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

78
label distribution between components (%)
18
16
14
12
10
8
6
4
2
0
1 2 4 10 16 24 35 96 240
hours after labeling
Aboveground
Below ground
Fig.6 Allocation of the recovered label between aboveground and belowground respiration during the gas
sampling periods, taking the sum of the recovered label as a 100%.
total label recovered (%)
80
70
60
50
40
30
20
10
0
total
aboveground
below ground
0-24h 24-240h
Fig.7 Allocation of total label recovered between above and belowground respiration, the chase period was sub
divided into two time periods: 0-24h and 24-240h.
3.3.3. Mean Residence Time
The MRT for the label to be respired showed through below and aboveground plant parts
are presented in Table 3. For the first 24 hours after respiration the labeled C cycled rapidly, with
the MRT of less than one day for both components. For this period the MRT was generally shorter
for belowground (0.38 d) than for aboveground (0.74 d). Much slower cycling of recently
assimilated C was observed for the time period of 24-240h after the pulse labeling with an average
values of 6.3 for both above and belowground respiration.