title: Phosphorus speciation in manure-amended alkaline soils.
abstract: Two common manure storage practices are stockpiles and lagoons. The manure from stockpiles is applied to soils in solid form, while lagoon manure is applied as a liquid. Soil amendment with manure in any form introduces a significant amount of phosphorus (P) that exists in both organic and inorganic forms. However, little is known about P speciation in manure stored under different conditions, or the subsequent forms when applied to soils. We used solution (31)P nuclear magnetic resonance (NMR) spectroscopy and conventional P fractionation and speciation methods to investigate P forms in dairy manure and liquid lagoon manure, and to study how long-term amendment with these manures influenced surface and subsurface soil P speciation. Our results show that the P forms in solid and lagoon manure are similar. About 30% of the total P was organic, mostly as orthophosphate monoesters. On a dry weight basis, total P was much higher in the solid manure. In the manure-amended soils the total P concentrations of the surface soils were similar, regardless of manure type. Total P in the subsurface soil was greater in the lagoon-manure-amended soil than the solid-manure-amended subsurface soil. However, the fraction of organic P was greater in the subsurface of the solid-manure-amended soil. The NMR results indicate that the majority of organic P in the soils is phytic acid, which is enriched in the surface soils compared with the subsurface soils. These results provide insight into P speciation and dynamics in manure-amended soils that will further increase our understanding on how best to manage manure disposal on soils.
authors.affiliation: Department of Plant, Soil & Entomological Sciences, University of Idaho, Moscow, ID 83844-2339, USA.
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Hansen
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Cade-Menun
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Strawn
mesh_terms: D000818:Animals; D002417:Cattle; D003612:Dairying; D004784:Environmental Monitoring; D006863:Hydrogen-Ion Concentration; D008372:Manure; D010758:Phosphorus / Q000032:analysis* / Q000737:chemistry*; D012037:Refuse Disposal; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D008372:Manure; D012989:Soil Pollutants; D010758:Phosphorus