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Susumu Asakawa - One of the best experts on this subject based on the ideXlab platform.
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complete genome sequence of ferrigenium kumadai an22 a microaerophilic iron oxidizing bacterium isolated from a Paddy Field soil
Microbiology Resource Announcements, 2021Co-Authors: Takeshi Watanabe, Ashraf Y Z Khalifa, Susumu AsakawaAbstract:Ferrigenium kumadai An22T (= JCM 30584T = NBRC 112974T = ATCC TSD-51T) is a microaerophilic iron oxidizer isolated from Paddy Field soil and belongs to the family Gallionellaceae. Here, we report the complete genome sequence of F. kumadai An22T, which was obtained from the hybrid data of Oxford Nanopore long-read and Illumina short-read sequencing.
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ferrigenium kumadai gen nov sp nov a microaerophilic iron oxidizing bacterium isolated from a Paddy Field soil
International Journal of Systematic and Evolutionary Microbiology, 2018Co-Authors: Susumu Asakawa, Ashraf Y Z Khalifa, Yuta Nakasuji, Norikuni Saka, Hiroki Honjo, Takeshi WatanabeAbstract:An iron-oxidizing bacterium, designated strain An22T, which was isolated from a Paddy Field soil in Anjo, Japan, was described taxonomically. Strain An22T was motile by a single polar flagellum, curved-rod, Gram-negative bacterium that was able to grow at 12–37 °C (optimally at 25–30 °C) and at pH 5.2–6.8 (pH 5.9–6.1). The strain grew microaerobically and autotrophically by oxidizing ferrous iron, but did not form stalks, a unique structure of iron oxides. The major cellular fatty acids were C16 : 0 and C16 : 1ω7c/C16 : 1ω6c. The major respiratory quinones were UQ-10 and UQ-8. The strain possessed ribulose-1,5-bisphosphate carboxylase/oxygenase indicating an autotrophic nature via the Calvin–Benson–Bassham cycle. The total DNA G+C content was 61.4 mol%. 16S rRNA gene sequence analysis revealed that strain An22T was affiliated with the class Betaproteobacteria and clustered with iron-oxidizing bacteria, Gallionella ferruginea Johan (94.8 % similarity) and Ferriphaselus amnicola OYT1T (94.4 %) in the family Gallionellaceae . Based on the low 16S rRNA gene sequence similarity to the phylogenetically closest genera and the combination of unique morphological, physiological and biochemical characteristics, strain An22T represents a novel genus and species within the family Gallionellaceae , for which the name Ferrigenium kumadai gen. nov., sp. nov. is proposed. The type strain is An22T (=JCM 30584T=NBRC 112974T=ATCC TSD-51T).
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spatial and temporal changes of cyanophage communities in Paddy Field soils as revealed by the capsid assembly protein gene g20
FEMS Microbiology Ecology, 2011Co-Authors: Guanghua Wang, Susumu Asakawa, Makoto KimuraAbstract:Bacteriophages are ubiquitous in various environments. Our previous study revealed the diversity of the cyanophage community in Paddy floodwater. In this study, the phylogeny and genetic diversity of cyanophage communities in Paddy Field soils were reported. The viral capsid assembly protein gene (g20) of cyanophage was amplified with the primers CPS1 and CPS8 from soil DNA extracted during two different sampling times at three sampling sites in Japan. The sequencing results indicated that about 93% of the clones were g20 genes. In total, 70 clones of g20 genes were obtained in this study, of which 69 clones were of cyanophage origin. As evaluated by g20 sequence assemblages in Paddy Field soils, the unifrac analyses results indicated that cyanophage communities changed among the sampling sites and times and differed from those communities detected in Paddy floodwater. The phylogenetic analysis showed that the g20 sequences in Paddy Field soils were very diverse and distributed into Clusters α, β and ɛ, as well as four newly formed clusters. Within Clusters β and ɛ, four unique subclusters were formed from the g20 clones that were only observed in this study. These findings suggested that the cyanophage communities in Paddy Field soils are different from those found in freshwater, marine water and Paddy floodwater.
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Distinct members of a stable methanogenic archaeal community transcribe mcrA genes under flooded and drained conditions in Japanese Paddy Field soil
Soil Biology & Biochemistry, 2009Co-Authors: Takeshi Watanabe, Makoto Kimura, Susumu AsakawaAbstract:The composition and succession of methanogenic archaea in a Japanese Paddy Field were investigated during an annual cycle by analyses of methyl-coenzyme M reductase α subunit (mcrA) genes and their mRNA transcripts, which encode a key enzyme for methanogenesis. The Paddy Field was managed with a double-cropping cultivation, i.e. rice grown in summer under a flooded condition and wheat cultivated in winter under a drained condition. The mcrA genes and their transcripts were amplified from genomic DNA and total RNA extracted from soil samples, respectively. Numbers of the mcrA genes estimated by the most probable number-PCR showed little variation among the samples, whereas those of the transcripts and the transcripts/mcrA gene ratios increased in the late period of the rice cultivation under flooded condition. In addition, band patterns of denaturing gradient gel electrophoresis of the mcrA gene PCR products were similar among the samples, while those from the transcripts were different between the samples under flooded and drained conditions. Methanogenic activities of the Paddy soils were higher under flooded conditions than drained conditions. Clones belonging to Methanomicrobiales, Methanosarcinales, Methanocellales (Rice cluster I), mrtA cluster (isoenzyme genes) and Methanobacteriaceae were detected in the soils by the clone library analysis. However, the relative proportions in the libraries from the transcripts were completely different, i.e. transcripts derived from members of unidentified Methanosarcinales and Rice cluster I were predominantly detected in the soils under flooded and drained conditions, respectively. These results suggested that distinct members in a well-established methanogenic archaeal community transcribed mcrA genes and contributed to methane production corresponding to soil conditions.
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comparison of g23 gene sequence diversity between novosphingobium and sphingomonas phages and phage communities in the floodwater of a japanese Paddy Field
Soil Biology & Biochemistry, 2009Co-Authors: Natsuko Nakayama, Susumu Asakawa, Makoto KimuraAbstract:Abstract Our previous study indicated that the diversity of the major capsid gene ( g23 ) of T4-type bacteriophages (phages) of Novosphingobium and Sphingomonas strains isolated from the floodwater of a Japanese Paddy Field is comparable to those of the clones obtained from other Japanese Paddy Fields. For more strict comparison of the diversity, this study examined g23 sequences between Novosphingobium and Sphingomonas phages and phage communities in the identical floodwater of a Japanese Paddy Field. The clones were obtained by applying g23 -specific primers to DNA extracted from the floodwaters. Many 23 clones in the floodwater were grouped into the same clusters of Paddy Groups I–VI with g23 genes of Novosphingobium / Sphingomonas phages with some clones belonging to an additional cluster. In addition, the remaining clones belonged to the clusters of marine clones and T4-type enterophages. These findings indicate that the g23 genes in the floodwater are more diversified than those of Novosphingobium / Sphingomonas phages including g23 genes closely related to the genes of enterophages and marine origins.
Takeshi Watanabe - One of the best experts on this subject based on the ideXlab platform.
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complete genome sequence of ferrigenium kumadai an22 a microaerophilic iron oxidizing bacterium isolated from a Paddy Field soil
Microbiology Resource Announcements, 2021Co-Authors: Takeshi Watanabe, Ashraf Y Z Khalifa, Susumu AsakawaAbstract:Ferrigenium kumadai An22T (= JCM 30584T = NBRC 112974T = ATCC TSD-51T) is a microaerophilic iron oxidizer isolated from Paddy Field soil and belongs to the family Gallionellaceae. Here, we report the complete genome sequence of F. kumadai An22T, which was obtained from the hybrid data of Oxford Nanopore long-read and Illumina short-read sequencing.
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ferrigenium kumadai gen nov sp nov a microaerophilic iron oxidizing bacterium isolated from a Paddy Field soil
International Journal of Systematic and Evolutionary Microbiology, 2018Co-Authors: Susumu Asakawa, Ashraf Y Z Khalifa, Yuta Nakasuji, Norikuni Saka, Hiroki Honjo, Takeshi WatanabeAbstract:An iron-oxidizing bacterium, designated strain An22T, which was isolated from a Paddy Field soil in Anjo, Japan, was described taxonomically. Strain An22T was motile by a single polar flagellum, curved-rod, Gram-negative bacterium that was able to grow at 12–37 °C (optimally at 25–30 °C) and at pH 5.2–6.8 (pH 5.9–6.1). The strain grew microaerobically and autotrophically by oxidizing ferrous iron, but did not form stalks, a unique structure of iron oxides. The major cellular fatty acids were C16 : 0 and C16 : 1ω7c/C16 : 1ω6c. The major respiratory quinones were UQ-10 and UQ-8. The strain possessed ribulose-1,5-bisphosphate carboxylase/oxygenase indicating an autotrophic nature via the Calvin–Benson–Bassham cycle. The total DNA G+C content was 61.4 mol%. 16S rRNA gene sequence analysis revealed that strain An22T was affiliated with the class Betaproteobacteria and clustered with iron-oxidizing bacteria, Gallionella ferruginea Johan (94.8 % similarity) and Ferriphaselus amnicola OYT1T (94.4 %) in the family Gallionellaceae . Based on the low 16S rRNA gene sequence similarity to the phylogenetically closest genera and the combination of unique morphological, physiological and biochemical characteristics, strain An22T represents a novel genus and species within the family Gallionellaceae , for which the name Ferrigenium kumadai gen. nov., sp. nov. is proposed. The type strain is An22T (=JCM 30584T=NBRC 112974T=ATCC TSD-51T).
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Distinct members of a stable methanogenic archaeal community transcribe mcrA genes under flooded and drained conditions in Japanese Paddy Field soil
Soil Biology & Biochemistry, 2009Co-Authors: Takeshi Watanabe, Makoto Kimura, Susumu AsakawaAbstract:The composition and succession of methanogenic archaea in a Japanese Paddy Field were investigated during an annual cycle by analyses of methyl-coenzyme M reductase α subunit (mcrA) genes and their mRNA transcripts, which encode a key enzyme for methanogenesis. The Paddy Field was managed with a double-cropping cultivation, i.e. rice grown in summer under a flooded condition and wheat cultivated in winter under a drained condition. The mcrA genes and their transcripts were amplified from genomic DNA and total RNA extracted from soil samples, respectively. Numbers of the mcrA genes estimated by the most probable number-PCR showed little variation among the samples, whereas those of the transcripts and the transcripts/mcrA gene ratios increased in the late period of the rice cultivation under flooded condition. In addition, band patterns of denaturing gradient gel electrophoresis of the mcrA gene PCR products were similar among the samples, while those from the transcripts were different between the samples under flooded and drained conditions. Methanogenic activities of the Paddy soils were higher under flooded conditions than drained conditions. Clones belonging to Methanomicrobiales, Methanosarcinales, Methanocellales (Rice cluster I), mrtA cluster (isoenzyme genes) and Methanobacteriaceae were detected in the soils by the clone library analysis. However, the relative proportions in the libraries from the transcripts were completely different, i.e. transcripts derived from members of unidentified Methanosarcinales and Rice cluster I were predominantly detected in the soils under flooded and drained conditions, respectively. These results suggested that distinct members in a well-established methanogenic archaeal community transcribed mcrA genes and contributed to methane production corresponding to soil conditions.
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community structure of methanogenic archaea in Paddy Field soil under double cropping rice wheat
Soil Biology & Biochemistry, 2006Co-Authors: Takeshi Watanabe, Makoto Kimura, Susumu AsakawaAbstract:Abstract Community structure of methanogenic archaea in Paddy Field soil under double cropping (rice [Oryza sativa L.] and wheat [Triticum aestivum L.]) was studied by the denaturing gradient gel electrophoresis (DGGE) method. Soil samples under flooded and upland conditions were collected 7 and 6 times, respectively, from two Paddy Fields throughout a year, and two primer sets, 0357F-GC/0691R and newly designed 1106F-GC/1378R, were used for DGGE analysis. The 25 and 29 different bands were observed on the DGGE gels with the primers 0357F-GC/0691R and 1106F-GC/1378R, respectively. DGGE band patterns of the methanogenic archaeal community were stable throughout a year including the cultivation periods of rice under flooded conditions and of wheat under upland conditions. Cluster analysis and principal component analysis suggested that the difference in the soil type (sampling region) largely influenced the community structures of methanogenic archaea in Paddy Field soil, while the effects of sampling period and different fertilizer treatments on them were small. Most of the sequences obtained from the DGGE bands were closely related to Methanomicrobiales, Methanosarcinaceae, Methanosaetaceae and Rice cluster-I.
Ashraf Y Z Khalifa - One of the best experts on this subject based on the ideXlab platform.
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complete genome sequence of ferrigenium kumadai an22 a microaerophilic iron oxidizing bacterium isolated from a Paddy Field soil
Microbiology Resource Announcements, 2021Co-Authors: Takeshi Watanabe, Ashraf Y Z Khalifa, Susumu AsakawaAbstract:Ferrigenium kumadai An22T (= JCM 30584T = NBRC 112974T = ATCC TSD-51T) is a microaerophilic iron oxidizer isolated from Paddy Field soil and belongs to the family Gallionellaceae. Here, we report the complete genome sequence of F. kumadai An22T, which was obtained from the hybrid data of Oxford Nanopore long-read and Illumina short-read sequencing.
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ferrigenium kumadai gen nov sp nov a microaerophilic iron oxidizing bacterium isolated from a Paddy Field soil
International Journal of Systematic and Evolutionary Microbiology, 2018Co-Authors: Susumu Asakawa, Ashraf Y Z Khalifa, Yuta Nakasuji, Norikuni Saka, Hiroki Honjo, Takeshi WatanabeAbstract:An iron-oxidizing bacterium, designated strain An22T, which was isolated from a Paddy Field soil in Anjo, Japan, was described taxonomically. Strain An22T was motile by a single polar flagellum, curved-rod, Gram-negative bacterium that was able to grow at 12–37 °C (optimally at 25–30 °C) and at pH 5.2–6.8 (pH 5.9–6.1). The strain grew microaerobically and autotrophically by oxidizing ferrous iron, but did not form stalks, a unique structure of iron oxides. The major cellular fatty acids were C16 : 0 and C16 : 1ω7c/C16 : 1ω6c. The major respiratory quinones were UQ-10 and UQ-8. The strain possessed ribulose-1,5-bisphosphate carboxylase/oxygenase indicating an autotrophic nature via the Calvin–Benson–Bassham cycle. The total DNA G+C content was 61.4 mol%. 16S rRNA gene sequence analysis revealed that strain An22T was affiliated with the class Betaproteobacteria and clustered with iron-oxidizing bacteria, Gallionella ferruginea Johan (94.8 % similarity) and Ferriphaselus amnicola OYT1T (94.4 %) in the family Gallionellaceae . Based on the low 16S rRNA gene sequence similarity to the phylogenetically closest genera and the combination of unique morphological, physiological and biochemical characteristics, strain An22T represents a novel genus and species within the family Gallionellaceae , for which the name Ferrigenium kumadai gen. nov., sp. nov. is proposed. The type strain is An22T (=JCM 30584T=NBRC 112974T=ATCC TSD-51T).
Makoto Kimura - One of the best experts on this subject based on the ideXlab platform.
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spatial and temporal changes of cyanophage communities in Paddy Field soils as revealed by the capsid assembly protein gene g20
FEMS Microbiology Ecology, 2011Co-Authors: Guanghua Wang, Susumu Asakawa, Makoto KimuraAbstract:Bacteriophages are ubiquitous in various environments. Our previous study revealed the diversity of the cyanophage community in Paddy floodwater. In this study, the phylogeny and genetic diversity of cyanophage communities in Paddy Field soils were reported. The viral capsid assembly protein gene (g20) of cyanophage was amplified with the primers CPS1 and CPS8 from soil DNA extracted during two different sampling times at three sampling sites in Japan. The sequencing results indicated that about 93% of the clones were g20 genes. In total, 70 clones of g20 genes were obtained in this study, of which 69 clones were of cyanophage origin. As evaluated by g20 sequence assemblages in Paddy Field soils, the unifrac analyses results indicated that cyanophage communities changed among the sampling sites and times and differed from those communities detected in Paddy floodwater. The phylogenetic analysis showed that the g20 sequences in Paddy Field soils were very diverse and distributed into Clusters α, β and ɛ, as well as four newly formed clusters. Within Clusters β and ɛ, four unique subclusters were formed from the g20 clones that were only observed in this study. These findings suggested that the cyanophage communities in Paddy Field soils are different from those found in freshwater, marine water and Paddy floodwater.
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Distinct members of a stable methanogenic archaeal community transcribe mcrA genes under flooded and drained conditions in Japanese Paddy Field soil
Soil Biology & Biochemistry, 2009Co-Authors: Takeshi Watanabe, Makoto Kimura, Susumu AsakawaAbstract:The composition and succession of methanogenic archaea in a Japanese Paddy Field were investigated during an annual cycle by analyses of methyl-coenzyme M reductase α subunit (mcrA) genes and their mRNA transcripts, which encode a key enzyme for methanogenesis. The Paddy Field was managed with a double-cropping cultivation, i.e. rice grown in summer under a flooded condition and wheat cultivated in winter under a drained condition. The mcrA genes and their transcripts were amplified from genomic DNA and total RNA extracted from soil samples, respectively. Numbers of the mcrA genes estimated by the most probable number-PCR showed little variation among the samples, whereas those of the transcripts and the transcripts/mcrA gene ratios increased in the late period of the rice cultivation under flooded condition. In addition, band patterns of denaturing gradient gel electrophoresis of the mcrA gene PCR products were similar among the samples, while those from the transcripts were different between the samples under flooded and drained conditions. Methanogenic activities of the Paddy soils were higher under flooded conditions than drained conditions. Clones belonging to Methanomicrobiales, Methanosarcinales, Methanocellales (Rice cluster I), mrtA cluster (isoenzyme genes) and Methanobacteriaceae were detected in the soils by the clone library analysis. However, the relative proportions in the libraries from the transcripts were completely different, i.e. transcripts derived from members of unidentified Methanosarcinales and Rice cluster I were predominantly detected in the soils under flooded and drained conditions, respectively. These results suggested that distinct members in a well-established methanogenic archaeal community transcribed mcrA genes and contributed to methane production corresponding to soil conditions.
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comparison of g23 gene sequence diversity between novosphingobium and sphingomonas phages and phage communities in the floodwater of a japanese Paddy Field
Soil Biology & Biochemistry, 2009Co-Authors: Natsuko Nakayama, Susumu Asakawa, Makoto KimuraAbstract:Abstract Our previous study indicated that the diversity of the major capsid gene ( g23 ) of T4-type bacteriophages (phages) of Novosphingobium and Sphingomonas strains isolated from the floodwater of a Japanese Paddy Field is comparable to those of the clones obtained from other Japanese Paddy Fields. For more strict comparison of the diversity, this study examined g23 sequences between Novosphingobium and Sphingomonas phages and phage communities in the identical floodwater of a Japanese Paddy Field. The clones were obtained by applying g23 -specific primers to DNA extracted from the floodwaters. Many 23 clones in the floodwater were grouped into the same clusters of Paddy Groups I–VI with g23 genes of Novosphingobium / Sphingomonas phages with some clones belonging to an additional cluster. In addition, the remaining clones belonged to the clusters of marine clones and T4-type enterophages. These findings indicate that the g23 genes in the floodwater are more diversified than those of Novosphingobium / Sphingomonas phages including g23 genes closely related to the genes of enterophages and marine origins.
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comparison of bacterial community structures at main habitats in Paddy Field ecosystem based on dgge analysis
Soil Biology & Biochemistry, 2008Co-Authors: Susumu Asakawa, Makoto KimuraAbstract:Abstract Bacterial communities at different habitats in a Japanese Paddy Field ecosystem were compared to understand the bacterial world in the ecosystem as a whole by analyzing data of the denaturing gradient gel electrophoresis (DGGE) band patterns and the sequenced DGGE bands. The habitats were floodwater, percolating water, microcrustacean inhabiting in floodwater, plow layer soil, rice roots, rice straw and rice straw compost incorporated in soil, rice straw placed on the soil surface, plant residues in Paddy Fields, and rice straw under composting process. Phylotype (band) richness, diversity, evenness, and stability of the bacterial communities at the respective habitats were evaluated based on the DGGE profile data. Phylotype richness was greater near plant residues, rice straw buried in soil and rice straw placed on soil surface, while it was smaller at microcrustacean and rice straw compost buried in soil. The samples from plow layer soil and rice straw compost buried in soil showed considerably higher index values for diversity, evenness, and stability, while those from rice straw placed on soil surface and microcrustacean had lower values of the indices than other habitats. Sequences of totally 250 DGGE bands were assigned to phyla or classes. Distribution of bacterial members to phylogenetic taxa was different among the respective habitats. Inhabitants in plow layer soil were most widely distributed among the groups (nine phyla: Proteobacteria, Chloroflexi, Chlorobi, Verrucomicrobia, Acidobacteria, Nitrospira, candidate division OP10, Cyanobacteria, and Actinobacteria), while those in floodwater and microcrustacean were restricted to only three phyla (Proteobacteria, Bacteroidetes, and Actinobacteria). Proteobacteria and Bacteroidetes were found at all the habitats and the habitats except for plow layer soil, respectively, whereas abundant members belonged to Chloroflexi and Actinobacteria in plow layer soil. “Comprehensive mapping” of DGGE fragments was conducted by principal component analysis based on evolutionary distances of the fragments to 202 reference bacterial strains to overview phylogenetic relationships of bacterial members among the respective habitats. The score plots with the first and second principal components distinctly characterized bacterial members at the respective habitats, and the similarity between the respective communities was clearly demonstrated. Overall, bacterial communities at the respective habitats were distinct and different in the diversity and stability to each other, which may have contributed to the diversity of overall bacterial communities in the Paddy Field ecosystem.
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community structure of methanogenic archaea in Paddy Field soil under double cropping rice wheat
Soil Biology & Biochemistry, 2006Co-Authors: Takeshi Watanabe, Makoto Kimura, Susumu AsakawaAbstract:Abstract Community structure of methanogenic archaea in Paddy Field soil under double cropping (rice [Oryza sativa L.] and wheat [Triticum aestivum L.]) was studied by the denaturing gradient gel electrophoresis (DGGE) method. Soil samples under flooded and upland conditions were collected 7 and 6 times, respectively, from two Paddy Fields throughout a year, and two primer sets, 0357F-GC/0691R and newly designed 1106F-GC/1378R, were used for DGGE analysis. The 25 and 29 different bands were observed on the DGGE gels with the primers 0357F-GC/0691R and 1106F-GC/1378R, respectively. DGGE band patterns of the methanogenic archaeal community were stable throughout a year including the cultivation periods of rice under flooded conditions and of wheat under upland conditions. Cluster analysis and principal component analysis suggested that the difference in the soil type (sampling region) largely influenced the community structures of methanogenic archaea in Paddy Field soil, while the effects of sampling period and different fertilizer treatments on them were small. Most of the sequences obtained from the DGGE bands were closely related to Methanomicrobiales, Methanosarcinaceae, Methanosaetaceae and Rice cluster-I.
Kazunori Minamikawa - One of the best experts on this subject based on the ideXlab platform.
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increase in soil carbon sequestration using rice husk charcoal without stimulating ch4and n2o emissions in an andosol Paddy Field in japan
Soil Science and Plant Nutrition, 2015Co-Authors: Shinichi Koyama, Kazunori Minamikawa, Fumihiko Inazaki, Morio Kato, Hisayoshi HayashiAbstract:AbstractBiochar application has been recognized as an effective option for promoting carbon (C) sequestration, but it may also affect the production and consumption of methane (CH4) and nitrous oxide (N2O) in soil. A 1-year Field experiment was conducted to investigate the effects of rice husk charcoal application on rice (Oryza sativa L.) productivity and the balance of greenhouse gas exchanges in an Andosol Paddy Field. The experiment compared the treatments of rice husk charcoal applied at 10, 20 and 40 Mg ha−1 (RC10, RC20 and RC40, respectively), rice husk applied at 20 Mg ha−1 (RH20), and the control (CONT). Rice straw and grain yields did not significantly differ among the treatments. The seasonal cumulative CH4 emissions were 38–47% higher from RC10, RC20 and RC40 than from the CONT. However, the increases were not in proportion to the application rates of rice husk charcoal, and their values did not significantly differ from the CONT. On the contrary, the RH20 treatment significantly increased the...
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comparison of indirect nitrous oxide emission through lysimeter drainage between an andosol upland Field and a fluvisol Paddy Field
Soil Science and Plant Nutrition, 2011Co-Authors: Kazunori Minamikawa, Seiichi Nishimura, Hiroko Akiyama, Atsushi Hayakawa, Kazuyuki YagiAbstract:Indirect emission of nitrous oxide (N2O) due to nitrogen (N) leaching and runoff from agricultural soils is a major source of atmospheric N2O. To evaluate the effect of agricultural land use in combination with soil type on indirect N2O emission through groundwater, we compared the indirect N2O emission between an upland Field of Andosol and a Paddy Field of Fluvisol in a 1-year lysimeter experiment. We established a shallow groundwater table during the non-flooded fallow period in the Fluvisol Paddy Field to simulate moisture conditions in a lowland soil. Drainage was 795 mm yr−1 (median, n = 6) in the Andosol upland Field, versus 1583 mm yr−1 in the Fluvisol Paddy Field due to flooding during part of the year. The total leached nitrate in the Andosol upland Field (4.24 g N m−2 yr−1) was comparable to that in the Fluvisol Paddy Field (5.57 g N m−2 yr−1). The total indirect N2O emission in the Fluvisol Paddy Field (88.6 mg N m−2 yr−1) was 55 times that in the Andosol upland Field (1.62 mg N m−2 yr−1). The...
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the practical use of water management based on soil redox potential for decreasing methane emission from a Paddy Field in japan
Agriculture Ecosystems & Environment, 2006Co-Authors: Kazunori Minamikawa, Naoki SakaiAbstract:Abstract Water management is one of the most effective options in decreasing methane (CH4) emission from a Paddy Field. We have proposed the water management based on soil redox potential (Eh) named ‘Eh control’, and demonstrated the effectiveness of Eh control in decreasing CH4 emission in pot experiments. The objective of the present study was to consider the practicability of Eh control under Field conditions. Two-year experiments were carried out in a Paddy Field at the Agricultural and Forestry Research Center, University of Tsukuba, Japan in 2003 and 2004. Experimental factors were water management and rice (Oryza sativa L., cultivar: Koshihikari) straw treatment. Two methods of water management during rice growing period were continuous flooding and Eh control. For Eh control, drainage was carried out whenever the soil Eh decreased to −150 mV, and flooding was carried out whenever the soil Eh increased to 0 mV in 2003 and 100 mV in 2004. Two methods of rice straw treatment were application and removal in the preceding winters of all straw harvested. The CH4 flux was measured by a closed chamber method and the total emission during the growing period was estimated. Rice grain and straw yields were examined by a quadrat sampling method. The yield component was analyzed only in 2004. The total CH4 emission was decreased by Eh control to 36% of continuous flooding on the 2-year average. Although straw application hastened the decrease in soil Eh when compared with straw removal, it did not affect the total CH4 emission. Rice grain and straw yields were not affected by the experimental factors. However, yield component analysis showed that Eh control increased the number of panicles per hill and resulted in increased brown rice yield. Straw application also increased the number of panicles per hill, but did not affect brown rice yield. Consequently, the present study demonstrates the practicability of Eh control under the Field conditions on an experimental level. Two important suggestions were obtained from the above results. One is that Eh control decreases CH4 emission to a minimum level according to the range of soil Eh determined. Another is that it may be possible to change the range of soil Eh to a more positive value that will decrease CH4 emission more and increase rice grain yield.
