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Maintaining grain yield of Th. intermedium across stand age through constant spike fertility and spike density: understanding its response to various agronomic managements
No full textInternational audienceThinopyrum intermedium subsp. intermedium (Host) Barkworth & D.R. Dewey is a perennial grass proposed as a dual-use crop for both forage and grain. Being in the nascent stage of domestication, its grain yield potential is still low compared to annual counterparts. The understanding of Th. intermedium development and the resulting grain yield in field is limited along with its response to agronomic management. To identify the interrelations between development traits and their influence on grain yield, various crop measurements were evaluated during four growing seasons in field grown Th. intermedium conducted under various autumn defoliation operations and nitrogen (N) fertilizations. Under sufficient N treatments (i.e., 100 kg N ha−1), grain yield remained constant over the four years of the experiment with a mean of 1 t ha−1 resulting from a constant spike fertility and a spike density level above 400 spikes m−2. However, significant mortality and inhibition of reproductive growth of tillers can occur when number of tillers is too high and/or resources too scarce (e.g., unfertilized plots or water deficiencies). In addition, excessive aboveground production at the beginning of the reproductive phase can be detrimental to the final grain yield through the negative influence of tiller density and aboveground biomass (DM) on the yield per spike. The highest aboveground production was observed during the second year with 1415 tillers m−2 at the beginning of the reproductive phase and 16 t of DM ha−1 at grain harvest. Although grain yield response to N fertilization was positively associated to spike density, excessive aboveground biomass could be enhanced by N fertilization. The fertilization of 50 kg ha−1 in autumn combined with a fertilization of 50 kg ha−1 in early-spring could sustain tiller fertility without hampering grain production. In autumn, plant regrowth was low with the highest value of 1.3 t of DM ha−1 observed in the first year. Autumn defoliation could be used to maintain the yield per spike in case of excessive biomass production by the reduction of the DM and the final tiller density coupled with the increase of the grain weight the next year. Finally, shredding post-harvest crop residues at ground level to promote light penetration at the bases of plants may have a positive influence on the tiller fertility. Therefore, under fertile soil conditions (i.e., deep soils and sufficient N fertilization) combined with an optimal stand establishment (i.e., from 500 to 1000 tillers m−2 at the beginning of the growing season) we demonstrated that grain yield potential can be maintained as the crop ages. In the future, breeding should raise resource allocation to the grain by increasing yield per spike and avoid overproduction of new tillers through tillering or rhizome propagation without compromising the vigor of regrowth and its environmental performance
Mise en oeuvre des plantes de services : une grande diversité de modes d'insertion et de gestion
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/611756/)International audienc
D2.4 Agroecology Territories as targets of agroecological transformation in Europe
No full textClimate change and the ecological crisis force us to find ways to address the challenge of developing sustainable agricultural and food systems in Europe. Among the different approaches proposed, agroecology consist of a transformative approach of food systems based on core principles and promoting place-based approaches. Current literature emphasizes the importance to facilitate and foster agroecology transition at territorial level. Place-based approaches at community scale can play a great role in achieving conditions for transition. Related to this, the concept of Agroecology-Territories (AET) has been proposed and is based on territorial action on three dimension (i) the adaptation of agricultural practices, (ii) the conservation of biodiversity and natural resources, and (iii) the development of embedded food systems. The main goal of this work is to analyse the current development of AET or equivalent concepts in Europe and question the relevance of this concept as an upscaling pathway for agroecology, considering economic, environmental and social aspects. A literature review as well as semi-structured interviews with country informants and key informants regarding potential AET were achieved. In a first step, the literature review has allowed to understand the current use of AET as well as related concepts in the literature. Secondly, 17 interviews with country informants have been achieved, allowing a better understanding of the current development of the concept in different European countries. Building on those interviews, 9 interviews with key informants from Italy, France and Germany provided elements on potential AET and allowed an analysis of 8 case studies in those countries. The analysis achieved highlights the gradual emergence of different territorial schemes over Europe that support transitions to sustainable food systems, with three main roots in rural development, territorial food systems, and agri-environment and biodiversity conservation. Pathways of those schemes reveal that their scope enlarges progressively to integrate new issues and topics. The current use of the concept of AET in the literature seems to be limited to a specific community whereas an important body of literature was found on comparable territorial schemes or promoting the relevance of a territorial approaches. Three schemes have been identified as having a good potential toward AET: Bio-districts, Eco-model regions and Regional nature parks (PNR) in France. The comparison of those schemes through case studies provides interesting highlights regarding the conditions, levers and barriers for sustainable transition pathways at territorial level.The AET concept appears throughout this work as a fertile and promising frame to design and extend current existing territorial schemes and their area of action to promote the development of agroecology. Further work on the potential to implement the concept through existing territorial schemes seems to be necessary as well as a further analysis of the numerous existing territorial schemes and their area of action in relation with the concept of AET. Recommendation and perspectives towards the development of agroecology territories are drawn from this work
Generation of Viable Systemic Chimeras with Rabbit Induced Pluripotent Stem Cells Reprogrammed with KLF2, ERAS and PRMT6
No full textInternational audienceEmbryo-derived and induced pluripotent stem cells (ESCs and iPSCs, respectively) exist in two different states, designated naive and primed. Naïve and primed states differ by the signalling pathways, transcription factors and epigenetic regulators that hold the cells in one of either state. In rabbits, ESCs and iPSCs only exist in the primed state of pluripotency.We developed a strategy that led to identify factors capable of reprogramming rabbit iPSCs to a naïve-like, embryo-colonization competent state. We conducted an unbiased screening of a cDNA library encoding a panel of 36 factors, including transcription factors, epigenetic regulators and signalling molecules associated with naïve-state pluripotency in rodents and primates. All the factors were randomly introduced into rabbit primed iPSCs by means of lentivector infection, followed by clonogenic growth in a FGF2/KOSR-deprived culture media containing LIF, activin A, PKC and WNT inhibitors. The three transgenes most frequently detected were PRMT6 that encodes an arginine methyl transferase, ERAS that encodes a GTPase, and KLF2 that encodes Krüppel-like factor 2.To investigate the transgene action, KLF2, ERAS and PRMT6 were overexpressed, either separately, in pairwise combinations, or all three together, in rabbit iPSC cells, either constitutively or with induction. KLF2 was necessary and sufficient to sustain self-renewal in a naïve-like state. However, the addition of both ERAS and PRMT6 led to the appearance of a subset of cells expressing the naïve state-specific marker CD75 at a high level. These CD75high cell population underwent epigenetic reconfiguration typical of naïve-state pluripotency including reactivation of the 2nd X-chromosome.To investigate the ability of KLF2/ERAS/PRMT6 reprogrammed iPSCs to generate chimeras, we developed iPSC line that express the three factors in a reversible manner, using FKBP12 degron. Remarkably, CD75high cells displayed the ability to produce chimeric foetuses, newborns, and viable adults with almost 100% efficiency. The injected cells showed a high contribution in all major organs of the analysed foetuses and newborns.Our results describe systemic chimeras in rabbits for the first time. They pave the way for the creation of knock-out rabbits to study development in lagomorphs, and for the creation of rabbit models of human genetic diseases
Drying out fish ponds, for an entire growth season, as an agroecological practice: maintaining primary producers for fish production and biodiversity conservation
No full textInternational audienceAgroecology largely focusses on terrestrial agroecosystems, but it can also be applied to fish farming. Indeed, ponds are typically used for fish production in Europe, but are also important reservoirs of biodiversity. Numerous studies demonstrate that both fish production and biodiversity are strongly determined by human management. One key practice in extensive fish farming, although more rare in Europe, is to dry out ponds. They are left dry for a complete year after several years of fish production. However, the extent to which this practice affects the functioning of the ecosystem, its biodiversity and fish production remain unclear. We investigated data from 85 fish ponds in the Dombes region, France, sampled between 2007 and 2014. We related variation in key abiotic characteristics to the time since last dry out. The dataset included organic matter content in pond sediments and concentrations of inorganic nitrogen and phosphorus in the water column, and biotic components such as macrophytes cover and richness, phytoplankton concentration and richness, macroinvertebrates density, and fish yield. Our results show that drying out facilitates the mineralization of organic matter in sediments and results in higher concentrations of inorganic nitrogen in the water column. Macrophytes cover is highest during the first year after drying out, and gradually declines after at the expense of increasing phytoplankton concentration. The diversity of both is highest in the first year after drying out and declines rapidly, especially for macrophytes. Fish yield is at its maximum in the second year. Drying out fish ponds appears to be an important agroecological practice in extensive fish farming with an application every three to four years. By nutrient recycling, this practice has a positive impact on the balance between primary producers and indirectly on the whole food web during two years. It optimizes fish production and allows biodiversity conservation
Insectes dans l’alimentation humaine - Transformation et qualité
No full textInternational audienceTo meet today's environmental and nutritional challenges and the growing protein needs of the world's population, the search for sustainable and nutritious protein sources has become a top priority. After presenting the history and context of entomophagy, this article describes the potential benefits (nutritional and environmental) of insects, the potential risks associated with their consumption, and consumer perceptions of this alternative to conventional animal products. Finally, the regulatory aspects related to the use of insects in human food are discussed.Pour répondre aux défis environnementaux et nutritionnels actuels et aux besoins en protéines croissants de la population mondiale, la recherche de sources de protéines durables et nutritives est devenue une priorité absolue. Cet article examine l'opportunité des insectes comme source alimentaire pour les humains. Après une présentation de l’histoire et du contexte de l’entomophagie, il expose les intérêts potentiels (nutritionnels et environnementaux) des insectes, les risques potentiels associés à leur consommation et la perception des consommateurs de cette alternative aux produits animaux conventionnels. Enfin, les aspects réglementaires liés à l’utilisation des insectes dans l'alimentation humaine sont abordés
The socio-economic performance of agroecology. A review
No full textInternational audienceAbstract Agroecology is identified as an important solution to increase the sustainability of agricultural and food systems. Despite the increasing number of publications assessing the socio-economic outcomes of agroecology, very few studies have consolidated the scattered results obtained on various case studies. This paper provides new insights by consolidating evidence on the varied socio-economic effects of agroecology across a large number of cases at a global level. To this purpose, we used a rapid review methodology, screening more than 13,000 publications to retrieve evidence on the socio-economic outcomes of the implementation of agroecological practices. The results of the review indicate that (1) agroecological practices are associated more often with positive socio-economic outcomes across the broad range of evaluated metrics (51% positive, 30% negative, 10% neutral, and 9% inconclusive outcomes); (2) the socio-economic metrics associated with financial capital represent the vast majority of evaluated metrics (83% of total) and are affected positively in a large share of cases (53%), due to favourable outcomes on income, revenues, productivity and efficiency; (3) human capital metrics (16%) are associated with a larger number of negative outcomes (46% versus 38% positive), due to higher labour requirements and costs that are however partly compensated by an overall greater number of positive outcomes on labour productivity (55%); and (4) the results vary depending on the agroecological practice assessed; e.g. for agroforestry, we identify 53% positive outcomes while for cropping system diversification 35%. These results indicate an overall favourable potential for farms to benefit from a positive socio-economic performance with the use of agroecological practices. Yet, the magnitude, temporal aspects, and success factors related to these outcomes, as well as the trade-offs between them, and the system-level effects of an agroecological transition are to be further assessed, since they can have an important influence on the performance of individual farms
Plant–soil synchrony in nutrient cycles: Learning from ecosystems to design sustainable agrosystems
No full text1International audienceRedesigning agrosystems to include more ecological regulations can help feed a growing human population, preserve soils for future productivity, limit dependency on synthetic fertilizers, and reduce agriculture contribution to global changes such as eutrophication and warming. However, guidelines for redesigning cropping systems from natural systems to make them more sustainable remain limited. Synthetizing the knowledge on biogeochemical cycles in natural ecosystems, we outline four ecological systems that synchronize the supply of soluble nutrients by soil biota with the fluctuating nutrient demand of plants. This synchrony limits deficiencies and excesses of soluble nutrients, which usually penalize both production and regulating services of agrosystems such as nutrient retention and soil carbon storage. In the ecological systems outlined, synchrony emerges from plant–soil and plant–plant interactions, eco‐physiological processes, soil physicochemical processes, and the dynamics of various nutrient reservoirs, including soil organic matter, soil minerals, atmosphere, and a common market. We discuss the relative importance of these ecological systems in regulating nutrient cycles depending on the pedoclimatic context and on the functional diversity of plants and microbes. We offer ideas about how these systems could be stimulated within agrosystems to improve their sustainability. A review of the latest advances in agronomy shows that some of the practices suggested to promote synchrony (e.g., reduced tillage, rotation with perennial plant cover, crop diversification) have already been tested and shown to be effective in reducing nutrient losses, fertilizer use, and N2O emissions and/or improving biomass production and soil carbon storage. Our framework also highlights new management strategies and defines the conditions for the success of these nature‐based practices allowing for site‐specific modifications. This new synthetized knowledge should help practitioners to improve the long‐term productivity of agrosystems while reducing the negative impact of agriculture on the environment and the climate
Impacts et conséquences pour les chercheurs en agronomie des évolutions du travail en agriculture
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/610806/)International audienceCe texte s'appuie sur le travail de groupe mené sous forme d'atelier lors du séminaire conclusif des Entretiens agronomiques Olivier de Serres, le 12 juin 2024. L'objectif de l'atelier était d'analyser collectivement les enjeux et les conséquences, pour les agronomes chercheurs, des évolutions du travail en agriculture dans le contexte de la transition agroécologique