start-ver=1.4 cd-journal=joma no-vol=21 cd-vols= no-issue= article-no= start-page=100624 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2026 dt-pub=202603 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Assessing water resources availability and crop performance under climate change in Kenya's Bura irrigation scheme using SWAT and AquaCrop en-subtitle= kn-subtitle= en-abstract= kn-abstract=The current study focused on Tana River Basin in Kenya, home to the Bura irrigation scheme (BIS). The BIS faces water supply shortages during critical months of crop development. This study aimed to evaluate the available water resources and crop performance using the Soil and Water Assessment Tool (SWAT) and AquaCrop, respectively, under historical and future shared socioeconomic pathways (SSPs) at the BIS. SWAT estimated the total available flows (TAF) at the BIS intake, whereas AquaCrop estimated crop water requirements (CWR), yields, and water productivity (Wpet) of rice and maize at various carbon (IV) oxide (CO2) levels. The study suggested that the TAF will remain relatively low during the early critical crop development stages in the main cropping season, August-October. Maize yields remained steady over the two cropping seasons under both constant and elevated CO2 levels in the historical and future periods, as opposed to those of rice. Elevated CO2 levels led to diminishing CWR. Moreover, rice showed a stronger response to elevated CO2 than maize. As a result, maize which is less affected by variations in CO2 and temperatures and has less crop water requirements will be better suited than rice for cultivation in the BIS under climate change. To ensure a sustainable water supply in the scheme, the government should increase rainwater harvesting during periods of high TAF. Moreover, there should be a focus on introducing crops that are tolerant to water and temperature stresses and that can reap the most from the elevated CO2 levels. en-copyright= kn-copyright= en-aut-name=WambuaDaniel Mwendwa en-aut-sei=Wambua en-aut-mei=Daniel Mwendwa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SomuraHiroaki en-aut-sei=Somura en-aut-mei=Hiroaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MoroizumiToshitsugu en-aut-sei=Moroizumi en-aut-mei=Toshitsugu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MaedaMorihiro en-aut-sei=Maeda en-aut-mei=Morihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=Climate change kn-keyword=Climate change en-keyword=Shared socioeconomic pathways kn-keyword=Shared socioeconomic pathways en-keyword=Sustainable water management kn-keyword=Sustainable water management en-keyword=Temperature stress days kn-keyword=Temperature stress days en-keyword=Water stress days kn-keyword=Water stress days en-keyword=Water productivity kn-keyword=Water productivity en-keyword=Yields kn-keyword=Yields END start-ver=1.4 cd-journal=joma no-vol=89 cd-vols= no-issue=3 article-no= start-page=e70091 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=202505 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Autoclaved lightweight aerated concrete suppressed N2O and CO2 emissions from paddy soil en-subtitle= kn-subtitle= en-abstract= kn-abstract=Autoclaved lightweight aerated concrete (AAC), a construction waste that is utilized as a soil amendment, can influence terrestrial carbon dioxide (CO2) emissions. Still, no evidence exists regarding its impact on the emission of nitrous oxide (N2O), which has a higher global warming potential. This study examined effects of AAC on CO2 and N2O emissions from paddy soil under compacted and non-compacted conditions, under 60% and 100% water-holding capacity (WHC). Samples were incubated in glass vials (25‹C) for 21 days. Emissions of CO2 and N2O were measured on days 0, 1, 3, 7, 14, and 21 using gas chromatography. The results revealed that AAC significantly (p < 0.05) lowered N2O emission rate during the whole period of incubation, while it suppressed CO2 emission rate only at the early stages (?7 days) of incubation. In compacted soil, the emissions of CO2 were significantly lower, while N2O was significantly higher than that in non-compacted soil, showing the influence of soil physical conditions. The emissions of CO2 and N2O were significantly lower at 100% WHC than those at 60% WHC. AAC suppressed both CO2 and N2O emissions under both compaction and WHC levels. The results confirm that AAC supports suppressing terrestrial emission of both CO2 and N2O, indicating that AAC has a potential as a sustainable soil amendment that enhances the climate change resilience. en-copyright= kn-copyright= en-aut-name=RathnayakeNagoda R. R. W. S. en-aut-sei=Rathnayake en-aut-mei=Nagoda R. R. W. S. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MaedaMorihiro en-aut-sei=Maeda en-aut-mei=Morihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=LeelamanieDewpura A. L. en-aut-sei=Leelamanie en-aut-mei=Dewpura A. L. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YatagaiAtsushi en-aut-sei=Yatagai en-aut-mei=Atsushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Soil Science, Faculty of Agriculture, University of Ruhuna kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department of Soil Science, Faculty of Agriculture, University of Ruhuna kn-affil= affil-num=4 en-affil=Clion Co. Ltd kn-affil= END start-ver=1.4 cd-journal=joma no-vol=6 cd-vols= no-issue=4 article-no= start-page=116 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20251216 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Drip Fertigation in Greenhouse Eggplant Cultivation: Reducing N2O Emissions and Nitrate Leaching en-subtitle= kn-subtitle= en-abstract= kn-abstract=Drip fertigation (DF) is a sustainable agricultural management technique that optimizes water and nutrient usage, enhances crop productivity, and reduces environmental impact. Herein, we compared the effects of DF and conventional fertilization (CF) with a basal fertilizer on yield, soil inorganic nitrogen dynamics, N2O emissions, and nitrogen leaching during facility-grown eggplant cultivation. The experiment was conducted in a greenhouse from September 2023 to May 2024, with treatments arranged in three rows and three replicates. Soil, gas, and water samples were collected and analyzed throughout the growing season. The results revealed that the DF treatment produced yields comparable to those obtained with the CF treatment while significantly reducing nitrogen and phosphorus inputs. DF effectively prevented excessive nitrogen accumulation in the soil and reduced nitrogen loss through leaching and gas emissions. N2O emissions were significantly lower by more than 60% under DF than under CF. Precise nutrient management in DF suppressed nitrification and denitrification processes, mitigating N2O emissions. DF also significantly reduced nitrogen leaching by more than 70% compared with that in CF. These findings demonstrate that DF effectively enhances agricultural sustainability by improving nutrient use efficiency, reducing greenhouse gas emissions, and minimizing nitrogen leaching during the cultivation of facility-grown eggplant. en-copyright= kn-copyright= en-aut-name=ShiraishiWataru en-aut-sei=Shiraishi en-aut-mei=Wataru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NishimuraShion en-aut-sei=Nishimura en-aut-mei=Shion kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MaedaMorihiro en-aut-sei=Maeda en-aut-mei=Morihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=UenoHideto en-aut-sei=Ueno en-aut-mei=Hideto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Kochi Prefectural Agricultural Research Center kn-affil= affil-num=2 en-affil=Department of Bioresource Production Science, United Graduate School of Agriculture, Ehime University kn-affil= affil-num=3 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Department of Bioresource Production Science, United Graduate School of Agriculture, Ehime University kn-affil= en-keyword=drip fertigation kn-keyword=drip fertigation en-keyword=eggplant kn-keyword=eggplant en-keyword=greenhouse cultivation kn-keyword=greenhouse cultivation en-keyword=nitrogen leaching kn-keyword=nitrogen leaching en-keyword=nitrogen use efficiency kn-keyword=nitrogen use efficiency en-keyword=nitrous oxide emissions kn-keyword=nitrous oxide emissions END start-ver=1.4 cd-journal=joma no-vol=254 cd-vols= no-issue= article-no= start-page=108998 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=202506 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Cellulose nanofibers boost soil water availability, plant growth, and irrigation water use efficiency under deficit irrigation en-subtitle= kn-subtitle= en-abstract= kn-abstract=Under climate change, even previously rainfall-prone areas may experience droughts, and effective strategies are vital for soil conservation. Owing to their cutting-edge water absorption and storage properties, cellulose nanofibers (CNF) are expected to increase soil water availability and help plants resist water stress. However, the role of CNF in improving plant growth and soil water retention under various irrigation regimes is not yet known. We evaluated the effects of CNFs on plant available water (PAW), germination, plant growth, and irrigation water use efficiency (IWUE) under both adequate and deficit irrigation conditions. Plant cultivation experiments were conducted using different CNF dosages (0%, 0.1%, 0.5%, and 1.0%), irrigation levels (I100, I50, and I25), and soil types (sandy and silty loam). The results indicated that CNF significantly increased field capacity (FC) and PAW in both soil types, with PAW in CNF-amended soils increasing by up to 110% and 88% in sandy and silty loam soil, respectively, at 1% CNF dosage. In germination tests, CNF showed no phytotoxicity and supported the germination process during water stress, with enhancements of up to 64% and 163% at I50 and up to 125% and 214% at I25 in germination percentage and germination index, respectively. Plant growth experiments revealed that CNF addition helped plants resist water stress, maintaining plant height and weight close to those under full irrigation, while using 50% less water. IWUE analyses demonstrated that CNF enhanced IWUE, with increases of up to 56% under sufficient watering (I100), 169% under moderate water stress (I50), and 120% under severe water stress (I25), at 1% CNF dosage. These findings highlight the potential of CNF as a multifaceted amendment, offering practical solutions for addressing water scarcity challenges and contributing to more resilient and sustainable agricultural practices. en-copyright= kn-copyright= en-aut-name=NgoAn Thuy en-aut-sei=Ngo en-aut-mei=An Thuy kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NguyenManh Cong en-aut-sei=Nguyen en-aut-mei=Manh Cong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MaedaMorihiro en-aut-sei=Maeda en-aut-mei=Morihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MoriYasushi en-aut-sei=Mori en-aut-mei=Yasushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Nong Lam University kn-affil= affil-num=3 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=Cellulose nanofibers kn-keyword=Cellulose nanofibers en-keyword=Available water kn-keyword=Available water en-keyword=Plant growth kn-keyword=Plant growth en-keyword=Irrigation water use efficiency kn-keyword=Irrigation water use efficiency en-keyword=Deficit irrigation kn-keyword=Deficit irrigation en-keyword=Water stress kn-keyword=Water stress END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20251020 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Coupling effects of biochar and sediment microbial fuel cells on CH4 and CO2 emissions from straw-amended paddy soil en-subtitle= kn-subtitle= en-abstract= kn-abstract=Purpose The independent incorporation of biochar and sediment microbial fuel cells (SMFCs) into paddy soil has been shown to reduce methane (CH4) emissions. However, the application of rice straw into paddy soil enhances the availability of labile carbon that stimulates methanogen growth, counteracting the mitigation effects of both methods. This study, therefore, aimed to investigate the effect of coupling biochar and SMFC on CH4 and CO2 emissions from straw-amended paddy soil.
Materials and methods Single chamber SMFC setups constructed using acrylic columns (height, 25 cm; inner diameter, 9 cm) with six treatments were established using soil amended with 0% (0BC), 1% (1BC), and 2% (2BC) biochar: with and without SMFC conditions. Stainless steel mesh (15?~?3 cm) and graphite felt (6?~?5 cm) were used as anode and cathode materials, respectively.
Results Cumulative emission of CH4 in the 0BC treatment with SMFC was 39% less than in that without SMFC. Biochar addition and SMFC operation together further reduced CH4 emission by 57% and 60% in 1BC and 2BC treatments, respectively, compared to that in the 0BC treatment without SMFC operation. The relative abundance of microbial communities indicated methane-oxidizing bacteria were enriched in the presence of biochar and hydrogenotrophic Methanoregula were suppressed by SMFC operation. This suggested that SMFC mainly inhibited CH4 production by outcompeting hydrogenotrophic archaea.
Conclusion The use of biochar made from leftover rice straw has an interactive effect on SMFC operation and both methods can be used to reduce CH4 emission from straw-amended paddy soil. en-copyright= kn-copyright= en-aut-name=BekeleAdhena Tesfau en-aut-sei=Bekele en-aut-mei=Adhena Tesfau kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MaedaMorihiro en-aut-sei=Maeda en-aut-mei=Morihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NakaharaNozomi en-aut-sei=Nakahara en-aut-mei=Nozomi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=HashiguchiAyumi en-aut-sei=Hashiguchi en-aut-mei=Ayumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SomuraHiroaki en-aut-sei=Somura en-aut-mei=Hiroaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=AkaoSatoshi en-aut-sei=Akao en-aut-mei=Satoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=NakanoChiyu en-aut-sei=Nakano en-aut-mei=Chiyu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=NishinaYuta en-aut-sei=Nishina en-aut-mei=Yuta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Faculty of Science and Engineering, Doshisha University kn-affil= affil-num=7 en-affil=Department of Comprehensive Technical Solutions, Okayama University kn-affil= affil-num=8 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= en-keyword=Electrogenesis kn-keyword=Electrogenesis en-keyword=Methane oxidation kn-keyword=Methane oxidation en-keyword=Pyrolysis kn-keyword=Pyrolysis en-keyword=Paddy field kn-keyword=Paddy field en-keyword=Methanogens kn-keyword=Methanogens END start-ver=1.4 cd-journal=joma no-vol=23 cd-vols= no-issue=5 article-no= start-page=234 end-page=249 dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=2025 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Biochar-amended Sediment Microbial Fuel Cells for Water Quality Improvement in Intensive and Extensive Pond Drainages in Central Vietnam en-subtitle= kn-subtitle= en-abstract= kn-abstract=The use of nutrient-rich feed in shrimp farming in Central Vietnam has led to high nitrogen (N) and phosphorus (P) contents in the pond sediment. The objectives of the study were to assess the effectiveness of biochar-sediment microbial fuel cells (BC-SMFCs) in suppressing P and N release from two types of sediment in intensive (Int) and extensive (Ext) pond drainages in Central Vietnam. Single chamber SMFCs were set up and operated under open or closed-circuit (no SMFC or SMFC) conditions. Coconut shell biochar (BC) was amended to sediments at 1%. For Int-sediment, total phosphorus (TP) release was reduced by no BC-SMFCs through co-precipitation with Fe. On the other hand, BC-SMFCs did not suppress TP release because P was released from BC and organic matter decomposition was enhanced in the sediment. Application of BC enhanced organic N mineralization in the sediment. Nitrification and denitrification occurred in the overlying water, reducing mineral N concentrations. For Ext-sediment, BC addition and SMFC conditions did not affect TP and total nitrogen (TN) release because of low initial organic matter content, and less reductive condition. Our study suggested that the effect of SMFCs was masked by BC which released more P from Int-sediment to the water. en-copyright= kn-copyright= en-aut-name=NguyenUyen Tu en-aut-sei=Nguyen en-aut-mei=Uyen Tu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MaedaMorihiro en-aut-sei=Maeda en-aut-mei=Morihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SomuraHiroaki en-aut-sei=Somura en-aut-mei=Hiroaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NakaharaNozomi en-aut-sei=Nakahara en-aut-mei=Nozomi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=PereraGamamada Liyanage Erandi Priyangika en-aut-sei=Perera en-aut-mei=Gamamada Liyanage Erandi Priyangika kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NakanoChiyu en-aut-sei=Nakano en-aut-mei=Chiyu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=LeHuu Tien en-aut-sei=Le en-aut-mei=Huu Tien kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=NishinaYuta en-aut-sei=Nishina en-aut-mei=Yuta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Department of Comprehensive Technical Solutions, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=7 en-affil=Department of Education, Science and Technology Quang Tri Branch, Hue University kn-affil= affil-num=8 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= en-keyword=biochar kn-keyword=biochar en-keyword=Central Vietnam kn-keyword=Central Vietnam en-keyword=electricity generation kn-keyword=electricity generation en-keyword=redox potential kn-keyword=redox potential en-keyword=shrimp farming kn-keyword=shrimp farming END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250801 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=From sewage sludge to agriculture: governmental initiatives, technologies, and sustainable practices in Japan en-subtitle= kn-subtitle= en-abstract= kn-abstract=Sewage sludge (SS), an underutilized but valuable resource for agriculture, contains essential nutrients, such as phosphorus. In Japan, where dependence on imported fertilizers is high and global price fluctuations persist, using SS as fertilizer presents a sustainable alternative aligned with circular economy goals. This review analyzes Japanfs current efforts to repurpose SS, focusing on technological developments and key policy initiatives that promote safe and effective application. Selective phosphorus recovery technologies mitigate resource depletion, while holistic approaches, such as composting and carbonization, maximize sludge utilization for agricultural applications. Government-led initiatives, including public awareness campaigns, quality assurance standards and research support, have facilitated the adoption of sludge-based fertilizers. To contextualize Japanfs position, international trends, particularly in the EU, are also examined. These comparisons reveal both common strategies and areas for policy and technological advancement, especially regarding regulation of emerging contaminants. By integrating national case studies with global perspectives, the study offers insights into the economic, environmental, and social benefits of SS reuse, contributing to Japanfs goals of resource self-sufficiency and carbon neutrality, while also informing broader sustainable agriculture transitions worldwide. en-copyright= kn-copyright= en-aut-name=NguyenThu Huong en-aut-sei=Nguyen en-aut-mei=Thu Huong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FujiwaraTaku en-aut-sei=Fujiwara en-aut-mei=Taku kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YamashitaHiromasa en-aut-sei=Yamashita en-aut-mei=Hiromasa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=TogawaHironori en-aut-sei=Togawa en-aut-mei=Hironori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MiyakeHaruo en-aut-sei=Miyake en-aut-mei=Haruo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=GotoMasako en-aut-sei=Goto en-aut-mei=Masako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=NagareHideaki en-aut-sei=Nagare en-aut-mei=Hideaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=NakamuraMasato en-aut-sei=Nakamura en-aut-mei=Masato kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=OritateFumiko en-aut-sei=Oritate en-aut-mei=Fumiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=IharaHirotaka en-aut-sei=Ihara en-aut-mei=Hirotaka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=MaedaMorihiro en-aut-sei=Maeda en-aut-mei=Morihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil=Graduate School of Engineering, Kyoto University kn-affil= affil-num=2 en-affil=Graduate School of Engineering, Kyoto University kn-affil= affil-num=3 en-affil=Water Supply and Sewerage Department, National Institute for Land and Infrastructure Management kn-affil= affil-num=4 en-affil=Water Supply and Sewerage Department, National Institute for Land and Infrastructure Management kn-affil= affil-num=5 en-affil=R & D Department, Japan Sewage Works Agency kn-affil= affil-num=6 en-affil=1St Research Department, Japan Institute of Wastewater Engineering and Technology kn-affil= affil-num=7 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=8 en-affil=Institute for Rural Engineering, NARO kn-affil= affil-num=9 en-affil=Institute for Rural Engineering, NARO kn-affil= affil-num=10 en-affil=Institute for Agro-Environmental Sciences, NARO kn-affil= affil-num=11 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= en-keyword=Japan kn-keyword=Japan en-keyword=Sewage sludge kn-keyword=Sewage sludge en-keyword=Agriculture kn-keyword=Agriculture en-keyword=Sludge fertilizers kn-keyword=Sludge fertilizers en-keyword=Governmental initiatives kn-keyword=Governmental initiatives END start-ver=1.4 cd-journal=joma no-vol=22 cd-vols= no-issue=6 article-no= start-page=271 end-page=285 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=2024 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effects of Sediment Microbial Fuel Cells on CH4 and CO2 Emissions from Straw Amended Paddy Soil en-subtitle= kn-subtitle= en-abstract= kn-abstract=Straw returning into paddy soil enhances soil organic matter which usually promotes the emission of greenhouse gases to the atmosphere. The application of sediment microbial fuel cells (SMFCs) to paddy soil activates power-generating microorganisms and enhances organic matter biodegradation. In the present study, rice straw addition in SMFCs was examined to determine its effect on CH4 and CO2 emissions. Columns (height, 25?cm; inner diameter, 9?cm) with four treatments: soil without and with rice straw under SMFC and without SMFC conditions were incubated at 25‹C for 70 days. Anodic potential values at 7?cm depth sediment were kept higher by SMFCs than those without SMFCs. Cumulative CH4 emission was significantly reduced by SMFC with straw amendment (p < 0.05) with no significant effect on CO2 emission. 16S rRNA gene analysis results showed that Firmicutes at the phylum, Closteridiales and Acidobacteriales at order level were dominant on the anode of straw-added SMFC, whereas Methanomicrobiales were in the treatment without SMFC, indicating that a certain group of methanogens were suppressed by SMFC. Our results suggest that the anodic redox environment together with the enrichment of straw-degrading bacteria contributed to a competitive advantage of electrogenesis over methanogenesis in straw-added SMFC system. en-copyright= kn-copyright= en-aut-name=BekeleAdhena Tesfau en-aut-sei=Bekele en-aut-mei=Adhena Tesfau kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MaedaMorihiro en-aut-sei=Maeda en-aut-mei=Morihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=AkaoSatoshi en-aut-sei=Akao en-aut-mei=Satoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SomuraHiroaki en-aut-sei=Somura en-aut-mei=Hiroaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=NakanoChiyu en-aut-sei=Nakano en-aut-mei=Chiyu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NishinaYuta en-aut-sei=Nishina en-aut-mei=Yuta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Faculty of Science and Engineering, Doshisha University kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=5 en-affil=Organization for Research Strategy and Development, Okayama University kn-affil= affil-num=6 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= en-keyword=straw kn-keyword=straw en-keyword=methane mitigation kn-keyword=methane mitigation en-keyword=SMFC kn-keyword=SMFC en-keyword=microorganisms kn-keyword=microorganisms en-keyword=current generation kn-keyword=current generation END start-ver=1.4 cd-journal=joma no-vol=19 cd-vols= no-issue=1 article-no= start-page=36 end-page=43 dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=2025 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Evaluation of the temporal behavior of fulvic acid iron in Asahi River, Okayama, Japan en-subtitle= kn-subtitle= en-abstract= kn-abstract=Iron is essential for biogeochemical processes in aquatic ecosystems, but its riverine concentration can be affected by environmental conditions. This study assessed weekly fulvic acid iron (FAFe) concentration at a single sampling site in Asahi River from 2022?2023 to explore the differences in the temporal scales. The objectives of this study were to evaluate the effects of physicochemical properties of the river on the concentration of FAFe, analyze the concentration of FAFe in spring, summer, autumn and winter, and assess the relationship between FAFe concentration and land use types of the watershed. The results indicated that physicochemical parameters, such as pH and surface water temperature (SWT) seemed to influence FAFe concentration (p < 0.05). Hydrological dynamics influenced FAFe concentration and transport, revealing an increasing trend during spring (p < 0.001) and summer (p = 0.05), with non-significant trends during autumn and winter (p > 0.05). FAFe exhibited a strong positive correlation with total organic carbon (TOC) (p < 0.001). Upland fields significantly influenced FAFe concentration (p < 0.01) through runoff with abundant NO3? and PO43? into the river. Thus, FAFe concentration in Asahi River was influenced by pH, SWT, TOC, hydrological regime, and agricultural runoff. en-copyright= kn-copyright= en-aut-name=YengehRohdof Lactem en-aut-sei=Yengeh en-aut-mei=Rohdof Lactem kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SomuraHiroaki en-aut-sei=Somura en-aut-mei=Hiroaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MoroizumiToshitsugu en-aut-sei=Moroizumi en-aut-mei=Toshitsugu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MoriYasushi en-aut-sei=Mori en-aut-mei=Yasushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MaedaMorihiro en-aut-sei=Maeda en-aut-mei=Morihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=dissolved iron kn-keyword=dissolved iron en-keyword=seasonal variation kn-keyword=seasonal variation en-keyword=dissolved organic matter kn-keyword=dissolved organic matter en-keyword=fulvic acid iron kn-keyword=fulvic acid iron END start-ver=1.4 cd-journal=joma no-vol=71 cd-vols= no-issue=2 article-no= start-page=215 end-page=224 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20241214 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effects of aged microplastics on paddy soil properties and greenhouse gas emissions under laboratory aerobic conditions en-subtitle= kn-subtitle= en-abstract= kn-abstract=Microplastics (MPs) formed after changes in chemical or physical properties may alter soil properties, which in turn may affect microbial activities and greenhouse gas (GHG) emissions. However, few studies have focused on the effects of aged MPs changes on soil properties and greenhouse gas emissions. Therefore, we aimed to investigate the impact of MPs with different aging times on soil GHG emissions and dissolved organic carbon (DOC). Low-density polyethylene (PE) and polylactic acid (PLA) were treated with ultraviolet (UV) irradiation for 0?2?weeks. Soil was incubated with PE or PLA 1% (w/w) concentration at 60% water holding capacity (WHC) for 35?days. Emissions of nitrous oxide (N2O) and carbon dioxide (CO2) were measured on days 0, 1, 3, 5, 7, 14, 21, 28, and 35. Results showed that CO2 and N2O emissions were higher (p?