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Comparison of Denitrification in Two Riparian Soils
Author(s) -
Ambus Per,
Lowrance Richard
Publication year - 1991
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1991.03615995005500040017x
Subject(s) - denitrification , soil water , loam , riparian zone , environmental science , soil science , organic matter , hydrology (agriculture) , environmental chemistry , chemistry , geology , nitrogen , ecology , geotechnical engineering , organic chemistry , habitat , biology
The factors controlling NO 3 removal in riparian buffer systems are poorly understood. We measured denitrification rates for two Coastal Plain, forested riparian zone soils: Kinston fine loamy sand (fine‐loamy, siliceous, acid, thermic Typic Fluvaquent) and Alapaha loamy sand (loamy, siliceous, thermic Arenic Plinthic Paleaquult). Kinston soils are more poorly drained and have higher organic matter than Alapaha soils. Surface soil and shallow aquifer samples were treated with solutions that contained chloramphenicol with either distilled water, NO 3 ‐N, glucose‐C, or NO 3 plus glucose. Denitrification potentials (N 2 O production in the presence of acetylene) were significantly higher in Kinston soil for both depths. Surface samples from both soils showed significant responses to NO 3 additions but no response to C additions without NO 3 . Subsurface samples, taken from the top of the aquifer, showed no significant response to either NO 3 or C treatments for either soil. Both soils showed a high degree of stratification within the top 10 cm, with 88 and 68% of denitrification potential in the top 2 cm for Alapaha and Kinston soils, respectively. Denitrification rates in cores were much lower than in slurries but rates in cores with NO 3 or NO 3 ‐plus‐glucose additions were significantly higher than unamended or C‐amended cores for the Kinston soil. Although both soils respond to NO 3 additions, Kinston soils are better able to reduce incoming NO 3 . These results indicate that denitrification in the shallow aquifer is a more important NO 3 removal mechanism at the Kinston site than at the Alapaha site.