Potential benefits of a spatially targeted regulation based on detailed N-reduction maps to decrease N-load from...

Area of Science:

• Environmental Science
• Agricultural Science
• Water Resource Management

Background:

• Denmark faces pressure to reduce nitrogen (N) load to coastal waters, adhering to the Baltic Sea Action Plan and EU Water Framework Directive.
• Agricultural N-runoff is a significant contributor, necessitating improved mitigation strategies.

Purpose of the Study:

• To evaluate the benefits of a new spatially targeted regulation for N-mitigation in agricultural areas.
• To assess how uncertainty in N-reduction maps impacts the efficiency of targeted regulations.

Main Methods:

• Analysis of N-reduction processes within the 85 km² Norsminde catchment, Denmark.
• Modeling the impact of relocating agricultural practices based on N-reduction maps.
• Investigating the effect of N-reduction map uncertainty and spatial resolution on regulatory efficiency.

Main Results:

• A spatially targeted regulation can decrease total N-load by up to 8% by optimizing agricultural practices without reducing fertilization.
• Identifying areas with low natural N-reduction is crucial for effective mitigation measure placement.
• Uncertainty in N-reduction maps reduces the efficiency of targeted regulations, but ensemble averaging can mitigate this.

Conclusions:

• Spatially targeted N-mitigation strategies offer potential benefits over uniform approaches for reducing agricultural N-load.
• Reducing uncertainty in N-reduction maps is key to maximizing the effectiveness of targeted regulations.
• Balancing spatial resolution and map uncertainty is essential for optimizing N-mitigation strategies.