Figure 1.
Schematic diagram of the time sequence for the three temperature-change cycles.
RT signifies that the soil samples were incubated at room temperature.
Table 1.
Physicochemical composition of the soils.
Figure 2.
Relationship between CO2 emission rates from particle-size fractions and incubation temperature for grassland (A, B, C) and forest soils (D, E, F).
The panels from left to right represent temperature-change cycles in the order 1, 2, 3. The vertical bars denote the standard deviations (n = 4).
Table 2.
The Q10* values (±SD) of SOC decomposition for different particle-size fractions in grassland and forest soils (n = 4).
Figure 3.
Dependence of Q10 on incubation temperature for (A) clay, (B) silt, and (C) sand.
The Q10 for each temperature interval of 5 degrees (e.g., 5–10°C) and 10 degrees (e.g., 5–15°C) was calculated using Eqn. 4. The average temperature for each interval was taken as representative temperature. Data from all the three temperature-change cycles were included. Vertical bars denote the standard errors (n = 12).
Table 3.
Soil biological and chemical properties in different particle-size fractions at the end of incubation (mean±SE, n = 4).
Figure 4.
Dependence of Q10 in the third temperature-change cycle on microbial biomass carbon (A) and total dissolved nitrogen (B).
The Q10 (5−15°C) and Q10 (20−30°C) were calculated using Eqn. 4 for each replicate.
Table 4.
Pearson correlation coefficient for Q10 (15–25°C) in the third temperature-change cycle and soil biological and chemical properties.
Figure 5.
Dependence of parameters in the Q10−T curve on the soil microbial biomass carbon (A) and soil C: N ratio (B).
Vertical bars denote the 95% CI of the estimated parameters in Fig. 3. For each parameter α and β, six points represent the three particles of clay, silt, and sand from the grassland and forest soils. Horizontal bars represent the standard errors (n = 4).