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United States Department of Agriculture

Agricultural Research Service

Title: Phosphorus Compounds in Sequential Extracts of Animal Manures: Chemical Speciation and a Novel Fractionation Procedure

Authors
item Turner, Benjamin - UNIVERSITY OF FLORIDA
item LEYTEM, APRIL

Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 30, 2004
Publication Date: November 15, 2004
Citation: Turner, B.L., Leytem, A.B. 2004. Phosphorus compounds in sequential extracts of animal manures: Chemical speciation and a novel fractionation procedure. Environmental Science and Technology. 38:6101-6108.

Interpretive Summary: Pollution of water bodies by phosphorus in runoff from soil amended with animal manures is one of the greatest threats to water quality in developed countries. The environmental fate of manure phosphorus is determined in part by its chemical composition, yet extraction procedures to assess this are poorly developed and provide no structural information. We used solution phosphorus-31 NMR spectroscopy to quantify phosphorus compounds in sequential extracts of three contrasting manures (broiler litter, beef-cattle manure, swine manure). Using a procedure originally developed for soils, but commonly applied to manures, phosphorus was extracted sequentially with deionized water, sodium bicarbonate, sodium hydroxide and hydrochloric acid. Water and sodium bicarbonate extracted readily-soluble compounds, including phosphate, phospholipids, DNA, and simple phosphate monoesters, which are mobile in soil and biologically available. In contrast, sodium hydroxide and hydrochloric acid extracted poorly-soluble compounds, including phytic acid (myo-inositol hexakisphosphate). The latter is immobile in soil and of limited biological availability. Based on these results, we developed a simplified two-step fractionation procedure involving extraction of readily-soluble phosphorus in 0.5 molar sodium bicarbonate followed by extraction of stable phosphorus in a solution containing 0.5 molar sodium hydroxide and 50 millimolar sodium ethylene diamine tetraacetic acid. This revised procedure separates manure phosphorus into structurally-defined fractions with environmental relevance and will facilitate research on this important aspect of environmental science.

Technical Abstract: Pollution of water bodies by phosphorus in runoff from soil amended with animal manures is one of the greatest threats to water quality in developed countries. The environmental fate of manure phosphorus is determined in part by its chemical composition, yet extraction procedures to assess this are poorly developed and provide no structural information. We used solution phosphorus-31 NMR spectroscopy to quantify phosphorus compounds in sequential extracts of three contrasting manures (broiler litter, beef-cattle manure, swine manure). Using a procedure originally developed for soils, but commonly applied to manures, phosphorus was extracted sequentially with deionized water, sodium bicarbonate, sodium hydroxide and hydrochloric acid. Water and sodium bicarbonate extracted readily-soluble compounds, including phosphate, phospholipids, DNA, and simple phosphate monoesters, which are mobile in soil and biologically available. In contrast, sodium hydroxide and hydrochloric acid extracted poorly-soluble compounds, including phytic acid (myo-inositol hexakisphosphate). The latter is immobile in soil and of limited biological availability. Based on these results, we developed a simplified two-step fractionation procedure involving extraction of readily-soluble phosphorus in 0.5 molar sodium bicarbonate followed by extraction of stable phosphorus in a solution containing 0.5 molar sodium hydroxide and 50 millimolar sodium ethylene diamine tetraacetic acid. This revised procedure separates manure phosphorus into structurally-defined fractions with environmental relevance and will facilitate research on this important aspect of environmental science.

Last Modified: 8/19/2014
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