title: Gaseous nitrogen and bacterial responses to raw and digested dairy manure applications in incubated soil.
abstract: A study was conducted under laboratory conditions to compare rates of nitrous oxide (N(2)O) and ammonia (NH(3)) emissions when soil was amended with anaerobically digested dairy manure slurry containing <30% food byproducts, raw dairy manure slurry, or urea. Slurries were applied via surface and subsurface methods. A second objective was to correlate genes regulating nitrification and denitrification with rates of N(2)O production, slurry treatment, and application method. Ammonia volatilization from incubated soil ranged from 140 g kg(-1) of total N applied in digested slurry to 230 g kg(-1) in urea. Subsurface application of raw dairy manure slurry decreased ammonia volatilization compared with surface application. Anaerobic digestion increased N(2)O production. Cumulative N(2)O loss averaged 27 g kg(-1) of total N applied for digested slurry, compared with 5 g kg(-1) for raw dairy slurry. Genes of interest included a 16S rRNA gene selective for β-subgroup proteobacterial ammonia-oxidizers, amoA, narG, and nosZ quantified with quantitative polymerase chain reaction (qPCR) and real-time polymerase chain reaction (RT-PCR). Application of anaerobically digested slurry increased nitrifier and denitrifier gene copies that correlated with N(2)O production. Expression of all genes measured via mRNA levels was affected by N applications to soil. This study provides new information linking genetic markers in denitrifier and nitrifier populations to N(2)O production.
authors.affiliation: Department of Crop and Soil Science, Washington State University, Pullman, Washington 99164-6420, USA.
authors.forename: Olivia E
authors.initials: OE
authors.lastname: Saunders
authors.forename: Ann-Marie
authors.initials: AM
authors.lastname: Fortuna
authors.forename: Joe H
authors.initials: JH
authors.lastname: Harrison
authors.forename: Craig G
authors.initials: CG
authors.lastname: Cogger
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Whitefield
authors.forename: Tonia
authors.initials: T
authors.lastname: Green
mesh_terms: D000641:Ammonia / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D001105:Archaea / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D003612:Dairying; D005308:Fertilizers / Q000382:microbiology; D018628:Gene Dosage; D019766:Genes, Archaeal / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D008372:Manure / Q000382:microbiology*; D009609:Nitrous Oxide / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D014835:Volatilization
chemical_list: D005308:Fertilizers; D008372:Manure; D012333:RNA, Messenger; D012336:RNA, Ribosomal, 16S; D000641:Ammonia; D009609:Nitrous Oxide