Biochar built soil carbon over a decade by stabilizing rhizodeposits

TitleBiochar built soil carbon over a decade by stabilizing rhizodeposits
Publication TypeJournal Article
Year of Publication2017
AuthorsWeng Z, Van Zwieten L, Singh BP, Tavakkoli E, Joseph S, Macdonald LM, Rose TJ, Rose MT, Kimber SWL, Morris S, Cozzolino D, Araujo JR, Archanjo BS, Cowie A
JournalNature Climate Change
Date PublishedMay
Type of ArticleArticle
ISBN Number1758-678X
Accession NumberWOS:000400373500019
KeywordsBLACK CARBON, climate-change, dynamics, Environmental Sciences & Ecology, food security, MATTER, Meteorology & Atmospheric Sciences, mineralization, nexafs, organic-carbon, pasture, sequestration

Biochar can increase the stable C content of soil. However, studies on the longer-term role of plant-soil-biochar interactions and the consequent changes to native soil organic carbon (SOC) are lacking. Periodic (CO2)-C-13 pulse labelling of ryegrass was used to monitor belowground C allocation, SOC priming, and stabilization of root-derived C for a 15-month period-commencing 8.2 years after biochar (Eucalyptus saligna, 550 degrees C) was amended into a subtropical ferralsol. We found that field-aged biochar enhanced the belowground recovery of new root-derived C (C-13) by 20%, and facilitated negative rhizosphere priming (it slowed SOC mineralization by 5.5%, that is, 46 g CO2-C m(-2) yr(-1)). Retention of root-derived 13C in the stable organo-mineral fraction (<53 mu m) was also increased (6%, P < 0.05). Through synchrotron-based spectroscopic analysis of bulk soil, field-aged biochar and microaggregates (< 250 mu m), we demonstrate that biochar accelerates the formation of microaggregates via organo-mineral interactions, resulting in the stabilization and accumulation of SOC in a rhodic ferralsol.

Alternate JournalNat. Clim. Chang.