|CAVADINI, JASON - University Of Wisconsin|
|BERTRAM, MICHAEL - University Of Wisconsin|
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/19/2014
Publication Date: 1/12/2015
Citation: Jokela, W.E., Cavadini, J., Bertram, M. 2015. Low-disturbance manure application methods in a corn silage-rye cover crop system. Meeting Proceedings. 2015.
Technical Abstract: Incorporation of manure by tillage can conserve manure N by reducing ammonia volatilization losses, but tillage also incorporates crop residue, which increases erosion potential. This study compared several low-disturbance manure application methods, designed to incorporate manure while still 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, sweep injection with paired disks (strip-till), coulter injection, aerator-band, and broadcast with and without disk harrow incorporation (all fall-applied), plus pre-plant fertilizer N rates ranging from 0 to 180 lb/acre in separate non-manured plots. There were some differences in ear leaf N concentrations and N uptake among injected/incorporated manure treatments, but all were greater than surface-applied manure, which was equal to or slightly greater than no-manure control. Pre-sidedress soil nitrate test results were consistent with those of plant N. 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. Residue cover of 30-40% pre-manure was reduced by manure application depending on intensity of injection or tillage action. Cover increased by spring due to growth of rye cover crop, except for disk incorporation; but cover in all treatments except strip-till (no spring tillage) was greatly reduced by spring field cultivation. Phosphorus runoff losses from simulated rain shortly after manure application reflected the degree of manure incorporation, with greatest loss from surface broadcast and the least from injection. These results indicate that low-disturbance manure application methods can greatly reduce ammonia-N emission and nutrient runoff losses and improve manure N availability compared to surface application and maintain residue cover better than disk incorporation of manure.