<正>对福建省来舟林场引种的 1 4年生台湾桤木人工林生物量及 9种营养元素的含量、积累、分配和生物循环的研究结果表明 ,( 1 )林分总生物量为 2 85 .8t/hm2 ,其中乔木层占 93.2 4 % ;林分净初级生产力为 36.0 5t/(hm2 ·a) ;( 2 )台湾桤木单株林木营养元素含量以根瘤、叶和果实为较高 ,不同元素平均含量的大小顺序依次为 :Ca,N ,K ,Mg ,Fe,P ,Mn ,Zn ,Cu;( 3)林分营养元素的积累总量为 481 3.5 4kg/hm2 ,地上部分和地下部分各占 83.4%和 1 6.6%。林分年吸收量、归还量、存留量分别为 1 1 81 .48、646.61和 5 34.87kg/(hm2 ·a) ;( 4 ) 9种元素的循环系数、利用系数和周转期分别为 0 .2 5～ 0 .64、0 .2 3～ 0 .69和 3.96～ 9.7a

The biomass and the contents of 9 nutrient elements and their accumulation,distribution and biological cycling of the Alnus formosana plantation have been studied in Laizhou experimental forest farm of Fujian province.The results included:(1)the total stand biomass was 285.8 t/hm 2 ,of which trees accounted for 93.24%;The net primary productivity of the whole stand was 36.05 t/(hm 2 ·a).(2)the different organs of A.formosana stand had different nutrient contents.The order of total contents in different organs was nodules>leaves>fruits>barks>branches>roots>stems without barks.The order of average content of different nutrients was Ca>N>K>Mg>Fe>P>Mn>Zn>Cu.(3)the total accumulation of 9 elements in the plantation was 4 813.54 kg/hm 2 ,of which the aboveground part and the underground part accounted for 83.4% and 16.6% respectively.The amount of uptake,retention and return of 9 elements in the plantation were 1 181.48 kg/(hm 2 ·a),534.87 kg/(hm 2 ·a) and 646.61 kg/(hm 2 ·a) respectively.(4)the cycling coefficient,utilization coefficient and circulation period were 0.25～0.64,0.23～0.69 and 3.96～9.7 respectively.