Biochar built soil carbon over a decade by stabilizing rhizodeposits

Author:

Weng, Zhe; van Zwieten, Lukas; Singh, Bhupinder Pal; Joseph, Stephen; Macdonald, Lynne ; Tavakkoli, Ehsan; Rose, T; Kimber, Stephen; Morris, Stephen; Araujo, Joyce; Cowie, Annette

Date of Publication:

2017-04-24

Publication Type:

Journal Article

Journal Title:

Nature Climate Change

Volume:

7

Issue:

5

Part:

May 2017

Pages:

371-376

Abstract:

While biochar has been widely promoted for its potential to enhance soil organic carbon (SOC), short-term studies have shown that biochar can both stimulate (positive priming) or lower (negative priming) mineralisation of SOC. Understanding plant-soil-biochar interactions over the long-term is crucial to accurately predict the carbon (C) storage potential of biochar additional to its own inherent recalcitrant C content. We performed periodic 13CO2 pulse-labelling of ryegrass in the field, and monitored belowground C allocation, SOC priming, and root-derived C stabilisation between 8.2 and 9.5 years in a nearly decade-aged biochar (hardwood, 550°C) -amended Ferralsol. We provide evidence that field-aged biochar (a) enhanced belowground C recovery by 20%, (b) promoted negative priming (lowered C loss through respiration by 160 g CO2-C m-2 y-1) and (c) increased the retention of root-derived 13C in the stable organo-mineral fractions (53 μm) by 6% (P 0.05). Through synchrotron-based spectroscopic analysis of bulk soil, field-aged biochar and microaggregates (250 μm), we mechanistically demonstrate the role of biochar in accelerating formation of micro-agglomerates via organo-mineral interactions.

Publisher:

Nature Publishing Group

Field Of Research:

Carbon Sequestration Science

DOI:

https://doi.org/10.1038/nclimate3276

URL:

Link to Publisher's Version

Funding Sources:

Funding Body Name	Project/Grant ID
Australia. Department of Agriculture

Identifier:

EP161493

Publication Sub Type:

Journal article - Refereed

Language:

English

Attribution Statement:

Weng, Zhe; van Zwieten, Lukas; Singh, Bhupinder Pal; Joseph, Stephen; Macdonald, Lynne; Tavakkoli, Ehsan; Rose, T; Kimber, Stephen; Morris, Stephen; Araujo, Joyce; Cowie, Annette. Biochar built soil carbon over a decade by stabilizing rhizodeposits. Nature Climate Change. 2017; 7(5 May 2017):371-376. https://doi.org/10.1038/nclimate3276