title: [Effect of lignite humic acid on soil ammonia oxidizing archaea community].
abstract: OBJECTIVE
  To illuminate the impact of humic acid (HA) on soil ammonia oxidizing archaea and then reveal the effect of HA on soil nitrogen cycle.
  
  
  METHODS
  Two humic acids (cHA and bHA) were added into the soil amended with urea. Community changes of ammonia oxidizing archaea (AOA) and total archaea were studied with terminal restricted fragment length polymorphism (T-RFLP) and real time PCR in the microcosm experiment.
  
  
  RESULTS
  We found that the AOA population size increased significantly and AOA community changed greatly in the urea only treatment. However, HA could inhibit the increase of AOA population, moreover, HA could buffer the change in AOA community showed by canonical correspondence analysis (CCA) result. On the other hand, the total archaeal population decreased significantly in the urea only treatment, but stabilized in the urea with HA treatments, which indicated HA could eliminate the toxicity of urea to total archaea. CCA results showed that incubation time was the most important factor for the total archaeal community, and partial CCA (pCCA, when time as a covariable) result demonstrated that cHA was the most important environmental variable for total archaeal community.
  
  
  CONCLUSIONS
  These results showed that HA diminished ammonia loss by inhibiting the increase of AOA competing with plant for ammonia, thus HA can increase the urea efficiency.
authors.affiliation: State Key Lab for Agro-biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China. lianhuadong@gmail.com
authors.forename: Lianhua
authors.initials: L
authors.lastname: Dong
authors.forename: Baozhen
authors.initials: B
authors.lastname: Li
authors.forename: Hongli
authors.initials: H
authors.lastname: Yuan
authors.forename: Kate M
authors.initials: KM
authors.lastname: Scow
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001105:Archaea / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D006812:Humic Substances / Q000032:analysis*; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D014508:Urea / Q000378:metabolism
chemical_list: D006812:Humic Substances; D012987:Soil; D000641:Ammonia; D014508:Urea