|Liu, Jian - Pennsylvania State University|
|Spargo, John - Pennsylvania State University|
|Meinen, Robert - Pennsylvania State University|
|Beegle, Douglas - Retired Non ARS Employee|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2018
Publication Date: 6/1/2018
Citation: Liu, J., Spargo, J.T., Kleinman, P.J., Meinen, R., Moore Jr, P.A., Beegle, D.B. 2018. Water extractable phosphorus in animal manure and manure compost: quantities, characteristics, and temporal changes. Journal of Environmental Quality. 47(3):471-479. https://doi.org/10.2134/jeq2017.12.0467.
DOI: https://doi.org/10.2134/jeq2017.12.0467 Interpretive Summary: American agriculture has been challenged to improve its management of animal manures to improve resource use efficiency and reduce impacts on the environment. This survey of animal manures in the mid-Atlantic region examines trends in water soluble phosphorus, a key indicator of the potential for a manure to adversely impact water quality when it is land applied. Findings highlight how water extractable phosphorus in manure has declined over the past decade in dairy, swine and layer poultry industries.
Technical Abstract: Water extractable phosphorus (WEP) in manure and manure compost is widely used as an indicator of P release to runoff from manures and composts that are land applied. A survey of 600 manures and composts was conducted to assess trends in WEP related to manure and compost types from sources in Pennsylvania and other Mid-Atlantic states. Manure and compost WEP ranged from 0.02 to 2.08% dry matter (DM). Mean WEP was highest in turkey and swine (manure: 0.41-0.56%; no composts), followed by chicken layers and broilers (manure: 0.30-0.35%; compost: 0.46-0.51%), followed by cattle (dairy and beef manure: 0.21-0.28%; compost: 0.11-0.27%) and horses (manure: 0.27%; compost: 0.19%). Across all manures and composts, WEP was negatively correlated with DM content. Moreover, WEP was strongly correlated (r = 0.66) to degree of P saturation (DPS) expressed as a ratio of total P to total metals (calcium, magnesium, iron, aluminum, and manganese). While WEP of beef, broiler and turkey manures from this survey are similar to a decade ago, WEP is now significantly lower for dairy (30%; p < 0.001), swine (46%; p < 0.001) and layers (39%; p < 0.05). Lesser WEP in manures resulted from decreasing total P and/or increasing P sorption capacity, combined with increasing DM content. Results highlight the potential to use DPS to predict WEP in manures and composts, and point to the opportunities to reduce WEP by managing manure handling, storage, and chemistry.