摘要
凋落物层作为森林生态系统独特的结构层次 ,不仅在森林土壤的发育、生态系统物质循环和能量流动过程中具有重要的作用 ,而且其水文生态效应显著 .研究结果表明 ,凋落物层具有很强持水能力 ,最大持水率变化为 1 78 4%～ 332 1 % ;凋落物层对降水的年截留率为 5 7%～ 1 2 7% ,截留量 2 7 9～ 93 6mm .阻滞径流速度的效应显著 ,坡面流速 (V)与径流深度 (q)、坡度 (α)、凋落物层厚 (L)之间的关系为 :油松 (Pinustabulaeformis)凋落物层V =1 7 2q0 3 4 6α0 3 65L0 0 50 ;山杨 (Populusdavidiana)凋落物层V =1 8 2q0 3 65α0 3 60 L0 0 48.林地凋落物层的分解 ,增加了土壤的有机质含量、改善了土壤结构和理化性质 ,提高了孔隙率 ,增强了土壤入渗性能 ,从而可以明显削减地表径流和冲刷量 .林地去除凋落物层后 ,油松林地径流量比原林分增加了 1 96倍 ,冲刷量增加了 2 87倍 ;山杨林地径流量比原林分增加了 1 67倍 ,冲刷量增加了 8 1
As one of the structural layers of a forest ecosystem, litter layer not only plays an important role in forest soil formation,substance recycle and energy flow of an ecosystem,but also displays a significant ecological effects. It is resulted that litter layer exhibits a quite strong moisture holding capacity. Maximal rate of moisture holding capacity varies from 178 4% to 332 1%. Annual rate of water holding capacity in litter layer ranges from 5 7% to 12 7%,which equals to an amount of 27 9～93 6mm. Its effects on slowing runoff speed are significant. Regression relationship among flow velocity (V) and depth( q ) of runoff, sloping degree( α )and thickness of litter layer ( L ) may be constructed for: Pinus tabulaeformis forest V=17 2q 0 346 α 0 365 L 0 050 , Populus davidiana forest V=18 2q 0 365 α 0 360 L 0 048 . Decomposition of litters in forests may increase content of soil organic matters, improve soil structure and physical chemical characteristics, increase pore rate and enhance soil permeability,so that amount of runoff and soil erosion in forest land are evidently reduced. Without litters in forests amount of runoff is increased by 1 96 times and soil scouring 2 87 times as much as their original stands for Pinus tabulaeformis, and 1 67 and 8 15 times respectively for Populus davidiana.
出处
《北京林业大学学报》
CAS
CSCD
北大核心
2002年第5期30-34,共5页
Journal of Beijing Forestry University
基金
中国博士后基金资助项目
"十五"国家科技攻关课题 ( 2 0 0 1BA510B0 1)资助项目
