Effects of Near Soil Surface Characteristics on Velocity of Overland Flow in a Natural Succession Grassland
The implement of the“grain for green project”may cause great changes in near soil surface characteris-tics,which are represented by increasing in vegetation stem and litter cover,developing in biological soil crusts, and forming in plant root system. Overland flow is the driving force for soil detachment and sediment transport and its velocity is probably affected by the changes in near soil surface characteristics greatly. However,the quantitative impacts of the near soil surface characteristics of natural restorated grassland on velocity of overland flow are still unclear. This study was performed to investigate the effects of the near soil surface characteristics( stem-litter,bio-logical soil crust,plant roots)on overland flow velocity in a natural succession grassland under different slope gra-dients(12°~14°)and flow discharges(0. 002 ~0. 006 m2/s). The results indicated that the near soil surface characteristics influenced overland flow velocity significantly. As the near soil surface factors( stem-litter,biologi-cal soil crust,plant roots)overlapped successively,the flow velocity decreased correspondingly. Compared to ve-locity of Loess soil,the mean flow velocity of stem-litter,biological soil curst,and plant roots reduced by 68. 78%, 41. 53%,12. 76%,respectively. The velocity of overland flow decreased as a power function with litter dry weight and root mass density. The results of this study have vital significance to understand the variation and mechanism of erosion dynamics in the natural succession grassland.
The Loess Plateauoverland flow velocitystem-litterbiological soil crustsplant roots
NETL
NSTL
万方数据
维普
