|Ginting, Daniel - UNIV OF NE/LINCOLN|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 21, 2003
Publication Date: November 1, 2003
Citation: GINTING, D., EGHBALL, B. SPATIAL AND DIURNAL VARIABILITY OF SOIL GREENHOUSE GAS FLUXES. AMERICAN SOCIETY OF AGRONOMY ABSTRACTS #507379. 2003. Technical Abstract: Understanding N2O flux spatial and temporal variabiliy due to landscape position and time of sampling is critical for N2O flux estimation. Our objective was to evaluate the effects of spatial, temporal, and diurnal variability of N2O emission along a toposequence under an irrigated corn. Point (once a day) measurements of N2O fluxes were made on five dates from May to August 2002 for three different tractor wheel tracts i.e. N-fertilized inner-wheel-tract (NIWT), N-fertilized gage-wheel-tract (NGWT), and non-fertilized no-wheel tract (NWT). Within each tract along the toposequence, six locations were selected to include summit, footslope, and toeslope positions. Diurnal gas measurements were also made at the summit, footslope, and toeslope positions of the NGWT areas every four hours from 8:00 am to 8:00 am the next day at four different dates. The N2O fluxes from the NIWT or NGWT were 3 times of that from the NWT. There was no significant effect of landscape position on N2O flux. Flux increased from 0.18 (8:00 am) to 0.37 (12:00 pm), and then decreased to 0.19 g N2O-N ha<SUP>1</SUP> h<SUP>1</SUP> (4:00 pm). The N2O flux at 4:00 pm was similar to other hours, while 12:00 pm was similar to 8:00 pm. There was no effect of landscape position on N2O fluxes and diurnal pattern of N2O fluxes was not evident. Nitrogen fertilization of wheel tract areas increased N2O flux.