西藏色季拉山急尖长苞冷杉林粗木质残体养分元素特征

摘要

Typical sample plot method was usedto investigate the coarse woody debris in Abies georgei var. smithii forest in Sejilamountains, Tibet. With five decay classification systems to classify and grade coarse woody debris. Nutrient elements concentrations of organic C, total N, total K, total P, Ca, Mg were assayed. The ratios of C/N, C/P and N/P were analyzed. The results showed that Each decay class nutrient element content and nutrient reserves are as follows: the organic C>Ca>N>K>Mg >P; C/P and C/N are gradually decreased with the deepening of the degree of decomposition of coarse woody debris, N/P is gradually increased from I to III, III to IV suddenly decreasing and then increasing; on different types of CWD, the southern slope of nutrient total reserves of 49 164.80 kg·hm-2higher than 34 846.19 kg·hm-2that of the north, and the two are all shown as: logs > snags>stumps >large branch.%以西藏色季拉山急尖长苞冷杉林Abies georgei var.smithii为研究对象,运用典型样地调查法对林下粗木质残体进行调查,采用5级腐烂系统对粗木质残体进行分等定级,测定有机C、全N、全K、全P、Ca和Mg 6种养分元素含量,分析C/N、C/P及N/P比值.结果表明:各腐烂等级养分元素含量及养分储量均表现为有机C>Ca>全N>全K>Mg>全P;C/N、C/P随粗木质残体腐烂程度的加深逐渐减小,N/P则是从Ⅰ至Ⅲ级逐渐增大,Ⅲ到Ⅳ级突然减小,之后又开始增大;在不同类型粗木质残体上,南坡养分总储量为49164.8 kg·hm-2,高于北坡的34846.19 kg·hm-2,且二者均表现为倒木>枯立木>树桩>大枯枝.