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.