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Conservation Choices: Contour Buffer Strip

Contour Buffer Strip

Contour Buffer StripWhat it is

Contour buffer strips are strips of grass or a mixture of grasses and legumes that run along the contour of a farmed field. They alternate down the slope of a field with wider cropped strips.

How it helps

Established contour buffer strips can significantly reduce sheet and rill erosion. Strips slow runoff and trap sediment. Contaminants such as sediment, nutrients, and pesticides are removed from the runoff as they pass through a buffer strip. Buffer strips may also provide food and nesting cover for wildlife and pollinators.

Planning ahead

  • Have you decided whether to have parallel crop strips or parallel buffer strips?
  • Are other conservation measures, such as crop residue management, installed or planned to help reduce grass strip siltation?
  • Will planned acres in row crops meet your production objectives?

Tech Notes

  • Buffer strips must be at least 15 feet wide. Width depends on slope, soil type, field conditions, climate, and erosion potential.
  • Either crop strips or grass strips may be parallel. When parallel, crop strips are easier to farm with no point rows, but that results in less of the slope in row crops.
  • Grass buffers commonly make up 20-30 percent of the slope.
  • Species to use for contour buffer strips depends on soil type, climate, and planned use.


  • Control weeds and brush in grass filter strips.
  • Delay mowing until July 15 to help ground-nesting birds.
  • Keep vegetation tall in spring and early summer to help slow runoff flow.
  • Fertilize as needed.
  • Buffer strips may be moved up or down the slope to help re-establish vegetation or for other maintenance needs.

Iowa Practice Standard

Iowa Job Sheet