The role of plant input physical-chemical properties, and microbial and soil chemical diversity on the formation of particulate and mineral-associated organic matter

Soil organic matter (SOM) is a fundamental resource to humanity for the many ecosystem services it provides. Increasing its stocks can significantly contribute climate change mitigation and sustainability of agricultural production. Elucidating mechanisms drivers formation main components SOM, particulate (POM) mineral associated (MAOM) matter, from decomposition plant inputs therefore critical inform management policy designed promote SOM regeneration. We two-tiered laboratory incubation experiment using 13 C 15 N labeled material investigate effects physical nature (i.e., structural versus soluble) as well their chemical composition on (1) pathways formation, (2) soil microbial community diversity, (3) interaction stabilization efficiency litter-derived in POM MAOM, topsoil subsoil. found that: i) input (structural vs drove both efficiencies formation; ii) residues increased more decomposed were residues, linearly with latter only subsoil; input-derived retained subsoil because higher MAOM POM, slower residue decay. Our results also confirm importance direct sorption soluble silt- clay-sized minerals bulk soils. Taken together these finding suggest that highest potential accrual subsoils characterized by saturation deficit, separate addition inputs. • Plant drive formation. forms most efficiently inputs, likely sorption. highly residues. diversity but not form due lower decay saturation.