indicating that the nutrient and clay supplies are extremely low. Therefore, as
microorganism activity is limited, CO 2 and CH 4 emissions are relatively low, and
peat accumulation is relatively high. In cuvette-type peatlands, water is also supplied
from rain; however, when the large rivers flood in the rainy season, small amounts of
clay and nutrients are supplied to the peatland (if large amounts of nutrients and clay
were supplied, the peat would be quickly extinguished). Therefore, as microorganism activity increases, CO 2 and CH 4 emissions increase, and peat accumulation
decreases.
Thus, it is hypothesized that redox potential conditions are essential for peatland
formation and peat accumulation because the redox potential depends on the oxygen
conditions in water (because of low O 2 solubility into water) and nutrient supply
systems.
Peatland is a typical ecosystem that lacks oxygen (which is related to water, the
most serious limiting factor for O 2 solubilization) and nutrients. Thus, peatland
management depends on controlling the oxygen and nutrient balance. The simplest
tropical peatland management method is to drain the water from the peatland and
apply chemical fertilizer. However, this drainage management method is antithetical
to the peatland formation process.
In native peatland forests, tree productivity (t dry matter/ha/year) at high groundwater is much higher than that in tropical rainforests in mineral soils. This presents
an ecological mystery because oxygen and nutrient levels are extremely low in the
peat and peat water. Under these conditions, trees cannot survive, and grasses or
palms will grow instead. How can trees survive and grow well in these severe
conditions? From observations of native peatland forests, two survival strategies
were found on the land surface: aerial root formation and mound root (roots that
form mounds) formation.
Therefore, we have been developing two innovative strategic techniques for
peatland eco-management: (1) comparing stock-based water management with
drainage-based water management and (2) the AeroHydro culture system, which
applies several key materials from the land surface under high ground water level
conditions.
The AeroHydro culture system is a new idea and concept that has not been
previously proposed. AeroHydro culture focuses on rhizosphere function and rhizosphere management as they relate to nutrient physiology, symbiosis, plant growthpromoting (PGP) substances and microbes, and root–shoot interactions (nutrient
supply and nutrient cycling). As the whole system of physiological strategies in
plants that grow in tropical peatlands has never been described, the plant metabolic
map in leaves and roots is described for the first time, focusing on carbon, nitrogen,
phosphorus, potassium, and micronutrients.
In peat-dome ecosystems, the water is supplied mainly from rain; therefore, the
nutrient input is also very limited. Strategies for addressing this low nutrient supply
are as follows:
Nitrogen: N 2 fixing in aerial roots and probably in mound roots.
Phosphorus: an efficient cycling system (1) among organic P in litter, Pi from the
decomposition of organic P by secreted organic acids and enzymes, Pi uptake by
52
M. Osaki et al.
microorganism activity is limited, CO 2 and CH 4 emissions are relatively low, and
peat accumulation is relatively high. In cuvette-type peatlands, water is also supplied
from rain; however, when the large rivers flood in the rainy season, small amounts of
clay and nutrients are supplied to the peatland (if large amounts of nutrients and clay
were supplied, the peat would be quickly extinguished). Therefore, as microorganism activity increases, CO 2 and CH 4 emissions increase, and peat accumulation
decreases.
Thus, it is hypothesized that redox potential conditions are essential for peatland
formation and peat accumulation because the redox potential depends on the oxygen
conditions in water (because of low O 2 solubility into water) and nutrient supply
systems.
Peatland is a typical ecosystem that lacks oxygen (which is related to water, the
most serious limiting factor for O 2 solubilization) and nutrients. Thus, peatland
management depends on controlling the oxygen and nutrient balance. The simplest
tropical peatland management method is to drain the water from the peatland and
apply chemical fertilizer. However, this drainage management method is antithetical
to the peatland formation process.
In native peatland forests, tree productivity (t dry matter/ha/year) at high groundwater is much higher than that in tropical rainforests in mineral soils. This presents
an ecological mystery because oxygen and nutrient levels are extremely low in the
peat and peat water. Under these conditions, trees cannot survive, and grasses or
palms will grow instead. How can trees survive and grow well in these severe
conditions? From observations of native peatland forests, two survival strategies
were found on the land surface: aerial root formation and mound root (roots that
form mounds) formation.
Therefore, we have been developing two innovative strategic techniques for
peatland eco-management: (1) comparing stock-based water management with
drainage-based water management and (2) the AeroHydro culture system, which
applies several key materials from the land surface under high ground water level
conditions.
The AeroHydro culture system is a new idea and concept that has not been
previously proposed. AeroHydro culture focuses on rhizosphere function and rhizosphere management as they relate to nutrient physiology, symbiosis, plant growthpromoting (PGP) substances and microbes, and root–shoot interactions (nutrient
supply and nutrient cycling). As the whole system of physiological strategies in
plants that grow in tropical peatlands has never been described, the plant metabolic
map in leaves and roots is described for the first time, focusing on carbon, nitrogen,
phosphorus, potassium, and micronutrients.
In peat-dome ecosystems, the water is supplied mainly from rain; therefore, the
nutrient input is also very limited. Strategies for addressing this low nutrient supply
are as follows:
Nitrogen: N 2 fixing in aerial roots and probably in mound roots.
Phosphorus: an efficient cycling system (1) among organic P in litter, Pi from the
decomposition of organic P by secreted organic acids and enzymes, Pi uptake by
52
M. Osaki et al.