As a rainfed spring-sown crop, sunflower (Helianthus annuus L.) is increasingly exposed to negative impacts of climate change, especially to high temperatures and drought stress. Incremental, systemic and transformative adaptations have been suggested for reducing the crop vulnerability to these stressful conditions. In addition, innovative cropping systems based on low-input management, organic farming, soil and water conservation practices, intercropping, double-cropping, and/or agroforestry are undergoing marked in agriculture. Because of its plasticity and low-input requirements (nitrogen, water, pesticides), sunflower crop is likely to take part to these new agroecological systems. Aside from current production outputs (yield, oil and cake), ecosystem services (e.g. bee feeding, soil phytoremediation…), and non-food industrial uses are now expected externalities for the crop. The combination of climatic and societal contexts could deeply modify the characteristics of genotypes to be cultivated in the main production areas (either traditional or adoptive). After reviewing these changes, we identify how innovative cropping systems and new environments could modify the traits classically considered up to now, especially in relation to expected ecosystem services. Finally, we consider how research could provide methods to help identifying traits of interest and design ideotypes.

Soybean (Glycine max (L.) Merr.) may contribute to the agro-ecological transition of cropping systems in Europe, but its productivity is severely affected by summer drought. New drought-avoidance cropping strategies, such as early sowing, require cultivars with high early plant growth under suboptimal conditions. This study aims at phenotyping early-stage root and shoot traits of 10 cultivars commonly grown in Europe. Cultivars were grown in minirhizotrons under two soil moisture status in controlled conditions. Root and shoot traits were evaluated at 10 days after sowing. Field early growth of two cultivars was also analyzed under early and conventional sowing dates. A significant intraspecific variability (p < 0.05) was found for most investigated shoot and root morpho-physiological traits regardless of the soil moisture status under controlled conditions. However, no significant difference among cultivars (p > 0.05) was found in terms of root architectural traits that were mainly affected by water stress. Total root length was positively correlated with shoot length and shoot dry matter (p < 0.05). Under field conditions, the differences between cultivars were expressed by the canopy cover at emergence, which determines the subsequent canopy cover dynamics. The significant early growth difference among cultivars was not related to the maturity group. Cultivars characterized by high root depth and length, high root density and narrow root angle could be considered as good candidates to cope with water stress via better soil exploration. New agronomic strategies mobilizing the diversity of cultivars could thus be tested to improve soybean water use efficiency in response to climate change.

Forecasting sunflower grain yield a few weeks before crop harvesting is of strategic interest for cooperatives that collect and store grains. With such information, they can optimize their logistics and thus reduce the financial and environmental costs of grain storage. To provide these predictions, data assimilation approaches involving the crop model SUNFLO are used. The methods are based on the re-estimation of soil conditions and on the sequential update of crop model states using an ensemble Kalman filter. They combine the simulation of the crop model and time series of leaf area index (LAI) derived from remote sensors and extracted over 281 fields near Toulouse, France. A sensitivity analysis is used to identify the most relevant model inputs to consider into the data assimilation process. Results show that data assimilation leads to statistically significant better predictions than the simulation alone (from an RMSE of 9.88 q·ha${}^{-1}$ to an RMSE 7.49 q·ha${}^{-1}$). Significant improvement is achieved by relying on smoothed LAI rather than raw LAI. Nevertheless, there is still an over estimation of the grain yield that can be partially explained by the limiting factors observed on the fields and the forecast yield still need improvements to meet the required applications’ accuracy.

The European Union has a high demand for plant proteins for food and feed. Its self-sufficiency rate is about 5% for soya crude proteins. The European Union and its Member States have launched initiatives for reducing soya imports that come mainly from South America and promoting domestic production of protein-rich crops. In the future, climate suitability for soybean cultivation is likely to increase in oceanic and continental Europe. The recent AE2050 study (INRAE. 2020. Role of European agriculture in world trade by 2050: Balancing climate change and global food security issues. Summary report of the study. INRAE (France), 12 p; Tibi A, Forslund A, Debaeke P, et al. 2020. Place des agricultures européennes dans le monde à l’horizon 2050 : entre enjeux climatiques et défis de la sécurité alimentaire. Rapport de synthèse de l’étude. INRAE (France), 159 p + Annexes) concluded that, in some parts of Europe (defined here as the European Union-27 plus other Balkan countries, Switzerland, Norway and the United Kingdom), cropland requirements in 2050 may be lower than “2010” cropland areas given possible changes in European food demand (related to glooming demographic growth and under the assumption of healthy diets) and in crop yields (influenced by technological developments and climate change). In this study, we examine to what extent this “cropland surplus” could be used to increase soybean production in Europe and reduce the dependency ratio on protein imports. Only in the case of a Healthy Diets scenario (less meat consumption, inducing less animals fed with cakes), substantial soybean acreages could be envisaged to reduce the European reliance on imports. In addition to the surplus allowed by increasing yields, land surplus was also made available by the reduction of livestock production and its grain feed requirements. The best-case scenario, combining healthy diets and trend-based yield growth, would reduce European imports to only 15% of its total domestic requirements versus 45% for the Trend-based Diets scenario. This can be compared to a dependency rate of 51% in our base year “2010”, and of 53%–54% for the two 2050 scenarios without growing soybean on cropland surplus. If the range of these quite optimistic estimations of surplus land dedicated to soybean was reduced to more plausible levels (limited to 10% of annual field cropland in 2050) and considering current soybean yield levels (“2019” instead of “2010”), the decrease in Europe’s oil cake imports levels would be lower. However, its dependency rate could still be reduced from 54% to 46% in the Trend-based Diets scenario, and from 53% to 38% in the Healthy Diets scenario. One important conclusion is that adopting healthy diets would allow a significant reduction of imports of soybean cakes from abroad with expected environmental benefits in Europe and overseas. On the supply side, challenges for a higher self-sufficiency rate of proteins in Europe resulting from the development of soybean domestic production will come from both available and suitable crop areas, attainable yields and relative profitability.

Growing a second food, fodder or bioenergy crop during the fallow period commonly refers to sequential double cropping or relay cropping practices, as a function of sowing date (following or within the primary crop, respectively). Such practice may generate an additional income while supplying support and regulation services. As such, it could be referred as a form of ecologically intensive agriculture but also an opportunity offered by climate change. The decision-making process in the adoption of double cropping relies on many factors related to soil and climate conditions, but also on profit expectation and risk perception. The CASDAR project “3C2A: Three crops in two years” (2019–2023) strived to create references for sequential double cropping in the South-West of France, which encompasses the regions of Nouvelle-Aquitaine and Occitanie. The project focused mainly on grain crops and raised the interest of the use of oil-protein crops such as soybean (Glycine max(L.) Merrill) and sunflower (Helianthus annuusL.) for such practice. As a preliminary contribution of 3C2A project, this paper aims at illustrating the potential interest of soybean and sunflower as double crops in the South-West of France through a qualitative analysis of farmers’ perceptions about the risks and opportunities of double-cropping completed by a 4-years on-farm evaluation of agronomic and economic performances of this practice (110 fields).

In order to make more efficient plant breeding and gain in competitiveness, the sector of oil-protein crops decided to intensify agronomic research on sunflower crop. The “Sunflower” Joint Technological Unit (Unité Mixte Technologique (UMT) “Tournesol”, in French) was launched in the Toulouse area in 2006, associating closely INRA and Terres Inovia. First focused on improving oil production through an agronomic approach, the UMT was renewed in 2011 with a broader partnership and a more assertive orientation towards the development of decision-making tools. The objective of this paper is to highlight the relevance and productivity of this user-oriented research facility. The main results relate to (i) the co-construction of a simulation model (SUNFLO) that can be parameterized and manipulated by Terres Inovia engineers, (ii) the joint exploration of supra-field scales and new methods for agronomic diagnosis and yield forecasting based on remote sensing, (iii) the tuning and dissemination of operational decision rules, (iv) the production of essential knowledge on emergent and/or damaging fungal diseases, as well as on complex interactions between genotype, environment and crop management. After a concluding symposium in 2016, new requests for sunflower research were formulated by the participants. They also advocated for a diversification of crops to consider in order to better meet the needs of the whole oil-protein sector.