Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/14/2015
Publication Date: 3/4/2015
Citation: Jokela, W.E., Sherman, J.F., Sternweis, T.J. 2015. Nutrient runoff losses from liquid dairy manure applied with low-disturbance methods. Meeting Abstract. 2015.
Technical Abstract: Manure applied to cropland is a source of phosphorus and nitrogen in surface runoff and can contribute to impairment of surface waters. Immediate tillage incorporates manure into the soil, thus reducing nutrient loss in runoff, as well as nitrogen loss via ammonia volatilization. But tillage also incorporates crop residue, which may increase erosion potential. We applied liquid dairy manure in a silage corn-rye cover crop system in late October using methods designed to incorporate manure with minimal soil and residue disturbance. These include low-disturbance sweep injection with paired disks that create a ridge for planting in the spring (strip-till) and tine aerator-band manure application, which applies bands of manure over aerator slots to encourage manure infiltration. These were compared to standard broadcast application, either incorporated with a disk or left on the surface. Runoff generated from a portable rainfall simulator two or more days after manure application was collected from 2 x 2 m subplots bordered by a steel frame with a PVC gutter at the lower end to collect runoff. Preliminary results show the highest runoff losses of total and dissolved P from surface-applied manure, as would be expected. Total P loss was reduced by approximately 35% by the aerator band method, 70% by disk incorporation, and almost 90% by strip-till injection, which was not statistically different from the control treatment that received no manure. Results for dissolved P losses followed a similar pattern, but with even greater reductions from injected or incorporated manure. Overall, preliminary results from this study show that the low-disturbance manure application methods can greatly reduce nutrient runoff losses (and ammonia emission) compared to surface application; and that they maintain residue cover better than disk incorporation of manure.