2023 Fiscal Year Final Research Report

Mechanism of high yield and high water productivity cultivation method for ratooning rice and its effect on reducing environmental impact

Research Project

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Project/Area Number	20K20456
Project/Area Number (Other)	19H05541 (2019)
Research Category	Grant-in-Aid for Challenging Research (Pioneering)
Allocation Type	Multi-year Fund (2020) Single-year Grants (2019)
Review Section	Medium-sized Section 41:Agricultural economics and rural sociology, agricultural engineering, and related fields
Research Institution	Japan International Research Center for Agricultural Sciences
Principal Investigator	Shiraki Shutaro 国立研究開発法人国際農林水産業研究センター, 農村開発領域, 主任研究員 (90837501)
Co-Investigator(Kenkyū-buntansha)	山岡和純国立研究開発法人国際農林水産業研究センター, 企画連携部, 再雇用職員 (70463883) 溝口勝東京大学, 大学院農学生命科学研究科(農学部), 教授 (00181917) 木村匡臣近畿大学, 農学部, 准教授 (80725664)
Project Period (FY)	2020-04-01 – 2024-03-31
Keywords	水稲再生栽培 / 生育モニタリング / 栄養塩類
Outline of Final Research Achievements	Results from the cultivation trials found that soil drying during the harvest period of the main crop increased the grain yield of ratoon crop by over 50%. This indicates that water management before and after the main crop's harvest is crucial for improving the yield of ratoon crop. Additionally, our study revealed that the water consumption features of ratoon crop differ from those of the main crop, influenced by the vigorous tillering of the ratoon crop. Therefore, irrigation planning for the ratoon rice cropping needs to consider these differences in water consumption features. Our analysis showed that the number of panicles in ratoon crop increased by 19% compared to the main rice crop, while the growth period was shortened by 41%, and the number of spikelets per panicle and grain yield decreased by 48% and 56%, respectively. Our study also showed that the ratoon crop has a yield component dependent on the number of panicles.
Free Research Field	灌漑農業、再生稲栽培
Academic Significance and Societal Importance of the Research Achievements	本研究では、低収量を引き起こすイネの再生特性を明らかにし、その特性に応じた栽培技術や水管理に関する新たな知見を提供した。これにより、農学分野における再生イネ研究の関心が高まり、新たな栽培技術の開発が促進されることが期待される。また、低投入型の再生イネ栽培技術が向上し普及することで、持続可能な農業の推進と食料安全保障の向上に寄与する。特に、途上国における農業生産の効率化と環境負荷の低減に貢献することが期待される。