Distribution of organic carbon fractions in soil aggregates in Chinese fir plantations with different stand ages

Ecological Processes

Table 5 Effects of aggregate sizes (> 2, 2–1, 1–0.25, and < 0.25 mm) and stand ages (0, 9, 17, and 26 years) on the soil particulate organic carbon concentration in a chronosequence of Chinese fir plantations

Stand age (years)	Soil particulate organic carbon concentration (g kg⁻¹)				Effects
	> 2 mm	2–1 mm	1–0.25 mm	< 0.25 mm	Aggregate size (A), df = 3		Stand age (S), df = 3		A × S, df = 9
	> 2 mm	2–1 mm	1–0.25 mm	< 0.25 mm	F	P	F	P	F	P
0	2.02 ± 0.17 bc	2.69 ± 0.20 bc	3.06 ± 0.19 c	3.66 ± 0.11 c	65.524	< 0.0001	267.583	< 0.0001	4.718	< 0.0001
9	2.41 ± 0.10 b	3.25 ± 0.17 b	3.76 ± 0.29 b	4.09 ± 0.17 b
17	3.81 ± 0.14 a	5.09 ± 0.22 a	5.59 ± 0.11 a	5.95 ± 0.08 a
26	1.67 ± 0.08 c	2.08 ± 0.06 c	2.47 ± 0.16 c	1.98 ± 0.05 d
Mean	2.48 ± 0.26 B	3.28 ± 0.35 AB	3.72 ± 0.38 A	3.92 ± 0.44 A

Data represent the average of 3 replicates ± standard errors. Different lower caseletters indicate significant differences among the different stand ages. Different capital letters indicate significant differences among the different aggregate sizes