Comparison in Micro Meteorological Phenomena and Growth of 3-Year-Old Panax ginseng C. A. Meyer in Shading Facility According to Shading Materials
Background : Ginseng is a semi-shade plant which prefers cool temperature and mild lighting, and artificially installed shading facility is required from preventing photo-oxidation occurrence when ginseng is exposed to direct sunlight. High temperature damages are commonly noticed due to recent global warming although more farmers are using aluminum foil and blue light-proof screen instead of 4-layered polyethylene shade net (blue 3 + black 1) to prevent the rise in temperature and influx of rainwater, there are insufficient research conducted. Methods and Results : In mid-March, 2015, we have installed steel A type shading facility after transplanting 2-year-old domestic variety ginseng in 7 lines, 10 rows per 3.3㎡. We have prevented the excessive influx of direct light by fixing 4-layered shade net, aluminum foil and blue light-proof screen as shading materials on facilities and adding 2-layered black polyethylene shade net. During July and August with high temperature, light transmission rates have shown varying according to shading materials used: blue light-proof screen (8.4%) > aluminum foil (5.9%) > 4-layered shade net (3.3%). In case of the highest temperature reached, the order followed blue light-proof screen (42.3℃) > 4-layered shade net (40.8℃) > aluminum foil (38.3℃), and in case of average temperature it followed blue light-proof screen (48.7%) > 4-layered shade net (37.6%) > aluminum foil (33.2%). Although there were no difference about leaf area among the shading materials, ginseng leaf grown in aluminum foil has lower chlorophyll content than the other two treatment plot because of photooxidation by light damage. The 3-yr-old ginseng root weight harvested in end of October increased as follows light-proof screen (14.4g) > 4-layered shade net (11.9g) > aluminum foil (9.8g). Conclusion : Aluminum foil showed greater influx of light but lower temperature than 4-layered shade net due to its materialistic character. However the front side of foil can reflect light and cause photo-oxidation of rear-planted ginseng leaves, so it is a need for improvement. In case of blue light-proof screen, although it had higher inside temperature, the root weight of ginseng was the heaviest because of less influx of light and destruction of chlorophyll.