Utilization of Azolla in rice cultivation for environmental conservation and adaptation to climate change

利用满江红进行水稻种植以保护环境和适应气候变化

• 批准号: 21J14630
• 负责人: KIMANI Samuel Munyaka
• 金额: $ 1.25万
• 依托单位: Yamagata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for JSPS Fellows
• 财政年份: 2021
• 资助国家: 日本
• 起止时间: 2021-04-28 至 2023-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-21J14630/
• 关键词: Azolla; Dual crop; Methane; Nitrous oxide; Green manure; Paddy field

Azolla was either grown as a dual crop (Cover) or incorporated as green manure plus dual cropping (herein AGM + Cover) at the beginning of the experiment along with rice. Compared with the control (chemical fertilizer; NPK), NPK + Cover and AGM + Cover treatments did not influence cumulative CH4 emissions throughout the rice growth period. However, AGM + Cover treatment affected significant CH4 emissions at early, middle, and later rice growth stages by 141%, 25%, and 33%, respectively, compared with NPK + Cover treatment. These emissions were attributed to the readily available carbon substrate for methanogens following the incorporation of Azolla as green manure. Compared with NPK, NPK + Cover and AGM + Cover significantly increased N2O emissions by 646% and 816%, respectively, during the middle rice growth stage. No significant N2O emission differences were observed in the three treatments in the early or later rice growth stages. The higher N2O emissions from the middle rice growth stage were ascribed to high substrate availability from the dead Azolla by higher summer air temperature. AGM + Cover significantly decreased rice yield by 38% (NPK) and 35% (NPK + Cover), with no significant differences between NPK and NPK + Cover. This reduction was attributed to nitrogen immobilization from the incorporated Azolla during the early stage. Therefore, to ascertain the potential of Azolla in paddy fields to address environmental safety while sustaining yield, emphasis on the interaction of different application methods with various management practices is necessary.

满江红要么作为双季作物（覆盖）种植，要么在实验开始时与水稻一起作为绿肥加双季作物（此处为 AGM + 覆盖）种植。与对照（化肥；NPK）相比，NPK + Cover 和 AGM + Cover 处理不会影响整个水稻生育期的累积 CH4 排放量。然而，与 NPK + Cover 处理相比，AGM + Cover 处理对水稻早、中、后期的 CH4 排放影响显着，分别达 141%、25% 和 33%。这些排放归因于红萍作为绿肥掺入后，产甲烷菌容易获得碳底物。与NPK相比，NPK+Cover和AGM+Cover在中稻生育期分别显着增加了N2O排放量646%和816%。在水稻生长前期和后期，3个处理的N2O排放量没有观察到显着差异。中稻生长阶段较高的 N2O 排放量归因于夏季气温较高，死满江红的底物可用性较高。 AGM + Cover 显着降低了水稻产量 38%（NPK）和 35%（NPK + Cover），但 NPK 和 NPK + Cover 之间没有显着差异。这种减少归因于早期阶段掺入的满江红中的氮固定化。因此，为了确定满江红在稻田中解决环境安全问题同时保持产量的潜力，有必要强调不同施用方法与各种管理实践的相互作用。

项目成果

Influence of Azolla incorporation and/or dual cropping on CH₄ and N₂O emission from a paddy field

红萍掺入和/或双作对稻田CH₄和N₂O排放的影响

• DOI: 10.1080/00380768.2022.2047580
• 发表时间: 2022
• 期刊: Soil Science and Plant Nutrition
• 影响因子: 2
• 作者: Kimani Samuel Munyaka;Bimantara Putu Oki;Kautsar Valensi;Torita Ren;Hattori Satoshi;Tawaraya Keitaro;Sudo Shigeto;Cheng Weiguo
• 通讯作者: Cheng Weiguo

Poultry litter biochar application in combination with chemical fertilizer and Azolla green manure improves rice grain yield and nitrogen use efficiency in paddy soil

• DOI: 10.1007/s42773-021-00116-z
• 发表时间: 2021-08-10
• 期刊: BIOCHAR
• 影响因子: 12.7
• 作者: Kimani, Samuel Munyaka;Bimantara, Putu Oki;Cheng, Weiguo
• 通讯作者: Cheng, Weiguo