Agriculture Reference
In-Depth Information
Nmicr
b
a
800
a
700
600
500
400
300
a
200
100
0
t1
to
time
Cmicr
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
a
b
b
a
t1
to
time
Figure 4. Nmicr and Cmicr concentration before (to, November 2001) and after the incubation (t1, May
2002). Different letters indicate significant differences between stratum I and stratum II (p<0.05).
Asterisks indicate significant differences between to and t1 in the same stratum.
The microclimatic conditions at the site I have caused a great accumulation of soil
organic matter leading to formation of an organosol with histic characteristics (Gobat et al.,
2004). The large presence of
Sphagnum spp.
has contributed to C accumulation. These
species are reported to decompose more slowly than vascular plant species (Clymo and
Hayward, 1982; Ovenden, 1990) probably because of the high resistance to degradation of
their lignin-like compounds and lipid-derived polymers (Johnson and Damman, 1991). The
high C/N ratios are index of the low organic matter decomposition (Anderson 1973; Edwards
1975; Nadelhoffer et al. 1991; Reichstein et al. 2000). Surprisingly, a low C/N ratio was
found in the OH horizon of the stunted forest, but it cannot be attributed to higher
