滨海沙地尾巨桉人工林凋落物及其分解

摘要

应用尼龙网框收获法和网袋分解法，对沿海沙地10年生尾巨桉人工林的凋落物进行1 a的分析。结果表明：凋落物量在1 a中月动态呈“双峰”变化趋势，年总凋落物量为6745．93 kg· hm-2· a-1，每年归还林地的养分总量为212．09 kg· hm-2·a -1；凋落物不同组成营养元素质量分数不同，在所测定的营养元素中，N的归还量最大为69．89 kg· hm-2· a-1，占养分总归还量的32．95％；凋落物各组成中养分归还量由大到小的顺序为：叶、枝、皮、花果、碎屑。尾巨桉凋落物的分解速度表现为慢-快-慢模式，7月份分解速度最快；凋落物分解Olson指数模型为：Y＝100· e-0．61383·t ，R2＝0．973，说明该模型拟合程度高，分解50％和95％所用时间分别为1．13 a和4．88 a。%With the methods of nylon net box harvest and mesh bag decomposition , an experiment was conducted to analyze the litterfall over one year in ten-year-old Eucalyptus urophylla×E.grandis plantation on coastal sandy soil.The monthly dy-namics of total amount of litterfall showed the double-peak model, annual amount of litterfall was 6 745.93 kg· hm-2 , and the yearly amount of nutrient elements in litter returning to ground was 212.09 kg· hm-2 · a-1 .Different nutrient element content of litterfall was different.The amount of returned N was 69.89 kg· hm-2 · a-1 , accounting for 32.95%of the nu-trient return total amount.The nutrient of litterfall of returned amount was leaf>branch>bark>fruit and flower>detritus. The decomposition of litterfall showed slow-fast-slow model, and the litterfall decompose fastest in July.Olson index model of litterfall of decomposition was Y=100· e-0.613 83· t with R2=0.973 and good regression.It took about 1.13 a and 4.88 a, when 50%and 95%of litterfall was decomposed, respectively.