Quantitative characterization of pore structure of several biochars with 3D imaging
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Pore space characteristics of biochars may vary depending on the used raw material and processing technology. Pore structure has significant effects on the water retention properties of biochar amended soils. In this work, several biochars were characterized with three-dimensional imaging and image analysis. X-ray computed microtomography was used to image biochars at resolution of 1.14 μm and the obtained images were analysed for porosity, pore size distribution, specific surface area and structural anisotropy. In addition, random walk simulations were used to relate structural anisotropy to diffusive transport. Image analysis showed that considerable part of the biochar volume consist of pores in size range relevant to hydrological processes and storage of plant available water. Porosity and pore size distribution were found to depend on the biochar type and the structural anisotopy analysis showed that used raw material considerably affects the pore characteristics at micrometre scale. Therefore, attention should be paid to raw material selection and quality in applications requiring optimized pore structure.
KeywordsBiochar Soil amendment Pore structure Water retention X-ray tomography Image analysis
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 637020 – MOBILE FLIP.
- Hapca SM, Houston AN, Otten W, Baveye PC (2013) New local thresholding method for soil images by minimizing grayscale Intra-Class variance. Vadose Zone J 12. doi: 10.2136/vzj2012.0172
- Jeffery S, Meinders MBJ, Stoof CR, Bezemer TM, van de Voorde TFJ, Mommer L, van Groenigen JW (2015) Biochar application does not improve the soil hydrological function of a sandy soil. Geoderma 251-252:47–54Google Scholar
- Quin PR, Cowie AL, Flavel RJ, Keen BP, Macdonald LM, Morris SG, Singh BP, Young IM, Van Zwieten L (2014) Oil mallee biochar improves soil structural properties—a study with x-ray micro-CT. Agr Ecosyst Environ 191:142–149Google Scholar
- Verheijen FGA, Jeffery S, Bastos AC, van der Velde M, Diafas I (2010) Biochar application to soils—a critical scientific review of effects on soil properties, processes and functions 149 pp (EUR 24099 EN, Office for the Official Publications of the European Communities, LuxembourgGoogle Scholar