Organic coating on biochar explains its nutrient retention and stimulation of soil fertility

Nikolas Hagemann, Stephen Joseph, Hans Peter Schmidt, C.I. Kammann, Johannes Harter, Thomas Broch, Robert Young, Krisztina Varga, Sarasadat Taherymoosavi, K. Wade Elliott, Amy McKenna, Mihaela Albu, Claudia Mayrhofer, Martin Obst, Pellegrino Conte, Alba Dieguez-Alonso, Silvia Orsetti, Edisson Subdiaga, Sebastian Behrens, Andreas Kappler

Research output: Contribution to journalArticle

Abstract

Amending soil with biochar (pyrolized biomass) is suggested as a globally applicable approach to address climate change and soil degradation by carbon sequestration, reducing soil-borne greenhouse-gas emissions and increasing soil nutrient retention. Biochar was shown to promote plant growth, especially when combined with nutrient-rich organic matter, e.g., co-composted biochar. Plant growth promotion was explained by slow release of nutrients, although a mechanistic understanding of nutrient storage in biochar is missing. Here we identify a complex, nutrient-rich organic coating on co-composted biochar that covers the outer and inner (pore) surfaces of biochar particles using high-resolution spectro(micro)scopy and mass spectrometry. Fast field cycling nuclear magnetic resonance, electrochemical analysis and gas adsorption demonstrated that this coating adds hydrophilicity, redox-active moieties, and additional mesoporosity, which strengthens biochar-water interactions and thus enhances nutrient retention. This implies that the functioning of biochar in soil is determined by the formation of an organic coating, rather than biochar surface oxidation, as previously suggested
Original languageEnglish
Article number1089
Number of pages11
JournalNature Communications
DOIs
Publication statusPublished - 2017

ASJC Scopus subject areas

  • Materials Science(all)

Fields of Expertise

  • Advanced Materials Science

Treatment code (Nähere Zuordnung)

  • Basic - Fundamental (Grundlagenforschung)

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