-Sunflower (Helianthus annuus L.) crop is often labelled as environmental-friendly for many objective reasons: limited amounts of N fertiliser, no irrigation, and limited use of pesticides. In addition, sunflower has a potential for providing multiple ecosystem services in diverse cropping systems (e.g. pollinators feeding). However agroecological innovations have been less developed or disseminated than for cereals or oilseed rape. Based on results from the sunflower research consortium in Toulouse (Mestries and Debaeke. 2016. Journées d'échanges Tournesol, 28 et 29 juin 2016, Toulouse (France)), we illustrate some innovating and promising approaches for more agroecological practices in sunflower cropping. Our results suggested that: integrated crop management could be proposed to limit the use of pesticides and mitigate crop damages; cover crops could be used as biofumigants to control soilborne diseases in sunflower; intercropping sunflower with soybean could be a valuable option for maximizing resource-use efficiency in low-input environments; sunflower yield could be maintained at good level in very low input cropping systems. Previous examples point out how agroecological principles could be applied to sunflower crop to improve its production in low-input conditions, and enhance the ecosystem services deliverable by this oilseed crop.Keywords: cultural control / intercropping / ecosystem services / cropping systems / low-input Résumé -La culture de tournesol : respectueuse de l'environnement et agroécologique. La culture de tournesol (Helianthus annuus L.) est souvent qualifiée de respectueuse de l'environnement en raison de sa faible dépendance aux apports d'engrais, à l'eau d'irrigation et aux applications de pesticides en végétation. Par ailleurs, le tournesol contribue à de nombreux services écosystémiques au premier rang desquels l'alimentation des pollinisateurs. Cependant, très peu d'innovations agroécologiques ont été mises en avant sur cette culture contrairement à ce qui a été développé en céréales ou en colza. En nous basant sur les travaux récents du consortium de recherche sur le tournesol basé à Toulouse (Mestries et Debaeke. 2016. Journées d'échanges Tournesol, 28 et 29 juin 2016, Toulouse (France)), nous illustrerons plusieurs approches innovantes et prometteuses pour augmenter la performance agroécologique de la culture de tournesol. Ainsi nos résultats montrent que : des méthodes de protection intégrée peuvent être proposées pour limiter l'application de pesticides et atténuer les pertes de rendement ; des cultures intermédiaires (brassicacées) pourraient être utilisées pour la biofumigation des sols et le contrôle de maladies telluriques en tournesol ; l'association culturale avec le soja pourrait constituer une option intéressante pour maximiser l'utilisation des ressources en bas intrants ; le rendement du tournesol peut être maintenu à un bon niveau dans des systèmes à très bas niveaux d'intrants. Les exemples précédents illustrent comment les principes de l'agroécologie peuv...

Growing concern for economic and environmental issues emphasizes the potential value of intercropping systems in temperate regions. However, the selection of relevant tree species to be associated with crops has been little documented. The growth and the nitrogen nutrition of two economically valuable species, wild cherry (Prunus avium L.) and hybrid walnut (Juglans nigra L.·Juglans regia L.), were compared over six years after plantation. These two species were associated with non-irrigated cereal crops in the agroforestry treatment or grown separately (weeded control and fallow). Intercropping increased diameter growth as soon as year 2 in the two species. Leaf biomass assessment using allometric models showed an earlier and greater leaf biomass increase in hybrid walnut than in wild cherry tree. After six years, the relative growth increase of the agroforestry trees with respect to the control trees varied with the parameter considered (diameter at breast height from +26 to +65%, leaf biomass from +54 to +142%) and with the tree species (higher relative growth for hybrid walnut trees). The beneficial effect on tree growth can be accounted for in terms of enhanced nitrogen nutrition. The tree-crop association in intercropping systems, which improves tree growth, might thus allow the planting of more demanding trees on soils of lower fertility.

Interdisciplinary research frameworks can be useful in providing answers to the environmental challenges facing rural environments, but concrete implementation of them remains empirical and requires better control. We present our practical experience of an interdisciplinary research project dealing with non-industrial private forestry in rural landscapes. The theoretical background, management, and methodological aspects, as well as results of the project, are presented in order to identify practical key factors that may influence its outcomes. Landscape ecology plays a central role in organizing the project. The efforts allocated for communication between scientists from different disciplines must be clearly stated in order to earn reciprocal trust. Sharing the same nested sampling areas, common approaches, and analytical tools (GIS) is important, but has to be balanced by autonomy for actual implementation of field work and data analysis in a modular and evolving framework. Data sets are at the heart of the collaboration and GIS is necessary to ensure their long-term management and sharing. The experience acquired from practical development of such projects should be shared more often in networks of teams to compare their behavior and identify common rules of functioning.

The online version of this article (doi:10.1007/s11104-016-3127-3) contains supplementary material, which is available to authorized users.AimsPhosphorus (P) is frequently limiting crop production in agroecosystems. Large progress was achieved in understanding root traits associated with P acquisition efficiency (PAE, i.e. P uptake achieved under low P conditions). Most former studies were performed in controlled environments, and avoided the complexity of soil-root interactions. This may lead to an oversimplification of the root-soil relations. The aim of the present study was, therefore, to identify the dominant root and rhizosphere-related traits determining PAE, in contrasting soil conditions in the field. Methods Twenty-three maize hybrids were grown at two contrasting P levels of a long-term P-fertilizer trial in two adjacent soil types: alkaline and neutral. Bulk soil, rhizosphere and root parameters were studied in relation to plant P acquisition. ResultsSoil type had robust effect on PAE. Hybrids’ performance in one soil type was not related to that in the other soil type. In the neutral soil, roots exhibited higher specific root length, higher root/shoot ratio but lower PAE. Best performing hybrids in the neutral soil were characterized by top soil exploration, i.e., greater root surface and topsoil foraging. In contrast, in the alkaline soil, PAE and foraging traits were not correlated, P availability in the rhizosphere was greater than the bulk soil and phosphatase activity was higher, suggesting a ‘mining strategy’ in that case (i.e. traits that facilitate elevated P availability). Conclusions These results indicate the key role of environmental factors for roots traits determining high PAE. The study highlights the need to consider soil properties when breeding for high PAE, as various soil types are likely to require different crop ideotypes

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