Agricultural soil communities after different amendments (control, manure, digestate) Raw sequence reads. Agricultural soil communities after different amendments (control, manure, digestate)

In the last two decades a change in land-use has taken place in Europe. Manures that used to be applied to agricultural soils are now used in biogas reactors and instead digestate is applied. Here we simulated soil amendment with either anaerobically digested or fresh cattle manure. The aim was to investigate the resistance and resilience of the resident microbiota and detect differences in the microbial biomass and activity after fertilizer amendment. Furthermore the physiological community profile was determined and the role of the indigenous microbial community was elucidated.In a microcosm experiment two kinds of agricultural soil (γ-irradiated versus non-irradiated) were amended with either treatment. The effect of amendments on the community structure and physiological activity was tested immediately, after one and three months of incubation through 16S rRNA gene amplicon sequencing (initial soil communities), genetic and physiological profiling (PCR-DGGE and MicroRespTM) and measurement of basal respiration, microbial biomass and the metabolic quotient.The community structure of dominant fungi and bacteria was not affected by either fertilizer, indicating the ability of the indigenous microbiota to outcompete allochthonous microorganisms. Soil microbial biomass was not changed, whereas basal respiration was significantly higher after amendment, especially when using fresh manure. MicroRespTM revealed slightly higher turnover for some substrates after one month, this finding was, however, not persistent and similar for manure and digestate. Generally, after one month, treatments returned to control levels for all parameters. In conclusion, amendment with anaerobically digested manure did not have a greater impact on soil microbial parameters.