Abstract:

In the process of shifting dune to fixed dune by constructing sand-fixing vegetation， vegetation changed the water redistribution process of dune， affected the hydrological regulation function of dune， and may even cause the imbalance of water resources in dune ecosystem. In order to explore the influence of vegetation on the hydrological mediation function of dunes， this experiment took dunes with different vegetation coverage and dune interdune water bodies in Horqin Sandy Land as the research objects. In the growing season of 2021， dynamic observations of dune vegetation coverage， characteristics of interdune lowland water and meteorological factors were carried out to clarify the impact of dune vegetation on the interdune lowland water. The results showed that： （1） Dune vegetation coverage affected the external water recharge capacity of dunes. With the increased of sand vegetation coverage， the external water recharge capacity of dunes per unit area decreased， in the order of mobile dune （58.25 mm） > semi-fixed dune （24.75 mm） > fixed dune （14.87 mm）， and the proportions of precipitation in the same period were 21.39%， 9.09% and 5.46%， respectively. （2） In the growing season， precipitation recharge， vegetation coverage and air temperature significantly affected the water replenishment amount of dune to the interdune lowland water body， which was significantly positively correlated with precipitation recharge， and significantly negatively correlated with dune coverage and air temperature. （3） Based on the principle of water balance， the relationship model between external water replenishment amount of dune and influencing factors is deduced， and the expression is as follows： Y=1052.737+0.1X₁-11.459X₂-37.585X₃， R²=0.641， where Y is the external water replenishment amount of dune， X₁ is the precipitation replenishment amount of the catchment， X₂ is vegetation coverage， X₃ is the average temperature. The model can be used to predict the external water supply of dune， which can provide a basis for the choice of mode for control mobile dune.

Key words: sandy land, water transport, vegetation coverage, precipitation recharge, water balance