The phosphorus cycle in North-West European agricultural soils

Phosphorus (P) concentrations in NW European surface waters generally exceed ecological thresholds. The Nitrates Directive and the Water Framework Directive have asked EU Member States to address this problem. The resulting monitoring networks and P concentration standards differ widely between Member States. Because agriculture is considered to have a large impact on the surface water P concentrations, the diffuse P losses from soils with high P contents are targeted. Attempts have been made to reduce the soil P concentration under the threshold above which P losses increase exponentially. However, agro-economic interests should also be taken into account. A target zone of soil P concentrations with optimum crop yields and limited P losses can be defined. In order to reach or stay in this target zone, fertilisation recommendations should be adapted to include the risk for P losses. Soil P application standards are ideally differentiated to soil P concentrations. In this way, soils with large P concentrations should receive less P in order to reduce the P losses and soils with small P concentrations can receive more P to ensure satisfactory crop yields.