|Rowe, Dennis - Mississippi State University|
Submitted to: ASABE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/2/2015
Publication Date: 7/26/2015
Citation: Miles, D.M., Brooks, J.P., Rowe, D.E., Moore Jr, P.A., Evans, J.D., Jenkins, J.N. 2015. Broiler house litter sampling: the final frontier. ASABE Annual International Meeting. Paper number 152152501. doi: 10.13031/aim.20152152501.
Technical Abstract: Today, the sustainability of broiler operations reaches beyond the need for litter nutrient management plans that came to the forefront of the industry’s attention in the last fifteen years. Thorough characterization of litter within houses provides the basis for emission models to benefit growers, integrators, and the environment. Four commercial broiler houses in Mississippi were intensively sampled along a 36-point grid with 8 additional samples between feeders and waterers in a zig-zag pattern. Results included litter temperature, moisture and pH, concentration of litter nutrients and minerals as well as in-situ estimation of NH3, N2O, and CO2 flux from the litter that had been reused for 8 to 30 flocks. Contour plots were developed to visually assess spatial characteristics; traditional statistics were employed to determine the effects of season (summer vs. winter), bird age (placement, mid-flock, market), and half of house (brood vs. fan) on the variables of interest. When birds were placed, spatial depiction clearly indicated the effects of brood heaters on litter temperature and moisture as well as litter chemical treatments on decreased litter pH. Mean gas fluxes were 488 ± 438 mg NH3 m-2 h-1, 15.5 ± 14.3 mg N2O m-2 h-1, and 14400 ± 10900 mg CO2 m-2 h-1 where litter temperature was 28 ± 5 °C, litter moisture was 28.1 ± 8.6 %, and litter pH was 8.32 ± 0.39. Overall N content was 2.76 ± 0.54 %. However, the complexity of litter surface parameters is not adequately described by mean values. The best examples were the extreme values in feeder/waterer samples where densely caked litter resulted in very low gas flux. For traditional statistics, most minerals had a greater concentration during summer growouts, but water soluble PO4, NH4, and NO3 were greater in winter flocks. There was a trend for decreased litter pH during the middle of flocks and the fan end of the house had greater litter pH overall. Ultimately, the user’s goal for the data will determine its utility. For growers, keeping litter dry is imperative to maintain lower NH3 emissions. For integrators, house structural remodeling and/or mid-flock litter treatment may be required to develop new management strategies. For researchers, the data set provides a basis for national emission modeling needed urgently to improve emission estimates.