Scheme Optimization of Light Substrate for Container Seedlings of Three Precious Timber Tree Species
An experiment with factorial design was conducted to investigate the effects of substrate composition, container size, slow-release fertilizers and air-cutting root on growth of one-year old seedling of Ormosia hosiei, Taxus wallichiana var. Mairei and Phoebe chekiangensis. T. Wallichiana var. Mairei and P. Chekiangensis were sensitive to substrate composition, while 0. Hosiei was scarcely affected by substrate composition. T. Wallichiana var. Mairei was favorite and tolerant to slow-release fertilizers fertilizers, and the height and ground diameter were promoted by the increased amount of the fertilizers. Slow release fertilizers also were beneficial to 0. Hosiei and P. Chekiangensis which showed the largest height and ground diameter when 2.0 kg·m-3 and 2.5 kg·m-3 slow-release fertilizers were applied, respectively. Height and ground diameter of T. Wallichiana var. Mairei, and ground diameter of 0. Hosiei were promoted with increasing container size. A 4. 5 cm x 10 cm container was found to be the optimal size for P. Chekiangensis. Root air-pruning promoted growth of 0. Hosiei and T. Wallichiana var. Mairei, but not for P. Chekiangensis. There were significant interactions between different factors, and the change in single factor might affect the relative performance of seedling growth. Based on the main effects and interaction effects, three optimal seedling cultivation schemes were selected for each of the three elite timber species.