不同林龄华北落叶松人工林叶凋落物分解及养分动态比较  

Litter Decomposition and Nutrient Dynamics of Larix principis-rupprechtii Plantations of Different Ages

作　　者：王欣[1] 高明达[2] 杨飞[1] 郭延鹏[2] 马长明[1] 

机构地区：[1]河北农业大学,保定071000 [2]河北省木兰围场国有林场管理局

出　　处：《东北林业大学学报》2012年第10期56-60,66,共6页Journal of Northeast Forestry University

基　　金：国家公益专项(20100400205)资助;河北省科技支撑计划项目(10230613)

摘　　要：采用网袋法,对0～540 d内不同林龄华北落叶松(Larix principis-rupprechtii)人工林叶凋落物的分解特征及营养元素质量分数变化动态进行了比较分析。结果表明:经过540 d的分解,幼、中、近、成熟林4个龄组的叶质量损失率为48.47%～61.72%,并呈极显著差异,不同林龄的叶凋落物分解速率呈现出成熟林>近熟林>中龄林>幼龄林。用含哑变量的Olson指数衰减模型对叶凋落物的分解动态进行拟合,结果显示,幼龄林、中龄林、近熟林和成熟林叶凋落物的分解系数为0.028 30～0.036 19;半衰期和周转期分别为1.59～2.04 a和6.90～8.82 a。在整个分解过程中,4个龄组的养分质量分数变化一致,随着时间的延长,N质量分数不断升高;P质量分数呈现出先降低后上升的趋势;K、C质量分数和C/N呈下降的趋势。在分解过程中,4个龄组的N、P、K、C的释放率在总体上变化一致,C和K不断释放,且为净释放状态,呈现直接释放模式;N的释放率为富集-释放模式;P的释放率表现为淋溶-富集-释放模式。结果表明,成熟林和近熟林的叶凋落物比幼龄林和中龄林的叶凋落物易分解,且成熟林和近熟林中的营养元素也较易释放。An experiment was condueted to study the decomposition characteristics and nutrient contents of leaf litter in Larix principis-rupprechtii plantations of different ages during 540 days of decomposition using nylon bag method. Results showed that the mass loss of litter in the plantations of different ages ranged from 48.47% to 61.72%, and a significant difference was observed between different age groups. The decomposition rate of leaf litter in the mature forest was the highest, fol- lowed by near-mature forest, middle-aged forest, and young forest. According to the dummy variable model simulated by Olson＇ s exponential function, the decomposition constant ranged from 0.028 30 to 0.036 19, and the times required for 50% and 95% of leaf decomposition were 1.59-2.04 years and 6.90-8.82 years, respectively. During the whole decom- position process, the dynamic changes of nutrient contents in four different age groups were consistent. As decomposition time prolonging, N content in leaf litter of four different age groups showed an increasing trend, and P content appeared to decrease firstly and then increased, and K, C contents and C/N ratio exhibited downward trends. The release rates and dynamic changes of nutrient elements （ N, P, K and C） in leaf litter were basically consistent between four different age groups. A net release was found in the release of C and K, and it displayed a direct release mode. The nutrient N showed a decomposition pattern of eluviation-enrichment-release, while nutrient P exhibited an accumulation-release mode. It means that the decomposition of leaf litter in mature forest and near-mature forest is easier than that in middle-aged forest and young forest, and also the nutrient elements release more easily in mature forest and near-mature forest than in middle- aged forest and young forest.

关 键 词：华北落叶松(Larix principis-rupprechtii) 凋落物分解 哑变量 养分释放 

分 类 号：S791.222[农业科学—林木遗传育种]