3个阔叶树种绿化苗木的施肥效应

对连香树、榉树和枫杨3树种进行尿素、核能素和磷酸二氢钾不同配方追肥试验，结果表明：配方施肥对3树种苗木生长的促进作用均十分明显，采用尿素每15d追肥1次，苗木生长正常的安全使用量为每次20g／m^2。以处理B（15d施1次尿素，用量为20g／m^2）和D（15d施1次尿素，用量为10g／m^2，并用核能素10mL／15kg＋磷酸二氢钾0．1％混合喷施）对苗木生长的促进作用较为显著，连香树和枫杨以处理D的效果最佳，榉树以处理B的效果最佳。处理D，连香树的苗高、地径和冠幅分别比对照高173．00％，39．26％和48．53％，枫杨的苗高、地径和冠幅分别比对照高50．56％．36．67％和38．40％；榉树处理B的苗高、地径和冠幅分别比对照高46．73％，18．14％和72．22％。

Formulated Fertilization Effects on Ornamental Saplings of Three Deciduous Tree Species

A formulated topdressing experiment was conducted with different compositions of urea, forchlorfenuron and potassium dihydrogen phosphate applied to three tree species i. e. , Cercidiphyllum japonicum, Zelkova serrata and Pterocarya stenoptera. It was showed that formulated fertilization had significant effect on seedling growth of above three tree species. The safe urea topdressing dosage to ensure normal growth of the seedlings was 20 g/m^2 and it was applied once every 15 days. Treatment B（20 g/m^2 urea by 15d interval） and Treatment D （10 g/m^2 urea by 15d interval plus 10 mL/15 kg forehlorfenuron and 0. 1% potassium dihydrogen phosphate for foliage dressing） had remarkable promotion effect on the seedling growth. The effect of Treatment D was the best on C. japonicum and P. stenoptera, while the effect of Treatment B seemed to be the most effective on Z. serrata. Compared to CK, the height, basal diameter and crown width of C. japonicum were increased by 173.00%, 39.26% and 48.53% respectively by Treatment D. Similarly, the height, basal diameter and crown width of P. stenoptera were increased by 50.56%, 36.67% and 38.40% respectively by Treatment D. The three growth indexes of Z. serrata seedlings were increased by 46.73%, 18.14% and 72.22% individually by Treatment B.