GUIDELINES / 1.0 Water Quality
1.13 Buffers for Phosphorus
Phosphorus (P) in runoff occurs either as particulate phosphorus or as dissolved phosphorus. Particulate phosphorus is sediment-bound and can be moderately-well trapped by deposition in buffers. Dissolved phosphorus must infiltrate with runoff water and be trapped in the soil.
Unlike N which can be released to the atmosphere through denitrification, P will accumulate in the buffer. Once a buffer is saturated with P, it can turn into a source for P. Other best management practices will be necessary to manage phosphorus.
Key Design Considerations
- Avoid trapping P in riparian buffers which can be remobilized by flood waters.
- See 1.19 for buffer width recommendations.
- Buffers consisting of unfertilized crops or hayfields can trap and utilize P. Removing this vegetation through harvest may help export P, as well as N, out of the watershed (see 1.26). Select plants with high nutrient demand.