Grass Barrier and Vegetative Filter Strip Effectiveness in Reducing Runoff, Sediment, Nitrogen, and Phosphorus Loss

soil and organic matter (Melville and Morgan, 2001), promote degradation of sediment-bound chemicals Addition of switchgrass (Panicum virgatum) barriers to vegetative (Groffman et al., 1991), and enhance wildlife habitat filter strips (FS) shows potential as conservation practice. This study evaluates the comparative effectiveness of three conservation prac(Schultz et al., 1995). This approach for reducing NPS tices in reducing runoff, sediment, N, and P losses from 1.5by 16-m pollution can be a less-costly alternative to terraces plots on an Aeric Epiaqualf. Three practices compared are a tradiwhere slopes are not too steep. tional fescue (Festuca arundinacea) filter strip (Fescue-FS), a Grass barriers differ from FS because FS are typically switchgrass barrier in combination with the Fescue-FS (B-Fescue-FS) much wider ( 5 m). Vegetative filter strips are estaband a switchgrass barrier in combination with a native grass and forbs lished between field borders and waterways. Narrowspecies filter strip (B-Native-FS). This study also predicts transport row stiff-stemmed barriers may be more acceptable to of sediment, N, and P in Fescue-FS and B-Fescue-FS. Fescue-FS and farmers because they occupy much less land than FS. B-Fescue-FS of equal widths (0.7 m) significantly reduced runoff and In addition, short statured plants such as fescue provide sediment transport as compared with a continuous cultivated fallow little benefit to wildlife. Vegetative filter strips of native (CCF) treatment, but B-Fescue-FS was more effective for reducing runoff (p 0.05) and sediment (p 0.01) transport. B-Fescue-FS perennial, usually tall, warm-season grass species when was also more effective than Fescue-FS for reducing losses of organic used with barriers may afford adequate control of NPS N, NO3–N, NH4–N, particulate P, and PO4–P (p 0.01). Fescue-FS pollutants and provide habitat for upland wildlife. and B-Native-FS were equally effective for reducing runoff, sediment, Studies on value of FS for reducing sediment, N, and and nutrient loss. Effectiveness of FS increased with distance with P in runoff have recently been published (Dillaha et al., 18% of runoff, 92% of sediment, and 71% of nutrient leaving the 1989; Daniels and Gilliam, 1996; Srivastava et al., 1996; source area being reduced in the first 4 m of the FS. An equation Melville and Morgan, 2001). Laboratory (Dabney et al., to predict sediment associated with runoff ponding above barriers 1995; Ghadiri et al., 2001) and field (Chaubey et al., explained approximately 70% of the variability between measured and 1995; Rankins et al., 2001) studies indicate that FS signifpredicted values of sediment, organic N, and particulate P transport. icantly reduce sediment and nutrient loss in runoff. The Combination of switchgrass barriers with FS is an effective alternative to Fescue-FS alone for reducing sediment and nutrients in runoff. most widely used grass for FS in the USA is fescue with extensive use in midwestern states (Sleper and Buckner, 1995; Rankins et al., 2001). Information on grass barriers is limited (Meyer et S N, and P in runoff are major sources of al., 1995; Dabney et al., 1999). Most studies have been nonpoint-source (NPS) pollution. Despite current conducted in the laboratory (Dabney et al., 1995; Meyer use of soil and water conservation practices, losses of et al., 1995; Ghadiri et al., 2001). Field studies are few sediment, N, and P from rural lands remain high (McGregor et al., 1999; Eghball et al., 2000; Gilley et (USEPA, 1996). Annual sediment loss in the USA exal., 2000). Moreover, few studies have evaluated comceeds 109 t and costs society $44 billion in degraded parative effectiveness of fescue FS vs. barriers when water resources (USEPA, 1996). Introduction of costused in combination with fescue or native plant species effective practices to reduce NPS pollution is desirable. FS for reducing NPS pollution (Lee et al., 2003). Grass barriers show promise as an economical alterModeling NPS pollution transport through FS and native to existing conservation practices for reducing grass barriers is needed to understand and predict polluNPS pollutants. Grass barriers are narrow strips (aption transport. While equations have been developed proximately 1.2 m) of tall, erect, stiff-stemmed, native to estimate effectiveness of FS for trapping sediments warm-season perennial grasses planted on the field con(Tollner et al., 1977; Foster, 1982; Flanagan et al., 1989), tour (Kemper et al., 1992). Barriers form natural tervalidation of equations with field and plot data is scarce. races (Dabney et al., 1999), slow runoff and promote Moreover, prediction of barrier performance for trapinfiltration (Meyer et al., 1995), enhance deposition of ping sediment has received little attention. Objectives of this study were: (i) to determine effecH. Blanco-Canqui, School of Natural Resources, The Ohio State Unitiveness of a fescue-FS vs. B-fescue-FS or B-Native-FS versity, 2021 Coffey Rd., Columbus, OH 43210-1085; C.J. Gantzer in reducing runoff, sediment, N, and P loss from 8-m and S.H. Anderson, Environmental Soil Science, Univ. of MissouriColumbia, 302 Anheuser-Busch Natural Resources Building, Columlong runoff plots on an Aeric Vertic Epiaqualf; and (ii) bia, MO 65211; E.E. Alberts, USDA-ARS, 268 Agricultural Engineerto evaluate methods to predict transport of sediment, ing Building, Columbia, MO 65211; A.L. Thompson, 251 Agricultural N, and P through switchgrass barriers and fescue filEngineering Building, Columbia, MO 65211. Contribution of Missouri ter strips. Agric. Exp. Stn. Proj. #260. Received 5 Sept. 2003. *Corresponding author ([email protected]). Abbreviations: B-Fescue-FS, switchgrass barrier in combination with the fescue-FS; B-Native-FS, switchgrass barrier in combination with Published in Soil Sci. Soc. Am. J. 68:1670–1678 (2004).  Soil Science Society of America a native grass and forbs species filter strip; CCF, continuous cultivated fallow; FS, vegetative filter strips; NPS, nonpoint source. 677 S. Segoe Rd., Madison, WI 53711 USA