SLIDE 1
Li et al 2004 Biol Fertil Soils
The rhizosphere: a hotspot of N 2 O action Liz Baggs Li et al 2004 - - PowerPoint PPT Presentation
The rhizosphere: a hotspot of N 2 O action Liz Baggs Li et al 2004 - - PowerPoint PPT Presentation
The rhizosphere: a hotspot of N 2 O action Liz Baggs Li et al 2004 Biol Fertil Soils 3 cores 1 core 15 N-KNO 3 - glucose Loick et al 2017. Geoderma Nitrogen Oxygen Rhizosphere adapted N 2 O Bulk soil adapted N 2 O N 2 O N 2 O Unsaturated
SLIDE 2
SLIDE 3
1 core 3 cores glucose
15N-KNO3
- Loick et al 2017. Geoderma
SLIDE 4
Giles et al 2012. Frontiers in Microbiology
Nitrogen Oxygen Rhizosphere adapted Bulk soil adapted Unsaturated soil
N2O N2O N2O N2O
SLIDE 5
Giles et al 2012. Frontiers in Microbiology
Nitrogen Oxygen Rhizosphere adapted Bulk soil adapted Root in unsaturated soil
N2O N2O N2O N2O N2O N2O
SLIDE 6
N2O N2 NO3
- NO2
- NO
C transfer
C
NO, N2O, N2
NO3
- NO2
- NH4
+
SLIDE 7
Succinate Butyrate Acetate Malic acid Sucrose Glucose Arginine Cysteine N2O : N2 mole ratio
0.00 0.02 0.04 0.06 0.08 0.10 0.60 0.80
75 µg C g-1 day-1 K15NO3 20 g N m-2
- rganic acids
sugars amino acids Morley et al 2014. PLoS one
SLIDE 8
4 8 12
Days
4 8 12
Days
4 8 12
Days
Organic acids: enhanced N2O reductase efficiency major constituent of labile root C exudation
- rganic acid
sugar amino acid
75 µg C g-1 day-1 K15NO3 20 g N m-2
Morley et al 2014. PLoS one
SLIDE 9
1 2 3 4 5 6 7 50 100 150 200 250 300
Distance from C source (cm)
Distance from C source (cm)
1 2 3 4 5 6 7 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Glutamine Citric acid .
l N2O-N L-1
Giles et al 2017. Soil Biol Biochem
SLIDE 10
N2O
a b
C flow
a
b
Denitrification Ammonia oxidation Water filled pore Sub-oxic microsite Oxic zone
a b
N2
Nitrate ammonification N uptake
SLIDE 11
Low SOM
Plant or SOM-derived C (mg CO2-C m-2 h-1)
- 20
20 40 60 80 100
g 15N-N2O m-2 d-1
200 400 600 800 1000 1200 1400 1600 Plant C SOM C
r = 0.51 r = 0.61
13C-CO2 to distinguish between plant- and SOM derived C
13C-depleted (-38.5‰) CO2
360 µmol mol-1 K15NO3 , 20 g N m-2
Plant- & soil-C driving N2O production
SLIDE 12
Plant-derived C (mg CO2-C m-2 h-1)
100 120 140 160 180 200 220 240 260
g 15N-N2O m-2 d-1
50 100 150 200 250 Plant C
r = 0.70
13C-depleted (-38.5‰) CO2
750 µmol mol-1 K15NO3 , 20 g N m-2 High SOM
Plant-C driving N2O production
SLIDE 13
Maize genotype screening for C & N cycling
SLIDE 14