Effectiveness of Grass Filters in Reducing Phosphorus and Sediment Runoff

Abstract

Surface water contamination can often be reduced by passing runoff water through perennial grass filters. Research was conducted in 2006 to 2008 to evaluate the size of cool season grass filters consisting primarily of tall fescue (Festuca arundinacea Schreb) with some orchard grass (Dactylis glomerata L.) relative to drainage area size in reducing runoff sediment and phosphorus (P). The soil was Pohocco silt loam Typic Eutrochrepts with a median slope of 5.5 %. The grass filters occupying 1.1 and 4.3 % of the plot area were compared with no filter with four replications. The filters were planted in the Vshaped plot outlets which were 3.7 × 11.0 m in size. The filter effect on sediment and P concentration was determined from four natural runoff events when nearly all plots had runoff. Filter effect on runoff volume and contaminant load was determined using total runoff and composites of samples collected from 12 runoff events. Sediment concentration was reduced by 25 % with filters compared with no filter (from 1.10 to 1.47 g L −1 ), but P concentration was not affected. The 1.1 and 4.3 % filters, respectively, compared with having no grass filter, reduced: runoff volume by 54 and 79 %; sediment load by 67 and 84 % (357 to 58 kg ha −1 ); total P load by 68 and 76 % (0.58 to 0.14 kg ha −1 ); particulate P (PP) load by 66 and 82 % (0.39 to 0.07 kg ha −1 ); and dissolved reactive P (DRP) load by 73 and 66 % (0.2 to 0.07 kg ha −1 ), respectfully. A snowmelt runoff event had 56 % greater DRP concentration compared with rainfall-induced runoff events. Grass filters reduced sediment and P load largely by reducing runoff volume rather than reducing concentration. Well-designed and well-placed grass filters that occupy 1.0 to 1.5 % of the drainage area and intercept a uniform flow of runoff from a drainage area can reduce sediment and nutrient loss in runoff by greater than 50 %.

Improved APEX Model Simulation of Buffer Water Quality Benefits at Field Scale

“…Seobi et al (2005) and Kumar et al (2012) determined that soil hydraulic conductivity values were four to 16 times higher in an agroforestry buffer than in the associated cropland or pasture. Reported trapping effectiveness values of upland and edge-of-field buffers vary widely among studies: from 41% to 100% for sediment and from 27% to 96% for total phosphorus (TP) (Dillaha et al, 1989;Daniels and Gilliam, 1996;Schmitt et al, 1999;Mayer et al, 1999;Lee et al, 2000;Blanco-Canqui et al, 2004;Vianello et al, 2005;Bhattarai et al, 2009;Caron et al, 2010;Al-wadaey et al, 2012).…”

Phosphorus dynamics in vegetated buffer strips in cold climates: a review

“…During the single snow event, concentrations of TP, DP, and PP were higher in both the 1.1% and 4.3% VBS plots than in the cultivated field containing 0% VBS. The 1.1% plot contained the highest concentrations of TP (4.8 mg•L −1 ) and DP (4.29 mg•L −1 ) of any sample during the study (Al-wadaey et al 2012).…”

“…In a similar study in Nebraska, USA (Köppen-Geiger climate classification Dfa: humid continental climate with at least 1 month with temperatures <0°C), Al-wadaey et al 2012compared concentrations of TP, DP, and PP in surface runoff from cultivated fields that contained 0%, 1.1%, or 4.3% VBS area within the field. The authors point out that even in Nebraska, which does not experience the prolonged periods of snow cover and freezing temperatures that are typical of the northern USA or Canada, soils are frozen and vegetation is not actively taking up nutrients over winter (Al-wadaey et al 2012). Thus, runoff with limited infiltration is likely occurring, which has been shown to increase DP loads to surface waters.…”

Giant Cane Vegetative Buffer for Improving Soil and Surface Water Quality

“…The P removal by vegetative buffers depends on buffer length, rate of inflow, type of vegetation, and density of vegetation coverage (Abu-Zreig et al, 2003). Al-wadaey et al (2012) found that vegetative filter of tall fescue (Festuca arundinacea Schreb) and orchardgrass did not affect P concentration but reduced DRP load by 66 to 73% and TP load by 68 to 76%. They concluded that a grass filter reduced sediment and P load through a reduction in runoff volume.…”