drivers of soil respiration of root and microbial ... - Unitus DSpace

Microbial respiration was also affected by treatment. To account for the above reported
differences in soil physical conditions (moisture and temperature), total and microbial-derived
respiration in MG and UM plots were calculated at a common temperature and SWC (Fig.8). For
these purposes respiration of managed plots was calculated at the same temperature of non managed
soil at the non limited SWC and during the drought period, when water content exerts a significant
influence on soil respiration, at the same SWC as for non managed soils.
Rs (%)
Rh (%)
160
140
120
100
80
60
40
20
0
200
180
160
140
120
100
80
60
40
20
0
21-apr
(a)
(b)
31-mag
10-lug
19-ago
Fig. 8 a) Total (Rs) and b) microbial (Rh) derived respiration of managed in % from unmanaged plots
corrected to a common Ts and SWC in 2006 and 2007. Arrows indicate the time of mowing.
Temperature and SWC response were derived from a regression using all soil respiration
measurements of the managed plots over the course of the experiment. When corrected for a
temperature and moisture effect, defoliation practices reduced soil respiration of microbial origin
and total CO2 efflux from soil by ca. 20%.
Microbial-derived respiration after normalization to soil temperature at a reference value of
15 o C demonstrated a different response to changes in SWC in MG and UM plots (Fig.9), indicating
possible functional changes between two microbial communities.
28-set
7-nov
17-dic
26-gen
7-mar
16-apr
26-mag
5-lug
14-ago
23-set
MG
UM
2-nov
103