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

Fig. 6 a) values above zero: root-derived CO2 from root-soil system with Lupinus albus (as a difference between
total and microbial respiration from bulk soil), values below zero (in red): microbial CO2 efflux from the bare
by three N treatments: averages for day and night periods b) Root-derived respiration (as a difference between
total and microbial respiration) respired from root-soil system with Lupinus albus per unit of root biomass.
Percentages indicate the increase of CO2 efflux after NH4 + or NO3 - fertilization as related to the CO2 from control
without N. Letters indicate the significance of the differences at p=0.05 between the treatments.
134
CO 2 efflux (mg C day -1 pot -1 )
specific respiration (CO 2 g -1 of root)
8
6
4
2
0
2
4
40
35
30
25
20
15
10
5
0
(a)
b
day night
Lupinus albus: Total and root-derived CO2 efflux from the soil in all planted treatments
showed a clear diurnal dynamic (Fig 6a). Average total CO2 respired from the plant-soil system was
lowest for the control (3.13 mg C d -1 pot -1 ), and amounted to 4.36 mg C d -1 pot -1 for NH4 + -N and
5.58 mg C d -1 pot -1 for NO3 - -N. The difference in total CO2 respired from soils with different types
of N applied was significant during the whole measurement period (p