Abstract: 【Objective】 Non-structural carbohydrates(NSCs)are a critical parameter affecting seedling quality and have not been widely adopted while optimizing fertilizer regimes. Controlled-release fertilizer(CRF)is a simple and effective substitute for fertigation and can be used to optimize nutrient delivery in nursery settings. However, the mechanisms by which fertilizer type and dosage interact to influence nursery performance of multiple-year-old seedlings is poorly understood. 【Method】 Two-year-old, container-grown Pinus tabulaeformis Carr.(Chinese pine)seedlings were fertilized with CRF, with either one or two coating layers applied at seven dosages, ranging from 0 to 9.2 g/L medium(0 to 1 350 mg N per seedling). At the end of the second growing season, the dry mass, mineral nutrients and NSCs of the seedlings were measured. 【Result】 There was a significant interaction between the P and NSC status. Dry mass and content of N and NSC exhibited a curvilinear relationship with fertilizer dosage, reaching optimal values with multiple-layer CRF at 4.5-6.1 g/L. Furthermore, it appeared that dosage levels of 9.2 g/L were toxic for plant diameter, dry mass and N content, whereas dosages of 7.6-9.2 g/L were toxic for starch and soluble sugar content. For luxury conditions, the recommended needle concentrations of N, P and K are 2.80%-3.05%, 0.20%-0.24% and 3.40%-3.41%, respectively. 【Conclusion】Based on cost and fertilizer use efficiency, the ideal fertilization regime for the two-year-old P. tabulaeformis seedlings was the use of two-layered CRF at a dosage of 4.5 g/L(675 mg N per seedling).

Key words: Pinus tabulaeformis Carr.(Chinese pine), fertilization regime, fertilizer type, luxury consumption, foliar N concentration