Agriculture Reference
In-Depth Information
Figure 2. Soil temperature (average daily values) recorded in the three soils at 10 cm depth from
November 2001 to May 2002.
Seasonal N and C Dynamics in the Buried Bags
The various forms of N and C were evaluated during the period November-May. The
comparison inside and outside bags allow to estimate the amounts of nutrients that can be up
taken by plants and mosses or leached along the profile.
During the winter months a significant reduction of ammonium concentration was
recorded in both strata (Figure 3) and no statistical differences were observed between the
incubated and the undisturbed soil (Table 4). Conversely, net nitrification (the difference of
NO
3
-
concentration before and after the incubation) was positive in both strata (Figure 3),
with a higher nitrate production in stratum II and in the incubated soil (Table 4).
A positive net N mineralization was found in both strata, equal to 12.3 and 6.1 mg N kg
-1
in stratum I and II, respectively.
The microbial N and C increased in stratum I (Figure 4), and, for microbial C, more in
the buried bag than in the not incubated soil (Table 4). In the stratum II no statistical
differences in the microbial N were observed along the winter season (Figure 4), while
microbial C increased and slightly more in the buried bag (Table 4). The microbial N
immobilization was equal to 560.7 mg N kg
-1
and -147 mg N kg
-1
respectively in site I and II.
DON and DOC decreased in both sites (Figure 5), with no influence of incubation in
stratum II (Table 4).
