How are prairie strips different from contour buffers and grass strips?
Contour buffers are typically planted with fixed widths. In contrast, we vary the width of the prairie strips based on the amount of water they intercept, with the goal of treating all of the runoff leaving the crop field. Where more water is flowing down-slope, prairie strips should be wider, and where less water is flowing down-slope, the strips can be narrower.
The types of plants used for conservation buffers and filter strips can affect how they function. For example,
- Cool season exotic grasses such as smooth brome, tall fescue, orchard grass, and Kentucky bluegrass are widely used to provide ground cover in agricultural areas of the U.S. Corn Belt, but are relatively weak-stemmed and prone to laying flat under heavy rain. They are useful for grassed waterways that are intended to convey water while preventing erosion. In contrast, native tall-grass prairie communities are typically dominated by stiff-stemmed warm season grasses such as Indiangrass, big bluestem, little bluestem, and a wide range of erect forb (i.e., wildflowers) species that are less prone to collapse under heavy rain. These native plants are more effective in providing resistance to water flow and sediment movement.
- Typical contour buffers and grass strips are planted to monocultures of the cool season exotic grasses. For this reason, they provide less support for pollinators and potentially other wildlife. Pollinators require flowering plants, also known as forbs, for nectar and pollen that comprise their food. The best pollinator habitat as enough diversity that there are multiple species of plants in flower throughout the growing season; so, from April through September. Contour buffers planted to monocultures furthermore will not have as diverse and abundant root systems, and thus will require more time to provide soil health benefits such as breaking up compaction, improving infiltration, or raising soil organic matter. They are also less resilient to weather extremes.