ASHS 2024 Conference

Tomatoes, strawberries, paprika, and Korean melons, which are major fruit vegetables in Korea, are primarily grown in protected horticultural greenhouses, and their production is significantly influenced by seasonal and climatic factors. Extreme low irradiance caused by abnormal weather conditions not only reduces light input but also affects the internal temperature and relative humidity of greenhouses, thereby greatly impacting the growth and production of fruit vegetables. In 2024, fluctuations in production due to prolonged abnormal low irradiance during the flowering, fruit-setting, and fruit-enlargement periods (January to March) have become a significant issue in Korea. The duration of irradiance hours in the winter of 2024 (December to February) was 427.8 hours, a 20% decrease compared to the average of 535.4 hours (1990-2020). In particular, in February, it decreased sharply by 42.1% to only 104.7 hours. Additionally, there were two occurrences of low irradiance lasting more than five days, with the longest period extending up to 11.6 days. As a result, the market volume of strawberries, paprika, and Korean melons from February to April decreased by 19.3%, 29.4%, and 46.8%, respectively. The average selling price of strawberries increased by 1.3 times during this period. Therefore, there is an urgent need to develop environmental control and crop cultivation techniques to mitigate the damage caused by reduced yields due to abnormal low irradiance.