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Améliorer l'insertion en relais de cultures de service dans un système céréalier pour faire face au changement climatique
No full textInternational audienceIntroducing service crops into rotations promotes ecosystem services, but these services are highly dependent on the production of biomass by the service crop (Vrignon-Brenas et al., 2016b). Relay intercropping into winter cereal makes it possible to limit economic risk thanks to minimal competition with cash crops (Gardarin et al., 2022), but sowing the service crop into an established crop is not straightforward. It may hinder its establishment and the provision of services (Vrignon-Brenas et al., 2016a). Complex interactions between cash crops, companion crops, weeds, and various soil and climatic conditions inevitably lead to uneven success (Vrignon-Brenas et al., 2016a). Therefore, the work presented has two objectives, based on two analysis approaches: 1) identify critical success factors based on 15 years of on-farm experimentation, 2) experiment and evaluate the relevance of the specific establishment practices of a legume service crop mentioned and used by innovative farmers
Mapping the development of agroecology in Europe - Country Reports Series, Vol. 2
No full textInternational audienceThis second volume of the country reports series enlarges the documentation, analysis, and development of agroecology in Europe, and provides examples of implementation in different countries. The 11 countries studied within this volume show somewhat similar results as found in with the first 13 countries mapped in volume 1. There are quite contrasted situations regarding the development of agroecology in different countries. In some countries many existing initiatives with a direct or indirect link to agroecology and some of its principles can be document, whereas the implementation of agroecology or the use of the concept and approaches are still limited in other countries. This does not mean that some countries are better than others, only that agroecology evolves distinctly through the history of agriculture and foods systems as well as the policy framework.Diverse visions, definitions, and use of the concept of agroecology exist in different countries, but a gradual convergence can be observed. Only a few clearly defined educational and training programmes can be documented for the majority of the countries analysed, some of these already exist for years. Dedicated research units, programmes, and projects with the name agroecology are limited in most countries, but they are growing in numbers over the last years. A lot of research related to agroecology is carried out in many countries without being explicitly on agroecology. Living labs are not much known, even less so in relation to agroecology, however, their numbers are increasing in the past years, but in most cases without explicitly referring to agroecology.In addition to expanding the body of knowledge on initiatives linked to agroecology, this volume illustrates what needs to happen for the development of agroecology in Europe. Yet more countries are being mapped for following volumes of this series to give broad analysis and enhanced insights for the future development of agroecology in Europe
Les cyanobactéries benthiques : facteurs de prolifération et risques écologiques dans les eaux continentales
No full textInternational audienceBenthic cyanobacteria are photosynthetic micro-organisms that grow at the interface between sediment and water.The ability of certain strains to produce toxins and the increasingly frequent death of mammals linked to their ingestion highlight the health and ecological risks associated associated with their proliferation in rivers and ponds. In addition, thermal and hydrological changes hydrological changes resulting from climate change could exacerbate these proliferations. While planktonic blooms planktonic blooms are well documented, the ecological impact of benthic cyanobacterial as well as the periods and locations most at risk are little known. In this context, the objectives of Charlotte Robichon's thesis were (i) to identify the main environmental factors influencing the development of benthic cyanobacteria, (ii) investigate the link between these ecological and the concentrations of toxins produced, and (iii) to study the ecological impact of benthic cyanobacteriadevelopment of benthic cyanobacteria on benthic macroinvertebrate communities.The results of this work show that:(1) Hydraulic factors (current speed, depth, flow) exert a major influence on cyanobacteria development. This influence varies over the course of the summer, in line with the life cycle of biofilms of biofilms and in relation to variations in other environmental factors (nutrient concentrationsdevelopment of Chlorophyceae). These results provide a management framework that calls into question current river water release practices;(2) Anatoxin-a concentrations measured in biofilms are generally higher in areas of low current underlining the potential health risk of these areas, which are generally used for bathing;(3) The presence of cyanobacteria in biofilms has a negative impact on the distribution of certain taxa benthic macroinvertebrates, but does not adversely affect their overall abundance or their biodiversity.Les cyanobactéries benthiques sont des micro-organismes photosynthétiques qui se développent à l’interface entre le sédiment et l’eau. La capacité de certaines souches à produire des toxines et les mortalités de mammifères de plus en plus fréquentes liées à leur ingestion mettent en lumière les risques sanitaires et écologiques associés à leur prolifération en rivières et étangs. De plus, les changements thermiques et hydrologiques résultant du dérèglement climatique pourraient exacerber ces proliférations. Si les proliférations planctoniques sont bien documentées, l’impact écologique des développements de cyanobactéries benthiques ainsi que les périodes et les localisations les plus à risques sont peu connus. Dans ce contexte, lathèse de Charlotte Robichon avait pour objectifs (i) d’identifier les facteurs environnementaux principaux influençant le développement des cyanobactéries benthiques, (ii) de rechercher l’existence de lien entre ces facteurs écologiques et les concentrations en anatoxines produites, et (iii) d’étudier l’impact écologique du développement des cyanobactéries benthiques sur les communautés de macroinvertébrés benthiques.Les résultats de ce travail montrent que :(1) Les facteurs hydrauliques (vitesse du courant, profondeur, débit) exercent une influence majeure sur le développement des cyanobactéries. Cette influence est variable au cours de l’été en lien avec le cycle de vie des biofilms et en fonction des variations des autres facteurs environnementaux (concentrations en nutriments, développement des Chlorophycées). Ces résultats fournissent un cadre de gestion qui remet enquestion les pratiques actuelles de lâchers d’eau en rivière ;(2) Les concentrations en anatoxine-a mesurées dans les biofilms sont généralement plus élevées dans les zones de faible courant, soulignant le potentiel risque sanitaire de ces zones généralement dévolues à la baignade ;(3) La présence de cyanobactéries dans les biofilms impacte négativement la distribution de quelques taxons de macroinvertébrés benthiques mais ne nuit pas à l’abondance globale des macroinvertébrés benthiques ni à leur biodiversité
Deciphering the mechanisms of embryo colonization by mouse and chimpanzee pluripotent stem cells at single-cell resolution
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In vitro cell competition between pluripotent stem cell lines predicts their ability to make chimeric embryos in primates : the role of PI3K/AKT and MAPK pathways in embryo colonization
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Introducing intermediate wheatgrass as a perennial grain crop into farming systems: insights into the decision-making process of pioneer farmers
No full textInternational audienceThe perennial grain intermediate wheatgrass (Thinopyrum intermedium , commercial name Kernza TM) has been proposed as a diversification crop for producing forage and grain and providing ecosystem services to farmers. Although a few studies have addressed farmers’ interests in the crop, information is lacking about the links between farmers’ goals and crop management, i.e., how farmers aim at integrating this crop in their systems. Closing this gap, this paper analyzes for the first time the introduction of intermediate wheatgrass (IWG) from a farmer perspective, as a set of decision plans and goals. The overarching orientations of the farm and organization of the production system, referred as strategic decisions, interact with short-term crop management (i.e., tactical decisions) and farmers’ goals for IWG. In total, 17 individual semi-structured interviews and 2 collective crop management prototyping workshops in France were used to analyze farmers’ rationales as a function of their farm systems, agronomic constraints, and know-how. The study demonstrates that farmers’ interests in IWG revolved around multiple ecosystem services and financial returns. Three ideal-types of farms testing IWG emerged from the relationships between existing farming systems and goals for IWG. The strategic and tactical decisions regarding the integration and management of IWG were contingent on the farming systems, the goals for IWG, the farmers’ know-how, and their ability to mitigate risks. Implications for the future development of intermediate wheatgrass as a niche innovation are considered based on farmers’ points of view. This study provides insights into the ideas and concerns of French farmers regarding IWG and proposes a framework for discussing the introduction of a new crop in a farm system
Improving relay intercropping of service crop in cereal systems to cope with climate change
No full textInternational audienceService crops into crop rotations may provide ecosystem services and reduce dependency to inputs. Its relay intercropping into a winter cereal allows better conditions for service crop emergence in spring, compared to summer sowing, with limited risks for crop productivity (Gardarin et al., 2022). Nevertheless, sowing the service crop into an established crop is constraining and may hinder its establishment as the provision of services (Vrignon-Brenas et al., 2016). The risk of failure, increased with climate change, is a serious impediment to the implementation of such practice. This work aims at evaluating options, based on farmers innovations, increasing success of relay intercropping of a legume service crop in cereal cropping systems. The research program CASTOR (TERRA ISARA) consists first in interviewing inspiring farmers and expert having experience in relay intercropping of service crop. It permitted to identify the main lock-in farmers were facing but also the rationale for action innovative farmers developed to overcome some of them. Thereafter, on farm experiments were designed with volunteer farmers to test some of the identified techniques in different agricultural, soil and climate conditions. 16 experiments were implemented in 2 years, mainly focused on service crop implementation and services evaluation. 2 main factors were crossed: 1/ service crop species and 2/ sowing methods leading to 7 to 10 experimental plots per field. Sowing methods principles were common (1/ broadcast sowing (BS); 2/ BS + harrowing (BSH) and optional 3/ row seeding (RS) but the implementation was adapted to conditions and available machinery. Cash crop, service crop and weeds density, biomass and nitrogen content were monitored from service crop sowing to the next crop harvest. In the same period, soil water and nitrogen dynamics were monitored. No significant impact on winter wheat yield or protein content was observed. Due to bad climate conditions, the mean emergence rate of service crops was low (~20%). In most cases (12/16 fields), sowing of red clover (cv. Lestris-RC) led to a faster and denser establishment (183pl/m² at wheat flowering) compared to white clover (cv. Melifer-WC-~108pl/m²)(p-value<0.01). WC also led to lower mean biomass production at wheat harvest (125kgDM/ha vs. 300kgDM/ha – p-value<0.01) and higher risk of failure (almost 50% of WC treatments presented no clover biomass vs. 30% for RC). The mixture of red (50%) and white (50%) clovers (MC) presented intermediate emergence and biomass production. BS generally permitted low emergence of clovers, whatever the sown species. Subsequent harrowing (BSH) significantly improved this emergence. RS permitted to increase rate of emergence of RC but not WC. WC small seeds were not adapted to some seeders used, making very difficult to control WC sowing density. Yet, WC survival was significantly increased with RS (~25% with no biomass compared to 55% for BS treatments) but this does not lead to higher biomass production. RS only permitted to increase significantly (p<0.01) the MC biomass at wheat harvest to a level almost equivalent to RC treatments (~350kgDM/ha vs. ~400kgDM/ha).White clover, considered less competitive for cash crop, is often implemented by farmers testing relay intercropping. However, competition with an already established winter cereal disqualifies this species in our conditions, as WC is too sensitive to radiation limitation (Frame, 2005), being less adapted to cereal competition. Broadcast seeding of service crop, largely used by farmers clearly underperforms but subsequent harrowing significantly improves the service crop establishment. Some interviewed farmers suggest RS as a way to strongly reduce sowing failure but others feared potential damage to the cereal. If no significant impact on cereal yield was measured, this technique may not be adapted to every condition (e.g. soil compaction). It is time consuming and the question of profitability of such technique has to be addressed in comparison with the broadcast seeding with harrowing technique. The machinery used strongly influences the result of the sowing (e.g. seeder not adapted to very small grains). Frame, J., 2005. Forage Legumes For Temperate Grasslands. FAO.Gardarin, A., Celette, F., Naudin, C., Piva, G., Valantin-Morison, M., Vrignon-Brenas, S., Verret, V., Médiène, S., 2022. Intercropping with service crops provides multiple services in temperate arable systems: a review. Agron. Sustain. Dev. 42, 39. https://doi.org/10.1007/s13593-022-00771-xVrignon-Brenas, S., Celette, F., Piquet-Pissaloux, A., Jeuffroy, M.-H., David, C., 2016. Early assessment of ecological services provided by forage legumes in relay intercropping. Eur. J. Agron. 75, 89–98. https://doi.org/10.1016/j.eja.2016.01.01
Preconception and/or preimplantation exposure to a mixture of environmental contaminants altered fetoplacental development and placental function in a rabbit model
No full text3International audiencePregnant women are daily exposed to environmental contaminants, including endocrine disruptors that can impact the offspring's health. This study aimed to evaluate the effects of maternal oral exposure to a mixture of contaminants at a dose mimicking women's exposure, during folliculogenesis and/or preimplantation period (FED and ED groups, respectively) on the fetoplacental phenotype in a rabbit model. The mixture (DEHP, pp'DDE, β-HCH, HCB, BDE-47, BPS, PFOS, PFOA) was defined based on data from HELIX and INMA cohorts. FED and ED females or unexposed females (control) were inseminated, their embryos were collected and transferred to unexposed control recipient rabbits at 80 h post-insemination. The effects of maternal FED and ED exposure were evaluated on fetoplacental growth and development by ultrasound, fetoplacental biometry, fetal metabolism, placental structure and function. The results demonstrated that the mixture weakly affected ultrasound measurements, as only placental volume increased significantly in FED vs ED. Analysis of placental structure demonstrated that the volume fraction of the maternal blood space was increased in FED vs control. Pre- and/or periconception exposure did not affect biometric at the end of gestation, but affected FED fetal biochemistry. Plasma triglyceride concentration was reduced compared to control. However, total cholesterol, urea, ASAT and ALAT in fetal blood were affected in both exposed groups. Multiple factor analysis, including biometric, biochemical, and stereological datasets, indicated that the three groups were significantly different. Additionally, several placental genes were differentially expressed between groups, compared two by two, in a sex-specific manner, with more difference in females than in males. The differentially expressed genes were involved in lipid, cholesterol, and drug/xenobiotic metabolism in both sexes. These results indicate that maternal exposure to environmental contaminants during crucial developmental windows only mildly impaired fetoplacental development but disturbed fetal blood biochemistry and placental gene expression with potential long-term effects on offspring phenotype
Forage potential of Thinopyrum intermedium through near‐infrared spectrometry and grown in mixture with various legumes
No full textInternational audienceAbstract Intermediate wheatgrass [IWG; Thinopyrum intermedium (Host) Barkworth & D.R. Dewey] is a perennial grass, dual‐purpose crop that can provide environmental services. In addition to the grain production, assessing its forage potential is crucial. We developed models for near‐infrared (NIR) spectrometry prediction of the chemical composition and digestibility of IWG across various experimental sites. Among these, a Belgian field was used to compare its dual production in pure stands or in mixture with legumes. Good quality NIR predictions were observed, offering an efficient tool to characterize the forage composition of IWG. Its forage parameters were mainly influenced by the phenological stage with an increase of fiber and a decrease of protein, digestibility, and energy content (NE L ) during the growing season. IWG forage at vegetative stages could be used to feed lactating dairy cattle with a NE L of 1625 kcal kg −1 of DM but, its biomass was low averaging 1.8 t of DM ha −1 . At grain maturity, biomass was higher (i.e., 5.3 t of DM ha −1 ), representing 73%–92% of the total biomass production, and could replace straw in high‐starch dairy diets with a NE L averaging 849 kcal kg −1 of DM. Although the mixture of IWG with legumes enhanced some forage parameters, its value as animal feed was not improved. In mixture, we observed a tradeoff between the increase of the forage yield and the reproductive potential of IWG. These insights can inform the on‐going process of breeding and help farmers to design relevant systems to experiment this new crop
Chapter 9 - Environmental changes and plant disease epidemics
No full textInternational audienceThis chapter discusses human influence on the severity of plant disease epidemics through changing environmental factors. It considers: (1) The impacts of man-induced climate change on the severity of disease epidemics; increased greenhouse gas emissions, increased temperature, changing weather patterns, and changing seasons all affect severity of epidemics. (2) The effects of environmental conditions influenced by agricultural practices for climate change adaptation and mitigation on the severity of epidemics. (3) The consequences of other man-made environmental changes (e.g., increase in air-borne pollutants) on the severity of epidemics of plant diseases