92-3 Enhanced Efficiency Urea Sources and Placement Effects on N2O Emissions.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Agricultural Practices to Improve Nitrogen-Use Efficiency and Mitigate Greenhouse Gas Emission: I
Monday, November 3, 2014: 8:30 AM
Long Beach Convention Center, Room 201B
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Mario Tenuta1, Xiaopeng Gao2, Donald Flaten2 and Haben Asgedom3, (1)Soil Science, University of Manitoba, Winnipeg, MB, Canada
(2)University of Manitoba, Winnipeg, MB, Canada
(3)Farmers Edge, Winnipeg, MB, Canada
Nitrogen fertilizer management is important in determining soil nitrous oxide (N2O) emissions. The effects of enhanced efficiency granular urea and placement on N2O emissions from spring wheat at two locations in Manitoba, Canada in 2011 and 2012 were examined. Treatments were a control of no N addition and application of 80 kg N ha-1 at planting with five combinations of urea sources and placement: broadcast-incorporated urea (UreaI) and, subsurface side-banded urea (UreaS), midrow-banded urea (UreaM), midrow-banded ESN (ESNM), and midrow-banded SuperU (SuperUM). Planting in 2011 was delayed 40 days compared to 2012 because of late snow-melt. Planting coincided with higher soil temperature and moisture resulting in 3-7 fold more growing season N2O emissions (∑N2O) in 2011 than 2012 for all N treatments. In 2011, SuperUM and ESNM reduced ∑N2O, emission factor scaled by N applied (EF), as well as yield-scaled N2O emission intensity (EI) by 47%, 67% and 55%, respectively, compared with UreaI. Although not significant, in 2011, banding treatments of urea tended to decrease ∑N2O, EF, and EI of granular urea compared to broadcast-incorporation. The ∑N2O and nitrate exposure, an integration of soil NO3- concentrations over time, were correlated with R2 ranging from 0.46 to 0.67 over the site-years, indicating N availability from treatments in part determined emissions. Grain yield and crop N uptake did not vary with N sources and placement. These results suggest that for early season wet and warm conditions at application, EEF N sources can reduce emissions. The effect of banding in affecting emissions requires further investigations.
See more from this Division: ASA Section: Environmental Quality
See more from this Session: Agricultural Practices to Improve Nitrogen-Use Efficiency and Mitigate Greenhouse Gas Emission: I
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