Phostering Sustainability – Integrating Agronomic and Environmental Objectives in Phosphorus Fertilizer Recommendations

Phosphorus fertilization is essential for growing food, but phosphorus leaching from agricultural fields into ditches, rivers and lakes negatively impacts water quality. This research contributes to producing food within environmental boundaries by integrating agronomic and environmental objectives in phosphorus fertilizer recommendations. We advocate moving beyond recommendations that focus only on optimizing crop yields, toward agri-environmental recommendations that explicitly include environmental risk. This revision requires (i) shifting from agronomic to agri-environmental soil phosphorus testing protocols; and (ii) assessing the phosphorus binding capacity of soils, as this soil property strongly influences leaching risks. For the Netherlands, we mapped the binding capacity of soils and proposed environmental soil phosphorus thresholds to protect water quality. This work shows that current soil phosphorus levels can be reduced to these thresholds with minimal effects on crop yields, except for areas where soils have an exceptionally low binding capacity. In those areas, more extensive agriculture or the provision of other ecosystem services may be more suitable.