A data-driven impact evaluation of nutrient input reduction on wheat yields across Europe

The European Union (EU) is one of the largest cereal producers in the world, with wheat covering around one-third of its agricultural area. Sustainable soil management has been put as a key point of EU Green Deal policies, with concrete measures to reduce fertilizer application by 2030. However, uncertainty still exists about the expected impact of such a reduction on wheat yield across the EU. In this work, we construct a regression model to evaluate the possible impacts of fertilizer reduction and climate change on wheat yields by 2050. The regression model quantifies the effects of soil properties, soil management, and climate on wheat yields at the EU scale. In addition, we simulate two scenarios, one based on the EU fertilizer targets only and the other focusing on climate change impact (+4 °C). The results show an important effect of soil phosphorus, nitrogen, and potassium content, soil carbon-to-nitrogen ratio, and nitrogen inputs on the variation in wheat yields across the EU, next to climate. The scenario analysis suggests that reducing N and P inputs by 20 % leads to wheat yield losses of up to 5 %, an effect that can rise to 50 % yield reduction by 2050 under climate change. Fertilizer reduction leads to most significant yield decreases in France, Germany and Northern Italy, while climate change reduces yields mostly in Southern Europe. Beyond highlighting relevant regional patterns, our results show how EU fertilizer reduction targets are expected to have a small impact on wheat production compared to climate change.