Physicochemical changes in pyrogenic organic matter (biochar) after 15 months of field aging

• Published in: Solid earth (Göttingen) Vol. 5; no. 2; pp. 693 - 704
• Main Authors: Mukherjee, A, Zimmerman, A. R, Hamdan, R, Cooper, W. T
• Format: Journal Article
• Language: English
• Published: Gottingen Copernicus GmbH 23-07-2014; Copernicus Publications
• Subjects: Aging (natural); Coatings; Crops; Earth science; Electronics; Microorganisms; Microscopy; Scanning; Soil (material); Soil chemistry; Soil microbiology
• ISSN: 1869-9529; 1869-9510; 1869-9529
• DOI: 10.5194/se-5-693-2014

Predicting the effects of pyrogenic organic matter (OM) addition (either natural or intentional as in the case of biochar amendment) on soil chemistry and crop yields has been hampered by a lack of understanding of how pyrogenic OM evolves in the environment over time. This work compared the physicochemical characteristics of newly made and 15-month-field-aged biochars and biochar-soil mixtures. Scanning electronic microscopy (SEM) images of biochar particles aged with soil showed colonization by microbes and widespread OM coatings. Thus, sorption of both microbially produced and soil OM are likely processes that enhanced biochar aging. Thus, biochar's full beneficial effects on soil properties likely increase over time, and proper assignment of C sequestration credits to biochar users will require consideration of soil-biochar interactions.