title: Biogas digestates affect crop P uptake and soil microbial community composition.
abstract: Fermentation residues from biogas production are known as valuable organic fertilisers. This study deals with the effect of cattle slurry, co-digested cattle slurry, co-digested energy crops and mineral fertilisers on the activity and composition of soil microbiota. Furthermore, the effect of solid-liquid separation as a common pre-treatment of digestate was tested. The fertilising effects were analysed in an 8-week pot experiment on loamy sand using two crops, Amaranthus cruentus and Sorghum bicolor. Amaranth, as a crop with significantly higher P uptake, triggered stress for occurring soil microbes and thereby caused a reduction of microbial biomass C in the soil. Irrespective of the crop, microbial basal respiration and metabolic quotient were higher with the digestates than with the untreated slurry or the mineral treatments. Community level physiological profiles with MicroResp showed considerable differences among the treatments, with particularly strong effects of solid-liquid separation. Similar results were also found on a structural level (PCR-DGGE). Alkaline phosphatase gene analyses revealed high sensitivity to different fertilisation regimes.
authors.affiliation: Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria. Electronic address: Sebastian.Hupfauf@uibk.ac.at.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hupfauf
authors.affiliation: Department of Crop Husbandry, Faculty of Agricultural and Environmental Sciences, University of Rostock, Justus-von-Liebig-Weg 6, 18051 Rostock, Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Bachmann
authors.affiliation: Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria.
authors.forename: Marina
authors.initials: M
authors.lastname: Fernández-Delgado Juárez
authors.affiliation: Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria.
authors.forename: Heribert
authors.initials: H
authors.lastname: Insam
authors.affiliation: Department of Crop Husbandry, Faculty of Agricultural and Environmental Sciences, University of Rostock, Justus-von-Liebig-Weg 6, 18051 Rostock, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Eichler-Löbermann
mesh_terms: D000383:Agriculture; D056804:Biofuels; D018556:Crops, Agricultural / Q000378:metabolism*; D005308:Fertilizers; D010758:Phosphorus / Q000378:metabolism*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D014865:Waste Disposal, Fluid
chemical_list: D056804:Biofuels; D005308:Fertilizers; D012987:Soil; D010758:Phosphorus
keywords: ALPS; Biogas residues; CLPP; Phosphate solubilising bacteria; Phosphorus; Soil; Solid–liquid separation