590 - 1 NATURAL RESOURCES CONSERVATION SERVICE CONSERVATION PRACTICE STANDARD

FILTER STRIP (Ac.)

CODE 393

DEFINITION to surface and ground waters, Excess A strip or area of herbaceous vegetation pathogens and chemicals from that removes contaminants from overland manure, bio-solids or compost flow. applications, and Excessive sediment in surface waters). PURPOSE CONDITIONS WHERE PRACTICE This practice supports one or more of the APPLIES following purposes: Filter strips are established where * Reduce suspended solids and environmentally-sensitive areas need to associated contaminants in runoff – be protected from sediment; other Resource concerns (WATER suspended solids and dissolved QUALITY DEGRADATION – Excess contaminants in runoff. nutrients in surface and ground waters, Pesticides transported to CRITERIA surface and ground waters, Excess General Criteria Applicable to All pathogens and chemicals from Purposes manure, bio-solids or compost applications, and Excessive sediment Overland flow entering the filter strip shall in surface waters). be uniform sheet flow. * Reduce dissolved contaminant Concentrated flow shall be dispersed loadings in runoff – Resource before it enters the filter strip. concerns (WATER QUALITY The maximum gradient along the leading DEGRADATION – Excess nutrients in edge of the filter strip shall not exceed surface and ground waters, Pesticides one-half of the up-and-down hill slope transported to surface and ground percent, immediately upslope from the waters, and Excess pathogens and filter strip, up to a maximum of 5%. chemicals from manure, bio-solids or State-listed noxious or invasive plants will compost applications). not be established in the filter strip. See * Reduce suspended solids and http://www.tneppc.org/invasive_plants. associated contaminants in irrigation Filter strips shall not be used as a travel tailwater – Resource concern lane for equipment or livestock. (WATER QUALITY DEGRADATION – Excess nutrients in surface and Filter strip establishment shall comply ground waters, Pesticides transported with local, state, and federal regulations.

NRCS, TN February 2015 393 - 2 Additional Criteria to Reduce application. Only viable, high quality Suspended Solids and seed or planting stock will be used. See Associated Contaminants in Table 1. Runoff Site preparation and seeding or planting The filter strip will be designed to have a shall be done at a time and in a manner 10-year life span, following the procedure that best ensures survival and growth of in the Agronomy Technical Note No. 2 the selected species. What constitutes (Using RUSLE2 for the Design and successful establishment, e.g. minimum Predicted Effectiveness of Vegetative percent ground/canopy cover, percent Filter Strips (VFS) for Sediment), based survival, stand density, etc. shall be on the sediment delivery in RUSLE2 to specified before application. the upper edge of the filter strip and ratio of the filter strip flow length to the length Planting dates shall be scheduled during of the flow path from the contributing periods when soil moisture is adequate for germination and/or establishment. area. The minimum flow length through Seeding shall be timed so that tillage for the filter strip shall be 20 feet. adjacent crop does not damage the The filter strip shall be located seeded filter strip. immediately downslope from the source The minimum seeding and stem density area of contaminants. shall be equivalent to a high quality grass The drainage area above the filter strip hay seeding rate for the climate area or shall have a slope of 1% or greater. the density of vegetation selected in RUSLE2 to determine trapping efficiency, Vegetation. The filter strip shall be whichever is the higher seeding rate. established to permanent herbaceous vegetation. Additional Criteria to Reduce Dissolved Contaminants in Species selected shall be: Runoff * able to withstand partial burial from The criteria given in “Additional criteria sediment deposition and to reduce suspended solids and * tolerant of herbicides used on the area associated contaminants in runoff” for that contributes runoff to the filter strip. location, drainage area and vegetation characteristics also apply to this purpose. Species selected shall have stiff stems and a high stem density near the ground The minimum flow length for this purpose surface. shall be 30 feet. Species selected for seeding or planting Additional Criteria to Reduce shall be suited to current site conditions Suspended Solids and and intended uses. Selected species will Associated Contaminants in have the capacity to achieve adequate Irrigation Tailwater density and vigor within an appropriate Filter strip vegetation shall be a small period to stabilize the site sufficiently to grain or other suitable annual plant. permit suited uses with ordinary The seeding rate shall be sufficient to management activities. ensure that the plant spacing does not Species, rates of seeding or planting, exceed 4 inches (about 16-18 plants per minimum quality of planting stock, such square foot). For annuals, seed the high as PLS or stem caliper, and method of rate recommended in Forage and establishment shall be specified before Biomass Standard or University of

NRCS, TN February 2015 590 - 3 Tennessee Forage and Field Crop * Where site appropriate, use native Seeding Guide for Tennessee PB 378. grass species that fulfill the purposes Refer to: of the practice while also providing https://utextension.tennessee.edu/publica habitat for priority wildlife. tions/Pages/default.aspx * Adding herbaceous plant species Filter strips shall be established early including native forbs to the filter strip enough prior to the irrigation season so seeding mix that are beneficial to that the vegetation is mature enough to wildlife and pollinators and be filter sediment from the first irrigation. compatible for one of the listed The minimum flow length for this purpose purposes. Changing the seeding mix shall be 20 feet. should not detract from the purpose for which the filter strip was CONSIDERATIONS established. General. Filter strip width (flow length) * Increasing the width beyond the can be increased as necessary to minimum required. This additional accommodate harvest and maintenance area can increase food and cover for equipment. wildlife and pollinators. Filters strips with the leading edge on the * Management activities on filter strips, contour will function better than those such as mowing, burning, or light with a gradient along the leading edge. disking, should not be done more often than every other year with Seeding rates that establish a higher frequency dependent on geographical stem density than the normal density for a location to maintain the purposes of high quality grass hay crop will be more the practice. effective in trapping and treating contaminants. * Management activities on the filter strip should be completed outside of If needed, invasive plant species may be the primary nesting, fawning, and controlled through mowing, herbicides calving seasons. Activities should be and hand weeding based on the land timed to allow for regrowth before the user’s situation. growing season ends whenever Reducing Suspended Solids and possible. Associated Contaminants in * Organic producers may have to Runoff. submit plans and specifications to Increasing the width of the filter strip their certifying agent for approval prior beyond the minimum required will to installation, as part of the organic increase the potential for capturing producer’s Organic System Plan. contaminants in runoff. Maintain or Enhance Watershed Creating, Restoring or Enhancing Functions and Values. Herbaceous Habitat for Wildlife Filter strips can: and Beneficial Insects and Pollinators.  enhance connectivity of corridors and non-cultivated patches of vegetation Filter strips are often the only break in the within the watershed. monotony of intensively-cropped areas. The wildlife and pollinator benefits of this  enhance the aesthetics of a herbaceous cover can be enhanced by: watershed.

NRCS, TN February 2015 393 - 4  be strategically located to reduce appropriate to encourage dense growth, runoff, and increase infiltration and maintain an upright growth habit and ground water recharge throughout the remove nutrients and other contaminants watershed. that are contained in the plant tissue. Increase Carbon Storage. Increasing Control undesired weed species, the width of a filter strip beyond the especially state-listed noxious weeds. minimum required will increase the If prescribed burning is used to manage potential for carbon sequestration. and maintain the filter strip, an approved burn plan must be developed. PLANS AND SPECIFICATIONS Inspect the filter strip after storm events Applicable to All and repair any gullies that have formed, Plans and specifications shall be remove unevenly deposited sediment prepared for each field site where a filter accumulation that will disrupt sheet flow, strip will be installed. Record practice reseed disturbed areas and take other specifications on the Filter Strip measures to prevent concentrated flow Implementation Requirement document. through the filter strip. A plan includes information about the Apply supplemental nutrients as needed location, construction sequence, to maintain the desired species vegetation establishment, and composition and stand density of the filter management and maintenance strip. Follow UT soil testing guidelines requirements. and recommendations to apply needed As a minimum, the plans shall include: fertilizer and lime. For additional * Length, width (width refers to flow information refer to: length through the filter strip), and http://soilplantandpest.utk.edu/publication slope of the filter strip to accomplish s/soilfertilizerpubs.htm the planned purpose. Periodically re-grade and re-establish the * Species selection and seeding or filter strip area when sediment deposition sprigging rates to accomplish the at the filter strip-field interface jeopardizes planned purpose. its function. Reestablish the filter strip vegetation in these regraded areas, if * Planting dates, care and handling of needed. the seed to ensure that planted materials have an acceptable rate of Filter strips are designed to have a survival. minimum life span of ten (10) years. To maintain the filter strip, the rate of * A statement that only viable, high sediment accumulation should not quality and regionally adapted seed exceed 0.6 inches per year. Once the will be used. accumulation reaches six (6) inches, the * Site preparation instructions sufficient filter strip will need to be re-graded and to establish and grow selected re-established. species. If grazing is used to harvest vegetation from the filter strip, the grazing plan must OPERATION AND MAINTENANCE insure that the integrity and function of For the purposes of filtering the filter strip is not adversely affected. contaminants, permanent filter strip If grazing or haying a filter strip, maintain vegetative plantings shall be harvested as height of four (4) inches for introduced

NRCS, TN February 2015 590 - 5 grasses and eight (8) inches for native coordinators. 1997. Predicting Soil warm season grasses. Erosion by Water: A Guide to Organic producers may have to maintain Conservation Planning with the Revised records for five years, as part of their Universal Soil Loss Equation (RUSLE). Organic System Plan. U.S. Department of Agriculture. Agriculture Handbook 703. REFERENCES Revised Universal Soil Loss Equation Dillaha, T.A., and J.C. Hayes. 1991. A Version 2 (RUSLE2) website (checked Procedure for the Design of Vegetative May 2007): Filter Strips: Final Report Prepared for http://fargo.nserl.purdue.edu/rusle2_data U.S. Soil Conservation Service. web/RUSLE2_Index.htm. Dillaha, T.A., J.H. Sherrard, and D. Lee. Sources of Organic and Untreated Non- 1986. Long-Term Effectiveness and GMO Seeds. National Sustainable Maintenance of Vegetative Filter Strips. Agriculture Information Service. VPI-VWRRC Bulletin 153. http://attra.ncat.org/sorg/seeds.html Foster, G.R. Revised Universal Soil Loss USDA-AMS National Organic Program Equation, Version 2 (RUSLE2) Science National List of Allowed and Prohibited Documentation (In Draft). USDA-ARS, Substances. Washington, DC. 2005. http://www.ams.usda.gov/AMSv1.0/nop M.G. Dosskey, M.J Helmers, and D.E. USDA-AMS National Organic Program Eisenhauer 2008 A Design Aid for Regulations, 7 CFR Part 205. Determining Width of Filter Strips, Journal http://www.ams.usda.gov/AMSv1.0/nop of Soil and Water Conservation OMRI Organic Seeds Database. Organic Tennessee Department of Agriculture, Materials Review Institute. Seed Regulations. http://www.omri.org/seeds http://www.tn.gov/sos/rules/0080/0080- Renard, K.G., G.R. Foster, G.A. Weesies, 05/0080-05-06.pdf D.K. McCool, and D.C. Yoder,

NRCS, TN February 2015 393 - 6 TABLE 1. LIST OF POSSIBLE PLANT MATERIALS CONSIDERED SUITABLE FOR FILTER STRIPS (NOT TO BE CONSIDERED A COMPLETE LIST)1/ SEEDING RATE PER SEED OR PLANTS SEEDING DATE ACRE

Common Bermudagrass 10 lbs May 1 – July 1

February 20 – April 1 Fescue (Tall) 40 lbs August 15 – White Clover 2 lbs September 15

Switchgrass2/ 15 lbs (PLS)3/ December 1 – July 1

Switchgrass 5 lbs (PLS) Big Bluestem 5 lbs (PLS) December 1 – July 1 Indiangrass 5 lbs (PLS)

Switchgrass 5 lbs (PLS) Big Bluestem 5 lbs (PLS) December 1 – July 1 Illinois Bundleflower 1 lb Partridge Pea 3 lbs

Eastern Gamagrass 10 lbs (PLS) December 1 – July 1 Switchgrass 7 lbs (PLS)

Switchgrass 10 lbs March 1 – June 1 Kobe or Koran Lespedeza 5 lbs

1/ All seeding rates in this table are high for filtering purposes. 2/ Switchgrass seed should be at least two years old, if available. 3/ PLS = Pure Live Seed

NRCS, TN February 2015