SOM formation efficiency
Post-incubation C contents of the model soils, expressed on the basis of initial litter C content, were used to represent their formation efficiency of SOM. The formation efficiency of SOM ranged from 328.8 g-C kg-1 litter C to 960.9 g-C kg-1litter C (Supplementary Table 2) and was significantly (P< 0.05) affected by litter and clay mineral types and their interaction. It was higher for maize litter than for soya litter in all model soils and was higher in the vermiculitic soil than in other soils for both litter types. Apart from the vermiculitic soils, other model soils were significantly separated only for maize litter.