title: Field and microcosm experiments to evaluate the effects of agricultural Cu treatment on the density and genetic structure of microbial communities in two different soils.
abstract: The effects of Cu amendment on indigenous soil microorganisms were investigated in two soils, a calcareous silty clay (Ep) and a sandy soil (Au), by means of a 1-year field experiment and a two-month microcosm incubation. Cu was added as 'Bordeaux mixture' [CuSO(4), Ca(OH)(2)] at the standard rate used in viticulture (B1=16 kg Cu kg(-1) soil) and at a higher level of contamination (B3=48 kg Cu ha(-1) soil). More extractable Cu was observed in sandy soil (Au) than in silty soil (Ep). Furthermore, total Cu and Cu-EDTA declined with time in Au soil, whereas they remained stable in Ep soil. Quantitative modifications of the microflora were assessed by C-biomass measurements and qualitative modifications were assessed by the characterization of the genetic structure of bacterial and fungal communities from DNA directly extracted from the soil, using B- and F-ARISA (bacterial and fungal automated ribosomal intergenic spacer analysis). In the field study, no significant modifications were observed in C-biomass whereas microcosm incubation showed a decrease in B3 contamination only. ARISA fingerprinting showed slight but significant modifications of bacterial and fungal communities in field and microcosm incubation. These modifications were transient in all cases, suggesting a short-term effect of Cu stress. Microcosm experiments detected the microbial community modifications with greater precision in the short-term, while field experiments showed that the biological effects of Cu contamination may be overcome or hidden by pedo-climatic variations.
authors.affiliation: INRA-Université de Bourgogne, UMR Microbiologie et Géochimie des Sols, CMSE, Dijon, France. ranjard@dijon.inra.fr
authors.forename: Lionel
authors.initials: L
authors.lastname: Ranjard
authors.forename: Abdelwahad
authors.initials: A
authors.lastname: Echairi
authors.forename: Virginie
authors.initials: V
authors.lastname: Nowak
authors.forename: David P H
authors.initials: DP
authors.lastname: Lejon
authors.forename: Rachida
authors.initials: R
authors.lastname: Nouaïm
authors.forename: Rémi
authors.initials: R
authors.lastname: Chaussod
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000235:genetics; D044822:Biodiversity; D018533:Biomass; D003300:Copper / Q000032:analysis / Q000494:pharmacology*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004271:DNA, Fungal / Q000235:genetics / Q000302:isolation & purification; D021903:DNA, Ribosomal Spacer / Q000235:genetics / Q000302:isolation & purification; D005658:Fungi / Q000187:drug effects* / Q000235:genetics; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D004269:DNA, Bacterial; D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D012987:Soil; D003300:Copper; C006788:Bordeaux mixture