Effect of organic material additions on between-group heterogeneity (Qb) for soil organic C decomposition rate.

*PK: the number of mean comparisons within each level of analysis.a: categories were 20 g kg−1 for SOC, 2 g kg−1 for nitrogen content, 10 for C:N ratio, Fine, Medium and Coarse for soil texture.b: categories were Low and High for material quality, 15d for incubation time, 4% soil C for addition rate, ≤20°C, 20–25°C and >25°C for incubation temperature.Several studies were excluded because the level of soil organic C, soil total N was not available in those studies.