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United States Department of Agriculture

Agricultural Research Service

Title: Nitrogen Transformations During a Long-Term Incubation

Authors
item Lee, Daniel - UNIVERSITY OF MINNESOTA
item Clapp, Charles
item Molina, Jean - UNIVERSITY OF MINNESOTA
item Miller, Margaret - UNIVERSITY OF MINNESOTA
item Dowdy, Robert - USDA-ARS RETIRED

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 21, 2001
Publication Date: N/A

Technical Abstract: Inorganic N (No) was determined on a Waukegan silt loam soil during a 2-yr aerobic incubation experiment. 15-N labeled soil samples with N fertilization (2 g/m^2) were taken from 2 different tillage treatments [till (T) or no-till (NT)], and 2 residue management techniques [returned (r) or harvested (h)]. Triplicate samples of 4 treatment combinations were eincubated in plyethylene bags at 35 C under constant water conditions. Sub-samples were taken at periodic intervals for NO3-N determination after extraction with KCl. Extracted samples were converted into NH4-N by a Mason jar diffusion technique, for analyses of total N and 15-N. The initial NO3-N concentration for till and no-till residue-returned treatments were 30 to 70 mg/L higher than the till and no-till residue- removed treatments (10 mg/L). After week 105, the values had risen to 150, 170, 425, and 550 mg/L NO3-N with slight increases still occurring. Estimates of No values were determined using the computer model NCSOIL.

Last Modified: 8/1/2014