Abstract
Nutrient retention in biochar amended soil has yielded variable results, with poorly understood mechanisms. Identification of changes on biochar surfaces during in situ soil aging can provide mechanistic information on the role of biochar on nutrient retention. In the current greenhouse study, we analyzed changes of biochar surface characteristics from aging in two soils with different iron levels and amended with two types of manure under corn. On pristine biochar surfaces, we detected no iron species. In contrast, after soil aging (70 days), a self-functionalization of biochar surfaces with iron oxides was observed, which can be explained by soil redox cycles allowing reduced iron(II) to migrate on biochar surfaces followed by its re-oxidation. This self-functionalization is proposed as an underlying mechanism explaining the significantly (p < 0.01) increased nitrate retention by 29–180 % in biochar amended soil. Significant (p < 0.05) reductions in leachate phosphate (18–41 %) and dissolved organic carbon (8.8–55 %) were also observed after biochar surface functionalization. Our results indicate that redox-driven iron oxide formation on surfaces of biochar in the soil can be a critical process explaining the dynamic nature of nutrient retention observed in biochar amended soils. Identifying soil environmental conditions most beneficial for such surface functionalization, which has the potential to increase nutrient retention, is critical for implementing efficient biochar amendment strategies and for increased resource efficiency in agroecosystems.
Accepted Version (
Free)
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
