Fig. 1 | Schematic representation of two mineral
protection mechanisms. a, A diagram of each mechanism: surface
adsorption (top panels) and pore entrapment of SOM (bottom panels) by
different types of clay minerals. Litter residues are associated with
clay minerals to a higher strength through surface adsorption than
through pore entrapment and decomposed to different degrees by
microorganisms. b, Temporal changes in the chemical composition
of labile (yellow) versus recalcitrant (brown) litter residues and the
compositions of microbial functional communities and necromass (blue,
bacteria; red, fungi) for each mechanism.
Fig. 2 | Chemical structures and composition of
litter-derived SOM. a, CP/TOSS 13C NMR spectra of
maize and soya litter and their derived SOM in four model soils.b , Differences in the chemical composition of litter-derived
SOM between litter and clay mineral types. Principal component analysis
of the relative abundance of functional C groups determined by13C NMR among four model soils by two litter types in
comparison with original maize and soya litters (top panel) and the
loadings of individual functional C groups to the first two principal
components (bottom panel). Open symbols are for soya litter and filled
symbols for maize litte
Fig. 3 | Community compositions of microbial biomass
and necromass. a, b, Microbial biomass (represented by total
phospholipid fatty acids) and microbial necromass (represented by amino
sugars) of different communities in model soils mixed with maize litter
(left column) and soya litter (right column). Lower case letters
indicate differenences in total microbial biomass or necromass among
model soils for each litter type and * indicates difference between
litter types for each model soil P < 0.05 (n = 3).
Error bars represent standard errors (n=3).