尾叶桉无性系幼林施肥效应的研究

在广东省开平市镇海林场进行了尾叶桉无性系幼林施肥试验，４．５ａ试验结果表明，８个不同施肥处理（肥料配方）间的生长差异极显著，尤以Ｎ７５Ｐ２００Ｋ５０处理最好，其平均树高为１５．２３ｍ，平均胸径为１１．０７ｃｍ，每公顷材积为１０７．５ｍ３。８个施肥处理均与不施肥处理有极显著的差异。最好施肥处理的平均树高、平均胸径和每公顷材积分别是不施肥的１．３、１．６５和３．１倍。以最佳施肥处理Ｎ７５Ｐ２００Ｋ５０的经济效益最好，投入与产出比为１∶２．２，与施肥量最高的处理相比，投入少，产出大，内部收益率为２５．９６％。

The Effect of Fertilization on Young Clone Plantation for Eucalyptus urophylla

The fertilizer trial of young clone plantation for Eucalyptus urophylla has been established at Zhenghai Forest Farm in Kaiping of Guangdong Province.The results of trial at 4.5 yearold have showed that there are significant differences on growth among eight fertilizer treatments.Especially in No.4 treatment (N75P200K50),its superior to that of the other seven treatments of fertilizer with the mean height of 15.23 m,mean DBH of 11.07 cm,and volume of 107.5 m3hm-2.There are significant differences between eight fertilizer treatments and the control treatment (no fertilizer).The mean height,mean DBH and volume per hectare of the best fertilizer treatment of N75P200K50 are respectively 1.3,1.65 and 3.1 times that of the control treatment (no fertilizer). The fertilizer treatment of N75P200K50 also has the best economic benefit with a ratio for input and output of 1 to 2.2 and a NPV of 25.96%.