Effects of Substrate Application of Nitrogen, Phosphorus and Potassium Fertilizers on the Preservation and Growth of Pinus yunnanensis Seedlings

In order to understand the effects of nitrogen （N）, phosphorus （P） and potassium （K） fertilizer on seed germination, seedling survival rate, growth and biomass accumulation of Pinus yunnanensis, L₉（3⁴） orthogonal design was employed to carry out the experiment. The results showed that the mean germination rates （GR）, seedling survival rates （SSR） and seed seedling percentages （SSP） of treatment combinations （TCs） were 56.3%−84.7%, 62.6%−87.4% and 37.0%−74.0%, respectively, and there were significant or extremely significant differences among the treatment combinations （P<0.05 or P<0.01）. When the seedling age was 108d days, the ground diameter （BD）, seedling height （SH）, taproot length （TRL） and the number of first-class lateral root （NPLR） of the TCs were 0.75−0.97 mm, 4.5−5.9, 4.9−6.0 cm and 4.5−7.2 root/seedling, respectively. Meanwhile, the biomass of seedling root, stem, leaf and whole parts of the seedling were 0.006−0.010, 0.010−0.014, 0.052−0.079 and 0.069−0.103 g·seedling⁻¹ of the TCs, respectively. Except for the TRL, there were significant differences of above mentioned paramerters between the TCs （P<0.01）. Urea was the dominant factor affecting seed germination, seedling survival and growth, and biomass accumulation. It was beneficial for the biomass accumulation, but had inhibitory effects on other parameters. During the seed germination of P. yunnanensis seedlings, urea and other nitrogen-containing fertilizers should be carefully applied to the substrate. Application of substrate calcium superphosphate and potassium chloride at 0.50 and 0.25 kgm⁻³ had the best seed GR, SSR, SSP and SH, which can be applied to the production practice of P. yunnanensis seedlings cultivation.