Understanding the Long-term Spatial and Temporal Dynamics of Phosphorus Surplus Across Europe

Phosphorus (P) is an essential nutrient for plant growth, yet much of the P in agricultural soils remains inaccessible to plants, necessitating external inputs. Since the 1920s, agricultural intensification in Europe has led to significant P accumulation in soils, resulting in P surpluses (the difference between P inputs and outputs) that exceed plant needs. These surpluses contribute to environmental issues, including water quality degradation, biodiversity loss, and breaches of planetary boundaries. Despite regulatory efforts, elevated P levels persist in European water bodies, highlighting the need for long-term understanding of soil P surplus to guide future land and water management practices.

The goal of this study is to characterize the spatial and temporal pattern of the P surplus across Europe¹. To achieve this goal, we constructed a long-term (1850-2019) yearly P surplus dataset across Europe at a 5 arcmin spatial resolution for agricultural and non-agricultural soils. Our gridded dataset allows for aggregating P surplus at different spatial scales of interest for soil and water management. Specifically, the dataset includes 48 P surplus estimates addressing uncertainties in key components such as fertilizers, manure, and P removal rates, acknowledging the inherent variability in nutrient budgets.

Our results show that P surplus (evaluated as one standard deviation around the mean of the 48 estimates) in the EU-27 has tripled over 170 years, increasing from 1.19±0.28 kg ha⁻¹ of physical area in 1850 to 2.48±0.97 kg ha⁻¹ of physical area in recent years. Spatially, our analysis indicates that Central European countries mainly rely on mineral fertilizers, except regions like the Netherlands, Belgium, and Denmark, where animal manure dominates due to high livestock densities. Furthermore, the long-term database allowed us to identify four distinct phases of P surplus: 1850–1920 (Pre-modern agriculture), (ii) 1921–1960 (Industrialization before the Green Revolution), (iii) 1961–1990 (Green Revolution and synthetic fertilizer expansion), and (iv) 1991–2019 (Environmental awareness and policy intervention phase). Complimenting our earlier Nitrogen (N) surplus dataset², this work emphasizes the importance of long-term analyses to address persistent nutrient-related environmental challenges.

¹Batool, M., Sarrazin, F. J., and Kumar, R.: Century Long Reconstruction of Gridded Phosphorus Surplus Across Europe (1850–2019), Earth Syst. Sci. Data Discuss. [preprint], https://doi.org/10.5194/essd-2024-294, in review, 2024.

²Batool, M., Sarrazin, F.J., Attinger, S. et al. Long-term annual soil nitrogen surplus across Europe (1850–2019). Sci Data 9, 612 (2022). https://doi.org/10.1038/s41597-022-01693-9