Date of this Version
This chapter describes the use of buffers and vegetative filter strips relative to water quality. In particular, we primarily discuss the herbaceous components of the following NRCS Conservation Practice Standards:
Filter Strip (393)
Alley Cropping (311)
Riparian Forest Buffer (391)
Vegetative Barrier (601)
Conservation Cover (327)
Riparian Herbaceous Cover (390)
Contour Buffer Strips (332)
Grassed Waterway (412)
Placement of most of these practices is illustrated in figure 4-1. Common purposes of these herbaceous components (as defined by the NRCS Conservation Practice Standards) are to:
• Reduce the sediment, particulate organics, and sediment-adsorbed contaminant loadings in runoff.
• Reduce dissolved contaminant loadings in runoff.
• Serve as Zone 3 of a riparian forest buffer.
• Reduce sediment, particulate organics, and sediment-adsorbed contaminant loadings in surface irrigation tailwater.
• Restore, create, or enhance herbaceous habitat for wildlife and beneficial insects.
• Maintain or enhance watershed functions and values.
• Reduce sheet and rill erosion.
• Convey runoff from terraces, diversions, or other water concentrations without causing erosion or flooding (grassed waterway).
• Reduce gully erosion (grassed waterway and vegetative barrier).
The term buffer is used here to generally refer to all eight practice standards noted above. These can be further identified as “edge-of-field” and “in-field” buffers consistent with the terminology used by Dabney et al. (2006). Edge-of-field buffers include filter strips, riparian forest buffers, and riparian herbaceous cover. In-field buffers include conservation cover, contour buffer strips, alley cropping, and grassed waterways. Vegetative barriers could be either in-field or edge-of-field buffers.