[Characteristics of soil water infiltration in sub-alpine dark coniferous ecosystem of upper reaches of Yangtze River].
Dark coniferous forest is the predominant type of vegetation in the upper reaches of Yangtze River. Difference among different types of soil exists. The sand content of soil is higher and the soil texture is coarser in the early stage of forest succession. The sand content of soil decreases with the advancement of the forest succession while that of soil in Abies fabri over-mature forest is the lowest. In slope wash soil, the sand content of soil decreases with the increasing soil depth. The soil porosity and soil water-holding capacity increases and soil bulk density decreases with the advancement of forest succession and decrease of soil depth. The deeper soil depth or the smaller soil water content are, the smaller the unsaturated hydraulic conductivity of soil measured by CGA method. Moreover, the correlation of soil water content with unsaturated hydraulic conductivity of soil can be simulated by an exponential function. The saturated hydraulic conductivity of soil decreases exponentially with the increasing soil depth. The time to attain the stable infiltration rate is different among different soil depth, while the deeper the soil depth is, the longer the time needs. The variation in soil texture, soil physical properties and the high infiltration rate of soil there implicated that there are scarce surface runoff, but abundant in subsurface flow, return flow and seepage, which is the result of regulation by dark coniferous forest on hydrological processes.
Soil and Water Conservation Laboratory of National Forestry Bureau, Beijing Forestry University, Beijing 100083, China. Xinxiao@bjfu.edu.cn
Xinxiao
X
Yu
Yutao
Y
Zhao
Zhiqiang
Z
Zhang
Genwei
G
Cheng
D002681:China; D032462:Cycadopsida / Q000254:growth & development* / Q000378:metabolism; D017753:Ecosystem; D005618:Fresh Water; D010316:Particle Size; D012987:Soil / Q000032:analysis*; D014867:Water / Q000032:analysis*
D012987:Soil; D014867:Water