Oxygen
Water
Nutrient
O 2 Bubbles from Bubbling Air
Low O 2
diffusion
even in Rice
Nodule require O 2 and
Micronutrient for N 2 fixation
Q: What is Tropical Peatland?
A: Water/Oxygen/Nutrients Ecosystem!
Fig. 1.13 Limiting factors for hydroculture in peatlands. Limiting factors: oxygen (very low
solubility into water) and nutrients. Nonlimiting factors: water (no toxic compounds) with aeration
700
600
500
400
300
Eh (mV vs NHE)
Elevation (cm)
200
100
0
0
500
1000
Distance (cm)
Distance (cm)
1500
2000
0
500
1000
1500
2000
40
20
–20
0
Fig. 1.14 Redox potential (Eh) in mound and non-mound areas of a tropical native peatland.
Brown line: mound area, blue line: non-mound area. Figure is modified from Haraguchi and Yabe
(2002)
22
M. Osaki et al.