Climatic Drivers of Cereal Productivity in Romania (1997-2024):

a Macro-Level Analysis Integrating Era5 Precipitation Data

and National Crop Statistics

Mihaela Pila, Silvius Stanciu

”Dunărea de Jos” University of Galaţi

Keywords: precipitation, cereal yields, ERA5, climate variability, Romania.

Abstract: A thorough understanding of how climate variability influences crop productivity is essential for the development of sustainable agricultural technologies and the refinement of crop management practices. This study investigates the impact of precipitation patterns on the productivity of Romania’s major cereal crops - wheat (Triticum aestivum L.), maize (Zea mays L.) and barley (Hordeum vulgare L.) - over a 28-year period (1997-2024). The analysis integrates ERA5 reanalysis precipitation data with national statistics on sown area, total output and yield levels. Monthly precipitation values from ERA5 were aggregated to compute annual totals and were further organized into crop-specific seasonal windows: April-June for wheat, June-August for maize and March-May for barley. Results indicate that rainfall remains a keyt determinant of interannual yield variability, particularly for crops harvested in summer. Maize shows the strongest climatic sensitivity, with a moderate positive correlation between production and June-August rainfall (r ≈ 0.36), which highlights the crop’s vulnerability to summer drought during pollination and grain-filling. Wheat exhibits moderate correlations between both production and yield and April-June precipitation (r ≈ 0.27-0.29), confirming the relevance of spring moisture during stem elongation and kernel development. Barley presents weaker correlations (r ≈ 0.13-0.20), consistent with its earlier phenology and comparatively higher tolerance to early-season moisture fluctuations.
At the national scale, the association between annual precipitation and total cereal output is weak (r ≈ 0.13), largely due to compensatory effects among crops with different seasonal requirements and the influence of technological progress in breeding, crop management and input efficency. Nevertheless, seasonal rainfall indicators provide valuable insights into the climatic constraints affecting each crop and underline the need for adaptive strategies, including drought-tolerant germplasm, optimized sowing schedules and precision water management.
Overall, the study offers a macro-level diagnostic framework for assessing how climate drivers of cereal productivity in Romania and supports the development of resilient agricultural technologies under increasing climatic variability.