Characteristics of the Relationship between Natural ¹⁵N Abundances in Organic Rice and Soil

Areal variation in the relationship between natural15N abundances of rice (Oryza sativaL.) and soil

“…We showed that linear regression between the δ 15 N values of rice and unamended soil at Tohoku Agricultural Research Center, National Agriculture and Food Research Organization (NARO/TARC) located in Daisen, Akita Prefecture, Japan, could be used to discriminate between organic and conventional rice grown in Daisen and a neighboring city, Yokote. The δ 15 N values of organic rice tended to be located above the regression line, whereas the δ 15 N values of conventional rice tended to be located below the regression line (Nishida and Sato 2015). However, to the best of our knowledge, the relationship between the δ 15 N values of rice and those of unamended soil in other places has not been investigated.…”

“…In a previous study (Nishida and Sato 2015), we found that the relationship between natural nitrogen-15 ( 15 N) abundances (δ 15 N value) of rice (Oryza sativa L.) and those of an unamended soil with no applied N source can aid in discriminating between organic and conventional rice. We showed that linear regression between the δ 15 N values of rice and unamended soil at Tohoku Agricultural Research Center, National Agriculture and Food Research Organization (NARO/TARC) located in Daisen, Akita Prefecture, Japan, could be used to discriminate between organic and conventional rice grown in Daisen and a neighboring city, Yokote.…”

Authenticity of the Geographical Origin and Production Methods of Agricultural Products

“…The characteristics of δ 15 N values between rice and soil in organic farming and conventional farming were examined, and the possibility of discriminating organically grown rice from conventionally (non-organically) grown rice by using this relationship was explored (Nishida & Sato 2015). The δ 15 N values of organically grown rice tended to be higher than the regression line obtained from the δ 15 N values of rice and soil without N source application (consisting of mostly soil and water nitrogen).…”

Natural ¹⁵N Abundance Can Aid the Discrimination of Organic and Conventional Rice

“…The δ 15 N values of total N in 18 types of commercially available organic fertilizer in Akita Prefecture were determined (Nishida & Sato 2015). Finely ground samples were used for 15 N analysis.…”

“…In order to apply the discriminant approach based on the δ 15 N values of rice and soil in other areas, it is essential to determine the existence (or otherwise) of regional variation in the relationship. Nishida and Sato (2016) undertook a study to investigate possible regional variation by comparing the relationship between the δ 15 N values of rice and unamended soil at Ogata Farm, Akita Agricultural Experiment Station (N40°01′, E139°58′) with those at TARC/NARO (Nishida & Sato 2015). The two sites are approximately 70 km apart.…”