Production and emission of methane from experimental paddy soils
Greater methane concentrations in the atmosphere has received increasing attention. Flooded rice culture is considered to be one of the major biogenic methane sources. Because of this, the effects of rice cultivation practices on the change of inorganics (NO{sub 3}{sup {minus}}, SO{sub 4}{sup 2{minus}}) and organics (volatile fatty acids) were followed and the production and emission of methane from experimental soil studied under glasshouse conditions. Initially, nitrate in pore water was high after the flooding of the dry soil, and then declined rapidly. Sulfate concentrations followed the same pattern; however, the rate of sulfate depletion was lower than that of nitrate. The concentration of volatile fatty acids increased gradually after dry soil flooding and reached a maximum concentration at 30 days after rice transplanting followed by a rapid decline. Methane concentration in soils increased markedly during the first 20 days after flooding. The non-planted soil had higher methane concentration than the planted soil. Highest methane production rates were observed at 40 days after flooding, while the lowest rates of production were observed at 20 days. Rates of methane emission from planted soils ranged from 0.73 (0.13) to 15.69 (4.4) mg CH{sub 4}/m{sup 2}/hr. which was significantly (5%) higher than that observed from non-planted soils 0.11 (0.04) to 1.43 (0.6) mg CH{sub 4}m{sup 2}/hr. The highest emission rates were observed during heading and flowering stage, while the lowest during the tillering and maturing stage of growth. Most of the methane was emitted through the rice plant. The addition of previous crop residues resulted in an increase in methane production and subsequent emission in both planted and non-planted treatments. However, no significant differences were observed in the production or emission of methane from fertilized treatments over the controls.
- Research Organization:
- Michigan State Univ., East Lansing, MI (USA)
- OSTI ID:
- 7068537
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
540220 -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
ALKANES
CARBOXYLIC ACIDS
CEREALS
CROPS
DATA
DISASTERS
EMISSION
ENVIRONMENTAL TRANSPORT
EXPERIMENTAL DATA
FLOODS
GRASS
HYDROCARBONS
INFORMATION
LILIOPSIDA
MAGNOLIOPHYTA
MASS TRANSFER
METHANE
NITRATES
NITROGEN COMPOUNDS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PLANTS
POLLUTION SOURCES
RICE
SOILS
SULFATES
SULFUR COMPOUNDS