine over five experiments was 83% (significantly lower than 100%). Nitrous oxide emissions from stored urine, nitrified concentrated urine and ammonium nitrate were low. We concluded that urine-based fertilizers could replace mineral fertilizers if NH3 volatilization is limited. The constraints linked to the field application of a large volume call for further investigation.
firstname.lastname@example.org (Tristan Martin) 21 Aug 2023
[hal-03952680] Consideration of unmeasured micropollutants released from WWTP for potential impact estimations
During wastewater treatment, micropollutants are only partly eliminated and may present a risk for human health and aquatic ecosystems. The potential impacts these substances may have are currently underestimated due to the lack in available concentrations that lie below the limit of quantification (LOQ) for an important set of micropollutants. Here, the potential impacts due to 261 organic micropollutants on human health and aquatic environments were investigated at the scale of France. Even with concentrations below the LOQ, certain micropollutants were found to have a significant potential impact. For unmeasured concentrations, a global concentration distribution built from several datasets with different LOQ was used. By disregarding the unmeasured micropollutants, the potential impacts have been underestimated by more than 300% on both human health and aquatic environments. Certain substances, such as hydrazine, endrin, or 2,3,7,8-TetraCDD, could lead to very strong potential impacts, even with unmeasured concentration levels. Moreover, the usual convention of LOQ/2 to replace unmeasured concentrations also appeared to overestimate the potential impact. The present work can be adapted to any other compartment or geographical context.
email@example.com (Rémi Servien) 21 Aug 2023
[hal-04182751] Is plant biomass input driving soil organic matter formation processes in grassland soil under contrasting management?
Grassland management practices vary in stocking rates and plant removal strategies (grazing versus mowing). They influence organic matter (OM) inputs, which were postulated as main controls of soil organic carbon (SOC) sequestration and might therefore control SOC stabilization. The aim of this study was to test this hypothesis by investigating the impacts of grassland harvesting regimes on parameters related to soil microbial functioning and soil organic matter (SOM) formation processes. We used a thirteen-year experiment in Central France under contrasting management (unmanaged, grazing with two intensities, mowing, bare fallow) to establish a carbon input gradient based on biomass leftovers after harvest. We investigated microbial biomass, basal respiration and enzyme activities as indicators of microbial functioning, and amino sugar content and composition as indicator of persistent SOM formation and origin through necromass accumulation. Responses of these parameters to carbon input along the gradient were contrasting and in most cases unrelated. Only the microbial C/N ratio and amino sugar contents showed a linear response indicating that they are influenced by plant-derived OM input. Other parameters were most probably more influenced by root activity, presence of herbivores, and/or physicochemical changes following management activities impacting soil
firstname.lastname@example.org (Aliia Gilmullina) 18 Aug 2023
[hal-04182586] The consolidated European synthesis of CH<sub>4</sub> and N<sub>2</sub>O emissions for the European Union and United Kingdom: 1990–2019
Knowledge of the spatial distribution of the fluxes of greenhouse gases (GHGs) and their temporal variability as well as flux attribution to natural and anthropogenic processes is essential to monitoring the progress in mitigating anthropogenic emissions under the Paris Agreement and to inform its global stocktake. This study provides a consolidated synthesis of CH4 and N2O emissions using bottom-up (BU) and top-down (TD) approaches for the European Union and UK (EU27 + UK) and updates earlier syntheses (Petrescu et al., 2020, 2021). The work integrates updated emission inventory data, process-based model results, data-driven sector model results and inverse modeling estimates, and it extends the previous period of 1990-2017 to 2019. BU and TD products are compared with European national greenhouse gas inventories (NGHGIs) reported by parties under the United Nations Framework Convention on Climate Change (UNFCCC) in 2021. Uncertainties in NGHGIs, as reported to the UNFCCC by the EU and its member states, are also included in the synthesis. Variations in estimates produced with other methods, such as atmospheric inversion models (TD) or spatially disaggregated inventory datasets (BU), arise from diverse sources including within-model uncertainty related to parameterization as well as structural differences between models. By comparing NGHGIs with other approaches, the activities included are a key source of bias between estimates, e.g., anthropogenic and natural fluxes, which in atmospheric inversions are sensitive to the prior geospatial distribution of emissions. For CH4 emissions, over the updated 2015-2019 period, which covers a sufficiently robust number of overlapping estimates, and most importantly the NGHGIs, the anthropogenic BU approaches are directly comparable, accounting for mean emissions of 20.5 TgCH(4) yr(-1) (EDGARv6.0, last year 2018) and 18.4 TgCH(4) yr(-1) (GAINS, last year 2015), close to the NGHGI estimates of 17 :5 +/- 2 :1 TgCH(4) yr(-1). TD inversion estimates give higher emission estimates, as they also detect natural emissions. Over the same period, high-resolution regional TD inversions report a mean emission of 34 TgCH(4) yr(-1). Coarser-resolution global-scale TD inversions result in emission estimates of 23 and 24 TgCH(4) yr(-1) inferred from GOSAT and surface (SURF) network atmospheric measurements, respectively. The magnitude of natural peatland and mineral soil emissions from the JSBACH-HIMMELI model, natural rivers, lake and reservoir emissions, geological sources, and biomass burning together could account for the gap between NGHGI and inversions and account for 8 TgCH(4) yr(-1). For N2O emissions, over the 2015-2019 period, both BU products (EDGARv6.0 and GAINS) report a mean value of anthropogenic emissions of 0.9 TgN(2)Oyr(-1), close to the NGHGI data (0 :8 +/- 55% TgN(2)Oyr(-1)). Over the same period, the mean of TD global and regional inversions was 1.4 TgN(2)Oyr(-1) (excluding TOMCAT, which reported no data). The TD and BU comparison method defined in this study can be operationalized for future annual updates for the calculation of CH4 and N2O budgets at the national and EU27 C UK scales. Future comparability will be enhanced with further steps involving analysis at finer temporal resolutions and estimation of emissions over intra-annual timescales, which is of great importance for CH4 and N2O, and may help identify sector contributions to divergence between prior and posterior estimates at the annual and/or inter-annual scale. Even if currently comparison between CH4 and N2O inversion estimates and NGHGIs is highly uncertain because of the large spread in the inversion results, TD inversions inferred from atmospheric observations represent the most independent data against which inventory totals can be compared. With anticipated improvements in atmospheric modeling and observations, as well as modeling of natural fluxes, TD inversions may arguably emerge as the most powerful tool for verifying emission inventories for CH4, N2O and other GHGs. The referenced dataset srelated to figures are visualized at https://doi.org/10.5281/zenodo.7553800 (Petrescu et al., 2023).
email@example.com (Ana Maria Roxana Petrescu) 17 Aug 2023
[hal-04178020] ADDI-Spraydrift: A comprehensive model of pesticide spray drift with an assessment in vineyards
Spray drift is a major contributor to pesticide losses in the atmosphere leading to nontargeted ecosystem exposure. An overview of currently used ground-application spray drift models highlighted gaps in the description of the processes occurring during and after spraying. The ADDI-Spraydrift model was developed to bridge some of these gaps and provide a comprehensive, yet concise description of spray drift processes. The model is based on a random walk approach that describes droplet emission, dispersion and evaporation, ground deposition and canopy interception, and accounts for atmospheric stability regimes, and in-canopy turbulence. It predicts airborne concentration, canopy interception and deposition to the ground downwind from the sprayer. The sensitivity analysis to wind speed, active matter content, leaf angle, canopy height, leaf area index, ejection angle and velocity demonstrated the consistency of the model behaviour. The model was calibrated and evaluated against the Ganzelmeier et al. (1995) sedimentary spray drift data in vineyards. The model satisfactorily predicted droplets deposition to the ground downwind from the field boundary with a mean deviation between modelled and measured deposition of 1.3%. A discrepancy was observed at 3 and 5 m downwind from the field boundary attributed to the sensitivity to spraying conditions for which several hypotheses are discussed. Bearing in mind the need to explicitly describe the emitted droplet size and velocity, the overall predictive performance of the model appeared to be sufficient for assessing and comparing application techniques efficiency, quantifying pesticide loss and bystanders or resident exposure and evaluating the efficiency of mitigation measures.
firstname.lastname@example.org (Meriem Djouhri) 07 Aug 2023
[hal-04171456] The role of green roofs as urban habitats for biodiversity modulated by their design: a review
In view of the demographic revolution and the rapid development of urban environments, the installation of green roofs could be a tool to ensure human well-being (e.g. heat island reduction, rainwater management), or to increase urban biodiversity. However, the relationships between biodiversity and green roofs are not yet clear and little research has looked into this. We therefore reviewed studies on the overall biodiversity of green roofs. Our review has shown that there is a lack of knowledge of the biodiversity of green roofs, with recent consideration. We highlighted the importance of green roof contribution, in maintaining urban biodiversity through three lines of research: characterization, modes of use and design. Furthermore, we found that there were very few studies on soil biodiversity on this topic. We concluded that green roof construction guidelines should integrate soil communities into their design and aim to be heterogeneous at roof and landscape level. Future research should focus on the diversification and redundancy of rooftop conditions in the urban matrix. This would increase the area of green habitats and the success of species dispersal in cities.
email@example.com (Sékou F M Coulibaly) 26 Jul 2023
[hal-04166791] National soil data in EU countries, where do we stand?
At European scale, soil characteristics are needed to evaluate soil quality, soil health and soi l-based ecosystem services in the context of the European Green Deal. While some soil databases exist at the European scale, a much larger wealth of data is present in individual European countries, al l owing a more detailed soil assessment. There is thus an urgent and crucial need to combine these data at t h e European scale. In the frame of a large European Joint Programme on agricultural soils launched by the European Commission, a survey was conducted in the spring of 2020, i n the 24 European participating countries to assess the existing soil data sources, focusing on agricultural soils. The survey will become a contribution to the European Soil Observatory, launched in December 2020, which aims to collect metadata of soil databases related to all kind of land uses, including fores t and urban soils. Based upon a comprehensive questionnaire, 170 soil databases were identified at local, regional and national scales. Soil parameters were divided into f i ve groups: 1. main soil parametersaccording to the Global Soil Map specifications; 2. other soil chemical parameters; 3. oth e r physical parameters; 4. other pedological parameters; and 5. soil biological features. A classification based onthe environmental zones of Europe was used to distinguish the climatic zones. This survey shows that while most of the main pedological and chemical parameters are included in more than 70 % of the country soil databases, water content, contamination with organic pollutants and biological parameters are the least frequently reported parameters. Such differences will have conse que nce s when developing an EU policy on soil health as proposed under the EU soil strategy for 2023 and using the data to derive soil health indicators. Many differences in the me thods used in collecting, preparing, and analysing the soils were found, thus requiring harmonisation procedures and more cooperation among countries and with the EU to use the data at the European scale Additionally, choosing harmonized and useful interpretation and threshold values f or EU soil indicators may be challenging due to the different methods used and the wide variety of soil land-use and climate combinations influencing possible thresholds. The temporal scale of the soil databases reported is also extremely wide, starting from the ‘20s of the 20th century.
firstname.lastname@example.org (Sophie Cornu) 20 Jul 2023
[hal-04066268] Crop mixtures outperform rotations and landscape mosaics in regulation of two fungal wheat pathogens: a simulation study
Context Crop rotations, within-field mixtures, and landscape mosaics including susceptible and resistant crops are three commonly adopted crop diversification strategies that can limit crop epidemics. Typically, the effects of crop diversification at these three scales have been studied separately, on single pathogen species, and with low environmental variability. Objectives We aim to compare the disease-limitation effect of these three types of crop diversification on two highly damaging fungal pathogens of wheat Puccinia recondita (WLR) and Zymoseptoria tritici (STB) and under varying weather conditions (warmer or cooler climate for WLR, wetter or drier conditions for STB). Methods We built a dynamic mathematical model of epidemics at the field scale (based on classical Susceptible-Exposed-Infectious-Removed epidemiological models) embedded in a spatially explicit landscape grid framework. We use it to simulate an agricultural landscape in which diversification translates into different proportions of wheat and resistant crops in the landscape. Results In our simulations, for both pathogens and in all weather conditions, within-field crop mixtures had the greatest impact in limiting epidemics, crop rotations were second-best, while landscape mosaics were the least effective. We also found that the threshold above which further addition of resistant plants to crop mixtures would not cause further disease limitation to be dependent on weather conditions. The more favorable the weather is for pathogens the more resistant plants are required. Conclusions Our findings imply that interactions between spatial scale of crop diversification, pathogen characteristics and weather conditions should be considered in order to maximize benefits from disease-regulation properties of diversified cropping systems under climate change.
email@example.com (Pierre-Antoine Précigout) 04 Jul 2023
[hal-04145798] Effect of monetary policy shocks on the racial unemployment rates in the US
This study analyzes the effect of monetary policy shocks on the unemployment rate of different racial groups in the US, using data from 1969Q2 to 2015Q4. Employing a narrative approach to identify monetary policy shocks and local projections, we find that although an expansionary monetary shock affects White workers positively and significantly, the effect on Black workers is larger, and for Hispanic workers it is not statistically different from zero. These results are robust when considering unconventional monetary policy measures in the specification, and when exploring the impact of monetary policy on different genders and age groups. We also highlight how recession affects the transmission channel of monetary policy to the labor market for White and Hispanic workers. Finally, further extensions suggest that the Fed's monetary policy is effective in reducing the racial unemployment gap, particularly between Whites and Blacks, and during economic booms.
firstname.lastname@example.org (Hamza Bennani) 29 Jun 2023
[hal-04014202] An indicator to assess risks on water and air of pesticide spraying in crop fields
Stakeholders involved in actions to reduce the use and the impacts on the environment or human health of pesticides need operational tools to assess crop protection strategies in regard to these impacts. I-Phy3 brings together all improvements introduced since the first version of the indicator to better meet user's needs and requirements of integrating processes. I-Phy3 was deeply modified to ensure its predictive quality. I-Phy 3 is structured in three levels of aggregation in form of hierarchical fuzzy decision trees designed with the CONTRA method. At the 1st level, five basic subindicators assess the risk of contamination (RC) for the different transfer pathways involved in surface water, ground water and atmosphere contamination: leaching, runoff, drainage, drift, volatilization. At the 2nd level, RC subindicators are aggregated with a toxicity variable (human or aquatic) in a risk indicator. At the 3rd level, the global indicator I-Phy3 results from the aggregation of three risk indicators for groundwater, surface waters and air. I-Phy3 yielded better validation results than its previous versions. This effort to assess the predictive quality of the indicator should be pursued and completed by a feasibility and utility test by end-users. A subindicator on risk of soil contamination is a gap which remains to fill.
email@example.com (Frédéric Pierlot) 22 Jun 2023
[hal-04137870] Increasing riverine export of dissolved organic carbon from China
River transport of dissolved organic carbon (DOC) to the ocean is a crucial but poorly quantified regional carbon cycle component. Large uncertainties remaining on the riverine DOC export from China, as well as its trend and drivers of change, have challenged the reconciliation between atmosphere-based and land-based estimates of China's land carbon sink. Here, we harmonized a large database of riverine in-situ measurements and applied a random forest model, to quantify riverine DOC fluxes (FDOC) and DOC concentrations (CDOC) in rivers across China. This study proposes the first DOC modeling effort capable of reproducing well the magnitude of riverine CDOC and FDOC, as well as its trends, on a monthly scale and with a much wider spatial distribution over China compared to previous studies that mainly focused on annual-scale estimates and large rivers. Results show that over the period 2001–2015, the average CDOC was 2.25 ± 0.45 mg/L and average FDOC was 4.04 ± 1.02 Tg/year. Simultaneously, we found a significant increase in FDOC (+0.044 Tg/year2, p = .01), but little change in CDOC (−0.001 mg/L/year, p > .10). Although the trend in CDOC is not significant at the country scale, it is significantly increasing in the Yangtze River Basin and Huaihe River Basin (0.005 and 0.013 mg/L/year, p < .05) while significantly decreasing in the Yellow River Basin and Southwest Rivers Basin (−0.043 and −0.014 mg/L/year, p = .01). Changes in hydrology, play a stronger role than direct impacts of anthropogenic activities in determining the spatio-temporal variability of FDOC and CDOC across China. However, and in contrast with other basins, the significant increase in CDOC in the Yangtze River Basin and Huaihe River Basin is attributable to direct anthropogenic activities. Given the dominance of hydrology in driving FDOC, the increase in FDOC is likely to continue under the projected increase in river discharge over China resulting from a future wetter climate.
firstname.lastname@example.org (Yanzi Yan) 22 Jun 2023
[hal-04129361] Debt financing and maintenance expenditure: Theory and evidence on government-operated toll roads in China
Transportation infrastructure is the foundation of economic growth, and the existence of high-quality roads is inseparable from their durable maintenance. However, the burden of heavy debt has brought risks to maintenance management and distorted resource allocation. This study builds a two-stage optimal theoretical model under different debt-financing constraints in China, who has the longest expressway mileage of any country in the world. We establish the two principles of “spend-and-debt” and “debt-and-spend” to demonstrate the substitution effect and the complementary effect of debt financing on maintenance, respectively. Furthermore, we use a time-varying differences-in-differences approach to estimate the effect of the financing of tollway bonds on maintenance and further discuss the mechanism. The results provide evidence that there is a significant improvement in the relationship between tollway bonds and maintenance expenditure, mainly due to the reduction of debt costs and the passive propelling of the government’s spending responsibility. Our proposed theoretical and empirical framework sheds new light on transportation infrastructure research. More specifically, the impetus for public expenditure comes from a decrease of the substitution effect, which not only alleviates the burden of debt scale on the public sector but also provides a reference for developing countries to balance infrastructure construction and maintenance.
email@example.com (Jiandong Chen) 15 Jun 2023
[hal-04126699] Remote Sensing Data for Digital Soil Mapping in French Research—A Review
Soils are at the crossroads of many existential issues that humanity is currently facing. Soils are a finite resource that is under threat, mainly due to human pressure. There is an urgent need to map and monitor them at field, regional, and global scales in order to improve their management and prevent their degradation. This remains a challenge due to the high and often complex spatial variability inherent to soils. Over the last four decades, major research efforts in the field of pedometrics have led to the development of methods allowing to capture the complex nature of soils. As a result, digital soil mapping (DSM) approaches have been developed for quantifying soils in space and time. DSM and monitoring have become operational thanks to the harmonization of soil databases, advances in spatial modeling and machine learning, and the increasing availability of spatiotemporal covariates, including the exponential increase in freely available remote sensing (RS) data. The latter boosted research in DSM, allowing the mapping of soils at high resolution and assessing the changes through time. We present a review of the main contributions and developments of French (inter)national research, which has a long history in both RS and DSM. Thanks to the French SPOT satellite constellation that started in the early 1980s, the French RS and soil research communities have pioneered DSM using remote sensing. This review describes the data, tools, and methods using RS imagery to support the spatial predictions of a wide range of soil properties and discusses their pros and cons. The review demonstrates that RS data are frequently used in soil mapping (i) by considering them as a substitute for analytical measurements, or (ii) by considering them as covariates related to the controlling factors of soil formation and evolution. It further highlights the great potential of RS imagery to improve DSM, and provides an overview of the main challenges and prospects related to digital soil mapping and future sensors. This opens up broad prospects for the use of RS for DSM and natural resource monitoring.
firstname.lastname@example.org (Anne Richer-De-Forges) 14 Jun 2023
[hal-04122770] Large-eddy simulations on pollutant reduction effects of road-center hedge and solid barriers in an idealized street canyon
This study conducted large-eddy simulations (LES) on the pollutant reduction effects of hedge and solid barriers in a three-dimensional idealized street canyon with an aspect ratio of 0.5. The wind direction was perpendicular and oblique (45°) to the street. The results were validated with data from wind tunnel experiments. LES accurately predicted the concentration distribution in the barrier-free case and reproduced well the barrier-induced concentration reduction. In the barrier-free case, a large recirculation vortex was observed. However, the central barriers forced the recirculated airflow in the middle of the canyon and newly formed vortices near the leeward walls. The two counter-direction vortices in the hedge and solid barrier cases transported pollutants toward the center of the canyon and enhanced the vertical pollutant removal at the top of the street canyon. The hedge barrier (solid barrier) reduced spatially-averaged concentration by about 59% (45%) near the leeward wall, 64% (20%) near the windward wall, and 45% (17%) in the whole street canyon compared to the barrier-free case. The effects of leaf area density (LAD) and barrier width were further investigated under the perpendicular wind direction. Increasing the LAD or the width of the hedge barrier decreased concentration near the leeward walls but increased canyon-averaged concentration. Increasing the width of the solid barrier decreased the concentration near the leeward walls and the canyon-averaged concentration. In an oblique wind direction, the hedge and solid barriers reduced by about 30% and 60% the spatially-averaged concentration near the building walls compared to the barrier-free case.
email@example.com (Chao Lin) 09 Jun 2023
[hal-04106589] Predicting the Stability of Organic Matter Originating from Different Waste Treatment Procedures
Recycling organic wastes into farmland faces a double challenge: increasing the carbon storage of soil while mitigating CO2 emission from soil. Predicting the stability of organic matter (OM) in wastes and treatment products can be helpful in dealing with this contradiction. This work proposed a modeling approach integrating an OM characterization protocol into partial least squares (PLS) regression. A total of 31 organic wastes, and their products issued from anaerobic digestion, composting, and digestion-composting treatment were characterized using sequential extraction and three-dimension (3D) fluorescence spectroscopy. The apportionment of carbon in different fractions and fluorescence spectra revealed that the OM became less accessible and biodegradable after treatments, especially the composting. This was proven by the decrease in CO2 emission from soil incubation. The PLS model successfully predicted the stability of solid digestate, compost, and compost of solid digestate in the soil by using only the characterized variables of non-treated wastes. The results suggested that it would be possible to predict the stability of OM from organic wastes after different treatment procedures. It is helpful to choose the most suitable and economic treatment procedure to stabilize labile organic carbon in wastes and hence minimize CO2 emission after the application of treatment products to the soil.
firstname.lastname@example.org (Yan Wang) 25 May 2023
[hal-04105702] Bank diversification and ESG activities: A global perspective
The present study uses data from 1385 banks in 89 countries from 2009 to 2020 to analyze whether the banks’ environmental, social, and governance (ESG) activities around the world affect their diversification. We use a two-step system dynamic generalized method of moments technique and find that the relationship between ESG activity and bank diversification is nonlinear. Environmental and social factors negatively impact bank diversification, whereas governance has a positive impact. Bank diversification is affected by ESG overall and individual ESG dimensions more in developed countries. In high-income countries, banks generate more scope for diversification through environmental disclosures. The social activities of the executive management and the board of directors in high-income countries are intended more to satisfy their own needs than those of their banks. Governance disclosure increases income and asset diversification more for banks in high- and upper-middle-income countries. Capitalization, management quality, and liquidity are the channels through which ESG affects bank diversification. We argue that policy makers and regulators need to design and implement tailor-made frameworks and incentivize banks to embrace sustainable finance best practices. The adoption of these practices and the financing of socially responsible projects would drive interest by various stakeholders and thereby attract higher investor interest and bank valuation.
email@example.com (Abdulazeez Y.H. Saif-Alyousfi) 25 May 2023
[hal-04098592] The multi-year effect of different agroecological practices on soil nematodes and soil respiration
Background and aims : Agroecology practices can induce profound positive changes in soil physical and chemical properties, and inevitably influence soil biological properties and soil functioning. However, we still lack understanding of how soil biodiversity responds to agroecology practices and to what extent such practices, alone or combined, can be beneficial for soil functioning and ecosystem services. Understanding soil biological activities under different agroecology practices is important for predicting carbon cycling in agroecosystems. Methods : By taking advantage of a long-term agricultural experimental research station in northern France, we monitored soil microbes, nematodes and soil respiration over three to five years in response to agroecology practices that varied in the rate of nitrogen (N) fertilization (low vs high), the tillage type (deep vs reduced), and the crop residue management (retain vs removal). Results : Shifting from conventional to agroecology practices had a strong effect on microbial biomass, nematode community and soil respiration. Specifically, reduced N and reduced tillage significantly increased microbial biomass carbon, bacterivore and fungivore density. Perennial biomass crop significantly decreased total nematode density and herbivore density, but increased microbial biomass carbon. Perennial biomass crop also significantly increased the structure and maturity index, but decreased the plant parasite index. Structural equation modelling showed that microbial biomass carbon had a positive correlation with soil respiration in reduced nitrogen, reduced tillage, and residue removal treatments. Bacterivores had a positive correlation with omnivores/predators and soil respiration, while herbivores had a negative correlation with soil respiration in all the treatments. Conclusions The different agroecological practices tested in this 5-year trial revealed the resilience of nematode communities and associated functions like CO2 respiration according to practices.
firstname.lastname@example.org (Feng Sun) 16 May 2023