This study was carried out to select optimal shade materials among four-layered polyethylene (PE) net
(FLPN), aluminium-coated PE sheet (APSS), and blue PE sheet (BPSS) in condition of paddy field cultivated 6-year-old ginseng.
The order of light-penetrated ratio and air temperature by shade materials was BPSS > APSS > FLPN. Light-penetrated
ratio of BPSS before two fold shade was more 3 times and 2 times than that of FLPN and APSS, respectively. Air
temperature of BPSS was also higher 1.6oC and 1.4oC than that of FLPN and APSS, respectively. BPSS showed good cultural
environment because all of light-penetrated ratio and air temperature were become higher in spring and fall season
but lower in summer season by additional shade with two-layered PE net. Survived-leaf ratio was highest in BPSS and lowest
in FLPN causing a little water leak on a rainy day. Rusty-root ratio was also highest in FLPN because soil moisture content
was increased by water leak. The order of root yield was BPSS > APSS > FLPN, and the cause of highest yield in BPSS
was higher light-penetrated ratio during spring and fall season, higher survived-leaf ratio, and lower rusty-root ratio than
that of APSS and FLPN. BPSS showed highest total ginsenoside content because of high light-penetrated ratio, blue light
effect, and the difference in dry matter partitioning ratio such as low taproot ratio, and high lateral root ratio.