title: Effects of plant-symbiotic relationships on the living soil microbial community and microbial necromass in a long-term agro-ecosystem.
abstract: We examined the impact of arbuscular mycorrhizal fungi and rhizobia on the living microbial community and microbial necromass under different long-term fertilization treatments at the long-term Static Fertilization Experiment Bad Lauchstädt (Germany). Phospholipid fatty acids (PLFA) and amino sugars plus muramic acid, were used as biomarkers for soil microbial bio- and necromass, respectively, and analyzed from six treatments imposed on two crop rotations, varying only in the inclusion/non-inclusion of a legume. Treatments included: two levels of only farmyard manure (FYM), only mineral fertilizer (NPK), the combined application of both fertilizer types and a non-fertilized control. PLFA profiles differed clearly between the investigated crop rotations and were significantly related to labile C, mineral N, and soil pH. This emphasizes the role of carbon, and of mycorrhizal and rhizobial symbioses, as driver for changes in the microbial community composition due to effects on the living conditions in soil. We found some evidence that legume associated symbiosis with arbuscular mycorrhizal fungi and rhizobia act as a buffer, reducing the impact of varying inputs of mineral nutrients on the decomposer community. While our results support former findings that living microbial populations vary within short-term periods and are reflective of a given crop grown in a given year, soil necromass composition indicates longer term changes across the two crop rotation types, mainly shaped by fertilizer related effects on the community composition and C turnover. However, there was some evidence that specifically the presence of a legume, affects the soil necromass composition not only over the whole crop rotation but even in the short-term.
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle, Germany. Electronic address: jana.schmidt@ufz.de.
authors.forename: J
authors.initials: J
authors.lastname: Schmidt
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstr. 15, D-04318 Leipzig, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Fester
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Schulz
authors.affiliation: Friedrich-Schiller-University of Jena, Institute of Geography, Löbdergraben 32, D-07743 Jena, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Michalzik
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle, Germany; German Centre of Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Buscot
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle, Germany; University of Minnesota, Twin Cities, Department of Soil, Water, and Climate, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, USA.
authors.forename: J
authors.initials: J
authors.lastname: Gutknecht
mesh_terms: D018556:Crops, Agricultural / Q000382:microbiology*; D017753:Ecosystem; D005308:Fertilizers; D005858:Germany; D012987:Soil; D012988:Soil Microbiology; D013559:Symbiosis
chemical_list: D005308:Fertilizers; D012987:Soil
keywords: AMF; Amino sugars; Long-term fertilization; PLFA; Rhizobia