Objective By studying the effects of substrate ratio, slow-release fertilizer dosage, container specification, and their combinations on the growth indexes of 2-year-old Alniphyllum fortunei container seedlings, this research aims to idendify the optimal container seedling scheme and provide insights for improving container seeding raising technique for A. fortunei.

Method Using 2-year-old A. fortunei container seedlings as the experimental material, a factorial experimental design was employed with three container specifications, three substrate ratios, and three slow-release fertilizer amounts, resulting in nine orthogonally combined treatments. The study examined the key factors on the growth and quality of 2-year-old A. fortunei container seedlings, and the comprehensive evaluation was conducted using the membership function method.

Results Among the three factors, the substrate ratio significantly affected the seedling height and height-to-diameter ratio of A. fortunei container seedlings (P<0.05), but it did not have significant impact on the ground diameter (P>0.05). Specifically, the substrate pH, organic matter content, hydrolyzed nitrogen, and bulk density were significantly correlated with seedling height and height-to-diameter ratio, total porosity was significantly correlated with seedling height, and available phosphorus content was significantly correlated with height-to-diameter ratio. The container specifications and slow-release fertilizer amounts had no significant effects on the ground diameter, seedling height, and height-to-diameter ratio of A. fortunei container seedlings (P>0.05). The comprehensive evaluation using the membership function method indicated that the combination of container specification A2 (10.0 cm×13.5 cm), substrate ratio B2 (coco coir 4 : peat 4 : soil 2), and slow-release fertilizer amount C3 (4 kg·m⁻³) was the best for container seedling raising of A. fortunei.

Conclusion The container specification, substrate ratio, and slow-release fertilizer amount singly or interactively significantly affect the growth of A. fortunei container seedlings. The best combination for raising container seedlings of A. fortunei is to use B2 (coconut coir 4 : peat 4 : soil 2) as the substrate, add C3 (4 kg·m⁻³) slow-release fertilizer, and use A2 (10.0 cm × 13.5 cm) as the container to cultivate container seedlings with a height of 167.22 cm and a ground diameter of 8.44 mm for 2-year-old seedlings. Our results provide a technical and scientific basis for container seedling raising of A. fortunei.