INFLUENCE OF BROILER LITTER BULK DENSITY ON METERING AND DISTRIBUTION FOR A SPINNER-DISC SPREADER S. S. Virk, J. P. Fulton, O. O. Fasina, T. P. McDonald
ABSTRACT. Poultry litter is commonly land applied as an organic fertilizer on crop and pastureland. However, the high variability in physical characteristics of litter, especially moisture content and bulk density, makes it difficult to maintain accurate metering and uniform distribution during application with spinner-disc spreaders. A study was conducted to understand the effect of litter bulk density on conveyor metering and spreading distribution for a spinner-disc, litter spreader. Two sources of broiler litter (termed as A and B) at different moisture contents (32% and 28% w.b., respectively) and bulk densities (416.5 and 480.6 kg/m3, respectively) were acquired and used in this study. Different spreader and rate controller settings (two gate heights: 17.8 and 34.9 cm; four application rates: 1743, 3424, 3486, and 6848 kg/ha; two correct density values: 416.5 and 480.6 kg/m3; and three incorrect density values: 352.4, 416.5, and 544.7 kg/m3) were established as treatments. The spreader rate controller used in this study required litter density as an input variable for managing the discharge rate. Actual and theoretical discharge rates were compared for conveyance data analysis whereas single-pass and standardized distribution patterns were generated and compared using standard pan testing. Results indicated that incorrect density treatments generated high rate errors (>15%) during conveyance tests. Field application rates were also outside the considered acceptable limits, i.e., not within 10% of the target application rate, for both litter types (A and B). For both litter types, the central peak of the single-pass patterns at different density treatments varied with actual application rate (mass flow rate). Standardized patterns at different density treatments for the same litter type were found to be statistically different (p 14.8% error) were recorded for incorrect density values of 416.5 and 544.7 kg/m3, respectively, compared to smaller errors (
