Abstract: [Objective] This study aimed at obtaining the most suitable container type and size for growing Chinese pine (Pinus tabulaeformis) under sub-irrigation, and thus, the effects of container types and sizes on water consumption and growth of containerized Chinese pine seedlings with bottom infiltration irrigation was studied.[Method] A nest-designed trial was performed on containerized Chinese pine seedlings. There were hard plastic container with sizes of 3.8 cm(cell diameter)×14 cm(length), 3.8 cm×21 cm; non-woven fabrics container with sizes of 4.5 cm×10 cm, 4.5 cm×15 cm; black plastic container with sizes of 10 cm×10 cm, 10 cm×15 cm. All seedlings were infiltration-irrigated at the bottom of containers. Watering amount and frequency, seedling growth, including shoot height, root collar diameter, biomass, taproot length, and root length were measured. [Result] During the irrigation, the watering amount showed non-woven fabrics container > black plastic container > hard plastic container, and the mean values were 1453 mL per seedling, 964 mL per seedling, 442 mL per seedling, respectively. The watering frequency showed non-woven fabrics container > hard plastic container > black plastic container. Hard plastic container had the largest water use efficiency (WUE_i), especially in the long one. Both long and short hard plastic container had shoot height of 15 cm, root collar diameter of 2.6 mm. Also, the shoot biomass of seedlings in hard plastic container was the largest, especially in the long one in which the shoot biomass was 0.4 g. Seedlings in the black plastic container had the largest root biomass, and they were even larger in long black plastic container (0.65 g). The average taproot length in black plastic container was around 23 cm. The shoot height, root collar diameter and biomass of seedlings in non-woven fabrics were all in the lowest level. Seedling quality index (QI) showed black plastic container > hard plastic container > non-woven fabrics container, and the QI of long black plastic container was 2.48. There were no differences in root length, root surface, root volume and specific root length between hard plastic container and black plastic container, but they were all greater than those in non-woven fabrics container.[Conclusion] The most suitable container for growing Chinese pine with bottom infiltration irrigation was hard plastic container which consumed the least water to grow the best seedlings so that the WUE_i was the highest. Black plastic container had also provided large seedlings, but the root was circled. The quality of seedlings in non-woven fabrics container was the worst though it had cost much more water than the other two container types, and the WUE_i of seedlings in non-woven fabrics container was the lowest. Besides, long containers were proved to be good for growing bigger seedlings.

Key words: Pinus tabulaeformis, sub-irrigation, container type, container size, water consumption, WUE_i