Abstract:

In order to study the effects of different proportion of N,P,K on seedling growth and physiological properties of hybrid clones of Populus tomentosa, seedlings were treated with fertilizer combinations of nitrogen, phosphorus and potassium at three different levels in an orthogonal experimental design L₉(3⁴). The results were as follows: Different fertilizing treatments produced different effects on seedlings of the same Populus tomentosa clone, and different clones responded differentially to the same fertilizing treatment. Therefore, optimum amounts and ratio of fertilization of N,P,K must be determined in terms of each individual clones; Seedling growth and phyosiological properties of the hydribd clones responded differentially to fertilizer treatments, and the optimum ratio of N,P,K for clone S86 was N (3 g)+P₂O₅ (2.25 g)+K₂O(0 g); The optimum ratio of N,P,K for clone No.46 was N (5 g)+P₂O₅(4.5 g)+K₂O(1 g). The effects of different fertilizing treatments on net photosynthetic rate× total leaf area (PTL) were more significantly different than that on net photosynthetic rate, and net photosynthetic rate×total leaf area showed a closer correlation with growth (r＜0.80). Different fertilizing treatments had significant effects on seedling growth and physiological properties of the hybrid clones. The effect of nitrogen was the greatest, followed by phosphorus and potassium. This research is of theoretical and practical significance for proper fertilization of hybrid clones of Populus tomentosa.

Key words: Populus tomentosa, seedling height, ground diameter, biomass