Abstract
Advanced knowledge of the binding of dissolved organic matter (DOM) with aluminum (Al) ions is essential for understanding the toxicity, mobilization, and fate of Al in acidic soils. In this study, parallel factor analysis (PARAFAC) and two-dimensional correlation spectroscopy (2D-COS) were combined to characterize the Al(III)-binding properties of DOM extracted from farmland topsoil (0–20 cm) subjected to long-term application of chemical fertilizers (CF) or manure (M). The total Al concentration of solid soil in the M treatment (7.57%) was lower than that in the CF treatment (8.56%). In contrast, the organic-complexed Al concentration of the aqueous DOM extract in the M treatment (79 μmol/L) was dramatically higher than that in the CF treatment (0.9 μmol/L). Compared with CF treatment, PARAFAC-derived components in soil DOM from the M treatment had stronger Al(III)-binding affinities (log KM value), suggesting that soil DOM from long-term manuring has stronger potential to mobilize Al in acidic soils than that from chemical fertilizer applications. Fourier transform infrared (FTIR) spectroscopy coupled with 2D-COS revealed that soil DOM from the M treatment exhibited more Al(III)-binding sites than that from the CF treatment. In addition, aliphatic –OH groups showed the fastest response to Al(III) binding. These results provide a more detailed theoretical basis, at the molecular level, of the interaction mechanism of Al(III) with soil DOM, which is helpful for a deeper understanding of DOM-influenced biogeochemical cycling in farmland subjected to long-term manuring.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.