scholarly journals Methane emissions in triple rice cropping: patterns and a method for reduction

F1000Research ◽  
2020 ◽  
Vol 8 ◽  
pp. 1675
Author(s):  
Masato Oda ◽  
Huu Chiem Nguyen
Keyword(s):  
Rice Straw ◽  
Methane Emission ◽  
Mekong Delta ◽  
Methane Emissions ◽  
Crop Season ◽  
Emission Pattern ◽  
Current Season ◽  
Cropping Patterns ◽  
The Third ◽  
Heading Stage

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. This suggests that methane was generated by the soil organic matter, because the small rice plants provide little carbon for methanogenesis. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies while total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that decomposing rice straw in paddy surface-water is an effective method to reduce methane emissions.

scholarly journals Methane emissions in triple rice cropping: patterns and a method for reduction

F1000Research ◽  
2020 ◽  
Vol 8 ◽  
pp. 1675
Author(s):  
Masato Oda ◽  
Huu Chiem Nguyen
Keyword(s):  
Rice Straw ◽  
Methane Emission ◽  
Mekong Delta ◽  
Methane Emissions ◽  
Crop Season ◽  
Emission Pattern ◽  
Current Season ◽  
Cropping Patterns ◽  
The Third ◽  
Heading Stage

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. This suggests that methane was generated by the soil organic matter, because the small rice plants provide little carbon for methanogenesis. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies while total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that decomposing rice straw in paddy surface-water is an effective method to reduce methane emissions.

scholarly journals Methane emissions in triple rice cropping: patterns and a method for reduction

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1675
Author(s):  
Masato Oda ◽  
Huu Chiem Nguyen
Keyword(s):  
Rice Straw ◽  
Methane Emission ◽  
Mekong Delta ◽  
Methane Emissions ◽  
Crop Season ◽  
Emission Pattern ◽  
Current Season ◽  
Cropping Patterns ◽  
The Third ◽  
Heading Stage

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. This suggests that methane was generated by the soil organic matter, because the small rice plants provide little carbon for methanogenesis. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies while total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that decomposing rice straw in paddy surface-water is an effective method to reduce methane emissions.

scholarly journals Methane emissions in triple rice cropping: patterns and a method for reduction

F1000Research ◽  
2020 ◽  
Vol 8 ◽  
pp. 1675
Author(s):  
Masato Oda ◽  
Huu Chiem Nguyen
Keyword(s):  
Rice Straw ◽  
Methane Emission ◽  
Mekong Delta ◽  
Methane Emissions ◽  
Crop Season ◽  
Emission Pattern ◽  
Current Season ◽  
Cropping Patterns ◽  
The Third ◽  
Heading Stage

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. This suggests that methane was generated by the soil organic matter, because the small rice plants provide little carbon for methanogenesis. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies while total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that decomposing rice straw in paddy surface-water is an effective method to reduce methane emissions.

scholarly journals Methane emissions in triple rice cropping: patterns and a method for reduction

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1675
Author(s):  
Masato Oda ◽  
Huu Chiem Nguyen
Keyword(s):  
Rice Straw ◽  
Methane Emission ◽  
Mekong Delta ◽  
Methane Emissions ◽  
Crop Season ◽  
Emission Pattern ◽  
Current Season ◽  
Cropping Patterns ◽  
The Third ◽  
Heading Stage

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. This suggests that methane was generated by the soil organic matter, because the small rice plants provide little carbon for methanogenesis. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies while total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that decomposing rice straw in paddy surface-water is an effective method to reduce methane emissions.

scholarly journals Methane emissions in triple rice cropping: patterns and a method for reduction

F1000Research ◽  
2021 ◽  
Vol 8 ◽  
pp. 1675
Author(s):  
Masato Oda ◽  
Huu Chiem Nguyen
Keyword(s):  
Rice Straw ◽  
Methane Emission ◽  
Mekong Delta ◽  
Methane Emissions ◽  
Crop Season ◽  
Emission Pattern ◽  
Current Season ◽  
Cropping Patterns ◽  
The Third ◽  
Heading Stage

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies because total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after the annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that avoiding rice straw incorporating into soil and decomposing rice straw in paddy surface-water reduces methane emissions.

scholarly journals Rice plants reduce methane emissions in high-emitting paddies

F1000Research ◽  
2019 ◽  
Vol 7 ◽  
pp. 1349 ◽  
Author(s):  
Masato Oda ◽  
Nguyen Huu Chiem
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Methane Emission ◽  
Rice Variety ◽  
Mekong Delta ◽  
Rice Paddy ◽  
Methane Emissions ◽  
Paddy Fields ◽  
Rice Plants ◽  
Oxygen Pathways

Background: Rice is understood to enhance methane emissions from paddy fields in IPCC guidelines. However, rice actually has two opposite functions related to methane: i) emission enhancement, such as by providing emission pathways (aerenchyma) and methanogenetic substrates; and ii) emission suppression by providing oxygen pathways, which suppress methanogenesis or enhance methane oxidation. The overall role of rice is thus determined by the balance between its enhancing and suppressing functions. Although previous studies have suggested that rice enhances total methane emissions, we aimed to demonstrate in high-emitting paddy fields that the overall methane emission is decreased by rice plants. Methods: We compared methane emissions with and without rice plants in triple cropping rice paddy fields in the Mekong Delta, Vietnam. The gas samples are collected using chamber method and ware analyzed by gas chromatography. Results: We found that rice, in fact, suppressed overall methane emissions in high-emitting paddies. The emission reductions increased with the growth of rice to the maximum tillering stage, then decreased after the heading stage, and finally recovered.  Discussion:  Our result indicates that the overall methane emission is larger than that of rice planted area. In addition, although many studies in standard-emitting paddies have found that the contribution of soil organic matter to methanogenesis is small, prior studies in high-emitting paddies suggest that methanogenesis depended mainly on soil organic matter accumulated from past crops. The higher the methane emission level, the lower the contribution of the rice-derived substrate; conversely, the higher the contribution of the rice providing oxygen. Finally, rice plants reduce methane emissions in high-emitting paddies. Conclusion: The present study demonstrates that during the growing season, rice is suppressing methane emissions in high-emitting paddies. This means the significance of using the rice variety which has high suppressing performance in high-emitting paddies.

scholarly journals Rice cultivation reduces methane emissions in high-emitting paddies

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1349
Author(s):  
Masato Oda ◽  
Nguyen Huu Chiem
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Methane Emission ◽  
Mekong Delta ◽  
Rice Paddy ◽  
Methane Emissions ◽  
Paddy Fields ◽  
Emission Reductions ◽  
Emission Level ◽  
High Emission

Background: Rice is typically understood to enhance methane emissions from paddy fields. However, rice actually has two separate functions related to methane: i) emission enhancement, such as by providing emission pathways (aerenchyma) and methanogenetic substrates; and ii) emission suppression by providing oxygen pathways, which suppress methanogenesis or enhance methane oxidation. The overall role of rice is thus determined by the balance between its enhancing and suppressing functions. Although existing studies have suggested that rice enhances total methane emissions, we aimed to demonstrate that the balance between rice’s emitting and suppressing functions changes according to overall methane emission levels, which have quite a large range (16‍–500 kg methane ha−1 crop−1). Methods: Using PVC chambers, we compared methane emissions emitted by rice paddy fields with and without rice plants in rice fields in the Mekong Delta, Vietnam. Samples were analyzed by gas chromatograph. Results: We found high overall methane emission levels and our results indicated that rice in fact suppressed methane emissions under these conditions. Emission reductions increased with the growth of rice, up to 60% of emission rate at the maximum tillering stage, then decreased to 20% after the heading stage, and finally recovering back to 60%.  Discussion: It is known that methane is emitted by ebullition when the emission level is high, and methane emission reductions in rice-planted fields are thought to be due to oxidation and methanogenesis suppression. However, although many studies have found that the contribution of soil organic matter to methanogenesis is small, our results suggested that methanogenesis depended mainly on soil organic matter accumulated from past crops. The higher the methane emission level, the lower the contribution of rice-providing substrate. Conclusion: As a result, during the growing season, rice enhanced methane emissions in low-emission paddy fields but suppressed methane emissions in high-emission paddy fields.

scholarly journals Rice plants reduce methane emissions in high-emitting paddies

F1000Research ◽  
2019 ◽  
Vol 7 ◽  
pp. 1349
Author(s):  
Masato Oda ◽  
Nguyen Huu Chiem
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Methane Emission ◽  
Rice Variety ◽  
Mekong Delta ◽  
Methane Emissions ◽  
Paddy Fields ◽  
Rice Plants ◽  
Oxygen Pathways

Background: Rice is understood to enhance methane emissions from paddy fields in IPCC guidelines. However, rice actually has two separate functions related to methane: i) emission enhancement, such as by providing emission pathways (aerenchyma) and methanogenetic substrates; and ii) emission suppression by providing oxygen pathways, which suppress methanogenesis or enhance methane oxidation. The overall role of rice is thus determined by the balance between its enhancing and suppressing functions. Although previous studies have suggested that rice enhances total methane emissions, we aimed to demonstrate in high-emitting paddy fields that the overall methane emission is decreased by rice plants. Methods: We compared methane emissions of with and without rice plants in triple cropping rice paddies in the Mekong Delta, Vietnam. The gas samples are collected using chamber method and ware analyzed by gas chromatography. Results: We found that rice, in fact, suppressed overall methane emissions in high-emitting paddies. The emission reductions increased with the growth of rice to the maximum tillering stage, then decreased after the heading stage, and finally recovered.  Discussion:  Our result indicates that the overall methane emission by ebullition is larger than the overall emission of rice planted area. In addition, although many studies in standard-emitting paddies have found that the contribution of soil organic matter to methanogenesis is small, our results in high-emitting paddies suggest that methanogenesis depended mainly on soil organic matter accumulated from past crops. The higher the methane emission level, the lower the contribution of the rice-derived substrate; therefore, the role of rice in high-emitting paddies is the opposite to in that of standard-emitting paddies. Conclusion: The present study demonstrates that during the growing season, rice is suppressing methane emissions in high-emitting paddies. This means the significance of using the rice variety which has high suppressing performance in high-emitting paddies.

scholarly journals Succession of methanogenic archaea in rice straw incorporated into a Japanese rice field: estimation by PCR-DGGE and sequence analyses

Archaea ◽  
2005 ◽  
Vol 1 (6) ◽  
pp. 391-397 ◽  
Author(s):  
Atsuo Sugano ◽  
Hidetaka Tsuchimoto ◽  
Tun Cho Cho ◽  
Makoto Kimura ◽  
Susumu Asakawa
Keyword(s):  
Rice Straw ◽  
Rice Field ◽  
Previous History ◽  
Methanogenic Archaea ◽  
Leaf Sheath ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Crop Season ◽  
Rdna Sequencing ◽  
Archaeal Communities

The succession and phylogenetic profiles of methanogenic archaeal communities associated with rice straw decomposition in rice-field soil were studied by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis followed by 16S rDNA sequencing. Nylon bags containing either leaf sheaths or blades were buried in the plowed layer of a Japanese rice field under drained conditions during the off-crop season and under flooded conditions after transplanting. In addition, rice straw samples that had been buried in the rice field under drained conditions during the off-crop season were temporarily removed during spring plowing and then re-buried in the same rice field under flooded conditions at transplanting. Populations of methanogenic archaea were examined by amplification of the 16S rRNA genes in the DNA extracted from the rice straw samples. No PCR product was produced for samples of leaf sheath or blade prior to burial or after burial under drained conditions, indicating that the methanogen population was very small during decomposition of rice straw under oxic conditions. Many common bands were observed in rice straw samples of leaf sheath and blade during decomposition of rice straw under flooded conditions. Cluster analysis based on DGGE patterns divided methanogenic archaeal communities into two groups before and after the mid-season drainage. Sequence analysis of DGGE bands that were commonly present were closely related toMethanomicrobialesand Rice cluster I.Methanomicrobiales, Rice cluster I andMethanosarcinaleswere major members before the mid-season drainage, whereas the DGGE bands that characterized methanogenic archaeal communities after the mid-season drainage were closely related toMethanomicrobiales. These results indicate that mid-season drainage affected the methanogenic archaeal communities irrespective of their location on rice straw (sheath and blade) and the previous history of decomposition during the off-crop season.

Sign in / Sign up

Export Citation Format

Share Document