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ARS Home » Midwest Area » St. Paul, Minnesota » Soil and Water Management Research » Research » Publications at this Location » Publication #181189
Title: MODELING NITROGEN TRANSFORMATIONS DURING A LONG-TERM INCUBATION

Author
item Clapp, Charles
item MOLINA, JEAN A.E.
item Lee, Daniel
item LAYESE, MEG
item Miller, Margaret
item HAYES, MICHAEL H.B.
item PALAZZO, ANTONY
item Baker, John

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/23/2005
Publication Date: 6/15/2005
Citation: Clapp, C.E., Molina, J., Lee, D.T., Layese, M.F., Miller, M.A., Hayes, M., Palazzo, A.J., Baker, J.M. 2005. Modeling nitrogen transformations during a long-term incubation [abstract]. EMSI/North Central NOM Workshop. p. 54.

Interpretive Summary:

Technical Abstract: Inorganic and organic N were determined on a Waukegan silt loam soil for a 90-wk aerobic incubation experiment. 15N labeled soil samples were taken from 2 different tillage treatments, till (T) or no-till (NT), and 2 residue management practices, returned (R) or harvested (NR). Triplicate samples of 4 treatment combinations (TR, NTR, TNR, and NTNR) were incubated in polyethylene bags (15 x 40 cm), 500 g each, at 35oC under constant water conditions. The initial NO3-N concentration for TR and NTR treatments were 30 to 70 mg L-1 higher than the TNR and NTNR treatments (10 mg L-1). At week 90, the values had risen to 425, 550, 150, and 180 mg L-1 NO3-N, respectively, with slight increases still occurring. Inorganic N concentration was determined at periodic intervals after KCl extraction. Extracted samples were converted into NH4-N by the Mason jar diffusion technique, for analyses of total N and 15N. Atom-% 15N (inorganic) increased than reached a plateau. The extent of each phase depended on the treatment. This information was used to estimate the 15N content in the organic pools of the model NCSOIL.