Mitigating Pesticide Hazards: Using Vegetative Filter Strips
Vegetative filter strips are strategically planted rows of vegetation that filter surface water runoff, trap as much as 75 to 100% of sediment, minimize erosion, and absorb nutrients, pollutants, and pathogens. Pesticides, especially pyrethroids that bind strongly to soil particles, can be reduced with vegetative filter strips, which help keep pesticides in the field.
Consider the following when designing a vegetative filter strip.
- Width. Generally, the wider the filter strip, the better.
- Slope. Vegetative filter strips are most effective on slopes of less than 5 percent and are not recommended for slopes greater than 15 percent.
In riparian areas. A single, dense strip about 30 feet wide is usually sufficient to protect riparian areas.
Vegetation. Tall, perennial, native grasses are ideal for trapping sediment. Hardy, drought-tolerant species are best, but consider local conditions and cultural practices before deciding on vegetation type.
Location. Identify where water flows on the property to ensure vegetative filter strips are planted where they have the best chance to catch runoff. Placing vegetative filter strips along field boundaries or near high upslopes within fields and orchards will be most effective. Also consider placement along roads, ditches, stream banks, and animal confinement facilities.
Maintenance. Channels and rills may develop over time. Repair, and if needed, reseed. Remove excess sediment buildup to prevent diversions around vegetative filter strips. Keep strips short (4-10 inches) to deter weeds and pathogens.
- Sloping terrain. Plant grasses in bands about 6 feet wide every 10 to 100 feet, depending on slope.
- Flat terrain. Plant grass in strips 10 to 15 feet wide at field boundaries.