They provide four basic forms of protection. They capture sediment, pesticides, and nutrients moving from adjoining cropland before they reach the stream or lake. The nutrients and pesticides are taken up by the buffer strip's grass, trees, or shrubs. 15C. Filter strips increase denitrification, a process in which microbes convert nitrate-nitrogen into a form that is lost to the atmosphere. Denitrification reduces the amount of nitrate available to move into groundwater and surface water supplies.
Filter strips increase the infiltration of runoff into the soil.
As a bonus, vegetative filters can serve as a natural classroom for children, a corridor for wildlife movement, and an important breeding ground for birds and other wildlife. Detailed image. . . 15E. Where controlling the surface movement of erosion, fertilizers, and pesticides is the goal, filter strips are most effective on slopes of 5 percent or less. Where controlling the subsurface movement of fertilizers and pesticides is the goal, filter strips are most effective on land that does not have a subsurface drainage system. A subsurface drainage system will bypass the filter.