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Bandes de couvert d’interculture conservées en culture de maïs : effets sur les arthropodes rampants, la prédation par les prédateurs généralistes, et les pollinisateurs
No full textThe intensification of agriculture with intensive use of inputs, simplification of the landscape, and reduction of semi-natural habitats, is known to contribute to the decline of arthropods. However, arthropods provide essential ecosystem functions and services in agroecosystems and for agricultural activities such as natural regulation of pests and weeds, and pollination. Increasing plant diversity in cultivated fields through the implementation of agroecological practices and infrastructures is a promising approach to promote the presence of arthropods and their associated ecosystem services. The overall objective of the thesis project was to design and experiment an innovative agroecological practice in maize cropping systems, which is easy to insert into existing cropping systems, and which provides an undisturbed habitat for ground-dwelling arthropods and supplementary floral resources for pollinators. The idea of the proposed practice was to capitalize on an already well known practice, the implementation of winter cover crops, by keeping a strip of a winter cover crop in the middle of the field during the whole maize cultivation period. Therefore, two research objectives were defined: i) to measure the impact of the practice on activity-density and diversity of ground-dwelling arthropods, on their dispersion in the cultivated area (spillover), and on the potential pest regulation in the adjacent cultivated area, and ii) to measure the interest of the practice for the conservation of wild pollinators in intensively cultivated landscapes.Field experiments took place on 12 commercial fields of volunteer farmers in 2019 and 2020, in order to take into account the technical and regulatory constraints of farmers in a conventional arable cropping system. Different species groups were surveyed: communities of ground-dwelling arthropods (carabids, spiders, staphylinids and harvestmen), slugs (the main maize pest in the study area), and pollinating insects (bees and hoverflies). Spatio-temporal dynamics of the different natural enemy groups were analysed, predation rates measured with sentinel prey, and the composition of carabid and wild bee communities investigated. Results show that the undestroyed cover crop strips constitute reservoirs of biodiversity, in particular for carabids, spiders, and bees. In the cropped area, no clear effect of the distance from the strip was detected for the different groups of ground-dwelling arthropods, thus no indication of a potential spillover of arthropods into the crop. However, two main carabid species (Poecilus cupreus and Pterostichus melanarius) were more abundant in the vicinity of the strip (10 meters), but not inside the strip, indicating a potential phenomenon of aggregation of these species towards the strip. Predation rates were higher in the strip and seemed to decrease with increasing distance from the strip into the cropped area. Moreover, carabid and bee communities showed to be different from one habitat to another, as well as the distribution of their ecological traits. Thus, the strips can provide complementary habitat and resources for natural enemies and pollinators. Finally, the spontaneous plants of field margins appeared to be essential for oligolectic and less common bees.The results of this thesis show that the conservation of a cover crop strip in the middle of cropped fields can be an effective practice for the conservation of beneficial arthropods in agricultural landscapes, but can also enhance ecosystem services such as pest regulation. Additionally, the results highlight the importance of preserving or even extending perennial semi-natural habitats such as field margins to contribute to biodiversity conservation in arable cropping systems and landscapes.L'intensification de l'agriculture, avec l’utilisation massive d’intrants, la simplification du paysage et la réduction des habitats semi-naturels, est identifiée comme un facteur important du déclin des arthropodes. Or, les arthropodes fournissent des fonctions et des services écosystémiques essentiels dans les agroécosystèmes et pour les activités agricoles, comme la régulation naturelle des ravageurs et des adventices ou la pollinisation. Augmenter la diversité végétale dans les parcelles cultivées, grâce aux pratiques et infrastructures agroécologiques, est une approche prometteuse pour favoriser la présence d’arthropodes et les services écosystémiques qu’ils fournissent. L’enjeu de cette thèse était de concevoir et d’expérimenter une pratique agroécologique innovante en culture de maïs, qui soit facile à insérer dans les systèmes de cultures existants, et qui fournisse un habitat peu perturbé pour les arthropodes rampants ainsi que des ressources florales supplémentaires pour les pollinisateurs. L’idée de la pratique proposée est de valoriser les couverts d’interculture en conservant une bande du couvert non détruite au milieu de la parcelle, et ce tout au long de la culture du maïs. Ainsi, les deux objectifs principaux du travail de thèse étaient : i) de mesurer l’impact de la pratique sur les arthropodes épigés, sur leur dispersion (spillover) dans la zone cultivée, et sur le potentiel service de régulation des ravageurs dans la culture, et ii) de mesurer l’intérêt de la pratique pour la conservation des pollinisateurs sauvages dans les milieux intensivement cultivés.Des expérimentations ont été mises en places sur 12 parcelles d’agriculteurs volontaires en 2019 et en 2020, afin de prendre en compte les contraintes techniques et réglementaires des agriculteurs en système de grandes cultures conventionnel. Nous avons suivi les communautés d’arthropodes rampants (carabes, araignées, staphylins et opilions), les limaces (le ravageur principal du maïs dans la zone d’étude), et les insectes pollinisateurs (abeilles et syrphes). Nous avons analysé les dynamiques spatio-temporelles de ces différents groupes, ainsi que des taux de prédation sur les proies sentinelles, et de la composition des communautés de carabes et d’abeilles sauvages.Les résultats montrent que les bandes de couvert conservées constituent des réservoirs de biodiversité, en particulier pour les carabes, les araignées et les abeilles. Dans la zone cultivée en maïs, aucun effet de la distance à la bande indiquant un potentiel spillover des arthropodes dans la culture n’a été détecté pour les différents groupes d’arthropodes rampants. Cependant, deux des espèces de carabes majoritaires (Poecilus cupreus et Pterostichus melanarius) étaient plus abondantes dans la culture à proximité de la bande (10 mètres) que dans la bande, indiquant un potentiel phénomène d’agrégation de ces espèces vers la bande. Les taux de prédation, quant à eux, étaient plus élevés dans la bande et semblaient diminuer à mesure de l’éloignement de la bande. Les analyses montrent que les communautés de carabes et d’abeilles sont différentes d’un habitat à l’autre, ainsi que la distribution de leurs traits écologiques. De fait, les résultats indiquent que les bandes fournissent un habitat et des ressources complémentaires aux cultures et aux bordures de champs. Enfin, les plantes à fleur spontanées se sont révélées essentielles pour les abeilles oligolectiques et moins communes.La conservation d’une bande de couvert d’interculture au centre des parcelles peut donc être une pratique efficace pour la préservation de la biodiversité dans les paysages agricoles, mais aussi pour augmenter le potentiel service de régulation des ravageurs au sein des cultures. De manière plus générale, les résultats mettent en avant l’importance de préserver voire d’étendre les habitats semi-naturels pérennes tels que les bordures de champs
Sustainable production and consumption of animal products
No full textInternational audienceLivestock and their productions are indicated among the activities with the highest impact on the environment. This short review reports a brief description of the latest research on the sustainability of livestock farming assessed both as climate-altering emissions, including the adequacy of methane metrics, the carbon stock balances, and water consumption. This review also describes the reductions in impacts by using agroecology to develop nutrient recycling, carbon-neutral livestock systems, and sustainable food with the adoption of sustainable diets and attention to food waste. This knowledge can be useful in better evaluating these issues from both scientific and policy perspectives
The sustainability debate on plastics: Cradle to grave Life Cycle Assessment and Techno-Economical Analysis of PP and PLA polymers with a “Polluter Pays Principle” perspective
No full textInternational audienceWe have studied the impacts of polypropylene (PP) and poly lactic acid (PLA) to quantify the differences between fossil-based and first generation biosourced plastics. Preliminary results on impact assessment from manufacturing stages suggested that the smaller the lot size and part weight of each injection molded plastic material, the higher the economic and environmental impacts. When lot size and part weight were equal, PLA performed better than PP. In three regional development scenarios, we have studied the impacts of end-of-life (EOL) options for smaller-sized and potentially landfilled single-use food packaging materials in town (population <10 k), city (population 30–250 k), and province (population >1 M) regional scales. The impacts of the change from PP to PLA as well as landfill (L) and open incineration (OI) to other EOL options, such as recycling (R), composting (CP), and incineration with energy recovery (IwE), were studied. Impacts of toxic damages are calculated as their impact on the healthcare sector. Thus, microplastics (MP) as a vector of bioaccumulation of toxins, such as dioxins, resulted in 16,5 $/kg MP on a province scale. In the Province scenario, where L PP (90%), a mix of R and OI PP was changed to a mix of R and CP PLA resulting in 63% economic gain and 39% lower global warming potential (GWP). In the City scenario, where L PP was changed to a mix of R PP (50%), IwE PP (25%), and IwE PLA (25%) resulting in 22% economic gain and 26% lower GWP. However, the higher the waste management activities such as sorting and waste processing, the higher the high-carcinogens (+137%), high non-carcinogens (+456%), and toxic release for total air (+9%) emissions. Future work should be done to study the impacts of other toxic compounds such as food contact chemicals to compare different food packaging materials to obtain more comprehensive results
PSDR4 TIP TOP - Un outil sur les paysages agricoles, l'eau et la transition agroécologique
No full textCe numéro regroupe des textes issus des projets ayant travaillé dans le cadre du Programme PSDR 4, sous l’égide d’INRAE et de 10 Régions françaises.The present article concerns the results acquired by the TIP TOP project of PSDR4 program. The ambition was to document agricultural landscapes to account for their water related eco-functionalities, such as the closure of the large water cycle, nutrient recovery, protection of soils, water resources and wetlands. We present an overview of the OPALE (OPerational Assesment of Landscape Ecofonctionnalities) interface developed for this purpose giving the principles of the constitutive models. In particular, we were involved, through collective participation, in the production of a module related to the construction of the landscape by farms, depending on the decision-making rules and constraints of farmers involved in breeding or crops or vegetable production. We then propose a description of the functioning of the landscape by means of functions related to: (i) the pressures exerted by agricultural activities on the landscape-watershed and; (ii) their transfer to the hydrographic network, evaluated by means of particle tracking techniques. Various examples illustrate the steps of the diagnostic carried out by OPALE and its usefulness for prospective simulations related to new agricultural dynamics or new configurations of landscape structures and mosaics.Cet article concerne les résultats acquis par le projet TIP TOP du Programme PSDR4. Il a eu pour ambition de documenter les paysages agricoles pour rendre compte d’éco-fonctionnalités liées aux écoulements d'eau, telles la fermeture du grand cycle de l’eau, la valorisation des éléments nutritifs et la protection des sols, des ressources en eau et des zones humides. Un aperçu de l’interface OPALE (OPerational Assesment of Landscape Ecofonctionnalities), développée dans cet objectif, est présenté, incluant les principes essentiels des modèles constitutifs. Il s’agit d’abord d’une construction collective, avec un module relatif à la fabrique du paysage par les exploitations, en lien avec les règles de décision et contraintes d’agriculteurs éleveurs, céréaliers ou maraîchers. On décrit ensuite le fonctionnement paysager par le biais de fonctions relatives: (i) aux pressions exercées par les activités agricoles sur le paysage-bassin versant et (ii) à leur transfert vers le réseau hydrographique par des techniques de traçage particulaire. Divers exemples illustrent les étapes du diagnostic opéré par OPALE et ses mises en perspective dans le cadre de simulations prospectives portant sur de nouvelles dynamiques agricoles ou de nouvelles configurations des structures et mosaïques paysagères
Editorial: crop diversification, a key pillar for the agroecological transition
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Can Mixed Intercropping Protect Cereals from Aphid-Borne Viruses? An Experimental Approach
No full textInternational audienceIntercropping, i.e., association of two or more species, is promising to reduce insect populations in fields. The cereal aphid Rhopalosiphum padi, a vector of the Barley yellow dwarf virus PAV (BYDV-PAV), represents a major threat for cereal grain production. In this study, we tested the potential of winter barley intercropped with clover to reduce the size of R. padi populations and to lower the BYDV-PAV incidence in fields. We used arenas (i.e., sets of 36 barley plants) intercropped with or without clover plants (at different sown densities). In each arena, a single viruliferous founder, R. padi, (with an alate or a wingless morph) was deposited to introduce aphids and viruses in the experiment. Thirteen days later, the number of aphids in the arena, the percentage of plants hosting aphids and the infection rates were monitored. Data produced through this experimental design showed that clover alters the distribution of the aphid progeny (lower aphid spread) produced by an alate founder morph. Moreover, clover reduces the size of aphid populations produced by a wingless founder morph. However, despite the effects of clover on biological parameters of R. padi, the presence of clover in barley arena did not modify BYDV infections, suggesting complex mechanisms between partners of the BYDV pathosystem for plant-to-plant virus spread
Les jardins dans les espaces ruraux de moyenne montagne en Auvergne Rhône-Alpes : les révélateurs d’un rapport à l’alimentaire en recomposition
No full textInternational audienceGardening and self-consumption practices face deep changes related to food transition in rural areas - the mountainous area Auvergne Rhône-Alpes region is no exception. Recent research about the role of gardens in daily consumption, mainly focuses on urban gardens. In this context, this paper aims to enlighten the role of gardens in food practices of the rural population living in intermediate areas of the mountain - the “mid-moutains”. It is based on research conducted as part of the Jardin’R project. We show that the garden is a gateway to individual and collective self-consumption practices in rural areas. Then we analyze the part these practices play in food policies conducted in our case studies. Finally, we show that reinvestment in self-consumption practices in rural mountains leads to their promotion as an element of the food heritage of these territories.Les pratiques jardinières et d’autoconsommation font l’objet de profonds renouvellements en lien avec les transitions alimentaires en cours dans les territoires ruraux dont les territoires montagnards de la région Auvergne-Rhône-Alpes. Les recherches qui commencent à explorer le rôle des jardins dans l’alimentation portent essentiellement sur les jardins en ville. Dans ce contexte, cet article se penche sur le rôle du jardin dans les pratiques alimentaires des populations rurales de moyenne montagne. Nous nous appuyons sur des travaux de recherche menés dans le cadre du projet Jardin’R en région Auvergne Rhône Alpes, au sein de plusieurs territoires de moyenne montagne. Nous montrons en quoi le jardin est une porte d’entrée sur les pratiques individuelles et collectives d’autoconsommation en milieu rural. Puis nous analysons la place de ces pratiques dans les politiques alimentaires conduites sur nos territoires d’étude. Enfin nous montrons que ce réinvestissement des pratiques d’autoconsommation en milieu rural de moyenne montagne conduit à leur valorisation en tant qu’élément du patrimoine alimentaire de ces territoires
How to create intermediated local food system partnerships? Collective performance, collective negotiation, and collective learning
No full textInternational audienceThis article describes the construction of innovative beef supply chains observed in the Loire and Isère departments in France. The aim for their promoters was to build intermediated local food networks without leaving the organizing power in the intermediaries' hands. The authors take the analytical framework of the sociology of "market agencements," which focuses on market shaping processes, to show how the ranchers, slaughterhouses, wholesalers, and retailers went about defining quality, prices, and the logistics and administrative organization of their supply chains. They also underscore three characteristics of intermediated supply chain partnerships, namely, the search for collective performance, collective negotiation of the rules of the game, and collective learning
Intercropping with service crops provides multiple services in temperate arable systems: a review
No full textInternational audienceService crops are crops grown to provide services to other cash crops, rather than for production purposes, with the ultimate aim of improving the environmental and production performances of cropping systems. Service crops can be intercropped with cash crops to facilitate interactions between crops and to optimize the use of the cropping season. Many terms exist to describe these practices, which highlights their diversity. However, this diversity of terms may be a source of confusion. Here, we present an overview of the current uses of intercropped service plants in temperate cropping systems, with the main services they provide and their management. (1) First, we show that a limited range of service crop species, mostly from the Fabaceae family, have been studied to date. This finding suggests that the diversity of species and cultivar resources that can be used as service crops has been poorly explored in the literature. In contrast, the combinations of service and cash crops tested appear wider. We address this diversity by defining synchronous intercropping, living mulch and relay intercropping. (2) Then, we show that intercropped service crops can efficiently reduce weed biomass and pest attacks and improve nitrogen cycling, thereby increasing soil fertility and improving crop nutrition. The intensity of these services is positively associated with service crop biomass, but excessive service crop biomass increases the risk of competition with cash crops. (3) The balance between the services and disservices provided can primarily be interpreted in terms of biomass production of coexisting crops. The resulting effect of service crops on cash crop yield is variable and reflects the integration of the effects of the various individual services, together with possible disservices. (4) The diversity in management methods makes it possible to manage this trade-off and to adapt the system to different conditions with a few tested species
Agro-éco-Syst'N : Identification de systèmes agroécologiques à hautes performances azotées par le diagnostic avec l'outil Syst'N ®
No full textCe volume regroupe les textes issus du programme Casdar "Innovation et Partenariat" et "Recherche technologique" de 2016. Il a été réalisé sous l’égide du GIS Relance Agronomique.International audienceLe projet Agro-éco-Syst’Nvisait à doter les conseillers agricoles, formateurs et enseignants de méthodes, outils et références leur permettant d’identifier et de concevoir des systèmes de culture à faibles pertes azotées vers l’environnement. A cette fin, une méthode de diagnostic des pertes d’azote vers l’eau (par lixiviation) et vers l’air (par volatilisation), utilisant l’outil Syst’N®, a été élaborée et formalisée. Elle a ensuite été utilisée pour évaluer et expliquer les performances azotées de plusieurs systèmes de culture dans des contextes pédoclimatiques variés.Quinze systèmes de culture ont ainsi été évalués et diagnostiqués. Leur analyse transversale a montré comment différentes combinaisons de pratiques dans un contexte donné conduisent à des performances variables en matière de pertes d’azote. Enfin, 21 cas-types ont été mis à disposition pour outiller les enseignants et conseillers sur le diagnostic des pertes d’azote, ressources mobilisables dans un éventail d’objectifs pédagogiques, de l’évaluation des pertes azotées à la reconception de systèmes de culture. Les systèmes simulés avec Syst’N®sont diffusés viala base de données Pertazote, mise à niveau au cours du proje