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Impact des digestats de méthanisation sur la qualité microbiologique des sols agricole
No full textNational audienc
Impact d'un apport répété de Digestat sur la communauté microbienne du sol (exemple du SOERE PRO d'EFELE)
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Wines for tomorrow: what is the potential consumer acceptability?
No full textInternational audienceIn the climate change context, wine industry is source of proposals to help producers’ adaptation. One of the major challenges is to move from the current grape varieties to new ones. The aim of this study is to evaluate the consumers’ acceptation of three new varietal adaptations. For this purpose, 65 French consumers from Lyon were recruited to carry out six pairwise preference tests composed of two sets (red and white) of three pairs of wine samples, one pair corresponding to a single adaptation. For example, a pair was composed of a Gamay wine (from current grape variety) and a Gamaret wine (from adaptation grape variety). For each pair, the selected wines came from the same area, producer, and vintage. Then, twenty participants were called back to conduct focus groups to better understand the importance given to the grape variety in their current and future wine choice, purchase, and consumption. Results showed that only one varietal adaptation was preferred by consumers in contrast to current grape varietal wines. These results could be explained in terms of a greater familiarity of consumers with the wine selected. Focus groups data showed that consumers were indifferent to the question of grape variety but not to that of appellation. The most important criterion finally remains hedonic combined with a strong demand of clarity and transparency about any production changes. This exploratory work highlights the richness of information provided by combining quantitative and qualitative approaches. Questioning consumers on their future expectations seems to be crucial to better guide professional current strategies. These first results revealed a discrepancy between the concerns of professionals and consumers regarding the grape variety and need to be confirmed with other consumers panels
Ancient and modern wheat varieties: A trade‐off between soil CO 2 emissions and grain yield?
No full textInternational audienceIntroduction : Humanity is facing two great challenges: producing enough food for a growing population and mitigating greenhouse gas emissions. In this study, we investigated the choice of specific wheat varieties to improve carbon storage in soil while producing enough grain to assure food security. We hypothesize that ancient wheat varieties could store more carbon than modern ones, due to a likely bigger and deeper root system or to more recalcitrant root organic matter. Materials and Methods : We conducted a field experiment with four modern and four ancient wheat varieties, on four different sites with contrasted soil properties. Root morphology was assessed by image analysis and potential CO 2 emissions by incubation for 60 days. Since in situ carbon storage differences between ancient and modern varieties were expected to be weak and not cumulated due to rotation, we estimated expected CO 2 emissions from root biomass and potential CO 2 emissions. The grain yield was also measured. Results : The breeding type (ancient vs. modern varieties) affected root length in two of our four sites, with longer roots for ancient varieties, but it did not affect other root traits such as biomass. The breeding type also affected CO 2 emissions, with higher measured CO 2 emissions for modern than ancient varieties in Arenic Cambisol conditions (Morvan), and higher estimated (considering root biomass variations) CO 2 emissions for modern varieties in Rendzic Leptosol conditions (Saint Romain). Root traits and estimated CO 2 emissions were also dependent on the soil properties of the different sites. We did not find any significant differences in grain yield between ancient and modern varieties. Conclusion : A possible trade‐off between carbon storage and grain production was expected, but our results suggest that some types of soil can support both high grain yield and C storage, especially those with an important depth, a neutral pH and a fine texture
The crispy cricket – Attitudes, habits, and tradition in insect consumption
No full textInternational audienceConsuming insects as a solution to climate change became popular in scientific publications but most of these publications focus on western countries. The objective of this study was to explore attitudes and motivations towards insect consumption in a country where insect consumption is common. A questionnaire was administered to 462 Mexicans in regions where insect consumption is frequent. The questionnaire included three main sections: 1) edible insect representations, 2) attitude and consumption drivers and 3) consumption habits. A majority of respondents declared eating insects (60%). The representation of edible insects of respondents not eating insects was not very different from that of the respondents eating insects, both being organized around the type of edible insects and their nutritional value. A Principal Component Analysis revealed four main attitude dimensions: Eating insect is 1) a habit from the past, 2) a tradition, 3) for snack and special occasions, 4) trendy. Most of noneaters disagreed with the tradition dimension. Insect-eaters’ drivers were mostly nutritional and sensory, liking crispy texture, spiciness, and salty taste of insects. Sustainability, convenience, and affordability were not important drivers. Concerning culinary habits, participants declared to prepare each insect in different ways (taco, complex dishes). To sum up, our results highlight that the fact of seeing eating insects as disgusting and that insects need to be “invisible” to be accepted is culturally acquired among western countries. We suggest that hedonic persuasion strategies based on current practices may be more efficient in promoting entomophagy than nutritional and sustainable messages
Experimental evolution forcing Oenococcus oeni acid tolerance highlights critical role of the citrate locus
No full textInternational audienceOenococcus oeni is the main lactic acid bacterium associated with malolactic fermentation (MLF) of wines. MLF plays an important role in determining the final quality of wines. Nevertheless, due to the stressful conditions inherent to wine and especially acidity, MLF may be delayed. This study aimed to explore by adaptive evolution improvements in the acid tolerance of starters but also to gain a better understanding of the mechanisms involved in adaptation toward acidity. Four independent populations of the O. oeni ATCC BAA-1163 strain were propagated (approximately 560 generations) in a temporally varying environment, consisting in a gradual pH decrease from pH 5.3 to pH 2.9. Whole genome sequence comparison of these populations revealed that more than 45 % of the substituted mutations occurred in only five loci for the evolved populations. One of these five fixed mutations affects mae, the first gene of the citrate operon. When grown in an acidic medium supplemented with citrate, a significantly higher bacterial biomass was produced with the evolved populations compared to the parental strain. Furthermore, the evolved populations slowed down their citrate consumption at low pH without impacting malolactic performance
Spectral Estimate for Stable Signals with P-Adic Time and Optimal Selection of Smoothing Parameter
No full textInternational audienceThe spectral density of stable signals with p-adic times is already estimated under various conditions. The estimate is made by constructing a periodogram that is subsequently smoothed by a spectral window. It is clear that the convergence rate of this estimator depends on the bandwidth of the spectral window (called the smoothing parameter). This work gives a method to select the smoothing parameter in an optimal way, i.e. the estimator converges to the spectral density with the bestrate.The method is inspired by the cross-validation method, which consists in minimizing the estimate of the integrated square error
The potential of microorganisms as biomonitoring and bioremediation tools for mercury-contaminated soils
No full textInternational audienceMercury (Hg) pollution is a global issue due to the high toxicity and wide dispersion of Hg around the world. Whether due to anthropogenic activities or natural processes, Hg emissions are steadily increasing, with very high levels in some regions, directly threatening human and ecosystem health. However, bacteria and fungi have evolved and adapted in response to Hg-induced stress and have developed tolerance mechanisms, notably based on the mer operon system that is involved in Hg uptake and biovolatilization via Hg reduction reactions. Other processes, such as bioaccumulation or extracellular sequestration, are involved in Hg resistance, and the study of contaminated soils has allowed the isolation of a number of microorganisms capable of these mechanisms, with strong potential for the implementation of bioremediation approaches. In addition to playing an important role in determining the fate of Hg in the biogeochemical cycle, these microorganisms can indeed be applied to reduce Hg concentrations or at least stabilize Hg for the remediation of polluted soils. Moreover, thanks to the development of biotechnological tools, bioremediation based on Hg-tolerant microorganisms can be optimized. Finally, these microorganisms are relevant candidates for biomonitoring, for example, through the engineering of biosensors, because the detection of Hg is a major issue in preserving the health of living beings
Site-Specific Herbicide Spraying Can Control Weeds as Well as Full Spraying in the Long-Term. A Simulation Study
No full textSite-specific herbicide spraying reduces herbicide use as it sprays only where weeds are detected. We studied the long-term impact of this weed-control measure on weed-impact indicators (crop yield loss, biodiversity, …). We developed a submodel to simulate the effects of site-specific spraying on weed floras and included this into the existing FlorSys model. The latter simulates multiannual multispecies weed dynamics and crop canopies at a daily time-step from cropping system, weather and soil. Global sensitivity and uncertainty analyses, based on 30-year-long simulations of different rotations and weather series, identified the most influential inputs and the most sensitive outputs. The cropping system (rotation with associated sowing patterns, herbicide products and treatment dates) was more influential than the spraying system (geometrical spraying pattern, weed detection). Finally, a real-life case study was simulated to demonstrate the feasibility of reconciling crop production with reduced herbicide use, thanks to site-specific spraying
Sécheresse et inconfort thermique : Le changement climatique se fait ressentir
No full textCrédits : l’association BFC Nature sous la direction de Daniel SIRUGUE rédacteur en chef de BFC Nature, Alice DESPINOY en rédaction et Daniel ALEXANDRE pour l’illustration.Biodiversité, rendements agricoles, élevage, pêche… Rien n’est épargné par le changement climatique. Zoom sur deux effets en passe de devenir tristement familiers