亚热带主要森林类型凋落物量和土壤养分的关系

Relationship Between Litterfall Production and Soil Nutrients in Main Subtropical Forest Types

凋落物是陆地生态系统净初级生产力的重要组成部分,其产量和组成影响有机质和养分的输入。对我国亚热带天然常绿阔叶林、格氏栲人工林、闽楠人工林和杉木人工林凋落物动态、年产量和组成进行了为期1 a的观测,并探讨不同组分凋落物产量与土壤碳氮含量的关系。结果表明,各林分凋落物均呈现出显著的季节动态,各林分凋落物总量高峰期均出现在3月份,凋落叶和枝的高峰期存在较大变异。天然林、格氏栲人工林、闽楠人工林和杉木人工林年凋落物量分别为(7.81±1.32)、(4.95±0.36)、(3.38±0.95)、(3.20±0.74) t·hm-2·a-1,天然林年凋落物量显著高于3种人工林。各林分凋落物叶、枝、花、果和其它组分的比例差异显著,凋落叶占总凋落物量的比例最大,依次为天然林(65.1%)>杉木(63.7%)>闽楠(62.5%)>格氏栲(51.4%)。4种林分年凋落叶量、年凋落物总量均与土壤有机碳及全氮含量呈极显著正相关,与土壤pH呈极显著负相关(P值均<0.001)。

Litterfall is an important component of the net primary productivity in terrestrial ecosystems.The quantity and the composition of litterfall affect soil organic matter and nutrients.The annual production,components and monthly dynamics of litterfall in evergreen broad-leaved forest(Natural forest),C.kawakamii plantation,P.bournei plantation and C.lanceolata plantationof subtropical China were measured for one year.The relationships between litterfall production and soil carbon and nitrogen concentrations were investigated.The results showed that total litterfall productions peaked in March over the four stands,while the peaks forleaf and branch litterfall varied greatly among stands.The annual litterfall production of Natural forest was(7.81±1.32)t·hm-2·a-1,significantly higher than that of C.kawakamii plantation,P.bournei plantation and C.lanceolata plantation,which the annual litterfall production were(4.95±0.36),(3.38±0.95),(3.20±0.74)t·hm-2·a-1,respectively.There were significant differences in the proportions of leaf,branch,flower,fruit and other components of litterfallamong the four stands,with the largest proportion of litter being leaf litter,which account for 65.1%,63.7%,62.5%and 51.4%,respectively,of total litterfall in Natural forest,C.lanceolata plantation,P.bournei plantation,and C.kawakamii plantation.Correlations showed that the total annual litterfall and leaf litterfall of the four stands were positively correlated with soil organic carbonand total nitrogen content,and negatively correlated with soil pH(all P values<0.001).