尾巨桉人工林凋落物量及养分归还动态

Dynamics of litterfall production and nutrient fluxes in Eucalyptus urophylla×E.grandis plantation

通过1 a的定位试验监测,研究了福建漳州地区5 a生尾巨桉（Eucalyptus urophylla×E.grandis）人工林凋落物量及养分归还量动态.结果表明,5 a生尾巨桉年凋落物总量为4 200.72 kg.hm^-2,各组分占凋落物总量的比例依次为落叶（86.73%）、碎屑物（6.70%）、落枝（3.43%）、树皮（2.64%）、落果（0.25%）.凋落物量表现出明显的季节动态变化,呈双峰型,峰值分别出现在4月和6月.凋落物各组分中主要养分元素的含量表现为N最高（15.28-20.53g.kg^-1）,其次是Ca（3.11-8.37 g.kg^-1）、K（0.57-4.31 g.kg^-1）和Mg（0.63-2.01 g.kg^-1）,P（0.42-0.83 g.kg^-1）最低.5种主要养分元素的年归还总量为124.99 kg.hm^-2,其中N、P、K、Ca、Mg的年归还量分别为76.68、2.39、7.89、32.02、6.02 kg.hm-2.

One-year observations and measurements on the litterfall production and its nutrient fluxes of 5-year old Eucalyptus urophylla × E. grandis plantations were conducted in Zhangzhou, Fujian Province. The results indicate that the annual litterfall production of 5-year old Eucalyptus urophylla x E. grandis plantations was 4 200.72 kg· hm^- 2. The litterfall production of 5-year old stands exhibited one peak in April and another peak in June. The contents in the litters decreased in the order：fallen leaves （86.73 % ） 〉 miscellaneous materials （6.70 % ） 〉 branches （3.43 % ） 〉 barks （2.64 % ） 〉 fruits （0.25 % ）. In the litters, the nutrient of N was the maximum content （ 15.28 - 20.53 g· kg ^- 1 ）, followed by Ca（3.11 - 8.37 g· kg ^- 1）, K （0.57 - 4.31 g· kg ^- 1）, Mg （0.63 - 2.01 g· kg ^- 1） and P（0.42 - 0.83 g· kg ^- 1 ）. The amounts of N, P, K, Ca and Mg annually returning to the forest floor were estimated at 76.68,2.39,7.89,32.02 and 6.02 kg· hm^- 2, respectively, totaling 124.99 kg·hm^-2