Search National Agricultural Library Digital Collections

NALDC Record Details:

Contrasting Nutrient Mitigation and Denitrification Potential of Agricultural Drainage Environments with Different Emergent Aquatic Macrophytes

Permanent URL:
Download [PDF File]
Remediation of excess nitrogen (N) in agricultural runoff can be enhanced by establishing wetland vegetation but the role of denitrification in N removal is not well understood in drainage ditches. We quantified differences in N retention during experimental runoff events followed by stagnant periods in mesocosms planted in three different vegetation treatments: unvegetated; cutgrass (Leersia orizoides (L.) Sw.); and common cattail (Typha latifolia L.). We also quantified denitrification rates using membrane inlet mass spectrometry (MIMS) from intact cores extracted from each mesocosm treatment. All treatments retained 60% or more of NO(3)(-)-N loads during the 6 h experimental runoff event, but mesocosms planted with cutgrass had significantly higher (68%) retention compared to cattail (60%) or unvegetated (61%) treatments. After the runoff event, mesocosms planted in cattails reduced NO3--N concentrations by > 95% within 24 h and cutgrass achieved similar reductions within 48 h, whereas reductions in unvegetated mesocosms were significantly less (65%). Cores from cutgrass mesocosms had significantly higher average denitrification rates (5.93 mg m(-2) h(-1)) accounting for as much as 56% of the immobilized NO(3)(-)-N within 48 h, whereas denitrification rates were minimal in cores from unvegetated (-0.19 mg m(-2) h(-1)) or cattail (0.2 mg m(-2) h(-1)) mesocosms. Our findings have implications for mitigating excess NO(3)(-)-N in agricultural runoff. While vegetated treatments removed excess NO(3)(-)-N from the water column at similar and significantly higher rates than unvegetated treatments, the high denitrification rates observed for cutgrass highlight the potential for permanent removal of excess N from agricultural runoff in vegetated ditches and wetlands.
Jason M. Taylor , Matthew T. Moore , J. Thad Scott
USDA Scientist Submission
Journal of environmental quality 2015 Jun. 12 v.44 no.4
Journal Articles, USDA Authors, Peer-Reviewed
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.