山地麻竹林生态系统养分分配格局

Nutrient allocation pattern of Dendrocalamus latiflorus forest ecosystem planted on hill

通过对不同年龄和器官山地麻竹养分垂直分布及生态系统现存养分分配格局研究 ,结果表明 :麻竹地上器官各养分浓度随高度的升高有增加的趋势 ;在竹林层中 ,各年龄单株麻竹地下器官含量低于地上部分 ,但 N、Ca、Si O2 养分现存总量高于地上部分 ,P、K低于地上部分器官总量 ;各养分在竹秆不同高度含量不同 ,呈现随高度增加而减少的变化规律 ,竹枝和竹叶养分量随高度的分配呈现“小 -大 -小”的变化规律 ,但两个年度麻竹养分量最大值出现的高度不同 ;不同年龄麻竹单株养分含量都以幼竹为最小 ,1年生麻竹 N、P、K含量高于 2年生麻竹 ,但 Ca、Si O2 含量低于 2年生麻竹 ;地下器官中 ,竹蔸各种养分含量高于根。在群落中 ,各种养分都以麻竹林层占绝对优势 ,N、P、K、Ca、Si O2 分别占群落养分的 89.0 931%、89.0 2 4 7%、89.5 0 2 7%、93.186 7%和 88.4 135 % ,凋落物层养分其次 。

Dendrocalamus latiflorus is one of important economic bamboo species in China. It has been cultivated largely on hills and mountains in some places. However, few study has been made on ecosystem of Dendrocalamus latiflorus forest. Therefore performing research in detail is imperatively necessary. Harvest method and nutrient analysis method were adopted to analyze nutrient content of forest ecosystem parts. Through studying on nutrient vertical distribution in different age and presently nutrient allocation pattern in bamboo forest ecosystem, results showed that nutrient concentration of bamboo organ above ground tended to increase with height. The individual nutrient content of bamboo organ above ground was larger than that of underground, but in ecosystem, N, Ca and SiO_2 were larger than those of above ground, P, K were reverse. Nutrient content in different height of culm was different, it tended to decrease with height increase. Vertical distribution of nutrient content in twig and leaf tended to small-large-small, but the height of the largest content were different between 1- and 2- year bamboo. Among three age bamboo, the smallest was juvenile bamboo, the content of N, P and K in one-year-old bamboo were larger than those in two-year-old bamboo, but the content of Ca and SiO_2 were reverse. For nutrient spacial distribution in the ecosystem, the layer of Dendrocalamus latiflorus was absolute predominance, the ratio of N、P、K、Ca、SiO_2 between bamboo layer and community were up to 89.0931%、89.0247%、89.5027%、93.1867% and 88.4135%,nutrient of litter layer was latter, the vegetation layer was smallest.