Global agronomy, a new field of research. A review

The global impact of agriculture has recently become a major research topic, stressed by the rapid growth of the world population. Agriculture management is indeed influencing the quality of water, air, soil, and biodiversity at the global scale. The main agricultural challenges have already been reviewed, but these reviews did not discuss in detail the adaptations of agricultural techniques to global issues and the research challenges for agronomy. Here, we propose a research planning for global agronomy including the following advices. Agronomists should update their research objects, methods, and tools to address global issues. Yield trends and variations among various regions should be analyzed to understand the sources of these variations. Crop model simulations should be upscaled to estimate potential yields and to assess the effect of climate change and resource scarcity at the global scale. Advanced methods should analyze output uncertainty of complex models used at a global scale. Indeed various global models are actually used, but these models are too complex and the output uncertainty is difficult to analyze. The meta-analysis of published data is a promising approach for addressing global issues, though meta-analysis must be applied carefully with appropriate techniques. Finally, global datasets on the performance and environmental impact of cropping systems should be developed to allow agronomists to identify promising cropping systems

Editorial

National audienceL'éditorial explique comment ce numéro de la revue cherche à éclairer la manière dont l’agronomie, seule ou avec d’autres disciplines, peut être mise à contribution pour faire face aux multiples enjeux concernant la raréfaction des ressources naturelles qui concernent l’agriculture

GC-Content evolution in bacterial genomes: The biased gene conversion hypothesis expands

The characterization of functional elements in genomes relies on the identification of the footprints of natural selection. In this quest, taking into account neutral evolutionary processes such as mutation and genetic drift is crucial because these forces can generate patterns that may obscure or mimic signatures of selection. In mammals, and probably in many eukaryotes, another such confounding factor called GC-Biased Gene Conversion (gBGC) has been documented. This mechanism generates patterns identical to what is expected under selection for higher GC-content, specifically in highly recombining genomic regions. Recent results have suggested that a mysterious selective force favouring higher GC-content exists in Bacteria but the possibility that it could be gBGC has been excluded. Here, we show that gBGC is probably at work in most if not all bacterial species. First we find a consistent positive relationship between the GC-content of a gene and evidence of intra-genic recombination throughout a broad spectrum of bacterial clades. Second, we show that the evolutionary force responsible for this pattern is acting independently from selection on codon usage, and could potentially interfere with selection in favor of optimal AU-ending codons. A comparison with data from human populations shows that the intensity of gBGC in Bacteria is comparable to what has been reported in mammals. We propose that gBGC is not restricted to sexual Eukaryotes but also widespread among Bacteria and could therefore be an ancestral feature of cellular organisms. We argue that if gBGC occurs in bacteria, it can account for previously unexplained observations, such as the apparent non-equilibrium of base substitution patterns and the heterogeneity of gene composition within bacterial genomes. Because gBGC produces patterns similar to positive selection, it is essential to take this process into account when studying the evolutionary forces at work in bacterial genomes

Soil organic carbon stocks potentially at risk of decline with organic farming expansion

Funding Information: We thank R. Girault and Y. Behara for help regarding carbon losses in manure management process; D. Angers, E. Ceschia and C. Poeplau for inputs on how to consider cover crops. This work was funded by ADEME, Bordeaux Sciences Agro (Univ. Bordeaux), INRAE’s committee on organic farming (MP Métabio) and Aberdeen University. M.K. and P.S. acknowledge support from the CIRCASA project, which received funding from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement no 774378. Publisher Copyright: © 2023, The Author(s), under exclusive licence to Springer Nature Limited.Peer reviewedPostprin

Agriculture et ressources naturelles : de quoi parlons-nous ?

National audienceL'agriculture entretient des relations complexes avec les ressources naturelles, complexité due à la diversité des ressources qu'elle mobilise et à la diversité des modalités par lesquelles elle les utilise. Cette complexité est de nature à brouiller l'analyse des relations entre agriculture et gestion des ressources naturelles et à présenter un obstacle à la mise au point de systèmes agricoles protégeant ces ressources. Dans cet article, nous es-sayons de clarifier ce sujet en explorant la diversité des ressources qui peuvent être mobilisées ou impactées lors des processus de production agricole. En particulier, nous proposons une typologie en quatre classes des ressources naturelles selon que celles-ci sont renouvelables, recyclables ou dissipées lors des processus de production agricoles. Nous utilisons cette typologie pour mettre en évidence la diversité des leviers agronomiques et des niveaux d'organisation qu'il convient d'activer pour mieux protéger les ressources naturelles

La production fruitière intégrée en France : le vert est-il dans le fruit ?

International audienceAvec la mise en place de la nouvelle Organisation commune de marché (OCM) des fruits et légumes en 1996 (Règlement CE n°2200/96), la production fruitière a été confrontée à une double évolution. D’un côté, la politique européenne se donne pour objectif de structurer l’offre. Elle institue les Organisations de producteurs, agents économiques (coopératives ou entreprises privées), qu’elle dote de moyens financiers afin d’inciter les arboriculteurs à concentrer les volumes mis en marché et à mieux prendre en compte les préoccupations en matière de santé, de qualité des produits et de protection de l’environnement. Un engagement contractuel, le programme opérationnel, se substitue à l’intervention publique sur l’offre au moyen de subventions au retrait de produits du marché. De l’autre, la libéralisation des marchés agricoles s’accompagne d’une prolifération de cahiers des charges, à l’initiative soit des producteurs, soit des metteurs en marché ou de la grande distribution qui devient un acteur majeur dans la commercialisation des fruits et légumes frais. La plupart de ces démarches se réclament du concept de Production fruitière intégrée (PFI) défini par l’Organisation internationale de lutte biologique (OILB) comme « un système de production économique de fruits de haute qualité donnant la priorité aux méthodes écologiquement plus sûres, minimisant les effets secondaires indésirables et l’utilisation de produits agrochimiques, afin d’améliorer la protection de l’environnement et la santé humaine » (OILB/SROP, 1997). La PFI se présente donc comme une qualification d’un genre nouveau en agriculture qui associe à l’objectif, classique, de qualité commerciale des fruits, un objectif de qualité écologique de leur mode de production. Elle met ainsi en relation, et en tension, plusieurs registres d’évaluation des pratiques des arboriculteurs (Codron et al., 2003)

Shared Research Questions On Soil Quality In Organic Farming Systems

"In 2018, a participatory national workshop was organized by ITAB (Organic Food and Farming Technical Institute) and INRA (National Institute for Agricultural Research) in order to highlight issues on soils in Organic Farming (OF) systems. The objectives were: i) to identify the key research questions to be addressed on soils in OF, ii) to make it possible to facilitate network and project building from interactions between academics and stakeholders.Over 150 participants from academic and professional origins attended the workshop which was designed according to The Town Hall Meeting (THM) methodology.High level discussions among participants and panel experts ended up with a list of 20 research questions which confirmed the important lack of knowledge on that topic and the needs for research on the following issues: soils functioning with a focus on biogeochemical cycling and biological interactions; long term effects of agricultural practices, more or less specific to OF; soils protection; tools for soils diagnosis and management.

Editorial

National audienceL'éditorial explique comment ce numéro de la revue cherche à éclairer la manière dont l’agronomie, seule ou avec d’autres disciplines, peut être mise à contribution pour faire face aux multiples enjeux concernant la raréfaction des ressources naturelles qui concernent l’agriculture

Global and regional phosphorus budgets in agricultural systems and their implications for phosphorus-use efficiency

Agraïments: This study was supported by the National Natural Science Foundation of China (41571022, 41625001), the Beijing Natural Science Foundation (Grant 8151002).The application of phosphorus (P) fertilizer to agricultural soils increased by 3.2 % annually from 2002 to 2010. We quantified in detail the P inputs and outputs of cropland and pasture, and the P fluxes through human and livestock consumers of agricultural products, at global, regional, and national scales from 2002 to 2010. Globally, half of the total P input (21.3 Tg P yr−1) into agricultural systems accumulated in agricultural soils during this period, with the rest lost to bodies of water through complex flows. Global P accumulation in agricultural soil increased from 2002 to 2010, despite decreases in 2008 and 2009, and the P accumulation occurred primarily in cropland. Despite the global increase of soil P, 32 % of the world's cropland and 43 % of the pasture had soil P deficits. Increasing soil P deficits were found for African cropland, versus increasing P accumulation in Eastern Asia. European and North American pasture had a soil P deficit because continuous removal of biomass P by grazing exceeded P inputs. International trade played a significant role in P redistribution among countries through the flows of P in fertilizer and food among countries. Based on country-scale budgets and trends we propose policy options to potentially mitigate regional P imbalances in agricultural soils, particularly by optimizing the use of phosphate fertilizer and recycling of waste P. The trend of increasing consumption of livestock products will require more P inputs to the agricultural system, implying a low P-use efficiency aggravating the P stocks scarcity in the future. The global and regional phosphorus budgets and their PUEs in agricultural systems is publicly available at https://doi.pangaea.de/10.1594/PANGAEA.875296