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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #273726
Title: Effect of land application of phosphorus-saturated gypsum on soil phosphorus in a laboratory incubation

Author
item GRUBB, KAREN - National Institute Of Food And Agriculture (NIFA)
item MCGRATH, JOSHUA - University Of Maryland
item PENN, CHAD - Oklahoma State University
item Bryant, Ray

Submitted to: Applied and Environmental Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2011
Publication Date: 2/7/2012
Citation: Grubb, K.L., Mcgrath, J.M., Penn, C.J., Bryant, R.B. 2012. Effect of land application of phosphorus-saturated gypsum on soil phosphorus in a laboratory incubation. Applied and Environmental Soil Science. DOI: 10.1155/2012/506951.

Interpretive Summary: Agricultural drainage ditches can deliver high loads of phosphorus (P) to surface water. Installation of filter structures containing P sorbing materials, including gypsum, is an emerging practice that has shown promise to reduce these P loads. The objective of this study was to evaluate what effect land application of “spent” gypsum that has accumulated P would have on soil P levels and forms. We conducted a soil incubation study using two soil types amended with gypsum containing a high and a low level of P. When applied at typical agronomic rates, neither high P nor low P gypsum application resulted in significant changes in soil test P levels. Gypsum filters appear to be a viable strategy to remove P from agricultural drainage waters, but subsequent land application of spent gypsum does not appear to provide any additional P fertilizer value.

Technical Abstract: Agricultural drainage ditches can deliver high loads of phosphorus (P) to surface water. Installation of filter structures containing P sorbing materials (PSMs), including gypsum, is an emerging practice that has shown promise to reduce these P loads. The objective of this study was to evaluate what effect land application of spent gypsum had on soil P levels and forms. Gypsum was saturated at two levels with P, and applied to a silt loam and a sandy loam at two rates. The treated soils were incubated in the laboratory at 25 deg C, and samples were collected on eight dates between 0 and 183 days after amendment. Spent gypsum application did not significantly increase soil water-extractable or Mehlich 3 P when applied at typical agronomic rates. This appears to be a viable strategy to remove P from agricultural drainage waters, but does not appear to provide any additional P fertilizer value.