Sub-irrigation with different container types and sizes for containerized root growth of Pinus tabuliformis seedlings

Abstract

An experiment was conducted to study the effect of sub-irrigation with different container types and sizes on root morphology and physiological indexes as well as water-use efficiency for containerized Pinus tabuliformis seedlings. A nested experimental design with treatments of two sizes of hard plastic containers (3.8 cm×14.0 cm and 3.8 cm×14.0 cm), two sizes of non-woven fabric containers (4.5 cm×10.0 cm and 4.5 cm×15.0 cm), and two sizes of black plastic containers (10.0 cm×10.0 cm and 10.0 cm×15.0 cm) was conducted. Results showed that different container types were significantly different for various indexes of seedling roots (P < 0.05) and the influence of root mass quality (P < 0.05). The taproot length of containerized P. tabuliformis seedlings cultivated in the hard plastic container was 15.56 cm; whereas, the black plastic container was 23.93 cm, which was 1.5 times of the length of the long container. The taproot dry weights for hard plastic containers (0.15 g) and black plastic containers (0.17 g) were not significantly different (P < 0.05), but both were significantly greater (P < 0.05) than the non-woven containers (0.13 g). The proportion of fine roots cultivated by hard long plastic containers was 71% (length), 52% (surface area), and 29% (volume), respectively. The hard plastic containers were significantly higher (P < 0.05) than the other two types of containers for accumulation of root nitrogen, phosphorus, and potassium (NPK). Meanwhile, water consumption of hard plastic containers was only 391.95 mL per plant. In summary, sub-irrigation with long, hard plastic containers (3.80 cm×21.00 cm), having more developed fine roots that could absorb nutrients, was most conducive for containerized P. tabuliformis seedlings, and thereby could improve survival. [Ch, 4 fig. 6 tab. 27 ref.]