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[hal-04756500] Soil bacterial community composition and function play roles in soil carbon balance in alpine timberline ecosystems
Abstract Purpose Soil microbial communities and related key ecological processes play critical roles in timberline delineation and soil carbon balance in alpine ecosystems, which are highly vulnerable to climate change. Accordingly, understanding their geographical differentiation will facilitate recognition of ecosystem functions and improve soil carbon models. In this study, we explored the biogeographic patterns of soil bacterial communities and their mechanisms in maintaining soil carbon balance in an alpine timberline ecosystem of the Sygera Mountains, Southeast Tibet. Materials and methods Soil samples were collected from typical forest belts above and below the timberline. The abundance and composition of bacterial communities, as well as functional genes, were assessed using the gene chip technology. The relationship of key microbial taxa, functional genes, and soil carbon maintenance was investigated using random forest analysis, multi-model inference, and structural equation modeling. Results and discussion The shrubland soil bacterial community exhibited greater diversity compared with the coniferous forest community, with higher Shannon Index and more functional genes at the taxonomic and functional levels, respectively. Bacterial community composition differed between the two forest types, with copiotrophic bacteria more abundant in shrubland, and oligotrophic bacteria more abundant in coniferous forest. The shrubland community was also more efficient at utilizing labile organic carbon, while the coniferous forest community utilized recalcitrant organic carbon more efficiently. Genes related to labile carbon degradation were more intense in shrubland, while genes related to recalcitrant carbon degradation were more concentrated in the coniferous forest. Soil temperature and C:N ratio were dominant drivers of bacterial community composition and function. Besides key soil-environment and microbial properties, certain bacterial taxa and functional genes also exerted unique roles in soil carbon variation. Conclusions Significant differences exist in soil bacterial community composition and functions between the two forest types above and below the timberline of the Sygera Mountains. These differences may be attributed to soil temperature and soil C:N ratio. Coupling these microbial variables into the earth system model can improve the predictive power of the carbon feedback process in terrestrial ecosystems.
ano.nymous@ccsd.cnrs.fr.invalid (Yuanyuan Yang) 28 Oct 2024
https://hal.inrae.fr/hal-04756500v1
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[hal-04741523] The consolidated European synthesis of CH 4 and N 2 O emissions for the European Union and United Kingdom: 1990–2019
Abstract. 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 Tg CH4 yr−1 (EDGARv6.0, last year 2018) and 18.4 Tg CH4 yr−1 (GAINS, last year 2015), close to the NGHGI estimates of 17.5±2.1 Tg CH4 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 Tg CH4 yr−1. Coarser-resolution global-scale TD inversions result in emission estimates of 23 and 24 Tg CH4 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 Tg CH4 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 Tg N2O yr−1, close to the NGHGI data (0.8±55 % Tg N2O yr−1). Over the same period, the mean of TD global and regional inversions was 1.4 Tg N2O yr−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 + 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 datasets related to figures are visualized at https://doi.org/10.5281/zenodo.7553800 (Petrescu et al., 2023).
ano.nymous@ccsd.cnrs.fr.invalid (Ana Maria Roxana Petrescu) 17 Oct 2024
https://hal.science/hal-04741523v1
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[hal-04687421] Detection and Mapping of Cover Crops Using Sentinel-1 SAR Remote Sensing Data
Cover crops are intermediary crops planted in between two main cash crops. They play a role in limiting nitrate leaching into groundwater. Currently, there is no database pertaining to cover crops despite their importance. The development period of cover crops is characterized by a dense cloud cover in Europe, which obstructs land surface monitoring using optical remote sensing. This study proposes a cover crops mapping method based on synthetic aperture radar remote sensing data from the Sentinel-1 (S1) constellation, which is unaffected by weather conditions. Our method is based on the dynamics of the S1 backscattering coefficient at the plot level. Using a decision tree, we mapped cover crops. In the decision tree algorithm, filters were added to eliminate other crops that temporally intersect with the cover crop, namely wheat and rapeseed. The proposed decision tree proved effective in detecting existing cover crop plots, as shown by the classification Recall values ranging between 83.5% and 95.0% and the high precision values ranging between 81.5% and 89.2%. Comparison with the Random Forest classifier showed that our proposed method yielded better and more consistent results. The main limitations in the classification approach were weak cover crops and residual vegetation. The results show that the developed approach, based on the S1 time series, is capable of remotely monitoring cover crops, giving managers and decision makers the ability to follow farmers' work and ascertain if they are applying the recommended agricultural practices that promote sustainable land use and limit the contamination of groundwater.
ano.nymous@ccsd.cnrs.fr.invalid (Sami Najem) 04 Sep 2024
https://hal.inrae.fr/hal-04687421v1
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[hal-04686903] RECCAP2 Future Component: Consistency and Potential for Regional Assessment to Constrain Global Projections
<div xmlns="http://www.tei-c.org/ns/1.0"><p>Projections of future carbon sinks and stocks are important because they show how the world's ecosystems will respond to elevated CO 2 and changes in climate. Moreover, they are crucial to inform policy decisions around emissions reductions to stay within the global warming levels identified by the Paris Agreement. However, Earth System Models from the 6th Coupled Model Intercomparison Project (CMIP6) show substantial spread in future projections-especially of the terrestrial carbon cycle, leading to a large uncertainty in our knowledge of any remaining carbon budget (RCB). Here we evaluate the global terrestrial carbon cycle projections on a region-by-region basis and compare the global models with regional assessments made by the REgional Carbon Cycle Assessment and Processes, Phase 2 activity. Results show that for each region, the CMIP6 multi-model mean is generally consistent with the regional assessment, but substantial cross-model spread exists. Nonetheless, all models perform well in some regions and no region is without some well performing models. This gives confidence that the CMIP6 models can be used to look at future changes in carbon stocks on a regional basis with appropriate model assessment and benchmarking. We find that most regions of the world remain cumulative net sources of CO 2 between now and 2100 when considering the balance of fossil-fuels and natural sinks, even under aggressive mitigation scenarios. This paper identifies strengths and weaknesses for each model in terms of its performance over a particular region including how process representation might impact those results and sets the agenda for applying stricter constraints at regional scales to reduce the uncertainty in global projections.</p><p>Plain Language Summary Future climate change, and higher levels of CO 2 in the atmosphere will have significant effects on ecosystems around the world. It is important that we can model these effects both because the ecosystems are important in their own right and because the carbon they store affects how much CO 2 accumulates in the atmosphere, and thus, how strongly we must reduce human emissions in order to meet internationally agreed climate goals. However, the models often give different results, leading to a large spread JONES ET AL.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Chris D Jones) 04 Sep 2024
https://hal.science/hal-04686903v1
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[hal-03618524] Transformation of PPCPs in the environment: Review of knowledge and classification of pathways according to parent molecule structures
Reviewing the transformation pathways and analyzing the reactions undergone according to the matrices and the parent compound chemical structures may help to progress in our understanding of transformation processes of PPCPs. Of the 199 parent molecules initially targeted, 42% had no information on their transformation products (TPs). The transformation of the remaining 116 PPCPs led to 1371 TPs formed by biotic (630), abiotic (568), and both biotic and abiotic (61) reactions in natural (solid waste, natural waters, soils, WWTP effluents, sediments) and/or synthetic matrices. For a small number of TPs (112) no information was found on the conditions of their formation. Eleven main transformation reactions (hydroxylation, dehydrogenation, cleavage, hydrolysis, dealkylation, oxygenation, dehalogenation, other eliminations, other substitutions, addition and rearrangement) were considered to describe the TPs dataset, that ended up with 3230 individual reactions (one TP can result from several successive reactions). Hydroxylation was the major reaction occurring at 28% followed by dehydrogenation (13%), then cleavage (11%). A majority of studies were performed in synthetic media whereas knowledge on transformation reactions in environmental matrices is very heterogeneous with less information on soils and sediments. Finally, we aimed at assessing the relationship between the transformation reactions and the chemical structures of the parent molecules using 1178 molecular fragments and molecular descriptors. Several clusters composed of sulfonamides, cyclines or macrolides showed trends between functional groups and reactions involved in the transformation pathways. Based on these data and results, some research needs were highlighted.
ano.nymous@ccsd.cnrs.fr.invalid (Kévin Bonnot) 03 Sep 2024
https://hal.inrae.fr/hal-03618524v1
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[hal-04665771] Contamination des milieux aquatiques par les produits phytopharmaceutiques : Etat des lieux et conséquences sur le bien-être humain
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ano.nymous@ccsd.cnrs.fr.invalid (Wilfried Sanchez) 31 Jul 2024
https://hal.inrae.fr/hal-04665771v1
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[hal-03996734] Land cover changes with the development of anaerobic digestion for biogas production in France
Anaerobic digestion is developing in various countries worldwide to produce renewable energy. In addition, the resulting digestates provide readily available nutrients when applied to cropping systems as fertilizers. The introduction of a biogas plant on a farm can induce land cover changes, in relation to the production of feedstock for the biogas plant and/or to the modification of the farming system. The aim of this study was therefore to characterize and quantify the land cover changes in farms associated with biogas plants in France. We combined two national spatialized databases: the Land Parcel Identification System (yearly French land cover at the parcel scale with farm identifier per parcel) and the SINOE database (biogas plant location and year of start-up). We showed that, on average, the changes were limited, with an increase in maize areas (+3.4% of the total farm areas) compensated by a decrease in wheat and rapeseed areas (−1.8% and −1.9%, respectively), but with a certain variability. The French regulation and market limiting the use of dedicated energy crops seems to have limited land cover changes in France compared to other countries. However, we elaborated a typology of land cover changes and characterized five clusters of farms across the country. The main one (67% of the farms) corresponded to unchanged land cover after the introduction of a biogas plant. The four other clusters showed contrasting changes, for example, an increase or a decrease in grassland areas, a strong increase in maize areas, or a replacement of winter wheat by winter barley. The diversity and the driving factors behind these changes deserve to be better studied and understood through further farmer surveys.
ano.nymous@ccsd.cnrs.fr.invalid (Florent Levavasseur) 30 Jul 2024
https://hal.inrae.fr/hal-03996734v1
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[hal-04341666] Life cycle assessment of eight urban farms and community gardens in France and California
Urban agriculture (UA) is often positioned as an senvironmentally sustainable food supply for cities. However, life cycle assessments (LCA) measuring environmental impacts of UA show mixed results, because of inconsistent application of LCA and reliance on hypothetical case studies. To address these shortcomings, we performed an LCA of eight urban farms and community gardens in Paris, France and San Francisco, California, USA. We collected primary data from sites representing diverse growing systems (low-intensity open-field to open-air hydroponics) and motivations (education, civic engagement, and commercial production). We found that medium-tech farms, with minimum social engagement had the lowest impacts using a kilogram-based functional unit, but socially-oriented farms had the lowest impacts with an area-based functional unit. Most impacts came from infrastructure (irrigation pipes, hydroponics structures), irrigation, compost, and peat for seedlings. Our findings can help LCA practitioners perform UA LCAs more completely/consistently, and help urban farmers/gardeners target high-environmental-impact practices to optimize.
ano.nymous@ccsd.cnrs.fr.invalid (Erica Dorr) 22 Jul 2024
https://hal.inrae.fr/hal-04341666v1
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[hal-04341695] Best practices for consistent and reliable life cycle assessments of urban agriculture
There is increasing interest in evaluating the environmental performance of urban agriculture (UA), primarily using life cycle assessment (LCA). However, LCA has been applied to UA inconsistently, making it difficult to confidently compare or draw conclusions from existing studies. This article outlines the key challenges of applying LCA to UA and recommends concrete steps to bring consistency and comprehensiveness to the topic. The research questions that LCA can address are framed before providing practical recommendations for performing LCAs of UA, considering several of its unique aspects that require special attention by practitioners. These include crop diversity, data availability, modeling compost, soil carbon sequestration, producing growing media, distribution of crops, and variability and uncertainty. Next, the article proposes future research areas that will benefit LCA generally and its application to UA, such as framing UA as urban green infrastructure, evaluating at the city scale, accounting for ecosystem services, and including social dimensions of UA. By following these recommendations, future LCAs of UA can be more consistent, comparable, and holistic, and will help build knowledge and inform policy-making and practices around UA.
ano.nymous@ccsd.cnrs.fr.invalid (Erica Dorr) 20 Jul 2024
https://hal.inrae.fr/hal-04341695v1
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[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.
ano.nymous@ccsd.cnrs.fr.invalid (Sylvestre Njakou Djomo) 20 Jul 2024
https://hal.inrae.fr/hal-04300031v1
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[hal-04653503] Collembola taxonomic and functional diversity in conventional, organic and conservation cropping systems
Intensive agriculture has been demonstrated to be a main threat to soil biodiversity through physical and chemical disturbances of soil. Alternative systems based on lower disturbances may help to promote soil biodiversity and its role in soil functioning. However, the effects of alternative systems on soil biodiversity are still poorly understood, especially regarding soil mesofauna. In this study, we aimed to assess the effects of alternative cropping systems and practice intensity on the taxonomic and functional diversity of Collembola. Collembola were sampled for two consecutive years in 21 fields (3 plots per field) under conventional or alternative systems, namely conservation or organic systems either stable (≥ 7 years) or in transition (≤ 3 years). Indicators and indices were computed to characterize separately tillage, pesticide treatments and organic fertilization in each field. Collembola species and functional traits were investigated. Functional diversity of Collembola was assessed using species traits (i.e. traits from the literature) and by conducting length measurements directly on collected Collembola individuals (body, head, leg, antenna and furca length). Collembola diversity was highly variable between and within cropping systems and years. Species richness was notably higher in conservation than in conventional systems in the second year of the study. More specifically, low tillage and high pesticide treatment intensities increased taxonomic and functional diversity and affected species with traits adapted to the surface (i.e. scales, trichobothria). Measured Collembola body length additionally revealed the presence of larger individuals under low tillage and high pesticide treatment intensities, with similar results for other length traits. Overall, our results revealed that 1) taxonomic and functional diversity are complementary to understand the effects of agricultural practices and systems on Collembola and 2) measurement of body length is relevant to assess the effects of disturbances on the local Collembola community.
ano.nymous@ccsd.cnrs.fr.invalid (Juliette Chassain) 18 Jul 2024
https://hal.science/hal-04653503v1
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[hal-04649156] Impact of a large-scale replacement of maize by soybean on water deficit in Europe
The EU imports large quantities of soybeans, mainly for livestock feed. However, there is a trend to increase domestic soybean production and reduce imports. In this study, we investigate the potential impact of an increased EU soybean cultivation on evapotranspiration (ET), water deficit, and irrigation needs. We focus on the consequences of replacing maize with soybeans, as both crops have similar cropping periods and high water demands. We implement a simple, well established crop water model that estimates crop water deficit (ETd) as the difference between simulated potential (ETc) and actual (ETa) ET. We apply this model over the EU from 2001 to 2020, using data on daily reference ET and precipitation, soil hydrological properties and three different crop calendars. Results indicate that a maize-to-soybean conversion would result in an average ETd increase of 49.0 ± 22.1 mm season−1 across the EU. In the four countries of France, Italy, Hungary and Romania, where most of the additional soybean production would be allocated, crop water deficits would increase on average by 21–34 % compared to that of maize, following an increased ETc and/or decreased ETa. However, the decrease in ETa is largely due to an assumed shorter root depth for soybean, while recent empirical results suggest that both crops may actually have comparable root depths. Using the same root depth for maize and soybean, the simulated average increase in ETd amounts to only 28.2 ± 18.3 mm season−1. Our results are sensitive to the choice of crop calendar, with reduced ETd for later sowing dates.
ano.nymous@ccsd.cnrs.fr.invalid (Ronny Lauerwald) 16 Jul 2024
https://hal.science/hal-04649156v1
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[hal-04356784] Sustainable soil management: Soil knowledge use and gaps in Europe
Soils are the foundation of agricultural production, ecosystem functioning and human well-being. Bridging soil knowledge gaps and improving the knowledge system is crucial to meet the growing EU soil policy ambitions in the face of climate change and the ongoing trend in soil degradation. The objective of this article is to assess the current state of knowledge, knowledge use and knowledge gaps concerning sustainable soil management in Europe. This study is based on interviews with 791 stakeholders and 254 researchers and on a comprehensive review of &gt;1800 documents carried out under the European Joint Programme on agricultural soils. Despite differences in stakeholder groups, the conclusions are rather consistent and complementary. We identified major knowledge gaps with respect to (1) soil carbon stocks, (2) soil degradation and fertility and (3) strategies for improved soil management. Transcending these three areas, particularly the loss of soil organic carbon, peatland degradation and soil compaction, are most critical, thus, we stress the urgency of developing more models and monitoring programmes on soils. Stakeholders further report that insufficient transfer of existing soil research findings to practitioners is a hindrance to the adoption of sustainable soil management practices. In addition to knowledge production, soil knowledge gaps may be addressed by considering seven recommendations from the stakeholders: (1) raising awareness, (2) strengthening knowledge brokers, (3) improving relevance of research activities and resource allocation for land users, (4) peer-to-peer communication, (5) targeting advice and information, (6) improving knowledge access, and (7) providing incentives. We argue that filling and bridging knowledge gaps should be a priority for policymakers and the insights provided in the article may help prioritise research and dissemination needs enabling a transition to more sustainable soil management in Europe.
ano.nymous@ccsd.cnrs.fr.invalid (Martin Hvarregaard Thorsøe) 24 Jun 2024
https://hal.inrae.fr/hal-04356784v1
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[hal-04568423] La méthanisation agricole en France, entre opportunité énergétique et transition agroécologique (partie 2)
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ano.nymous@ccsd.cnrs.fr.invalid (Fabrice Beline) 04 May 2024
https://hal.inrae.fr/hal-04568423v1
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[hal-04568420] La méthanisation agricole en France, entre opportunité énergétique et transition agroécologique (partie 1)
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ano.nymous@ccsd.cnrs.fr.invalid (Fabrice Beline) 04 May 2024
https://hal.inrae.fr/hal-04568420v1
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[hal-04549865] Remote sensing of the Earth's soil color in space and time
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ano.nymous@ccsd.cnrs.fr.invalid (Rodnei Rizzo) 17 Apr 2024
https://hal.inrae.fr/hal-04549865v1
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[hal-04547896] An empirical analysis of economic growth in countries exposed to coastal risks: Implications for their ecosystems
Using a novel database on countries exposed to coastal risks (CR), this paper estimates an augmented neoclassical growth model that encompasses eight other new growth models. To account for uncertainty related to the number of models and choice of growth determinant proxies, we use a Bayesian averaging of classical estimates (BACE) approach. A preliminary examination of the data reveals that a country that faces coastal risks is likely to be a former British colony characterized by a common law legal framework, a parliamentary political system, a high degree of international trade openness, little language and ethnic fractionalization, a low level of public sector corruption, and a high rate of fertility. The BACE-based model selection procedure shows that, in CR countries, the growth determinant proxies typically used in the neoclassical, macroeconomic policy, natural resources, and institutions theories are significantly correlated with growth. These results suggest two implications related to these countries’ coastal ecosystems. First, because they are heavily dependent on natural resources and have high fertility rates, these countries might seek short-term economic gains at the expense of deterioration in their ecosystems. Second, these countries’ good institutions and low levels of ethnic division might be conducive to sustainable management of these ecosystems.
ano.nymous@ccsd.cnrs.fr.invalid (Farid Gasmi) 16 Apr 2024
https://hal.science/hal-04547896v1
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[hal-04547825] Les risques environnementaux en 2020 : une feuille de route pour INRAE
INRAE a mené une réflexion prospective collective sur les risques environnementaux dans une perspective inter- et transdisciplinaire inscrite dans le cadre des sciences de la durabilité. Les risques pour les sociétés, les écosystèmes et les milieux ont été considérés conjointement et de façon holistique. Cet article résume les quatre priorités scientifiques identifiées, exprimées de manière transverse. Une feuille de route pour atteindre ces objectifs est également proposée, incluant les ressources humaines, les infrastructures, l’animation scientifique et les partenariats. Ces conclusions devraient participer à la structuration de la recherche française et internationale, et constituer ainsi une contribution significative à l’effort requis par l’urgence environnementale actuelle.
ano.nymous@ccsd.cnrs.fr.invalid (Nicolas Eckert) 16 Apr 2024
https://hal.inrae.fr/hal-04547825v1
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[hal-04535489] Using climate change scenarios to simulate mobility of metal contaminants in soils: the example of copper on a European scale
Soil contaminant deposition is highly dependent on anthropogenic activities while contaminant retention, mobility and availability are highly dependent on soil properties. The knowledge of partitioning between soil solid and solution phases is necessary to estimate whether deposited amounts of contaminants will rather be leached through runoff or accumulated. Besides pedological driven partitioning, runoff is expected to change during the next century due to changes in climate and in rainfall patterns. In this study, we aimed at estimating at the European scale the areas concerned by potential risk due to contaminant leaching (LP). We also defined in the same way the surface areas where limited Cu leaching occurred, leading to potential accumulation (AP) areas. Among contaminant, we focused on copper (Cu) widely used in agriculture, resulting in high spatial variations in deposited and incorporated amounts in soils. We developed a method using both Cu partition coefficients (Kf) between total and dissolved Cu forms, and runoff simulation results for historical and future climates. The calculation of Kf with pedo-transfer functions allowed us to avoid any uncertainties due to past management or future depositions that may affect total Cu concentrations. Areas with high potential risk of leaching or of accumulation were estimated over the XXIth century by comparing Kf and runoff to their respective European median. Thus, at three distinct times, we considered a grid point at risk of LP if its Kf was low compared to the European median and its runoff was high compared to the European median of the time. Similarly, a grid point was considered at risk of AP if its Kf was high and its runoff was low compared to their respective European median of the time. To deal with uncertainties in climate change scenarios and the associated model projections, we performed our study with two representative atmospheric greenhouse gases concentration pathways, defined with climate change associated to a large set of socio-economic scenarios found in the literature. We used two land surface models (ORCHIDEE and LPJmL, given soil hydrologic properties) and two global circulation models (ESM2m and CM5a, given rainfall forecast). Our results show that, for historical scenario 6.4 ± 0.1 % (median,median deviation) and 6.7 ± 1.1 % of the grid cells of the European land surfaces are concerned by LP and AP respectively. Interestingly, our results simulate a constant global surface concerned by LP and AP, around 13% of the grid cells, consistent with an increase in AP and a decrease in LP. Despite large variations in LP and AP extents depending on the land surface model used for estimations, the two trends were more pronounced with RCP 6.0 than with RCP 2.6, highlighting the global risk of combined climate change and contamination and the need for more local assessment. Results are discussed to highlight the points requiring improvement to refine predictions.
ano.nymous@ccsd.cnrs.fr.invalid (Laura Sereni) 06 Apr 2024
https://hal.science/hal-04535489v1
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[hal-04300005] Studies from global regions indicate promising avenues for maintaining and increasing soil organic carbon stocks
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ano.nymous@ccsd.cnrs.fr.invalid (Cornelia Rumpel) 04 Apr 2024
https://hal.inrae.fr/hal-04300005v1
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[hal-04531409] Stocktake study of current fertilisation recommendations across Europe and discussion towards a more harmonised approach
The European Commission has set targets for a reduction in nutrient losses by at least 50% and a reduction in fertiliser use by at least 20% by 2030 while ensuring no deterioration in soil fertility. Within the mandate of the European Joint Programme EJP Soil 'Towards climate-smart sustainable management of agricultural soils', the objective of this study was to assess current fertilisation practices across Europe and discuss the potential for harmonisation of fertilisation methodologies as a strategy to reduce nutrient loss and overall fertiliser use. A stocktake study of current methods of delivering fertilisation advice took place across 23 European countries. The stocktake was in the form of a questionnaire, comprising 46 questions. Information was gathered on a large range of factors, including soil analysis methods, along with soil, crop and climatic factors taken into consideration within fertilisation calculations. The questionnaire was completed by experts, who are involved in compiling fertilisation recommendations within their country. Substantial differences exist in the content, format and delivery of fertilisation guidelines across Europe. The barriers, constraints and potential benefits of a harmonised approach to fertilisation across Europe are discussed. The general consensus from all participating countries was that harmonisation of fertilisation guidelines should be increased, but it was unclear in what format this could be achieved. Shared learning in the delivery and format of fertilisation guidelines and mechanisms to adhere to environmental legislation were viewed as being beneficial. However, it would be very difficult, if not impossible, to harmonise all soil test data and fertilisation methodologies at EU level due to diverse soil types and agro-ecosystem influences. Nevertheless, increased future collaboration, especially between neighbouring countries within the same environmental zone, was seen as potentially very beneficial. This study is unique in providing current detail on fertilisation practices across European countries in a side-by-side comparison. The gathered data can provide a baseline for the development of scientifically based EU policy targets for nutrient loss and soil fertility evaluation.
ano.nymous@ccsd.cnrs.fr.invalid (Suzanne Higgins) 03 Apr 2024
https://hal.inrae.fr/hal-04531409v1
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[hal-04528076] The consolidated European synthesis of CO 2 emissions and removals for the European Union and United Kingdom: 1990–2020
Quantification of land surface–atmosphere fluxes of carbon dioxide (CO2) and their trends and uncertainties is essential for monitoring progress of the EU27+UK bloc as it strives to meet ambitious targets determined by both international agreements and internal regulation. This study provides a consolidated synthesis of fossil sources (CO2 fossil) and natural (including formally managed ecosystems) sources and sinks over land (CO2 land) using bottom-up (BU) and top-down (TD) approaches for the European Union and United Kingdom (EU27+UK), updating earlier syntheses (Petrescu et al., 2020, 2021). Given the wide scope of the work and the variety of approaches involved, this study aims to answer essential questions identified in the previous syntheses and understand the differences between datasets, particularly for poorly characterized fluxes from managed and unmanaged ecosystems. The work integrates updated emission inventory data, process-based model results, data-driven categorical model results, and inverse modeling estimates, extending the previous period 1990–2018 to the year 2020 to the extent possible. BU and TD products are compared with the European national greenhouse gas inventory (NGHGI) reported by parties including the year 2019 under the United Nations Framework Convention on Climate Change (UNFCCC). The uncertainties of the EU27+UK NGHGI were evaluated using the standard deviation reported by the EU member states following the guidelines of the Intergovernmental Panel on Climate Change (IPCC) and harmonized by gap-filling procedures. Variation in estimates produced with other methods, such as atmospheric inversion models (TD) or spatially disaggregated inventory datasets (BU), originate from within-model uncertainty related to parameterization as well as structural differences between models. By comparing the NGHGI with other approaches, key sources of differences between estimates arise primarily in activities. System boundaries and emission categories create differences in CO2 fossil datasets, while different land use definitions for reporting emissions from land use, land use change, and forestry (LULUCF) activities result in differences for CO2 land. The latter has important consequences for atmospheric inversions, leading to inversions reporting stronger sinks in vegetation and soils than are reported by the NGHGI. For CO2 fossil emissions, after harmonizing estimates based on common activities and selecting the most recent year available for all datasets, the UNFCCC NGHGI for the EU27+UK accounts for 926 ± 13 Tg C yr−1, while eight other BU sources report a mean value of 948 [937,961] Tg C yr−1 (25th, 75th percentiles). The sole top-down inversion of fossil emissions currently available accounts for 875 Tg C in this same year, a value outside the uncertainty of both the NGHGI and bottom-up ensemble estimates and for which uncertainty estimates are not currently available. For the net CO2 land fluxes, during the most recent 5-year period including the NGHGI estimates, the NGHGI accounted for −91 ± 32 Tg C yr−1, while six other BU approaches reported a mean sink of −62 [-117,-49] Tg C yr−1, and a 15-member ensemble of dynamic global vegetation models (DGVMs) reported −69 [-152,-5] Tg C yr−1. The 5-year mean of three TD regional ensembles combined with one non-ensemble inversion of −73 Tg C yr−1 has a slightly smaller spread (0th–100th percentiles of [-135,+45] Tg C yr−1), and it was calculated after removing net land–atmosphere CO2 fluxes caused by lateral transport of carbon (crop trade, wood trade, river transport, and net uptake from inland water bodies), resulting in increased agreement with the NGHGI and bottom-up approaches. Results at the category level (Forest Land, Cropland, Grassland) generally show good agreement between the NGHGI and category-specific models, but results for DGVMs are mixed. Overall, for both CO2 fossil and net CO2 land fluxes, we find that current independent approaches are consistent with the NGHGI at the scale of the EU27+UK. We conclude that CO2 emissions from fossil sources have decreased over the past 30 years in the EU27+UK, while land fluxes are relatively stable: positive or negative trends larger (smaller) than 0.07 (−0.61) Tg C yr−2 can be ruled out for the NGHGI. In addition, a gap on the order of 1000 Tg C yr−1 between CO2 fossil emissions and net CO2 uptake by the land exists regardless of the type of approach (NGHGI, TD, BU), falling well outside all available estimates of uncertainties. However, uncertainties in top-down approaches to estimate CO2 fossil emissions remain uncharacterized and are likely substantial, in addition to known uncertainties in top-down estimates of the land fluxes. The data used to plot the figures are available at https://doi.org/10.5281/zenodo.8148461 (McGrath et al., 2023).
ano.nymous@ccsd.cnrs.fr.invalid (Matthew Mcgrath) 02 Apr 2024
https://hal.inrae.fr/hal-04528076v1
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[hal-04369626] Modélisation de la qualité de l’air : vers l’évaluation de l’exposition atmosphérique aux pesticides
La détermination de l’exposition atmosphérique est critique pour évaluer l’impact sanitaire des pesticides mais peu d’outils permettent actuellement de réaliser une cartographie des concentrations à l’échelle nationale. Une méthode possible consisterait à utiliser des modèles de qualité de l’air comme le modèle CHIMERE pour simuler les concentrations de pesticides. Ce genre de modèle représente les processus physico-chimiques intervenant dans l’atmosphère pour calculer les concentrations de diverses substances. Une méthode a été récemment développée dans le modèle CHIMERE pour simuler les concentrations de pesticides en intégrant un modèle de calcul de flux de volatilisation afin de calculer les émissions dans l’air depuis les surfaces traitées. Utiliser une telle méthode exigerait de connaître la distribution spatiale et temporelle des applications de pesticides. Si la spatialisation des données de la Banque nationale des ventes de produits phytopharmaceutiques par les distributeurs agréés spatialisée (BNVD-S) fournit une bonne indication sur la distribution spatiale des applications en France, peu d’informations existent sur les calendriers de traitement. Bien que ce genre de modèles fonctionne à des résolutions de quelques kilomètres (ce qui ne permettrait pas une détermination fiable de l’exposition), il serait possible de déterminer des cartographies à haute résolution de pesticides sur l’ensemble de la France en utilisant des approches de descente d’échelle combinées à des résultats de modèles de dispersion à l’échelle locale. Une telle méthode permettrait à terme de fournir des cartographies de concentrations de pesticides pour les études épidémiologiques.
ano.nymous@ccsd.cnrs.fr.invalid (Florian Couvidat) 07 Mar 2024
https://hal.inrae.fr/hal-04369626v1
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[hal-04485095] Impacts des produits phytopharmaceutiques sur la biodiversité
Les produits phytopharmaceutiques, majoritairement utilisés pour protéger les cultures, contaminent tous les milieux (terrestre, aquatique continental, marin, aérien) et impactent la diversité de certains organismes qui y vivent. Après avoir décrit les méthodes existantes et en développement pour évaluer les impacts des produits phytopharmaceutiques sur la biodiversité, cet article présente les effets directs et indirects de ces produits sur les organismes terrestres et aquatiques, leurs effets sur les fonctions et services rendus par les écosystèmes, puis les leviers d’action permettant d’atténuer la contamination des milieux et ses impacts.
ano.nymous@ccsd.cnrs.fr.invalid (Laure Mamy) 01 Mar 2024
https://hal.inrae.fr/hal-04485095v1
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[hal-04472058] Dérive : les enjeux pour réduire l’exposition des riverains
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ano.nymous@ccsd.cnrs.fr.invalid (Jean Paul Douzals) 22 Feb 2024
https://hal.inrae.fr/hal-04472058v1
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[hal-04459758] Author Correction: Temperature extremes of 2022 reduced carbon uptake by forests in Europe
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ano.nymous@ccsd.cnrs.fr.invalid (Auke M van der Woude) 15 Feb 2024
https://hal.inrae.fr/hal-04459758v1
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[hal-04457354] Modelling concentration heterogeneities in streets using the street-network model MUNICH
Populations in urban areas are exposed to high local concentrations of pollutants, such as nitrogen dioxide and particulate matter, because of unfavourable dispersion conditions and the proximity to traffic. To simulate these concentrations over cities, models like the street-network model MUNICH (Model of Urban Network of Intersecting Canyons and Highways) rely on parameterizations to represent the air flow and the concentrations of pollutants in streets. In the current version, MUNICH v2.0, concentrations are assumed to be homogeneous in each street segment. A new version of MUNICH, where the street volume is discretized, is developed to represent the street gradients and to better estimate peoples' exposure. Three vertical levels are defined in each street segment. A horizontal discretization is also introduced under specific conditions by considering two zones with a parameterization taken from the Operational Street Pollution Model (OSPM). Simulations are performed over two districts of Copenhagen, Denmark, and one district of greater Paris, France. Results show an improvement in the comparison to observations, with higher concentrations at the bottom of the street, closer to traffic, of pollutants emitted by traffic (NOx, black carbon, organic matter). These increases reach up to 60 % for NO2 and 30 % for PM10 in comparison to MUNICH v2.0. The aspect ratio (ratio between building height and street width) influences the extent of the increase of the first-level concentrations compared to the average of the street. The increase is higher for wide streets (low aspect ratio and often higher traffic) by up to 53 % for NOx and 18 % for PM10. Finally, a sensitivity analysis with regard to the influence of the street network highlights the importance of using the model MUNICH with a network rather than with a single street.
ano.nymous@ccsd.cnrs.fr.invalid (Thibaud Sarica) 14 Feb 2024
https://hal.inrae.fr/hal-04457354v1
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[hal-04455077] Editorial : Eau, sol et changement climatique : quelles implications pour les agronomes et les pédologues ?
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ano.nymous@ccsd.cnrs.fr.invalid (Antoine Messéan) 13 Feb 2024
https://hal.inrae.fr/hal-04455077v1
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[hal-04448890] Management impacts on whole soil warming responses of CO2 production and efflux in temperate climate
Although global warming has the potential to increase soil CO2 efflux, the magnitude of these changes are uncertain, as CO2 production rates in deep soil are poorly constrained. In particular, management effects on the warming responses at depth are unknown. Here, we conducted an in-situ soil warming experiment down to 2.0-m depth in an agricultural Cambisol to study the warming responses of (1) CO2 production across different depths and (2) CO2 efflux from topsoil in different seasons under two management practices. To this end, we measured whole-soil profile water content, CO2 production and CO2 efflux under continuous grassland and cropland in response to elevated temperature (+4°C). Warming decreased soil water content for both management practices. We found contrasting warming effects on surface CO2 efflux, depending on season and land management practices. Subsoil CO2 production was more sensitive to warming than topsoil CO2 production with grassland subsoil showing a greater warming response than cropland subsoil. Topsoil CO2 production decreased in response to warming in the cropland but not the grassland. We concluded that warming responses of CO2 production and efflux are affected by soil management practices. Their effect on biological processes (roots and microbial activity) and factors affecting gas diffusivity, such as soil water availability and soil physical organization need to be assessed to model warming effects on carbon exchange between soil and the atmosphere in agricultural systems.
ano.nymous@ccsd.cnrs.fr.invalid (Md Zulfikar Khan) 09 Feb 2024
https://hal.inrae.fr/hal-04448890v1
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[hal-04440991] Mixing ratio and Nitrogen fertilization drive synergistic effects between biochar and compost
Compost and biochar mixtures used to replace mineral N fertilisers in agricultural systems showed contrasting results, especially when applied in combination. We hypothesised that their effect may depend on the mixing ratio between the two components. The aim of our study was to determine if varying ratios of biochar/compost mixtures in presence or absence of chemical nitrogen (N) fertilisation influence ryegrass growth and nutrient uptake. To this end, we set up a pot experiment with an agricultural soil amended with five compost and biochar mixtures differentiated by their mixing ratio. We followed soil fertility parameters and ryegrass growth over three harvests. Results showed that the addition of amendments improved nutrient availability. The highest nutrient availability was observed with pure compost. Despite their high C/N ratios, biochar and compost increased N availability while preventing its microbial immobilisation. Biomass and nutrient uptake by plants were improved by amendments, but were dependent on the biochar/compost ratio. Addition of a mixture containing less biochar than compost (30% biochar/70% compost, on a dry weight basis) showed highest plant growth response and nutrient uptake as compared to the chemical N fertilisation. In addition, the beneficial effects of biochar and compost on plant growth were strengthened by N fertiliser. All in all, we demonstrated the synergistic effects between biochar and compost, which were predominantly driven by the mixing ratio between those two materials, and highlighted their potential use as a sustainable alternative to chemical fertilisers.
ano.nymous@ccsd.cnrs.fr.invalid (Manhattan Lebrun) 06 Feb 2024
https://hal.science/hal-04440991v1
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[hal-04440459] A Comprehensive Assessment of Anthropogenic and Natural Sources and Sinks of Australasia's Carbon Budget
Regional carbon budget assessments attribute and track changes in carbon sources and sinks and support the development and monitoring the efficacy of climate policies. We present a comprehensive assessment of the natural and anthropogenic carbon (C-CO2) fluxes for Australasia as a whole, as well as for Australia and New Zealand individually, for the period from 2010 to 2019, using two approaches: bottom-up methods that integrate flux estimates from land-surface models, data-driven models, and inventory estimates; and top-down atmospheric inversions based on satellite and in situ measurements. Our bottom-up decadal assessment suggests that Australasia's net carbon balance was close to carbon neutral (−0.4 ± 77.0 TgC yr−1). However, substantial uncertainties remain in this estimate, primarily driven by the large spread between our regional terrestrial biosphere simulations and predictions from global ecosystem models. Within Australasia, Australia was a net source of 38.2 ± 75.8 TgC yr−1, and New Zealand was a net CO2 sink of −38.6 ± 13.4 TgC yr−1. The top-down approach using atmospheric CO2 inversions indicates that fluxes derived from the latest satellite retrievals are consistent within the range of uncertainties with Australia's bottom-up budget. For New Zealand, the best agreement was found with a national scale flux inversion estimate based on in situ measurements, which provide better constrained of fluxes than satellite flux inversions. This study marks an important step toward a more comprehensive understanding of the net CO2 balance in both countries, facilitating the improvement of carbon accounting approaches and strategies to reduce emissions.
ano.nymous@ccsd.cnrs.fr.invalid (Yohanna Villalobos) 06 Feb 2024
https://hal.science/hal-04440459v1
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[hal-04408857] Eau, sol et changement climatique – Présentation synthétique du contexte
Cet article présente quelques éléments de contexte proposés lors du débat agronomique de mars 2022, co-organisé par l’AFA, l’Association Française d’Agronomie, et l’AFES, l’Association Française pour l’Etude du Sol, sur la thématique « eau, sol et changement climatique : quelles implications pour les pédologues et les agronomes ? ». Les données sur l’évolution des surfaces agricoles et des ressources en eau, en France et dans le monde, montrent que la ressource en eau est déjà sous tension. L’augmentation brutale de la température, expérience inédite pour l’humanité, se traduira par des épisodes intenses pluvieux et de sécheresse plus fréquents. La gestion de l’état de surface des sols va être amenée à jouer un rôle de plus en plus important, du fait de l’intensification des précipitations et de l’augmentation des températures dues au changement climatique. En ce qui concerne l’adaptation au changement climatique, les solutions de stockage de l’eau dans des réservoirs de surface apparaissent comme une solution de court terme qui n’améliore pas l’efficience de l’eau. Un changement profond des systèmes de production est à engager pour maintenir la durabilité de nos systèmes agricoles.
ano.nymous@ccsd.cnrs.fr.invalid (Yves Coquet) 22 Jan 2024
https://hal.inrae.fr/hal-04408857v1
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[hal-04298724] Stakeholders' point of view on access to soil knowledge in France. What are the opportunities for further improvement?
Life on earth depends on soil health. However, soils are threatened across the world. To respond to the challenges posed by climate change and soil degradation, there is a need to better integrate scientific soil knowledge into the practice. The aim of this paper is to better understand the access to soil knowledge in France and identify opportunities for further improvement, with a particular focus on the difference of point of view between six categories of stakeholders. This study is based on 1951 responses from a participatory stakeholders’ consultation we conducted in France. Our results showed that most stakeholders considered the knowledge they have access to as not adapted to their needs. They also expressed that knowledge sharing between stakeholders was not sufficient. To improve access to soil knowledge, stakeholders suggested adapting at the territorial level the content of soil knowledge shared and transferred, as well as improving ways of sharing and transfer soil knowledge. Additionally, stakeholders valued different exchange networks based on their type of knowledge. Stakeholders with more theoretical soil knowledge (public authorities, NGOs, researchers) stated being more interested in networks between policy, science and society. However, networks with farmers and advisors were more favored by stakeholders with empirical soil knowledge. Considering our findings, in order to strengthen knowledge transfer and sharing, we encourage the promotion of the profession of scientific mediator, as well as the implementation of Living Labs and Lighthouse farms to bring together various stakeholders at a local level towards innovation, training and education. This will ensure a transition towards a more sustainable soil management in Europe.
ano.nymous@ccsd.cnrs.fr.invalid (Eloise Mason) 16 Jan 2024
https://hal.inrae.fr/hal-04298724v1
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[hal-04330096] Are carbon-storing soils more sensitive to climate change? A laboratory evaluation for agricultural temperate soils
A range of agroecological practices allow to increase soil organic carbon (SOC) stocks, which makes a positive impact on climate change mitigation and soil health, but the permanence of this additional SOC storage can be questioned, in particular in a climate change context. Increased temperatures, accentuated evaporation of terrestrial water and increased atmosphere moisture content are anticipated, resulting in more frequent droughts and heavy precipitation events. Understanding the SOC dynamics and assessing the sensitivity of carbon mineralization to these climatic events is necessary to anticipate future carbon losses in terrestrial ecosystems. To this respect, it seems relevant to investigate carbon-storing soils as increased carbon mineralization induced by climate change may limit the carbon storing potential in agricultural soils. Thus, we evaluated the sensitivity of SOC mineralization to increased temperature, decreased soil moisture and drying-rewetting cycles using soils from long-term field experiments. We performed an incubation experiment on topsoil (0-30 cm) samples from temperate luvisols that had been under 20 years under conservation agriculture (CA), organic agriculture (ORG) and conventional agriculture (CON-LC) at the La Cage experiment, and under organic waste products (OWPs) applications in QualiAgro experiment, including biowaste composts (BIOW), residual municipal solid waste composts (MSW), farmyard manure (FYM) and conventional agriculture without organic inputs (CON-QA). Soil samples were incubated in the lab for 3 months under different temperature conditions (20, 28 and 35 degrees C) or under different moisture conditions (matric potential: pF1.5; pF 2.5 and pF 4.2) or under several dry (pF 4.2)-wet (pF 1.5) cycles (DWC). The results shown that, whatever the agricultural practices, soil moisture regime and temperature significantly affect the SOC mineralization. Overall, the DWC did not stimulate soil carbon mineralization relative to wet controls (pF1.5 and pF2.5). Whatever the soil moisture regime and temperature, specific carbon mineralization was similar between agricultural practices at La Cage, while at QualiAgro, specific carbon mineralization was lower in soils receiving organic waste products (OWPs) compared to the baseline soil. These results suggest a strong carbon stabilization by OWPs in soils as assessed by laboratory incubation ex-periments. Within each long-term experiment, we observed no significant difference between the carbon-storing soils (CA, ORG, MSW, FYM and BIOW) and their respective baseline soils (CON-LC and CON-QA) in the delta SOC mineralized whatever the soil moisture regime. The Q10 also indicated no significant difference between carbon -storing soils and their respective baseline soils. These results indicate that the SOC mineralization in carbon -storing soils had a similar sensitivity to the soil moisture regime and temperature as the baseline ones. Hence, the implementation of these agroecological practices appears beneficial for climate change mitigation, even in the context of extreme climatic events.
ano.nymous@ccsd.cnrs.fr.invalid (Tchodjowiè P.I. Kpemoua) 03 Jan 2024
https://hal.inrae.fr/hal-04330096v1
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[hal-04327803] Mieux intégrer les sols dans la séquence "Éviter–Réduire–Compenser
Alors que les enjeux de la préservation des sols gagnent en visibilité au sein de la société, la loi française du 22 août 2021, dite loi Climat et Résilience, inscrit dans la législation française un objectif de « zéro artificialisation nette » (ZAN) et introduit la notion de compensation de l’artificialisation des sols, établissant un lien logique avec la séquence « éviter, réduire, compenser » (dite séquence ERC). Introduite en droit français par la loi sur la protection de la nature du 10 juillet 1976 et consolidée par la loi pour la reconquête de la biodiversité, de la nature et des paysages du 8 août 2016, la séquence ERC constitue un dispositif largement partagé à l’échelle internationale ayant pour but de limiter l’impact écologique des projets de travaux, ouvrages aménagements et des documents de planification (plans, schémas, programmes). Cette séquence est mise en oeuvre au travers d’actions visant à éviter, réduire puis si nécessaire à compenser les pertes en apportant des gains écologiques équivalents aux pertes, voire à les surcompenser (additionnalité écologique).Dans ce contexte, nous nous sommes interrogés sur la façon dont, à l’heure actuelle, les sols et leur multifonctionnalité sont pris en compte dans l’application de la séquence ERC sur le territoire hexagonal français. Pour cela, un travail d’enquête a été réalisé auprès de quatorze acteurs territoriaux, exerçant dans des services instructeurs ou participant à des missions régionales d’autorité environnementale, et de six experts de la compensation et de son dimensionnement. Les acteurs ont été interrogés sur leur vision de l’intégration des sols dans l’application de la séquence ERC, en particulier lors du diagnostic de l’état initial et pour le dimensionnement de la compensation, sur les connaissances et ressources disponibles pour prendre en compte les sols lors de l’application de cette séquence et sur les leviers d’actions envisageables. Ce travail d’enquête a été complété par une analyse des documents issus d’études d’impact de projets d’aménagements, à partir d’une lecture des dossiers par mots-clés définis selon une approche fonctionnelle des sols. Sept dossiers ont été sélectionnés (postérieurs à 2016, date à laquelle la réglementation ERC s’est vue renforcée), permettant d’étudier un panel de projets de différentes natures, dans différentes régions et relevant de diverses procédures réglementaires. À ces dossiers étudiés s’ajoutent quatre avis de l’autorité environnementale portant sur des projets d’aménagement et trois guides relatifs aux méthodes de dimensionnement de la compensation, et l’évaluation des fonctions des zones humides. Les experts interrogés font le constat unanime que les sols sont très peu pris en compte actuellement dans l’application de la séquence ERC, estimant que la réglementation actuelle sur les sols n’est pas suffisamment contraignante pour que les sols soient intégrés systématiquement dans les études d’impact. De fait, l’analyse des documents indique que les sols sont très peu étudiés dans les études d’impacts, avec une absence de prise en compte de leur multifonctionnalité dès le diagnostic de l’état initial de la zone à aménager. Ce travail a permis d’identifier 4 axes sur lesquels agir pour améliorer la prise en compte effective des sols dans la séquence ERC : le cadre juridique, l’adéquation entre exigences réglementaires et capacités techniques de réponses, la formation et l’information des acteurs des territoires et, enfin, l’échelle spatiale à considérer dans la mise en oeuvre de la séquence ERC.
ano.nymous@ccsd.cnrs.fr.invalid (Jérôme Cortet) 03 Jan 2024
https://hal.inrae.fr/hal-04327803v1
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[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.
ano.nymous@ccsd.cnrs.fr.invalid (Tchodjowiè P.I. Kpemoua) 03 Jan 2024
https://hal.inrae.fr/hal-04300044v1
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[hal-04369771] Spatially-explicit environmental assessment of bioethanol from miscanthus and switchgrass in France
Bioethanol is promoted as a means of tackling climate change, diversifying energy sources and securing energy supply. However, there also concerns that their wider deployment could lead to unintended environmental consequences. Life cycle assessment (LCA) is a widely used methodology to assess the environmental performance of biofuels. However, its outcomes strongly depend on the inventory data and modeling assumptions. Agronomic variables such as crop yields, nitrogen fertilizer rates or field emissions of nitrous oxide are very sensitive inputs, as are soil carbon dynamics in response to land use changes (LUC) entailed by the deployment of energy crops. Models simulating agroecosystem processes and the economics of agricultural farms are promising tools to predict such variables and improve the reliability of LCA. Here, we combined the agro-ecosystem model CERES-EGC, the farm economic model AROPAj and the LCA approach to investigate the effect of local drivers on the environmental impacts of bioethanol from miscanthus and switchgrass over France. Overall, lignocellulosic bioethanol achieved GHG abatement targets in the 74 %–94 % range compared to gasoline, and complied with the 50 % minimum imposed by European regulations. Miscanthus-based ethanol achieved up to twice lower environmental impacts than switchgrass due to 50 % higher biomass yields overall. Low fertilizer N input rates (in the 0-30 kg N ha-1 yr-1 range) proved the most efficient strategy to optimize energy return. Significant inter-regional variability occurred, especially in terms of soil C sequestration rates, which weighed in substantially on GHG budgets. Some regions were more efficient than others as a result, which advocates a site-specific approach and a potential prioritization when planning biorefineries, taking into account local production and environmental performance potentials. Compared to previous studies, ours provided high-resolution data in terms of crop yields, nitrous oxide emissions and soil C dynamics, factoring in LUC effects at local to regional scales.
ano.nymous@ccsd.cnrs.fr.invalid (Monia El Akkari) 02 Jan 2024
https://hal.inrae.fr/hal-04369771v1
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[hal-04369484] Interpretable Battery Cycle Life Range Prediction Using Early Cell Degradation Data
Battery cycle life prediction using early degradation data has many potential applications throughout the battery product life cycle. For that reason, various data-driven methods have been proposed for point prediction of battery cycle life with minimum knowledge of the battery degradation mechanisms. However, managing the rapidly increasing amounts of batteries at end of life with lower economic and technical risk requires prediction of cycle life with quantified uncertainty, which is still lacking. The interpretability (i.e., the reason for high prediction accuracy) of these advanced data-driven methods is also worthy of investigation. Here, a physics-informed quantile regression forest (QRF) model, having the advantage of not assuming any specific distribution of cycle life, is introduced to make cycle life range prediction with uncertainty quantified as the width of the prediction interval (PI), in addition to point predictions with high accuracy. The hyperparameters of the QRF model are optimized with a proposed alpha-logistic-weighted criterion so that the coverage probabilities associated with the PIs are calibrated. The interpretability of the final QRF model is explored with two global model-agnostic methods, namely, permutation importance and partial dependence plot.
ano.nymous@ccsd.cnrs.fr.invalid (Huang Zhang) 02 Jan 2024
https://hal.inrae.fr/hal-04369484v1
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[hal-04331853] 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.
ano.nymous@ccsd.cnrs.fr.invalid (Laurent Philippot) 08 Dec 2023
https://hal.inrae.fr/hal-04331853v1
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[hal-04330837] Efficacy, non-target impacts, and other considerations of unregistered fipronil-laced baits being used in multiple invasive ant eradication programs
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ano.nymous@ccsd.cnrs.fr.invalid (Benjamin Hoffmann) 08 Dec 2023
https://hal.inrae.fr/hal-04330837v1
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[hal-04330128] Stocktake study of current fertilisation recommendations across Europe and discussion towards a more harmonised approach
Abstract The European Commission has set targets for a reduction in nutrient losses by at least 50% and a reduction in fertiliser use by at least 20% by 2030 while ensuring no deterioration in soil fertility. Within the mandate of the European Joint Programme EJP Soil ‘Towards climate‐smart sustainable management of agricultural soils’, the objective of this study was to assess current fertilisation practices across Europe and discuss the potential for harmonisation of fertilisation methodologies as a strategy to reduce nutrient loss and overall fertiliser use. A stocktake study of current methods of delivering fertilisation advice took place across 23 European countries. The stocktake was in the form of a questionnaire, comprising 46 questions. Information was gathered on a large range of factors, including soil analysis methods, along with soil, crop and climatic factors taken into consideration within fertilisation calculations. The questionnaire was completed by experts, who are involved in compiling fertilisation recommendations within their country. Substantial differences exist in the content, format and delivery of fertilisation guidelines across Europe. The barriers, constraints and potential benefits of a harmonised approach to fertilisation across Europe are discussed. The general consensus from all participating countries was that harmonisation of fertilisation guidelines should be increased, but it was unclear in what format this could be achieved. Shared learning in the delivery and format of fertilisation guidelines and mechanisms to adhere to environmental legislation were viewed as being beneficial. However, it would be very difficult, if not impossible, to harmonise all soil test data and fertilisation methodologies at EU level due to diverse soil types and agro‐ecosystem influences. Nevertheless, increased future collaboration, especially between neighbouring countries within the same environmental zone, was seen as potentially very beneficial. This study is unique in providing current detail on fertilisation practices across European countries in a side‐by‐side comparison. The gathered data can provide a baseline for the development of scientifically based EU policy targets for nutrient loss and soil fertility evaluation.
ano.nymous@ccsd.cnrs.fr.invalid (Suzanne Higgins) 07 Dec 2023
https://hal.inrae.fr/hal-04330128v1
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[hal-04328740] Soil bacterial community composition and function play roles in soil carbon balance in alpine timberline ecosystems
Abstract Purpose Soil microbial communities and related key ecological processes play critical roles in timberline delineation and soil carbon balance in alpine ecosystems, which are highly vulnerable to climate change. Accordingly, understanding their geographical differentiation will facilitate recognition of ecosystem functions and improve soil carbon models. In this study, we explored the biogeographic patterns of soil bacterial communities and their mechanisms in maintaining soil carbon balance in an alpine timberline ecosystem of the Sygera Mountains, Southeast Tibet. Materials and methods Soil samples were collected from typical forest belts above and below the timberline. The abundance and composition of bacterial communities, as well as functional genes, were assessed using the gene chip technology. The relationship of key microbial taxa, functional genes, and soil carbon maintenance was investigated using random forest analysis, multi-model inference, and structural equation modeling. Results and discussion The shrubland soil bacterial community exhibited greater diversity compared with the coniferous forest community, with higher Shannon Index and more functional genes at the taxonomic and functional levels, respectively. Bacterial community composition differed between the two forest types, with copiotrophic bacteria more abundant in shrubland, and oligotrophic bacteria more abundant in coniferous forest. The shrubland community was also more efficient at utilizing labile organic carbon, while the coniferous forest community utilized recalcitrant organic carbon more efficiently. Genes related to labile carbon degradation were more intense in shrubland, while genes related to recalcitrant carbon degradation were more concentrated in the coniferous forest. Soil temperature and C:N ratio were dominant drivers of bacterial community composition and function. Besides key soil-environment and microbial properties, certain bacterial taxa and functional genes also exerted unique roles in soil carbon variation. Conclusions Significant differences exist in soil bacterial community composition and functions between the two forest types above and below the timberline of the Sygera Mountains. These differences may be attributed to soil temperature and soil C:N ratio. Coupling these microbial variables into the earth system model can improve the predictive power of the carbon feedback process in terrestrial ecosystems.
ano.nymous@ccsd.cnrs.fr.invalid (Yuanyuan Yang) 07 Dec 2023
https://hal.inrae.fr/hal-04328740v1
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[hal-04324581] Recommendations to reduce the streetlight effect and gray areas limiting the knowledge of the effects of plant protection products on biodiversity
Preserving biodiversity against the adverse effects of plant protection products (PPPs) is a major environmental and societal issue. However, despite intensive investigation into the ecotoxicological effects of PPPs, the knowledge produced remains fragmented given the sheer diversity of PPPs. This is due, at least in part, to a strong streetlight effect in the field of ecotoxicology. Indeed, while some PPPs have been investigated in numerous ecotoxicological studies, there are many for which the scientific literature still has little or no information on their ecotoxicological risks and effects. The PPPs under the streetlight include a large variety of legacy substances and a more limited number of more recent or currently-in-use substances, such as the herbicide glyphosate and the neonicotinoid insecticides. Furthermore, many of the most recent PPPs (including those used in biocontrol) and PPP transformation products (TPs) resulting from abiotic and/or biotic degradation are rarely addressed in the international literature in the field of ecotoxicology. Here, based on a recent collective scientific assessment of the effects of PPPs on biodiversity and ecosystem services in the French and European contexts, this article sets out to illustrate the limitations and biases caused by the streetlight effect and numbers of gray areas, and issue recommendations on how to overcome them.
ano.nymous@ccsd.cnrs.fr.invalid (Stéphane Pesce) 05 Dec 2023
https://hal.science/hal-04324581v1
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[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.
ano.nymous@ccsd.cnrs.fr.invalid (Sophie Cornu) 05 Dec 2023
https://hal.inrae.fr/hal-04166791v1
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[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.
ano.nymous@ccsd.cnrs.fr.invalid (Olivier Roques) 04 Dec 2023
https://hal.inrae.fr/hal-04321684v1
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[hal-04320428] Agricultural and municipal organic waste amendments to increase soil organic carbon: How much, how often, and to what end?
A new version of the Century ecosystem model, modified to better represent chemically and physically recalcitrant organic amendments by allowing the addition of organic waste products (OWP) as a mixture of plant material and surface slow soil organic matter (SOM) controlled by the Indicator of Residual Organic Carbon (IROC), and field observations from a 16‐year wheat corn rotation experiment near Paris, France, were used to assess the long‐term impacts of applying agricultural and municipal organic waste products (OWP) on soil carbon (C) sequestration, grain C and nutrient content, and soil nutrient status. Sixteen years of observed grain C, nitrogen (N), phosphorus (P), and potassium (K) and soil C and nutrient data were used to calibrate and validate the performance of IROC‐Century. A suite of future management scenarios, simulated using this calibrated model, explored multiple frequencies of applications of OWP and fertilizer to evaluate their long‐term impacts on grain C and nutrient content, soil C sequestration, and NO 3 − leaching. The model effectively simulated the impact of biennial additions of four OWP types on soil C, N, P, and K during the 16‐year experiment. Measured and simulated OWP +fertilizer resulted in higher soil C (highest for well‐decomposed [55%] vs. less‐decomposed [37%] OWP) and N content, while total soil accumulation of N, P, and K was determined by the content of the OWP, regardless of IROC, and OWP greatly reduced the need to add chemical fertilizer while increasing crop production and N, P, and K uptake by the crop. Simulation scenarios using IROC‐Century for future management suggest that the optimal cropping management system to maintain high corn and wheat production and reduce NO 3 − leaching is to apply OWP biennially for 12 years along with fertilizer and then reduce OWP to every fourth year while continuing to add fertilizer to the wheat crop only. However, reducing the number of OWP additions in these scenarios did decrease the rate of soil carbon sequestration.
ano.nymous@ccsd.cnrs.fr.invalid (William J Parton) 04 Dec 2023
https://hal.inrae.fr/hal-04320428v1
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[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.
ano.nymous@ccsd.cnrs.fr.invalid (Anne Barbillon) 29 Nov 2023
https://hal.inrae.fr/hal-04314568v1
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[hal-04307935] Soil Carbon Sequestration: Much More Than a Climate Solution
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ano.nymous@ccsd.cnrs.fr.invalid (Budiman Minasny) 26 Nov 2023
https://hal.inrae.fr/hal-04307935v1
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[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.
ano.nymous@ccsd.cnrs.fr.invalid (Sébastien Levionnois) 23 Nov 2023
https://inria.hal.science/hal-04302997v1
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[hal-04300094] Four-component net radiometers to quantify albedo and heat fluxes in conservation agriculture
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ano.nymous@ccsd.cnrs.fr.invalid (Souleymane Diop) 22 Nov 2023
https://hal.inrae.fr/hal-04300094v1
