林下层植物在退化马尾松林恢复初期养分循环中的作用  

Role of Understory Plants on Nutrient Cycling of a Restoring Degraded Pine Forests in a MAB Reserve of Subtropical China

作　　者：莫江明[1] SandraBrown 彭少麟[1] 孔国辉[1] 张德强[1] 张佑昌[1] 

机构地区：[1]中国科学院华南植物研究所,广东肇庆鼎湖526070 [2]WinrockInternational

出　　处：《生态学报》2002年第9期1407-1413,共7页Acta Ecologica Sinica

基　　金：国家自然科学基金重大资助项目 (3 98993 70 ) ;中国科学院知识创新资助项目 (KZCX2 -40 7) ;中国科学院资环局和 USA MAB资助项目 (1 75 3 -90 0 5 5 5 )

摘　　要：以鼎湖山退化马尾松 (Pinusmassoniana)林恢复过程中林下层植物凋落物、分解和养分动态为对象 ,研究了林下层植物在退化马尾松林恢复初期养分循环中的作用。结果表明 ,林下层年凋落物量除在第 5年有所下降外均随时间逐年上升 ,但其增加速率随年份不同而异 ,总平均年增长速率为 3 8%。第 4年凋落物量为 0 .2 0 t· hm- 2 · a- 1,第 1 1年为 1 .1 7t·hm- 2·a- 1。凋落物养分元素平均浓度为 (% ) :N0 .95 ,P0 .0 4,K0 .5 7,Ca0 .1 3和 Mg0 .0 8,基本上以夏季和秋季最高冬春交替月份最低。第 1 1年凋落物各元素养分归还量为 (kg· hm- 2·a- 1) :N1 1 .1 0 ,P0 .47,K6.65 ,Ca1 .48和 Mg 0 .91。凋落物在分解过程中失重率呈直线模型变化 ,第 1年的分解速率为 3 1 % ,至试验结束时凋落物的残存量占起始量的 66%。在凋落物分解过程中 ,N和 P浓度随时间逐渐上升 ,但 N增加的速度较 P快 ,其余元素浓度均下降 ,但 K下降的速度最快。在凋落物分解过程中 ,N是唯一表现残留量呈先上升然后下降变化的元素。P的残留量变化与凋落物的失重率变化几乎一致。各元素在分解试验结束时残留量占起始量的百分比分别为 :N 90 % ,P 67% ,K 9% ,Ca 3 0 %和Mg 1 4%。可见 ,林下层凋落物在退化马尾松林恢复初期碳及其它营养元素循?The role of understory plants on nutrient cycling of a restoring degraded pine forest in Dinghushan Biosphere Reserve of subtropical China was studied, by quantifying litterfall, decomposition and nutrient dynamics of understory plants in the ecosystem during an eleven year period During that period of restoration, litterfall of understory plants increased at a mean rate of 38 percent with years except for the fifth year. By the fourth year of the experiment, annual litterfall was 0 20 t·hm -2 ·a -1 and by the eleventh year it was 1 17 t·hm -2 ·a -1 . Nutrient concentrations of litterfall were (%): N 0 95, P 0 04, K 0 57, Ca 0 13 and Mg 0 08, with generally highest concentrations in summer and fall, and lowest in winter and spring. The annual nutrient contents of litterfall at the eleventh year of the experiment were: N 11 10, P 0 47, K 6 65, Ca 1 48 and Mg 0 91 kg·hm -2 ·a -1 . Rate of mass loss in decomposing litter was linear with a decomposition rate ( k ) of 0 31/year during the first year. Nitrogen and P concentrations increased in decomposing litter, but N increased faster than P did. Concentrations of other elements declined in decomposing litter throughout the total period of the experiment. Nitrogen was the only element whose content increased during decomposition for the first 207 days, followed by a slight decline over the next 224 day period to 90 percent of the original content. Contents of P declined, following the linear rate of mass loss during the total period of the experiment to 67 percent of the initial content. Calcium and Mg all decreased in a similar pattern during the whole course of the experiment to 30 percent for Ca and 14 percent for Mg. The highly mobile element K showed the greatest change with an approximate 80 percent loss over the first 95 days, followed by an additional 11 percent over the next 336 days. Generally, losses in the contents of all nutrients from the decomposing litter were in the order: K>Mg>Ca>P>N. Based on the resu

关 键 词：养分循环 林下层植物 退化马尾松林 恢复初期 

分 类 号：S718.5[农业科学—林学]