Soil Water Dynamics and Its Exchange with Shallow Groundwater in Sodic Soil Region

The soil water dynamics is the precondition to explore the formation and evolution of the sodic soil.Especially,in the shallow groundwater,the exchange of the soil water and groundwater has become one of the main factors to drive surficial eco-environment change.In order to get the dynamics of the soil water in the sodic soil region,the field experiment was conducted in Da'an Sodic Land Experimental Station of China in 2004.The results presented that the ratio of the evaporation to precipitation reached to 2∶1 and soil water content changed with evaporation and infiltration processes.As regulated by the shallow groundwater,the soil water was less changeable in the soil layer below 50 cm than in the upper soil layer.Furthermore,influenced by the strong evaporative demand,the exchange between groundwater and soil water reached 11.7∶1 and the groundwater has become one of the main water sources to influence the soil water dynamics.