Abiotic solubilization of soil organic matter, a less-seen aspect of dissolved organic matter production

► SOM solubilization was examined using 13C-ryegrass or its DOM in sterile and living soils. ► The proportion of solubilized C in both treatments was similar regardless of soil sterility. ► After adding ryegrass residue, still ∼70% of solubilized C originated from native SOM. ► After successive adding 13C-DOM, the SOM consistently supplied >10% of solubilized C. ► Microbial activity indirectly affected OM solubilization through accelerated DOM turnover.