Filter strip

Filtering strips Artificial wetlands Reduce water pollution Wu and Sardo (2009)... 

At a pin-to-pin center distance of 4.5 mm and with 250-p tip pins, it was possible to array 4800 samples onto 25- x 75-mm filter strips. Developed spots appeared sharp and uniform (Figure 6.11). The reported threshold sensitivity was calculated as approximately 10 nM for purified G3PDH protein (10 pg/25nL) spotted at several dilutions. The drawback to this approach is the extensive washing required to remove nonspecific proteins and reagents from the membrane. 

For collection of dried urine specimens, fresh random urine is processed as described for the liquid specimen (see above). Filter paper strips (3x5 cm, filter paper backing 165-0921, BioRad, Richmond, USA) are dipped into the clear supernatant of the oxidized urine up to 1 cm below the upper edge. Excess urine is wiped off and the filter paper is left to completely dry at room temperature in dim light. The filter strip is then sent to the laboratory in an envelope by express mail. 

No till Ridge till Chisel plow Incorporate Waterway Filter strip... 

Krutz, L.J., S.A. Senseman, R.M. Zablotowicz, and M.A. Matocha (2005). Reducing herbicide runoff from agricultural fields with vegetative filter strips A review. Weed Sci., 53 353-367. 

Tingle, C.H., D.R. Shaw, M. Boyette, and G.P. Murphy (1998). Metolachlor and metribuzin losses in runoff as affectd by width of vegetative filter strips. Weed Sci., 46 475 479. 

Webster, E.R and D.R. Shaw (1996a). Impact of vegetative filter strips on herbicide loss in runoff from soybean (Glycine max). Weed Sci., 44 662-671. 

Krutz et al. (2005) did a comprehensive review of research on herbicide retention in vegetative filter strips and found that strips reduced herbicide transport by 27% or more in all papers except two. However, they noted that an understanding of strip efficacy as a function of how rate was limited to a few experiments conducted under extreme conditions of inundation (saturation) or complete infiltration. Lacas et al. (2005) also reviewed the literature on grassed buffer ships and noted very variable results due to the number of interacting processes and dynamic contributing factors, some of which have not yet been quantitatively described or remain largely unknown (e.g., subsurface how processes). 

Schwer and Clausen (1989) reported that a fescue/ryegrass/bluegrass filter strip retained 89% of the phosphorus from dairy milk-house wastewater. Vought et al. (1994), summarizing his own research on phosphorus removal from surface runoff, noted exponential removal with 66% and 95% of soluble phosphorus retained in the first 8 and 16m of buffer strip, respectively. Daniels and Gilliam (1996) determined that fescue and riparian filter strips reduced total phosphorus load by 50%, but that 80% of the soluble phosphorus frequently moved through the strips. 

A vegetative filter strip reduced losses of metribuzin and metolachlor by more than 85% (Webster and Shaw, 1996). Grassed waterways reduced loads of 2,4-D by 69% and 71% under wet and dry conditions, respectively (Asmussen et al., 1977), while trifluralin retention dropped from 96% under dry conditions to 86% under wet conditions (Rhode et al., 1980). A 6-m vegetative buffer strip composed of trees, shrubs, and grass almost completely removed terbuthylazine from runoff (Vianello et al., 2005). Oats as a strip crop below corn reduced atrazine runoff losses by 91% and 65% after applications of 2.2 and 4.5kg/ha, respectively (Hall et al., 1983). Atrazine and metolachlor concentrations in runoff were reduced 83-94% and 82-96%, respectively, with 4.3- and 8.5-m vegetative filter strips (Barone et al., 1998). 

Webster and Shaw (1996) showed the importance of vegetative density on effectiveness of the filter strip. In the first years of strip establishment, total herbicide losses from no-till doublecrop soybeans were similar with and without filter strips, while metolachlor and metribuzin losses were reduced as much as 90% with the more established, denser filter strips in the third year. Both fresh and thatch switchgrass residue in vegetative filter strips can intercept and sorb herbicides (Mersie et al., 2006). 

Runoff of pesticides can be increased if sediment in the water reduces infiltration, indicating another important reason to prevent soil erosion. With 1 mg/L of herbicide applied in simulated runoff to smooth bromegrass filter strips, atrazine, cyanazine, and metolachlor losses were reduced 83-85% with no sediment present, but only 53-58% with 10 000 mg/L sediment (Misra, 1994). 

Characteristics of the pesticide can have a large impact on the effectiveness of vegetative filter strips (Boyd et al., 2003). In a large-scale field experiment using a com source area and an established bromegrass (81%)/bluegrass (12%)/other (7%) vegetative filter strip, pesticides that move predominantly in the water phase (atrazine and alachlor) depended mainly on infiltration capability of, rather than sediment reduction by, the strip. Vellidis (2002) indicated that a restored (2-3 year old) riparian forest buffer and a mature buffer (from a previous study) retained atrazine and alachlor similarly. 

Boyd, P.M., J.L. Baker, S.K. Mickelson, and S.I. Ahmed (2003). Pesticide transport with surface runoff and subsurface drainage through a vegetative filter strip. Tram. Am. Soc. Agric. Eng., 46(3) 675-684. 

Daniels, R.B. and J.W. Gilliam (1996). Sediment and chemical load reduction by grass and riparian filters. Soil Sci. Soc. Am. J., 60 246-251. Dillaha, T.A., R.B. Reneau, S. Mostaghimi, and D. Lee (1989). Vegetative filter strips for agricultural nonpoint source pollution control. 

Fasching, R.A. and J.W. Bauder (2001). Evaluation of agricultural sediment load reductions using vegetative filter strips of cool season grasses. Water Environ. Res., 73(5) 590-596. 

Helmers, M.J., T. Isenhart, M. Dosskey, S. Dabney (2006.) Buffers and Vegetative Filter Strips. EPA Symposium. US Environmental Protection Agency. http //www.epa.gov/msbasin/taskforce/2006symposia/4BuffersVegHelmers.pdf. 

Lalonde, M.N., R.P. Rudra, H.R. Whiteley, and N.K. Kaushik (1998). Vegetative filter strips Impact of design parameters on removal of nonpoint pollutants from Ontario s cropland runoff. Paper No. 982106. 1998 Annual International Meeting of the American Society of Agriculture Engineers, Orlando, FL. 

Munoz-Carpena, R. (1993). Modeling hydrology and sediment transport in vegetative filter strips. Ph.D. Dissertation, North Carolina State University, Raleigh, NC, 242 pp. 

Srivastava, P., D.R. Edwards, T.C. Daniel, P.A. Moore Ir., and T.A. Costello (1996). Performance of vegetative filter strips with varying pollutant source and filter strip lengths. Trans. Am. Soc. Agric. Eng., 39(6) 2231-2239. 

USDA-SCS (1986). Kansas Standards for Filter Strip (Ac.) - 393. Soil Conservation Service. 

Verstraeten, G., J. Poesen, K. Gillijns, and G. Covers (2006). The use of riparian vegetated filter strips to reduce river sediment loads an overestimated control measure Hydrolog. Process., 20 4259 -267. 

Vianello, M., C. Vischetti, L. Scarponi, and G. Zanin (2005). Herbicide losses in runoff events from a field with a low slope role of a vegetative filter strip. Chemosphere, 61 717-725. 

---