Spatial Distribution Of Soil Saturated Water Character In Loess Gully Region

Water is one of the limited factors for semi-arid loess gully region. The ability of water transport and storage in soil is pretty crucial for the growth of forests and crops. We selected surface samples and dug soil profiles to explore the horizontal and vertical distribution of saturated water character and its influenced factors in loess gully region. The results showed:(1) on the surface soil, the mean value of saturated hydraulic conductivity (Ks) was 1.063 mm/min and its coefficient of variance (CV) was 36.85%, saturated water content (SWC) was 45.91% and its CV was 20.20%, both of them were moderate variability. At the vertical direction, Ks and SWC decreased with the increase of soil depth. (2) At the surface soil, Ks was significantly influenced by vegetation type, slope position, slope gradient and altitude, slope aspect showed no significant influence on Ks. At the vertical direction, vegetation type, slope position and altitude had a significant influence on Ks at 0-40cm depth, slope gradient significantly influenced on Ks at 0-20cm depth and slope aspect did not significantly influence on Ks at any soil layers. At the surface soil, vegetation type, slope gradient and altitude had significant influence on SWC whereas slope position and slope aspect did not. At the vertical direction, vegetation type significantly influenced SWC at 0-20cm and 40-60cm depths, slope gradient and altitude had significant influence on SWC at 0-20cm depth, slope position and slope aspect had no significant influence on SWC at any layers. (3) Soil property factors influencing saturated water character were distinct in surface soil and subsurface soil. Surface Ks were mainly influenced by soil organic matter, clay content, bulk density and capillary porosity, and the subsequence of direct effects were:clay content> capillary porosity> soil organic matter> bulk density; subsurface Ks were mainly influenced by silt content, clay content, bulk density and capillary porosity, the subsequence was:clay content> silt content> capillary porosity> bulk density; surface SWC were mainly influenced by soil organic matter, clay content and bulk density, the subsequence was:bulk density> soil organic matter> clay content; subsurface SWC were mainly influenced by silt content, clay content and bulk density, the subsequence was:clay content> bulk density> silt content. Exploring the distribution of saturated water character and its influenced factors could provide theoretical basis of vegetation restoration.