The properties and dynamic changes of DOM subfractions during food waste and sugarcane leaves co-composting

The purpose of this research was to evaluate the properties and dynamic changes of humic acids (HA), fulvic acids (FA), hydrophobic neutrals (HoN), and hydrophilic (Hi) fractions of dissolved organic matter (DOM) during food waste and sugarcane leaves co-composting process. The pools of HA, FA, HoN, and Hi were separated from DOM by fractionation method, and characterized using spectroscopic (UV–vis, FTIR) and pyrolysis–GC/MS analyses. The least peaks in the HA pool were found in FTIR spectra with the simple structure in HA. The highest value of SUV 254 was observed in HA, indicating that the HA pool played a dominant role in aromaticity of DOM. Hydrophobic compounds (HA, FA, HoN) had higher percentages of alkanes and cyclo-alkanes at the end of composting, while lower contents in the Hi pool. Both DOM and its subfractions increased the Chinese flowering cabbage ( Brassica campestris L.) seed germination rate (SGR), whereas HA had a significant effect on promoting the root growth.