Modelling land use strategies to optimise crop production and protection of ecologically important weed species

There is a need to develop farming systems that enable both a satisfactory level of crop production and suitable environmental conditions for natural species. Wildlife-friendly cropping techniques, such as a reduced amount of applied herbicide or a lower crop density, might be adopted in order to maintain populations of weed species of biological interest. An alternative might be to adopt an intensive cropping system in a part of the field and spare the other part as set-aside or field margins, available for the natural development of plant species. The objective of this study was to present a method to compare two strategies for maintaining a desirable level of abundance of a given species of interest in agricultural areas, specifically (i) a strategy based on a wildlife-friendly cropping system in a large cultivated area and (ii) a strategy based on a more intensive cropping system in a reduced area of cultivation, i.e. with land-sparing. The principle is to calculate the ratio of crop production obtained with strategy (i) to the production obtained with strategy (ii) for a given target density of natural species. We show that the value of this ratio, and thus the relative performance of the two strategies, depends on the density of the weed species that can be maintained in an uncultivated ecological area. The method is applied in case studies of two plant species with contrasting ecology and conservation goals. The numerical results show that the strategy based on a wildlife-friendly cropping system is more profitable in most situations

Genetic and environmental effects on crop development determining adaptation and yield

Slafer, Gustavo Ariel. ICREA - AGROTECNIO - Spain.Kantolic, Adriana Graciela. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Appendino, María Laura. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Tranquilli, Gabriela Edith. Instituto Nacional de Tecnología Agropecuaria (INTA). Recursos Naturales. Instituto de Recursos Biológicos. Buenos Aires, Argentina.Miralles, Daniel Julio. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Savin, Roxana. ICREA - AGROTECNIO - Spain.Crop development is a sequence of phenological events controlled by the genetic background and influenced by external factors, which determines changes in the morphology and/or function of organs (Landsberg, 1977). Although development is a continuous process, the ontogeny of a crop is frequently divided into discrete periods, for instance ‘vegetative’, ‘reproductive’ and ‘grain - filling’ phases (Slafer, 2012). Patterns of phenological development largely determine the adaptation of a crop to a certain range of environments. For example, genetic improvement in grain yield of wheat has been associated with shorter time from sowing to anthesis in Mediterranean environments of western Australia (Siddique et al., 1989), whereas no consistent trends in phenology were found where drought is present but not necessarily terminal, including environments of Argentina, Canada and the USA (Slafer and Andrade, 1989, 1993; Slafer et al., 1994a) (Fig. 12.1). Even in agricultural lands of the Mediterranean Basin where wheat has been grown for many centuries, breeding during the last century did not clearly change phenological patterns (Acreche et al., 2008). This chapter focuses on two major morphologically and hysiologically contrasting grain crops: wheat and soybean. For both species, we have an advanced understanding of development and physiology in general. Wheat is a determinate, long-day grass of temperate origin, which is responsive to vernalization. Soybean is a typically indeterminate (but with determinate intermediate variants), short-day grain legume of tropical origin, which is insensitive to vernalization. Comparisons with other species are used to highlight the similarities and differences. The aims of this chapter are to outline the developmental characteristics of grain crops and the links between phenology and yield, to revise the mechanisms of environmental and genetic control of development and to explore the possibilities of improving crop adaptation and yield potential through the fine-tuning of developmental patterns

Drought or/and Heat-Stress Effects on Seed Filling in Food Crops: Impacts on Functional Biochemistry, Seed Yields, and Nutritional Quality

Drought (water deficits) and heat (high temperatures) stress are the prime abiotic constraints, under the current and climate change scenario in future. Any further increase in the occurrence, and extremity of these stresses, either individually or in combination, would severely reduce the crop productivity and food security, globally. Although, they obstruct productivity at all crop growth stages, the extent of damage at reproductive phase of crop growth, mainly the seed filling phase, is critical and causes considerable yield losses. Drought and heat stress substantially affect the seed yields by reducing seed size and number, eventually affecting the commercial trait ‘100 seed weight’ and seed quality. Seed filling is influenced by various metabolic processes occurring in the leaves, especially production and translocation of photoassimilates, importing precursors for biosynthesis of seed reserves, minerals and other functional constituents. These processes are highly sensitive to drought and heat, due to involvement of array of diverse enzymes and transporters, located in the leaves and seeds. We highlight here the findings in various food crops showing how their seed composition is drastically impacted at various cellular levels due to drought and heat stresses, applied separately, or in combination. The combined stresses are extremely detrimental for seed yield and its quality, and thus need more attention. Understanding the precise target sites regulating seed filling events in leaves and seeds, and how they are affected by abiotic stresses, is imperative to enhance the seed quality. It is vital to know the physiological, biochemical and genetic mechanisms, which govern the various seed filling events under stress environments, to devise strategies to improve stress tolerance. Converging modern advances in physiology, biochemistry and biotechnology, especially the “omics” technologies might provide a strong impetus to research on this aspect. Such application, along with effective agronomic management system would pave the way in developing crop genotypes/varieties with improved productivity under drought and/or heat stresses

Décoration de l’Ordre du Mérite agricole

EA GESTADDeux chercheurs de l’UMR Agroécologie décorés de l’ordre du Mérite agricole. Mardi 11 avril, à Paris, Stéphane Le Foll, ministre de l’Agriculture, de l’Agroalimentaire et de la Forêt a décoré de l’ordre du Mérite agricole Nicolas Munier-Jolain et Xavier Reboud, chercheurs à l’UMR Agroécologie de l’INRA Bourgogne-Franche-Comté. Ils ont été distingués pour leurs contributions respectives au développement de l’agroécologie. La cérémonie comptait une trentaine de récipiendaires, dont une dizaine d’agents de l’INRA. Nicolas Munier-Jolain a été récompensé pour sa contribution à l’animation et à la valorisation du réseau de fermes DEPHY pour la démonstration de systèmes de culture économes en pesticides, notamment en lien avec les résultats de la récente thèse de Martin Léchenet, qu’il a encadrée. Pour mémoire, ce travail montre que la réduction d’usage de pesticides est possible sans dégradation des performances productives et économiques à l’échelle des exploitations. Mieux : qu’une transition généralisée vers des systèmes plus économes en pesticides aurait des impacts bénéfiques sur l’indépendance protéique de la France et sur sa balance commerciale. Xavier Reboud, lui, s’est vu décoré pour sa contribution à l’animation du métaprogramme SMaCH (Sustainable Management of Crop Health = Gestion Durable de la Santé des Cultures), dont le défi est de mener des recherches pour réconcilier production agricole et durabilité. Pour cela, SMaCH vise à mettre au point de nouveaux systèmes de culture ainsi que les outils d’accompagnement de ces innovations et de porter la réflexion sur l’objectivation des bénéfices obtenus sur leurs facettes économique, sociale et environnementale

Gestion non-chimique de la flore adventice. Exemple de l'expérimentation PIC (Protection intégrée des cultures) et presentation du reseau DEPHY

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Demonstrating that reducing the reliance on pesticide is possible, based on networks of pioneer farmers. Experience of the DEPHY network in France and perspectives with IPMWORKS at the EU scale

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Conception et évaluation multicritères de prototypes de systèmes de culture dans le cadre de la Protection Intégrée contre la flore adventice

International audiencePas de résuméLa Protection Intégrée contre la flore adventice est un bon exemple d’objet d’étude complexe, du fait de la diversité des leviers agronomiques mobilisables, des interactions éventuelles entre ces leviers, de la diversité des espèces adventices, et des temps longs à considérer pour intégrer les effets cumulatifs. Cet article montre comment sont mobilisées la modélisation et l’expérimentation ‘systèmes’ pour appréhender cette complexité. Il illustre également la large gamme de compétences requises, de l’écologie comparative des espèces jusqu’aux sciences de l’environnement et aux sciences de gestion, nécessaires pour étudier l’insertion potentielle des innovations dans l’exploitation agricole. Les résultats indiquent que la maîtrise technique des infestations adventices est possible, avec des bénéfices environnementaux intéressants. La problématique de la diversification des cultures est un enjeu clef de la performance économique des systèmes économes en herbicides. Integrated Weed Management is an example of complex research area, because of (i) the number of potential management measures, (ii) the possible interactions between these measures, (iii) the range of weed species with various traits, and (iv) the long term consideration required for taking into account the cumulative effects of cropping systems. This paper shows how both modeling and a long term system experiment were used for dealing with this complexity. It also illustrates the diversity of skills required, from comparative ecology to characterize the diversity of weed species and predict their behavior as a function of cropping systems, up to environmental sciences and management sciences, which were used for studying the consequences of innovative cropping systems for the farm management. The results indicate that satisfying weed management can be achieved by combining various measures within a fully redesigned cropping system, with a range of environmental benefits. However, some management measures that are efficient for weed control at the field scale, such as delaying the sowing dates of winter cereals for escaping autumn emerging weeds, might be difficult to implement in practice because of induced bottlenecks in the labor organization at the farm scale. Some weed management measures tend to reduce yields, but this might be at least partly compensated for by reduced input costs. The overall economic profitability of Integrated Weed Management-based systems depends mostly on the possibilities for introducing diversifying crops with sufficient potential economic return

Stratégies de gestion de la flore adventice et alternatives au glyphosate : enseignements du réseau DEPHY

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Reducing pesticide use and improving cropping system sustainability without negative impact on productivity and profitability: key findings from a farm network in France

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