| Autor: |
Kosaka, Shinichi, Horaguchi, Kimitoshi, Saito, Naoki, Kamijyo, Kazuhiko, Murakami, Katsusuke |
| Jazyk: |
japonština |
| Rok vydání: |
2007 |
| Předmět: |
|
| Zdroj: |
照明学会誌. 91(2):87-93 |
| ISSN: |
0019-2341 |
| Popis: |
A supplemental lighting system was installed at a large-scale seedling greenhouse (12.5 m x 45 m), which supplies high quality and large quantity of seedlings to farmers through out the year. A test experiment of supplemental lighting for seedlings in this house was performed during the rainy season and winter-early spring to prepare for planting, when sunshine is sometimes insufficient. A mercury-free high pressure sodium lamp of 400W with a red to far-red photon flux (R/FR PF) ratio of 1.1 was developed and manufactured for this experiment. The average PPFD was 100µmol m⁻² s⁻¹. The experimental plants were lettuce, broccoli, and cabbage. In both rainy and winter-early spring experiments, we found that supplemental lighting was effective for seedling growth. Significant supplemental lighting effects in the rainy season were found for broccoli. Top fresh weights of both a 2h lit area before sunrise and after sunset were 30-60% greater than those of the non-lit area. A drop test of lettuce demonstrated that the remaining ratio of soil of both a 2h lit area before sunrise and after sunset were about 87%, and those of the non-lit areas were about 78%. Thus, good growth in roots was found. A significant supplemental lighting effect in winter-early spring was found in the lettuce experiment. Top fresh weights of both a 3h lit area before sunrise and after sunset were 165-200% greater than those of the non-lit area. In winter-early spring experiments, a clear difference between a 3h lit area before sunrise and after sunset was not found. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
