Environmental Engineering Reference
In-Depth Information
3.0
0~10cm
10~20cm
P.australis
T.chinensis;
S.glauca
Bare land
2.5
2.0
1.5
1.0
Month
0.18
Bare land
T.chinensis;
S.glauca
P.australis
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
Figure 6. Variations of NO
3
—
N and NH
4
+
-N for the soil in bare land and different vegetation types.
Month
0~10cm
10~20cm
50
P
.
australis
Bare land
T
.c
hinensis;
S.glau
c
a
40
30
20
10
0
Month
16
T.c
h
inensis;
S.gla
u
ca
P.aus
t
ra
l
is
Ba
r
e land
14
12
10
8
6
4
2
Month
Figure 7. Variations of TC and TN for the soil in bare land and different vegetation types.
3.4. Correlation between CO
2
and CH
4
Fluxes and Environmental Variables
The result of Pearson correlation analysis was as follows: significantly positive
correlation was found between CO
2
flux and air temperature (Table 2), especially in spring
and autumn. While significantly positive correlation between CO
2
flux and air temperature
was only observed in deep soil for bare land; Furthermore, only significant correlation
between CH
4
fluxes and deep soil temperature were observed in winter (Table 2).
In spring, CO
2
fluxes were negatively correlated with surface soil moisture in
P. australis
community
, but positively in T. chinensis
community. While the
significant correlations only
occurred in S. glauca
community in autumn.
Lacks of significant correlations between CH
4
fluxes and soil moisture variables were observed, except the positive significant correlations
occurred in surface sediment of S. glauca
community; moreover, most correlations between
CH
4
fluxes and soil moisture were not significant.
Significant negative correlations between CO
2
flux and the surface soil electric
