Proceedings of the Korean Society of Crop Science Conference (한국작물학회:학술대회논문집)
- 2017.06a
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- Pages.186-186
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- 2017
Studies on establishment rate of direct seeded rice in relay intercropping system
- Maki, Natsumi (Central Region Agricultural Research Center, NARO) ;
- Yasumoto, Satoko (Central Region Agricultural Research Center, NARO) ;
- Kojima, Makoto (Central Region Agricultural Research Center, NARO) ;
- Ohshita, Yasuo (Central Region Agricultural Research Center, NARO)
- Published : 2017.06.04
Abstract
Relay intercropping system of direct seeded rice and winter cereal is labor saving cultivation and has high land use efficiency in Japan. In this system, rice seeds are direct seeded into inter-row space of winter cereals (wheat or barley) in March or April. If the direct seeding of rice is conducted before stem elongation phase or using suitable seeder, these are little effect to yield of winter cereals. Though the seeds are generally thiuram treated, it's a matter that seedling establishment rate (SER) of direct seeded rice is low and unstable. The cause of low SER has not been revealed. In present study, with the aim to reveal causes of low SER, we conducted experiments and investigated the SER, and analyzed some factors that might affect SER. Experiment1: In 2015, 2016, we buried rice seeds underground, and investigated the transition of the seed survival rates (SSR). Seeds were thiuram-treated or non-treated. In 2 periods, SSR of thiuram-treated seeds were significantly higher than non-treated seeds. In 2016, thiuram-treated seeds were high in SSR (almost 75%) at April 30th, but low SER (10~27%) after harvest of winter cereals. Therefore, almost all of seed death might have been happen after germination. Analysis 1: We investigated the SER and cultivation conditions in Ibaraki pref. for several years. Meteorological factors were referred from the nearest point of AMeDAS. From mean temperature (MT) among 5days after and before the day, we divided the period of seeding ~June 20 to phase1~4. We defined each phase as below; Phase1: