秦岭南坡油松和锐齿栎群落凋落叶碳释放及其与分解的关系

利用野外分解袋法分别对秦岭南坡油松和锐齿栎群落内凋落叶进行了为期24个月的分解试验.研究了凋落叶C释放过程及其与凋落叶分解过程中N、P释放和C/N、C/P比值变化的关系.研究结果表明:(1)油松群落凋落层(11265.58kg/hm2)C密度显著大于锐齿栎群落凋落层C密度(3047.31kg/hm2)(P<0.01),达到了3.7倍;(2)在凋落叶分解初期,2个群落凋落叶中碳含量均呈现先增加后下降的趋势,锐齿栎凋落叶C释放速率大于油松凋落叶C释放速率(P<0.01);(3)在两种群落类型凋落叶分解过程中,碳剩余百分率随时间变化规律符合Olson分解指数模型(R>0.81);(4)凋落叶C剩余百分率与凋落叶和N、P剩余百分率之间具有显著的二项式回归关系(锐齿栎凋落叶P剩余百分率除外),与凋落叶C/N、C/P呈显著的线性相关关系.凋落叶的C释放对凋落叶分解速率、养分元素的释放以及整个森林生态系统的物质循环过程产生显著的影响.

The Relationship between Carbon Release Process and Decomposition Percentages of the Leaf-litter in the Pinus tabulaeformis and Quercus aliena var.acuteserrata Communities in the South Slope of Qinling Mountain

The carbon release process of leaf-litter in the Pinus tabulaeformis and Quercus aliena var.acuteserrata and changes of C/N and C/P values was discussed by using litterbag experiments,which lasted 24 month,in the south slope of Qinling region.Results showed:(1)Carbon density in Pinus tabulaeformis litter(1265.580kg/hm2)was 3.7 times greater than that of Quercus aliena var.acuteserrata litter(3047.313kg/hm2)(P<0.001);(2)In beginning of the leaf-litter decomposition,carbon content increased first,then decreased in two communities;carbon release rate in Quercus aliena var.acuteserrata was significantly faster than in Pinus tabulaeformis(P<0.001);(3)The change of carbon stock over time was accord with Olson’s exposition model during leaf-litter’s decomposition process;(4)The C residual percentage appeared a binomial regression correlation with residual percentages of leaf-litter,N and P(except P in Quercus aliena var.acuteserrata),a linear correlation with C/N and C/P values.Carbon release exerts a significant influence on decomposition rate of leaf-litter,release of nutrient elements and material cycle of forest ecosystem.