title: Wet chemical and phosphorus-31 nuclear magnetic resonance analysis of phosphorus speciation in a sandy soil receiving long-term fertilizer or animal manure applications.
abstract: In areas under intensive livestock farming and with high application rates of animal manure, inorganic and organic phosphorus (P) may be leached from soils. Since the contribution of these P compounds to P leaching may differ, it is important to determine the speciation of P in these soils. We determined the effect of various fertilization regimes on the P speciation in NaOH-Na2EDTA (ethylenediaminetetraacetic acid) and water extracts of acidic sandy soil samples from the top 5 cm of grassland with wet chemical analysis and 31P nuclear magnetic resonance (NMR) spectroscopy. These soils had been treated for a period of 11 years with no fertilizer (control), N (no P application), N-P-K, or different animal manures. Inorganic P was highly elevated in the NaOH-Na2EDTA extracts of the soils amended with N-P-K or animal manures, while organic P increased only in the soil treated with pig slurry. Water-extractable P showed a similar trend. As indicated by 31P NMR, orthophosphate monoesters were the main organic P compounds in all soils. Our results suggest that long-term applications of large amounts of P fertilizer and animal manures caused an accumulation of inorganic P, resulting in an increase of the potential risk related to mobilization of inorganic P in the top 5 cm of these soils.
authors.affiliation: Alterra, Wageningen University and Research Centre (WUR), P.O. Box 47, 6700 AA, Wageningen, The Netherlands. g.f.koopmans@alterra.wag-ur.nl
authors.forename: G F
authors.initials: GF
authors.lastname: Koopmans
authors.forename: W J
authors.initials: WJ
authors.lastname: Chardon
authors.forename: J
authors.initials: J
authors.lastname: Dolfing
authors.forename: O
authors.initials: O
authors.lastname: Oenema
authors.forename: P
authors.initials: P
authors.lastname: van der Meer
authors.forename: W H
authors.initials: WH
authors.lastname: van Riemsdijk
mesh_terms: D000818:Animals; D002614:Chelating Agents / Q000737:chemistry; D004492:Edetic Acid / Q000737:chemistry; D004784:Environmental Monitoring; D005308:Fertilizers; D009682:Magnetic Resonance Spectroscopy; D008372:Manure; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry*; D010759:Phosphorus Isotopes / Q000032:analysis; D018570:Risk Assessment; D012987:Soil; D013552:Swine
chemical_list: D002614:Chelating Agents; D005308:Fertilizers; D008372:Manure; D010759:Phosphorus Isotopes; D012987:Soil; D010758:Phosphorus; D004492:Edetic Acid