黄土高原水蚀风蚀交错带沟岸灌木林地土壤水分变化

选择黄土高原水蚀风蚀交错带典型切沟，采用人工取样和中子仪测定研究了柠条坡地不同坡位土壤水分变化，明确了切沟对沟岸柠条林地土壤水分的影响范围，建立了土壤储水量与距沟沿不同距离之间的关系。结果表明：在黄土高原雨季(7～10月)，天然降水对柠条坡地下位的补给深度达到了220 cm，对坡地上位和中位的补给深度分别为180 cm和160 cm。在土壤剖面200 cm深度范围内，坡下位土壤水分含量始终高于坡上位和坡中位，200 cm深度以下，坡地上、中、下位土壤水分趋于一致。切沟对柠条林地土壤水分影响水平宽度达到3～4 m，垂直深度达到6 m以下。沟岸柠条坡地距沟沿不同距离土壤剖面储水量与沟沿距离间的关系可以用线性函数来表达。研究沟岸地距沟沿不同距离的土壤水分变化规律对沟岸地植被的恢复具有重要的科学意义。

Soil water distribution of the shrub land at the gully bank in the wind-water erosion crisscross region of Loess Plateau in China

In the wind-water erosion crisscross region, a typical gully was selected and the distribution and change of soil water content of the slope land with the bank distance and the depth of the soil profile were studied by the methods of soil sampling and neutron probe. Meanwhile, the influencing extent of gully on the soil moisture in the shrub land at the gully bank was discussed and the relationship between soil water storage and the distance to the gully border was established. The results showed that the recovered depth reached 220 cm in the soil profile of the bottom of the slope bank land, 180 cm, and 160 cm at the top and middle part of the land, respectively. Within the profile depth of 200 cm, the soil moisture content of the bottom of the land was greater than that of the top and middle part of the land in the observation period. The change trend of the soil moisture content with depth of more than 200 cm in the profiles was almost the same for the three parts of the land. The soil moisture of the land was affected by the gully bank in 3~4 m in the horizontal direction and in excess of 6 m in the vertical direction. The relationship between soil water storage and the distance to the gully border can be fitted by a linear expression and the regression function was y=ax+b. It is of great significance to study the change in soil moisture of the land at the gully bank for the vegetation restoration in the Loess Plateau.