Sequential chemical fractionation as a tool for accessing the organic matter in biochar

conference paper

English

This contribution is focused on utilization of a sequential chemical fractionation method for determination of organic matter content, its distribution in biochar and the possible use of biochar as a soil conditioner in agriculture. For these purposes the optimized chemical fractionation procedure was used to reveal the content of organic matter in different biochar samples with different properties (samples with European biochar certification for usage in agriculture) which depend significantly on the temperature used during a pyrolysis of biomass residues in the process of biochar production. In parallel, these samples were also fractionated by classic alkaline extraction to obtain the so-called extractable fraction of organic matter (NOM).Biochar is one of the important soil conditioners, known for having positive effect on crop yield, soil quality, nutrient cycle and carbon sequestration due to the transfer of organic carbon from it to the soil. However, the effect depends on the properties of the biochar, its doses to the soil, but also on the properties of the soil itself. Surprisingly, some authors point to the fact that biochar does not always have a positive effect on soil, plants or microfauna. Therefore, it is necessary to perform its depth characterization to be able to predicts its role in soil and its optimal application dose.Individual fractions obtained from sequential chemical fractionation as well as NOM samples were characterized by methods of elemental analysis (determination of organic elements content), thermogravimetry (contents of ash, organic matter and moisture). The results showed that the method of sequential chemical fractionation gives higher yields of organic matter compared to classical alkaline extraction. Moreover, the obtained fractions divided according to solubility and strength of binding to residual inorganic matter of biochar can be better characterized by physical-chemical methods, which provides more detailed information about organic matter in biochar and its possible effect on soil properties.

Biochar, organic matter, chemical fractionation, elemental analysis, thermogravimetric analysis

ŠIRŮČEK, D.; KALINA, M.; KLUČÁKOVÁ, M.

22. 11. 2021

Brno

978-80-88365-00-6

CONFERENCE PROCEEDINGS - NANOCON 2021

430

435

6

https://www.confer.cz/nanocon/2021/4372-sequential-chemical-fractionation-as-a-tool-for-accessing-the-organic-matter-in-biochar