Potential for carbon sequestration after biochar-P fertilizer application: A biological and chemical assessment

Abstract
Innovation is required on many fronts in agriculture, not only to improve nutrient use efficiency but also to mitigate the effects of climate change. Our previous studies presented the high agronomic efficiency of an experimental phosphate fertilizer using a biochar-matrix, called ‘BioFert’. However, the efficiency of BioFert for soil carbon sequestration goals has not yet been evaluated. We incubated BioFert and initial raw sugarcane-biochar over 56 days in two soils (i.e., Ferralsol and Alisol) and measured the total CO2 and δ13C-CO2 to quantify the contribution of native soil organic matter, sugarcane-biochar, or BioFert to carbon mineralization. There was no significant difference in cumulative CO2 release between BioFert and the control (without carbon addition), and BioFert was less mineralized than carbon from sugarcane-biochar regardless of soil type. In addition, accelerated aging by thermal oxidation of these carbon sources revealed that more than 80% of BioFert-carbon was prevented from accelerated mineralization, while sugarcane-biochar achieved ~80% of carbon mineralization. The residual solids after oxidation were analysed by X-ray photoelectron spectroscopy and indicated aliphatic/aromatic and carboxylic chemical bonds on the BioFert surface, which might offer new cation exchange sites over time. We conclude that BioFert is not only a phosphate fertilizer with high phosphorus use efficiency but also a stable source of carbon for soil carbon sequestration purposes. Highlights - Similar CO2 cumulative release between BioFert and the control. - BioFert had more than 80% of its C stable against accelerated mineralization. - BioFert is a promising stable C source for soil C sequestration.
Description
This is the peer reviewed version of the following article: Borges, B. M. M. N., Barreto, M. S. C., Pavinato, P. S., Franco, H. C. J., Carvalho, J. L. N., Strauss, M., & Sohi, S. (2023). Potential for carbon sequestration after biochar-P fertilizer application: A biological and chemical assessment. European Journal of Soil Science, 74(4), e13400. https://doi.org/10.1111/ejss.13400, which has been published in final form at https://doi.org/10.1111/ejss.13400. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited. © 2023 British Society of Soil Science. This article will be embargoed until 7/17/2024.
Keywords
agriculture intensification, biochar, climate change, nutrient use efficiency, soil carbon sequestration, climate action
Citation
Borges, B. M. M. N., Barreto, M. S. C., Pavinato, P. S., Franco, H. C. J., Carvalho, J. L. N., Strauss, M., & Sohi, S. (2023). Potential for carbon sequestration after biochar-P fertilizer application: A biological and chemical assessment. European Journal of Soil Science, 74(4), e13400. https://doi.org/10.1111/ejss.13400