Journal of Bio-Environment Control ISSN:1229-4675(Print) 2765-3641(Online) 생물환경조절학회지

Objective of this research was to investigate the influence of pre-plant nitrogen levels in root media on plug seedling growth of radish cv. Soksungbommu. To achieve the research purpose, a root medium, the mixture of perlite, coir dust, and peatmoss (volume percentage of 30:35:35) was formulated and the N levels incorporated during mixing were controlled to 0, 100, 250, 500, 750, 1,000, and 1,500 mg·L^-1. Then, the seeds were sown into 72-cell plug trays in which the root medium was packed. The measurements of growth and analysis of tissue and root media were conducted 2 and 4 weeks after sowing. Elevation of pre-plant N levels raised EC and turned down pH of root media. But, as seedling grew, the pH rose and EC get lowered in all treatments. The EC as well as NH₄-N and NO₃-N concentrations of root media declined gradually until week 2, but those declined sharply between weeks 2 to 4. The seedling growth 2 weeks after sowing showed quadratic response to pre-plant N levels with the highest growth in 250 mg·L^-1 treatment and lagging growth in the treatments of lower or higher N levels than 250 mg·L^-1. The seedling growth 4 weeks after sowing showed also quadratic response with the highest growth in 500 mg·L^-1 treatment. The tissue N contents were get higher and those of K, Ca, and Mg were get lower as pre-plant N levels were elevated. Above results suggest that lower than 250 mg·L^-1 in pre-plant N levels is optimistic for growth of plug seedling and avoidance of toxic injury in very young stage.