Long-Term Performance Testing of Subsurface Dry Poultry Litter Application Technology.

Broadcast application of poultry litter to no-till soils can exacerbate water pollution issues due to nutrient losses in runoff. For the past six years, researchers at UMES, USDA-ARS, and other institutions have been testing a novel technology (the “Subsurfer”) that applies dry litter 3-10 cm below the soil surface with minimal soil disturbance. We evaluated runoff nutrient losses and odor emissions associated with various conventional litter application methods as well as with the Subsurfer. Losses of phosphorus and nitrogen in surface runoff and leachate did not differ significantly between the Subsurfer and the unamended control (α ≤ 0.05). However, differences in runoff and leachate nutrient losses between the Subsurfer and conventional litter application methods varied over time.  For instance, leachate phosphorus concentrations from the Subsurfer were significantly lower than those associated with broadcast and disked litter application methods, but leachate nitrogen concentrations were lower in 2012 only. Remarkably, the Subsurfer treatment increased average corn yields by 30%, while odor emissions were reduced by as much as 92% when compared to broadcasted litter treatment. Findings, confirm an array of environmental and agronomic benefits of using the Subsurfer but also point to some variability in expected benefits over time.

Key Words:  Poultry Litter, Odor Emissions, Water Pollution, Subsurface Litter Application, Leaching, Runoff