Soil organic carbon content and mineralization controlled by the composition, origin and molecular diversity of organic matter: A study in tropical alpine grasslands

The consensus for mechanisms controlling soil organic matter (SOM) persistence has shifted from traditional views based on SOM recalcitrance to a new paradigm stabilization controlled by minerals and aggregates. Recent studies indicate that the origin, composition molecular diversity of are crucial decomposition SOM. However, it is not fully understood how at level. objectives this study were investigate whether carbon (SOC) contents mineralization composition, origin Soil samples collected contrasting bedrocks with different precipitation levels tropical alpine grasslands Peruvian Andes. We applied combination 76-day incubation experiment pyrolysis-GC/MS assisted thermochemolysis results indicated high SOC (92.6 ± 7.6 g kg−1 soil) low had abundant derivates lignin, polysaccharides n-alkanes. After incubation, we observed neither selective any compound groups nor decline diversity. In contrast, (30.7 2.8 higher showed depletion plant-derived compounds, an accumulation microbial-derived compounds declined after incubation. Furthermore, these was positively correlated unsaturated fatty acids decrease in Therefore, proposed our soils (1) preservation (e.g. compounds), (2) associated changes during microbial decomposition. Due under environmental conditions, propose factors should be considered management ecosystem services such as sequestration studied region.