Biogas digestates affect crop P uptake and soil microbial community composition.
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.
['Hupfauf|Sebastian|S|', 'Bachmann|Silvia|S|', 'Fernández-Delgado Juárez|Marina|M|', 'Insam|Heribert|H|', 'Eichler-Löbermann|Bettina|B|']
D000383:Agriculture D056804:Biofuels D018556:Crops, Agricultural D005308:Fertilizers D010758:Phosphorus D012987:Soil D012988:Soil Microbiology D014865:Waste Disposal, Fluid
Soil ALPS Biogas residues CLPP Phosphate solubilising bacteria Phosphorus Solid–liquid separation