Phosphorus fate, management, and modeling in artificially drained systems

Area of Science:

• Agricultural Science
• Environmental Science
• Water Quality Management

Background:

• Phosphorus (P) loss via agricultural drainage (surface and subsurface) presents a significant nonpoint source pollution challenge.
• Artificial drainage systems, such as tile drainage, can exacerbate watershed P loads through rapid flow and shorter transport distances.

Purpose of the Study:

• To document field conditions contributing to P loss in drainage waters.
• To evaluate the effectiveness of drainage and nutrient management practices in controlling P losses.
• To assess the capability of current models in representing P loss to drainage systems.

Main Methods:

• Review of P in tile drainage literature.
• Analysis of case studies from North America, Europe, and New Zealand.
• Examination of P sources, including surface and legacy P.

Main Results:

• Drainage intensification, tillage, cover crops, and manure management involve trade-offs affecting P loss.
• P in drainage waters is often linked to concentrated surface sources, but legacy P can be present at deeper depths.
• Major fate-and-transport models fail to simulate dominant P loss processes to drainage waters.

Conclusions:

• Effective management of P loss to drainage waters requires significant investment in innovative drainage systems that promote P retention.
• Development of advanced models is crucial for accurately predicting P loss and evaluating management strategies.