Effects of NPK fertilization on growth of Toona sinensis seedlings

The quadratic regression rotation composite design was used to study the effects of nitrogen， phosphorus and potassium fertilization on the growth of Toona sinensis seedlings. The regression model among NPK fertilizer amount and the height ground diameter and stem biomass of T. sinensis seedling was established and their effects on seedling growth were analyzed. The effects of different fertilizers on seedling height，ground diameter and stem biomass showed N>P>K，and the effect of potassium fertilizer on growth of T. sinensis seedlings was not significant. When T. sinensis seedling was planted in the pot with 10 kg yellow soil，the seedling height was the highest with 141.96 cm in the pot with 4.277 g nitrogen and 2.450 g P2O5，the seedling diameter was the widest with 16.895 mm in the pot with 4.845 g nitrogen and 2.896 g P2O5，and the seedling stem biomass was the higest with 52.529 g in the pot with 4.845 g nitrogen and 4.101 g P2O5.