|CAVADINI, JASON - University Of Wisconsin|
|BERTRAM, MICHAEL - University Of Wisconsin|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/25/2015
Publication Date: 11/13/2015
Citation: Jokela, W.E., Sherman, J.F., Cavadini, J., Bertram, M. 2015. Effects of low-disturbance manure application methods on N2O and NH3 emissions in a silage corn - rye cover crop system. Meeting Abstract. ASA-CSSA-SSSA, Madison,WI.
Technical Abstract: Incorporation of manure by tillage can conserve manure N by reducing ammonia volatilization losses, but tillage also incorporates crop residue, which may increase erosion potential. This study compared several low-disturbance manure application methods, designed to incorporate manure while maintaining crop residue for erosion control, to conventional broadcast application in a silage corn/winter rye cover crop system. Treatments included low-disturbance sweep injection, strip-till injection (sweep injection ridged with paired disks), coulter injection, aerator-band, and broadcast with and without disk harrow incorporation, plus pre-plant fertilizer N rates ranging from 0 to 200 kg/ha in separate non-manured plots. All manure treatments were applied in late Oct/early Nov; all treatments except strip-till injection were field cultivated in the spring. Nitrous oxide flux was greatest in spring and early summer with most (but not all) peaks in flux explained by manure or N fertilizer application, wet soil conditions and/or recent rain events. Total estimated emission varied by year but was 2 to 4 times higher from manure and fertilizer than from the non-manured/fertilized control, with greatest amounts from N fertilizer, sweep injection, strip-till injection, and aerator-band. Ammonia emission was greatest from surface-applied manure, with reductions of 85% or more from injected manure and more modest reductions (30 to 55%) from aerator/band and disk incorporation. These results indicate that low-disturbance manure application methods can reduce ammonia-N loss compared to surface application but there may be tradeoffs with N2O emission.