Fate of CuO-derived lignin oxidation products during plant combustion: Application to the evaluation of char input to soil organic matter

Simulations using a two end member mixing model showed that different char samples, with different degrees of lignin alteration, could have a substantial effect on the biomarker signatures of soil organic matter (SOM). The shifts in lignin signatures in SOM vary widely, depending on the SOM characteristics (e.g. soil litter vs. mineral soil) and the proportion of char in the mixture. Overall, the input of high temperature char tends to dilute the lignin signal in SOM and may lead to underestimation of vascular plant OM input to environmental matrices. Our observations demonstrate that, in addition to photochemical degradation, thermal alteration is an important abiotic lignin degradation process.