Table 1.
Stand characteristics of three forests in DBR.
Figure 1.
Frequency histograms of soil N/P ratio in six subtropical forests in China.
Table 2.
The properties of pot soil before N addition treatment.
Figure 2.
SOC and total N concentrations among three forest types at different succession stages in DBR.
Error bars indicate one standard deviation. Different letters indicate significant differences at the confidence level of P<0.05 in the same soil layer among the three forests. (OneWay ANOVA, P<0.05).
Figure 3.
Soil total P and AP concentrations among three forest types at different succession stages in DBR.
Error bars indicate one standard deviation. Different letters indicate significant differences at the confidence level of P<0.05 in the same soil layer among the three forests. (OneWay ANOVA, P<0.05).
Figure 4.
The correlation between soil total P (a), total N (b), SOC (c) and AP concentrations in 0–20 cm soil of three forests in DBR.
(a): AP = 0.0062 P+0.536, R2 = 0.096, P = 0.920; (b) AP = 0.003784 N-0.0003, R2 = 0.699, P<0.0001; (c): AP = 0.0001 SOC-0.0016, R2 = 0.713, P<0.0001.
Figure 5.
The correlation between soil total N and SOC concentrations in 0–20 cm soil of three forests in DBR.
N = 0.029 SOC-66.627, R2 = 0.954, P<0.0001.
Figure 6.
Variation of pot soil total N (A), SOC (B) and AP (C) concentrations with the rate of N addition.
Error bar represents one standard deviation. (A): r2 = 0.307, P = 0.000; (B): r2 = 0.029, P = 0.072; (C): r2 = 0.222, P = 0.000.
Figure 7.
The correlation between pot soil C (A), N (B) and AP concentrations.
(A): AP = 0.00067 SOC-1.577, R2 = 0.359, P<0.0001; (B): AP = 0.006 N-2.443, R2 = 0.578, P<0.0001