Paddy soil used to have a low level of organic matters, generally below 3 %, because of its concerns of producing harmful materials to the crop growth in a less-oxygen decomposition process. On the other hand plowing-in composts and organic fertilizers improves the soil condition. If a carbon-capturing paddy management is described in a correct manner, it could become precision carbon farming of paddy aiming at both soil improvement and clean development mechanisms.

This paper describes the practice of Aguri Co., Ltd., a paddy grower, towards a new scheme of precision paddy. With the data collected from nine fields with more than 5-year organic management using the real-time soil sensor during 2004 to 2008, total carbon and total nitrogen were analyzed. As expected, increases in total carbon and total nitrogen were observed by more than 1 % and a significant spatial variability of total carbon was also detected, implying that the dynamics of sequestration rate depended on specific field conditions, and also field total carbon qualification issues. A vertical distribution of soil total carbon was investigated in the top 0.3 m and its average value was observed in a zone of 0.15-20 m depth. With the data of investigation a potential of carbon paddy will be discussed looking at two millions ha of paddy in Japan.