Poultry litter and the environment: Physiochemical properties of litter and soil during successive flock rotations and after remote site deposition

Authors: Crippen, Tawni - Tc; Sheffield, Cynthia; Byrd Ii, James - Allen; Esquivel, Jesus; Beier, Ross; Yeater, Kathleen

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2016
Publication Date: 5/15/2016
Publication URL: http://handle.nal.usda.gov/10113/62998
Citation: Crippen, T.L., Sheffield, C.L., Byrd, J.A., Esquivel, J.F., Beier, R.C., Yeater, K.M. 2016. Poultry litter and the environment: Physiochemical properties of litter and soil during successive flock rotations and after remote site deposition. Science of the Total Environment. 553:650-661.

Interpretive Summary: Broiler chickens are generally raised on bedding material like wood shavings or rice hulls. When this bedding material becomes mixed with chicken manure, feathers, feed, etc. it is called litter. Because of increasing cost of new bedding materials, modern broiler producers utilize the same litter for growing out multiple flocks. Yet, this prolonged use results in accumulation of many chemical pollutants in the litter, such as nitrates and the heavy metals iron, manganese, and zinc. These are of concern because they are potential sources of environmental contamination. This study was conducted to measure the effect of multiple flock rotations and poultry house management practices on these physical and chemical characteristics of the litter and soil beneath the litter. The results demonstrate that clean-out practices have the potential to reduce contaminant buildup within the broiler production facility, but also brings to light the fact that proper disposal of litter is necessary for environmental health.

Technical Abstract: The U.S. broiler meat market has grown over the past 16 years and destinations for U.S. broiler meat exports expanded to over 150 countries. This market opportunity has spurred a corresponding increase in industrialized poultry production, which due to the confined space in which high numbers of animals are housed, risks accumulating nutrients and pollutants. The purpose of this research was to determine the level of pollutants within poultry litter and the underlying soil within a production facility, and to explore the impact of spent litter deposition into the environment. The study follows a production facility for the first 2.5 years of production. It monitors the effects of successive flocks and management practices on 15 physiochemical parameters: Ca, Cu, electrical conductivity, Fe, K, Mg, Mn, moisture, Na, NO3-/N, organic matter, P, pH, S, and Zn. Litter samples were collected in-house, after clean-outs, and during stockpiling. The soil before house placement, after the clean-outs, and following litter stockpiling was monitored. Management practices markedly altered the physiochemical profiles of the litter in-house. A canonical discriminant analysis was used to describe the relationship between the parameters and sampling times. The litter profiles grouped into five clusters corresponding to time and management practices. The soil in-house exhibited increases in all physiochemical parameters (2 to 297 fold) except Fe, Mg, %M, and pH. The spent litter was followed after deposition onto a field for use as fertilizer. After 20 weeks, the soil beneath the litter exhibited increases in EC, Cu, K, Na, NO3-/N, %OM, P, S and Zn, while %M decreased. Understanding the impacts of industrialized poultry farms on the environment is vital as the cumulative ecological impact of this land usage could be substantial if not properly managed to reduce the risk of potential pollutant infiltration into the environment.