追施氮肥当年与翌年对桉树生长及各部位氮贮量的影响

Eucalypt growth and nitrogen storage in the current year and next year of nitrogen topdressing

采用田间定位试验方法,研究了追施氮肥当年与翌年对桉树各部位生物量和氮贮量的影响。结果表明:与对照相比,追施氮肥翌年桉树生物量增加幅度显著高于当年,说明氮肥对于提高桉树生物量具有一定累积作用,追肥的增产效果明显;追施氮肥也使全树氮贮量在2007年与2008年分别提高30.2%和73.5%;与2007年相比,2008年对照处理桉树生物量增加35.9%,追施氮肥处理生物量提高1倍以上,而对照处理树木体内氮贮量降低13.1%,追氮处理提高15.7%;这主要是由于3龄桉树树叶生物量的明显降低,对照与追施氮肥处理树叶中氮贮量分别降低46.5%和36.9%,其也是桉树中氮贮量降低最显著的部位。

A field experiment was conducted to study the biomass accumulation and nitrogen （N） storage in different parts of eucalypt in the current year （2007） and next year （2008） of N topdressing. Compared with the control,N topdressing increased the eucalypt biomass,and the increment was much higher in 2008 than in 2007,suggesting that N topdressing had definite positive and cumulative effect on eucalypt growth. Nitrogen topdressing also increased the N storage in eucalypt,with the increment in 2007 and 2008 being 30.2% and 73.5%,respectively. Compared with that in 2007,the eucalypt biomass and N storage in the control in 2008 was increased by 35.9% and decreased by 13.1%,respectively,while those under N topdressing in 2008 were increased by one-fold and 15.7%,respectively. The main reason for these was the foliage yield reduction in 2008. Among the organs of eucalypt,leaf had the most obvious decrease in N storage. In 2008,the leaf N storage in the control and under N topdressing was decreased by 46.5% and 36.9%,respectively,compared with that in 2007.