滨海沙地尾巨桉人工林凋落物及其分解

Litter Fall and Decomposition of Eucalyptus urophylla × E. grandis Plantation in Coastal Sandy Soil

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1a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6 745.93 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-0.613 83·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 dynamics of total amount of litterfall showed the double-peak model, annual amount of litterfall was 6 745.93kg·hm^-2, and the yearly amount of nutrient elements in litter returning to ground was 212.09kg·hm^-2·a^-1. Different nutrient element content of litterfall was different. The amount of returned N was 69.89kg·hm^-2·a^-1, accounting for 32.95% of the nutrient 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^-0.61383.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.