Grassed buffer strips as nitrate diffuse pollution remediation tools: management impact on the denitrification enzyme activity

Abstract

The management of grassed buffer strips proved to be an efficient remediation technique in controlling nitrogen losses to surface water. In south Belgium, agri-environmental policies have encouraged farmers to seed buffer strips along rivers, in zones where the soil was previously devoted to agricultural production. We wanted to assess how important denitrification is in a buffer strip in comparison with a cropped field. The study investigated the denitrifiying enzyme activity (DEA) of two contiguous buffer strips with different management stories. The eastern part of the buffer strip was seeded in 1999. The western part of the buffer strip is a piece of crop field abandoned by the farmer 20 years ago and not managed for the last 10 years. This experimental study demonstrates that the denitrification enzyme activity in a riparian buffer strip is significantly higher than in the adjacent cropped field (3.67 and 2.12 mgNkg(-1)d(-1) respectively). The DEA was significantly different between the two buffer strips under comparison, assessing that the management of the buffer strips has a dominant effect on DEA. The old unmown buffer strip is potentially more efficient in the nitrate removal process than the 6-year-old seeded buffer strip.

Supply of an ecosystem service—Farmers’ willingness to adopt riparian buffer zones in agricultural catchments

“…This is driven by reduction of sediment, pathogen and nutrient loads (Heathwaite et al, 1998;Line et al, 2000;Reed and Carpenter, 2002;McKergow et al, 2003;Sharply et al, 2003;Young and Briggs, 2005;Cors and Tychon, 2007;Haygarth et al, 2009;Wilcock et al, 2009). As noted by Lynch et al (2001) such findings have encouraged some policymakers to assign a high priority to establishing riparian buffers.…”

Recycling Vertical-Flow Biofilter: A Treatment System for Agricultural Subsurface Tile Water

“…Therefore, additional methods for nutrient removal and control are needed where subsurface tile drainage is common. Passive treatment systems such as vegetated riparian zones and biofilters have been shown to be effective in controlling nutrient inputs from surface runoff (Cors and Tychon, 2007;Dodds and Oakes, 2006;Mankin et al, 2007;Mayer et al, 2007;Spruill, 2004;Yamada et al, 2007). The preponderance of water flow in tile drainage systems though, is subsurface, within the vadose zone.…”

“…In addition, the use of separate modules should reduce maintenance costs since repair to a single component can be done by simply replacing the module without the need to disassemble the entire system and disrupting its operation. In exploiting the ability of vegetated soil systems to sequester and transform inorganic nutrients, the RVFB reflects the advantages of a riparian buffer, a well-established treatment modality for the prevention of surface water pollution from agricultural runoff (Cors and Tychon, 2007;Mankin et al, 2007;Mayer et al, 2007;Schoonover et al, 2005;Yamada et al, 2007). By adding a subsurface recirculating reservoir, the RVFB also is capable of intercepting and treating subsurface runoff, particularly tile water that normally bypasses riparian buffers.…”