Development of automatic fog culture system for year-round rice production in greenhouse

Though there are some drawbacks in the design of this rice culture system, the results showed that these can be alleviated. The culture system was set up in a glass greenhouse to avoid yield loss due to typhoon and heavy rain which led to an inadequate amount of solar radiation even during the summer. Inclining the seeding bed southwards at 30 degrees did not enable to improve the light absorption. Some favorable aspects of this fog culture system, however, are worth considering. Subsoil water temperature particularly in winter became more manageable. Carbon dioxide concentration in a particular growth phase could be enhanced. Nutrients could be replenished in the most suitable growing period and with the most appropriate amount. The oxygen supply to the root system was provided adequately during atomization. With all these advantages, year-round production increased 3 times or more due to the absence of seasonal effect. This experiment also indicated that the apparent photosynthetic rate could be enhanced by increasing the amount of insolation and solar energy conversion. This should certainly exert a beneficial effect on the panicle number, ripening efficiency and grain-straw ratio or total grain yield in general. Lastly, our group aims at redesigning the set-up in order to increase the production. In Japan, we are focusing on a stable, high-yielding and automatic year-round rice production while aiming at the same time at preserving the environment by reducing the consumption of expendable energy. To some extent, this study provides a basis for the development of a technology for desert or arid areas and subfrigid zones to increase productivity.