title: In situ dynamics of microbial communities during decomposition of wheat, rape, and alfalfa residues.
abstract: Microbial communities are of major importance in the decomposition of soil organic matter. However, the identities and dynamics of the populations involved are still poorly documented. We investigated, in an 11-month field experiment, how the initial biochemical quality of crop residues could lead to specific decomposition patterns, linking biochemical changes undergone by the crop residues to the respiration, biomass, and genetic structure of the soil microbial communities. Wheat, alfalfa, and rape residues were incorporated into the 0-15 cm layer of the soil of field plots by tilling. Biochemical changes in the residues occurring during degradation were assessed by near-infrared spectroscopy. Qualitative modifications in the genetic structure of the bacterial communities were determined by bacterial-automated ribosomal intergenic spacer analysis. Bacterial diversity in the three crop residues at early and late stages of decomposition process was further analyzed from a molecular inventory of the 16S rDNA. The decomposition of plant residues in croplands was shown to involve specific biochemical characteristics and microbial community dynamics which were clearly related to the quality of the organic inputs. Decay stage and seasonal shifts occurred by replacement of copiotrophic bacterial groups such as proteobacteria successful on younger residues with those successful on more extensively decayed material such as Actinobacteria. However, relative abundance of proteobacteria depended greatly on the composition of the residues, with a gradient observed from alfalfa to wheat, suggesting that this bacterial group may represent a good indicator of crop residues degradability and modifications during the decomposition process.
authors.affiliation: UMR Microbiologie du Sol et de l'Environnement, INRA/Université de Bourgogne, CMSE, BP 86510, Dijon, France.
authors.forename: Noémie
authors.initials: N
authors.lastname: Pascault
authors.forename: Lauric
authors.initials: L
authors.lastname: Cécillon
authors.forename: Olivier
authors.initials: O
authors.lastname: Mathieu
authors.forename: Catherine
authors.initials: C
authors.lastname: Hénault
authors.forename: Amadou
authors.initials: A
authors.lastname: Sarr
authors.forename: Jean
authors.initials: J
authors.lastname: Lévêque
authors.forename: Pascal
authors.initials: P
authors.lastname: Farcy
authors.forename: Lionel
authors.initials: L
authors.lastname: Ranjard
authors.forename: Pierre-Alain
authors.initials: PA
authors.lastname: Maron
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D044822:Biodiversity; D029741:Brassica rapa / Q000737:chemistry / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D000455:Medicago sativa / Q000737:chemistry / Q000382:microbiology*; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D014908:Triticum / Q000737:chemistry / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012987:Soil