How has climate variability affected regional crop production across Europe in the last 30 years?

Nitrogen plays a fundamental role in agri-food systems, as the primary component of proteins, a key limiting soil nutrient, and a significant driver of environmental pollution. The Generalized Representation of Agri-Food Systems (GRAFS; Billen et al., 2014) model provides a comprehensive and robust framework for quantifying nitrogen flows across regional, national, or continental scales. By employing a metabolic approach to analyze nitrogen dynamics, GRAFS enables detailed diagnostic assessments of historical and current trends in crop production linked to socio-technical, pedological, and climatic variables. The predictive capacity of this approach yet remains limited by the lack of explicit incorporation of climatic drivers on N flows, particularly those related to crop harvest.

Utilizing a newly compiled annual dataset from 1990 onwards, the model offers high-resolution diagnostics across Europe, capturing spatio-temporal variability across 127 subnational regions. This study focuses on quantifying the influence of climatic variables on the historical evolution of arable crop yields. The methodology is based on an empirical relationship between total nitrogen yields at the crop-rotation scale and total nitrogen inputs from synthetic fertilizers, manure, biological fixation, and atmospheric deposition. This yield response to nitrogen fertilization follows a hyperbolic curve characterized by a single parameter (Ymax; Lassaletta et al., 2014), representing the theoretical maximum yield for a given territory. 

We analyze the temporal evolution of this parameter for the 127 European regions in relation with shifts in climate-related factors, including precipitation, water balance, temperature, and extreme weather events. We establish a relationship between climatic variables and shifts in the Ymax value, which characterizes the yield-fertilization relationship. Our results provide foundation for developing prospective scenarios addressing the combined effects of climate change and transformations in agricultural systems on agronomic and environmental performances of food systems.

 

Reference

Billen, G., Lassaletta, L., Garnier, J., 2014. A biogeochemical view of the global agro-food system: Nitrogen flows associated with protein production, consumption and trade. Glob. Food Sec. 3, 209–219. https://doi.org/10.1016/j.gfs.2014.08.003.

Lassaletta, L., Billen, G., Grizzetti, B., Anglade, J., Garnier, J., 2014. 50 year trends in nitrogen use efficiency of world cropping systems: the relationship between yield and nitrogen input to cropland. Environ. Res. Lett. 9. https://doi.org/10.1088/1748-9326/9/10/105011.