Impacts of biochar concentration and particle size on hydraulic conductivity and DOC leaching of biochar-sand mixtures

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dc.citation.firstpage461en_US
dc.citation.journalTitleJournal of Hydrologyen_US
dc.citation.lastpage472en_US
dc.citation.volumeNumber533en_US
dc.contributor.authorLiu, Zuolinen_US
dc.contributor.authorDugan, Brandonen_US
dc.contributor.authorMasiello, Caroline A.en_US
dc.contributor.authorBarnes, Rebecca T.en_US
dc.contributor.authorGallagher, Morgan E.en_US
dc.contributor.authorGonnermann, Helgeen_US
dc.date.accessioned2016-01-15T17:21:43Zen_US
dc.date.available2016-01-15T17:21:43Zen_US
dc.date.issued2016en_US
dc.description.abstractThe amendment of soil with biochar can sequester carbon and alter hydrologic properties by changing physical and chemical characteristics of soil. To understand the effect of biochar amendment on soil hydrology, we measured the hydraulic conductivity (K) of biochar–sand mixtures as well as dissolved organic carbon (DOC) in leachate. Specifically, we assessed the effects of biochar concentration and particle size on K and amount of DOC in the soil leachate. To better understand how physical properties influenced K, we also measured the skeletal density of biochars and sand, and the bulk density, the water saturation, and the porosity of biochar–sand mixtures. Our model soil was sand (0.251–0.853 mm) with biochar rates from 2 to 10 wt% (g biochar/g total soil × 100%). As biochar (<0.853 mm) concentration increased from 0 to 10 wt%, K decreased by 72 ± 3%. When biochar particle size was equal to, greater than, and less than particle size of sand, we found that biochar in different particle sizes have different effects on K. For a 2 wt% biochar rate, K decreased by 72 ± 2% when biochar particles were finer than sand particles, and decreased by 15 ± 2% when biochar particles were coarser than sand particles. When biochar and sand particle size were comparable, we observed no significant effect on K. We propose that the decrease of K through the addition of fine biochar was because finer biochar particles filled spaces between sand particles, which increased tortuosity and reduced pore throat size of the mixture. The decrease of K associated with coarser biochar was caused by the bimodal particle size distribution, resulting in more compact packing and increased tortuosity. The loss of biochar C as DOC was related to both biochar rate and particle size. The cumulative DOC loss was 1350% higher from 10 wt% biochar compared to pure sand. This large increase reflected the very small DOC yield from pure sand. In addition, DOC in the leachate decreased as biochar particle size increased. For all treatments, the fraction of carbon lost as DOC ranged from 0.06 to 0.18 wt% of biochar. These experiments suggest that mixing sandy soils with biochar is likely to reduce infiltration rates, holding water near the surface longer with little loss of biochar-derived carbon to groundwater and streams.en_US
dc.identifier.citationLiu, Zuolin, Dugan, Brandon, Masiello, Caroline A., et al.. "Impacts of biochar concentration and particle size on hydraulic conductivity and DOC leaching of biochar-sand mixtures." <i>Journal of Hydrology,</i> 533, (2016) Elsevier: 461-472. http://dx.doi.org/10.1016/j.jhydrol.2015.12.007.en_US
dc.identifier.doihttp://dx.doi.org/10.1016/j.jhydrol.2015.12.007en_US
dc.identifier.urihttps://hdl.handle.net/1911/87841en_US
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.rightsThis is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier.en_US
dc.subject.keywordbiocharen_US
dc.subject.keywordhydraulic conductivityen_US
dc.subject.keywordparticle sizeen_US
dc.subject.keyworddissolved organic carbonen_US
dc.titleImpacts of biochar concentration and particle size on hydraulic conductivity and DOC leaching of biochar-sand mixturesen_US
dc.typeJournal articleen_US
dc.type.dcmiTexten_US
dc.type.publicationpost-printen_US
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