Grazing-induced alterations of soil hydraulic properties and functions in Inner Mongolia, PR China
Grazing-induced alterations of soil hydraulic properties and functions in Inner Mongolia, PR China
复制标题
DOI：
10.1002/jpln.200800218
复制
发表时间：
2009-12-01
影响因子：
2.5
通讯作者：
Horn, Rainer
中科院分区：
文献类型：
--
作者：
Kruemmelbein, Julia;Peth, Stephan;Horn, Rainer
绵羊和山羊放牧强度的增加会导致草地的日益退化。在中国内蒙古，我们调查了4个不同放牧强度的样地（重度放牧、冬季放牧、1999年以来未放牧和1979年以来未放牧），以研究践踏引起的机械应力对土壤水力性质的影响。利用HYDRUS-1D模型模拟了“重度放牧”和“1979年以来未放牧”条件下的土壤水分运移和有效蒸散。使用从实地研究中收集的数据进行模型校准。田间数据表明，放牧降低土壤C含量和疏水性。孔隙体积减小，保水特性改变，饱和导水率降低，其各向异性（垂直与水平导水率）受到影响。模拟结果显示，未放牧地的蒸散量较高（自1979年以来未放牧）与放牧地相比（严重放牧）由于土壤条件更潮湿，植被更密集，凋落物覆盖，径流和排水减少，放牧分别改变了蒸散分配，放牧地的蒸散量较低，蒸发量较高，这是由于蒸发量减少导致根系吸水量减少，土壤覆盖
Increasing grazing intensities of sheep and goats can lead to an increasing degradation of grasslands. We investigated four plots of different grazing intensities (heavily grazed, winter-grazed, ungrazed since 1999, and ungrazed since 1979) in Inner Mongolia, PR China, in order to study the effects of trampling-induced mechanical stresses on soil hydraulic properties. Soil water transport and effective evapotranspiration under "heavily grazed" and "ungrazed since 1979" were modeled using the HYDRUS-1D model. Model calibration was conducted using data collected from field studies. The field data indicate that grazing decreases soil C content and hydrophobicity. Pore volume is reduced, and water-retention characteristics are modified, the saturated hydraulic conductivity decreases, and its anisotropy (vertical vs. horizontal conductivity) is influenced. Modeling results revealed higher evapotranspiration on the ungrazed site (ungrazed since 1979) compared to the grazed site (heavily grazed) due to wetter soil conditions, more dense vegetation, litter cover, and decreased runoff and drainage, respectively Grazing modified the partitioning of evapotranspiration with lower transpiration and higher evaporation at the grazed site owing to reduced root water uptake due to reduced evaporation and a patchy soil cover.