Journal of Agricultural, Life and Environmental Sciences ISSN:2233-8322(Print) 2508-870X(Online) 농업생명환경연구

Three types of polyolefin (PO) film with haze values of 15.9 % (H16), 37.3 % (H37), and 81.0 % (H81) were tested. Compared to H16, H81 had a 14.4 %, 8.2 %, and 4. 5% lower transmittance atof ultraviolet, visible, and near-infrared wavelengths, respectively. Low UV-A transmittance may adversely affect anthocyanin production and red pigment expression. The average daily light integral (DLI) during the cultivation period was 48.0 mol･m^-2･d^-1, and the average total clouded and sunshine hours were 5.2 and 8.4, respectively. The average DLI by treatment was 18.4 mol･m^-2･d^-1 (H16), 19.3 mol･m^-2･d^-1 (H37), and 17.5 mol･m^-2･d^-1 (H81). The DLI deviation by location was the smallest in H81. The average temperatures during the high-temperature period were 26.8°C (H16), 26.9°C (H37), and 26.5°C (H81). that The optimum growth temperature for lettuce is 15－20 °C. Therefore, the yield was expected to be the highest in H81 due to the lower temperature. The average DLI during cultivation was 32－35 mol･m^-2･d^-1, which is a level that requires shading. the H81 had the highest shading effect, resulting in lettuce with the highest fresh weight. The low red pigment expression by lettuce in the H81 may be due to the low anthocyanin production in the high-temperature conditions with low UV-A transmittance.ato , The cultivation environment could be improved by applying a covering material with a high haze rate. However, in high-tunnel poly-greenhouses, applying an environmental control system is challenging (for example adding screens). To increase yield, it may be advantageous to use H81, but cultivating red lettuce requires addressing ,should be paid color defects.