Centrifugal spreader mass and nutrients distribution patterns for application of fresh and aged poultry litter

A spin-type centrifugal spreader was evaluated using fresh and aged poultry litter upon dry mass, product nitrogen (N), phosphorus (P) and potassium (K), incubation study soil available N and particle size distribution patterns. Relative to the aged litter (37% moisture content), the fresh litter (17% moisture content) had greater <1.00 mm particle size fraction weights and atmospheric particulate was launched, which posed as a potential fallout to adjacent fields, waterways and residences. Relative to the aged litter, the broadcast fresh litter resulted in higher coefficients of variation (CV) over its transverse distance, a narrower calculated space distance between passes for uniform spread and lower soil available N concentrations. For nitrogen application over the broadcast transverse distance the fresh litter displayed a high R2 best fit 4th order polynomial distribution pattern, while the aged litter showed high R2 best fit 6th order polynomial distribution pattern. A soil incubation study of the fresh and aged broadcast litter resulted in a more variable or lower R2 best fit 2nd order polynomial distribution pattern. For both the fresh and aged litter, the calculated distance between passes to achieve a uniform mass distribution was greater than that required for the broadcast of soil available N. For the fresh litter, the soil available N and litter P concentration levels strongly correlated (relatively high p and R2 values) with the <1.00 mm fraction weight, while for the aged litter this relationship was not as significant. In addition to reducing the health risk (i.e. pathogens, antibiotic residues and resistant bacteria) and/or environment issues (particulate fallout onto waterways, adjacent fields and/or residences) our study mass, particulate and N distribution patterns results suggest that poultry litter should be allowed to age before broadcast application is attempted.