Robustness of the autochthonous microbial soil community after amendment of cattle manure or its digestate

Abstract

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 fresh or anaerobically digested cattle manure. The aim was to investigate the resilience of the resident microbiota and detect differences in the microbial biomass and activity after fertilizer amendment. Furthermore, the physiological community profile 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 composition and physiological activity was tested immediately, after 1 and 3 months of incubation through 16S rRNA gene amplicon sequencing (initial soil community), genetic and physiological profiling (PCR-DGGE and MicroResp™), and measurement of basal respiration and microbial biomass. Either fertilizer did not affect the community composition of dominant fungi and bacteria in non-irradiated soils. This indicates 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. MicroResp™ revealed slightly higher respiration for some substrates after 1 month; this finding was, however, not persistent and similar for manure and digestate. Generally, after 1 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 properties.

Manure management and soil biodiversity: Towards more sustainable food systems in the EU

“…In another study, Barduca et al (2020) found anaerobic digestates to increase fungal activity while not changing microbial biomass. Also, no harmful effects have been observed on soil organisms after nine days (Johansen et al, 2013) or after one month of its application (Podmirseg et al, 2019). However, Westphal et al (2016) found only a minimal impact of anaerobic digestion on nematode, bacterial and fungi communities in soil one month after application of digestates.…”

“…Within the soil food web, microorganisms and soil fauna (micro-, meso-and macrofauna) have a dominant role in shredding, transforming and decomposing soil organic matter (Brussaard, 2012;de Vries et al, 2013;Frouz, 2018). As such, soil organisms drive nutrient cycling (Osler and Sommerkorn, 2007), including N fixation (Singh et al, 2016), plant nutrient and water uptake (Geisseler et al, 2010), plant productivity (Van Der Heijden et al, 2008) and pathogen and antibiotic resistance (Chen et al, 2017;Podmirseg et al, 2019).…”

Suitability of Black Soldier Fly Frass as Soil Amendment and Implication for Organic Waste Hygienization

“…Gram-negative bacteria predominated the cultivable microbiota in frass-amended soil with highest CFU counts of up to 10 5 in soil treated with frass from a FV diet. High microbial load and dominance of coliforms in frass shifted to lower CFU numbers and predominantly gram-negative bacteria in the frass-soil mix, indicating that the autochthonous soil microbiota outcompeted allochthonous microorganisms introduced with frass [49][50][51].…”

Temporal dynamics of total and active prokaryotic communities in two Mediterranean orchard soils treated with solid anaerobic digestate or managed under no-tillage

“…(2) these changes are primarily due to the physicochemical properties of the organic matrix rather than to newly introduced microorganisms, which are easily and rapidly outcompeted by members of the autochthonous soil microbiota (Podmirseg et al 2019). Don et al (2017) named this process as the "home-field advantage."…”