Effect of Fertilization Levels on Growth and Physiological Characteristics of Containerized Seedlings of Vaccinium oldhamii.

Vaccinium oldhamii, a blueberry species native to Korea, is a deciduous shrub in the Ericaceae family. Its fruit possesses various pharmacological properties, including anti-inflammatory effects and potential for treating osteoporosis. This study evaluated the effects of five fertilization concentration levels using Multifeed 20 (N:P:K = 20:20:20) on the growth and physiological characteristics of one-year-old V. oldhamii container seedlings. Treatments included 0 g·L-1 (control), 0.5, 1.0, 1.5, and 2.0 g·L-1. Increases in stem thickness, root length, and total dry weight were observed in the control, 0.5, 1.0, and 1.5 g·L-1 treatments, whereas growth declined at 2.0 g·L-1. Mortality rates exceeded 15% at concentrations above 1.0 g·L-1. Photosynthetic capacity and chlorophyll content increased with fertilization. However, while growth improved with increasing fertilizer up to a certain level, it declined at the highest concentration. A fertilization rate of 0.5 g·L-1 proved to be the most economically and environmentally efficient for producing healthy seedlings. This study provides the first fertilization threshold for V. oldhamii, offering practical guidance for nursery production and forming a foundation for future domestication strategies.