Organic Molecular Markers in Soils Ameliorated with Biochar

Abstract

The study analyzed the organic molecular marker signatures in a maize cultivated Fluvisol ameliorated with 5 and 10 t.ha−1 biochar at the experimental field of the ISSAPP N. Poushkarov institute in Bulgaria. The n-alkane signatures and the carbon preference index (CPI) in the biochar treated soils revealed that sources of SOM were predominantly of microbial/thermal origin, while the source was only thermal in the pure biochar sample, (CPIodd/even0.84). There was evidence from the molecular marker analysis that biochar addition may initially bring improvement of soil microbiological status. There was no significant co-occurrence of polycyclic aromatic hydrocarbons released from biochar several months after incorporation in the soil.

Changes in organic molecular marker signatures in soils amended with biochar during a three-year experiment with maize on a Fluvisol

“…The alkane distribution was uni-or bimodal, maximizing at n-C17 alkane, n-C18 or C18 branched alkanes. In this study, similarly to our previous study (Atanassova et al, 2022), there was an imprint of biomass burning, i.e. most likely from the biochar addition, associated with the predominance of short chain (< C20) homologues and/or increased microbial activity (branched alkanes).…”

“…PAHs and PAH derivatives were not detected in the autumn of the 3 rd year of the experiment, contrary to the first sampling in year 1 (Atanassova et al, 2022) in which 2,5-furandione and 1H-indene were detected. Figures 1a-2a present distributions corresponding to mixtures of isomers of branched C15-C31 alkanes, alkenes including iso-and anteiso-homologues.…”

“…A fatty acid distribution in the С4-С26 range, as well as the presence of branched homologues, point at bacterial contribution, while predominance in the С26-С38 range implies origin from higher plants (Naafs et al, 2004;Schnitzer et al, 1986). In our study, fatty acids and fatty alcohols distributions are characterized by predominance of even homologues and a maximum at C16, palmitic acid, and C12 alkanol, in contrast to C18 alkanol in our previous sampling (Atanassova et al, 2022), which implicates predominant microbial sources of SOM.…”

“…In the total lipid extracts (Table 1), once again metolachlor was detected, a herbicide, as in the 1 st year of the experiment when soils were sampled at 10-12 th leaf pheno-phase of maize development, as well as trans-13-docosenamide, a marker of biochar (Atanassova et al, 2012(Atanassova et al, , 2022.…”

Effect of biochar on heavy metal solubility and speciation in Technogenic soils around Aurubis-Pirdop copper smelter in Bulgaria

“…Biochar is obtained as a result of pyrolysis (incomplete combustion) of biomass and is the subject of research in many countries as a means of improving soil structure and fertility (Lehmann & Joseph, 2015). The presence of polycyclic and aromatic structures in biochar makes it very resistant to decomposition in soil, therefore its slow mineralization produces compounds involved in the synthesis of humic substances (Atanassova et al, 2022a). At the same time, biochar has a high ability to adsorb chemical substances, including contaminants, thus preventing the leaching of various contaminants and nutrients from soil with surface water.…”