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Denitrification from a Swine Lagoon Overland Flow Treatment System at a Pasture–Riparian Zone Interface
Author(s) -
Lowrance Richard,
Hubbard Robert K.
Publication year - 2001
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2001.302617x
Subject(s) - denitrification , environmental science , nitrate , manure , surface runoff , riparian zone , soil water , hydrology (agriculture) , agronomy , chemistry , nitrogen , soil science , ecology , geology , biology , geotechnical engineering , organic chemistry , habitat
In manure disposal systems, denitrification is a major pathway for N loss and to reduce N transport to surface and ground water. We measured denitrification and the changes in soil N pools in a liquid manure disposal system at the interface of a pasture and a riparian forest. Liquid swine manure was applied weekly at two rates (approximately 800 and 1600 kg N ha −1 yr −1 ) to triplicate plots of overland flow treatment systems with three different vegetation treatments. Denitrification (acetylene block technique on intact cores) and soil N pools were determined bimonthly for 3 yr. The higher rate of manure application had higher denitrification rates and higher soil nitrate. Depth 1 soil (0–6 cm) had higher denitrification, nitrate, and ammonium than depth 2 soil (6–12 cm). The vegetation treatment consisting of 20 m of grass and 10 m of forest had lower denitrification. Denitrification did not vary significantly with position in the plot (7, 14, 21, and 28 m downslope), but nitrate decreased in the downslope direction while ammonium increased downslope. Denitrification ranged from 4 to 12% of total N applied in the manure. Denitrification rates were similar to those from a nearby dairy manure irrigation site, but were generally a lower percent of N applied, especially at the high swine effluent rate. Denitrification rates for these soils range from 40 to 200 kg N ha −1 yr −1 for the top 12 cm of soil treated with typical liquid manure that is high in ammonium and low in nitrate.