Green Carbon Inc. Confirms Approximately 1.2 Times Greater Methane Reduction Effect with AWD Demonstration in Collaboration with Toyota City, Happy Nosan, Shiga Prefectural University, and Kyoto University Compared to Extended Mid-Season Drainage
Green Carbon Inc., in collaboration with Toyota City, Happy Nosan, Shiga Prefectural University, and Kyoto University, conducted a demonstration experiment on Alternate Wetting and Drying (AWD) in rice paddies. The results showed that implementing AWD after mid-season drainage has the potential to achieve approximately 1.2 times greater methane reduction effect compared to conventional mid-season drainage alone.
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- 📰 Published: March 31, 2026 at 22:00
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Green Carbon Inc. (Representative Director: Jun Okita, hereinafter Green Carbon), which develops and sells nature-based carbon credits, announces that it has conducted a demonstration experiment (hereinafter "this demonstration") on AWD (Alternate Wetting and Drying) (※1) in rice paddies in collaboration with Toyota City, local producers in Toyota City (Happy Nosan), Shiga Prefectural University, and Kyoto University.
In this demonstration, multiple water management conditions (AWD after mid-season drainage, AWD only, mid-season drainage only) were compared for a certain period during the cultivation season to evaluate methane emissions and their impact on yield. As a result, a higher methane emission reduction effect was confirmed under the condition of implementing AWD after mid-season drainage compared to conventional mid-season drainage alone.
Furthermore, based on the comparison under the conditions of this demonstration, using emissions that do not include emissions before AWD and before mid-season drainage, the possibility of achieving approximately 1.2 times greater methane reduction effect was indicated compared to the maximum reduction coefficient (4.3tCO₂/ha) (※2) for the Tokai region in the J-Credit mid-season drainage extension methodology. This has yielded useful insights for future additional demonstrations and methodology development.
◆ Background
Reducing methane emissions from rice paddies is one of the important themes in promoting decarbonization in Japan, and efforts related to paddy field management (extension of mid-season drainage period) have been progressing in the J-Credit scheme in recent years. Green Carbon has emphasized accumulating evidence-based knowledge through collaboration with local communities, local governments, research institutions, and farmers in its efforts to create carbon credits from rice paddies both domestically and internationally.
This demonstration, conducted in collaboration with Toyota City, Happy Nosan, Shiga Prefectural University, and Kyoto University, aimed to confirm the methane emission reduction effect and impact on crops under actual AWD operating conditions in local fields. In particular, through comparative data from actual fields, the goal was to verify the effectiveness of AWD operation in addition to extended mid-season drainage and to acquire basic data for future methodology development.
◆ Overview of the Demonstration Experiment
In this demonstration, the following three conditions were compared in fields within Toyota City.
In this demonstration, multiple water management conditions (AWD after mid-season drainage, AWD only, mid-season drainage only) were compared for a certain period during the cultivation season to evaluate methane emissions and their impact on yield. As a result, a higher methane emission reduction effect was confirmed under the condition of implementing AWD after mid-season drainage compared to conventional mid-season drainage alone.
Furthermore, based on the comparison under the conditions of this demonstration, using emissions that do not include emissions before AWD and before mid-season drainage, the possibility of achieving approximately 1.2 times greater methane reduction effect was indicated compared to the maximum reduction coefficient (4.3tCO₂/ha) (※2) for the Tokai region in the J-Credit mid-season drainage extension methodology. This has yielded useful insights for future additional demonstrations and methodology development.
◆ Background
Reducing methane emissions from rice paddies is one of the important themes in promoting decarbonization in Japan, and efforts related to paddy field management (extension of mid-season drainage period) have been progressing in the J-Credit scheme in recent years. Green Carbon has emphasized accumulating evidence-based knowledge through collaboration with local communities, local governments, research institutions, and farmers in its efforts to create carbon credits from rice paddies both domestically and internationally.
This demonstration, conducted in collaboration with Toyota City, Happy Nosan, Shiga Prefectural University, and Kyoto University, aimed to confirm the methane emission reduction effect and impact on crops under actual AWD operating conditions in local fields. In particular, through comparative data from actual fields, the goal was to verify the effectiveness of AWD operation in addition to extended mid-season drainage and to acquire basic data for future methodology development.
◆ Overview of the Demonstration Experiment
In this demonstration, the following three conditions were compared in fields within Toyota City.