Short-term effect of pig slurry and its digestate application on biochemical properties of soils and emissions of volatile organic compounds

Abstract

Production of biogas through anaerobic digestion of organic wastes should play an important role in sustainable development of energy supply, and the environmental effects of digestates have to be assessed. We investigated the effect of anaerobic digestion of pig slurry (PS) on the molecular quality of the digestate produced. The consequences of digested (DPS) and undigested PS use as organic soil fertilizer on soil microbial and biochemical properties and C-gas emissions (CO 2 and volatile organic compounds) were studied during a two-month incubation. PS and DPS differed in the amount of volatile organic compounds (VOCs) emitted, in their organic C and lignin contents but not in their active microbial composition. Application of both types of slurry to the soil immediately increased the content of soil dissolved organic carbon (DOC) compared to the control soil. The application of DPS induced few changes in the biochemical composition of soil organic matter compared to its raw material (PS) that increased the amount of phenolic compounds. After 60 days, both amended and control soils contained similar amounts of DOC, amended soils presenting a more diverse biochemical composition of their soil organic matter. Application of both slurries to soil triggered a succession of different active microbial communities, which could be attributed to the introduction of new microorganisms and the input of new labile organic carbon. Changes in fungal communities were stronger than those of bacteria and archaea; however, only slight differences were observed between the slurries. Different fluxes and emission dynamics of five VOCs (methanol, acetone, DMS, 2-pentanone and phenol) were observed during the incubation time following application of PS or DPS to soil while no differences in CO 2 emissions were observed. The present study calls for longterm field studies with VOC analyses as a promising tool to differentiate organic fertilization practices.

Swine manure dilution with lagoon effluent impact on odor reduction and manure digestion

“…This may be due to the low solid contents of LFBM and FBM with similar C pool to the effluent C pool (Table 1). The incubation period also played an important role in affecting the degradation rates because initial liable C was rapidly consumed, leaving more recalcitrant C behind (Monard et al., 2020; Tambone et al., 2009). Evidence supporting this observation is found in LFBM and FBM 14‐d samples showing no differences in degradation rates for whole (10:0) and diluted (7:3) manures (Table 4), but manures incubated for shorter time periods (10 and 4 d) had higher rates of degradation (Table 4).…”

Emissions of biogenic volatile organic compounds from agricultural lands and the impact of land-use and other management practices: A review

“…Using slurry and manure as fertilizers changes also soil pH conditions and therefore affects soil bacterial community structures (Case et al, 2018;Nightingale et al, 2022). The emission of dominant compounds, including methanol, acetone, 2pentanone, and dimethyl sulfide, increases after slurry and manure application (Monard et al, 2020). It has been noted that when applying pig slurry, the proportion of the living bacterial community of γ-Proteobacteria and Firmicutes both increased largely, which may work as methanotrophs and link to the increase of methanol emissions (Potard et al, 2017).…”

Solid and Liquid Phases of Anaerobic Digestate for Sustainable Use of Agricultural Soil

“…The content of WEOC in Fluvisol in the 0-30 cm layer in 2019 increased significantly compared to 2018. According to Monard et al [55], the amount of dissolved organic carbon in the soil increases instantly after the application of slurry. Similarly, we show that fertilization with LD and SD results in changes in topsoil WEOC, and the highest content of WEOC was found in the 0-10 cm layer (Figure 5A-D).…”