title: Phosphorus availability from the solid fraction of pig slurry is altered by composting or thermal treatment.
abstract: The alteration of easily available phosphorus (P) from the separated solid fraction of pig slurry by composting and thermal processing (pyrolysis or combustion at 300-1000 °C) was investigated by water and acidic extractions and the diffusive gradients in thin films (DGT) technique. Temporal changes in P availability were monitored by repeated DGT application in three amended temperate soils over 16 weeks. P availability was found to decrease in the order: drying>composting>pyrolysis>combustion with increasing degree of processing. Water extractions suggested that no P would be available after pyrolysis above 700 °C or combustion above 400 °C, respectively, but during soil incubation, even char and ash, processed at 800 °C, increased P availability. Low-temperature pyrolysis vs. combustion was found to favor P availability as did application to acidic vs. neutral soil. Composting and thermal treatment produced a slow-release P fertilizer, with P availability being governed by abiotic and biotic mechanisms.
authors.affiliation: Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark. Electronic address: wich@plen.ku.dk.
authors.forename: Wibke
authors.initials: W
authors.lastname: Christel
authors.affiliation: Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark. Electronic address: sab@plen.ku.dk.
authors.forename: Sander
authors.initials: S
authors.lastname: Bruun
authors.affiliation: Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark. Electronic address: jma@plen.ku.dk.
authors.forename: Jakob
authors.initials: J
authors.lastname: Magid
authors.affiliation: Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark. Electronic address: lsj@plen.ku.dk.
authors.forename: Lars Stoumann
authors.initials: LS
authors.lastname: Jensen
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D002244:Carbon / Q000032:analysis; D002606:Charcoal / Q000737:chemistry; D005591:Chemical Fractionation; D004058:Diffusion; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000302:isolation & purification*; D012722:Sewage / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D034421:Sus scrofa; D013696:Temperature; D013997:Time Factors
chemical_list: D012722:Sewage; D012987:Soil; C540010:biochar; D002606:Charcoal; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen
keywords: Combustion; Diffusive gradients in thin films (DGT); Digestate compost; Manure char; Slow pyrolysis