Abstract:

By disposing surveying nets of soil watersalt dynamics in Yangtze River Estuary and observing，collecting and statistically analyzing the data of soil watersalt dynamics，the characteristics of soil watersalt changes in different hydrological years and the relationships among dynamic factors of soil watersalt are studied.The results showed that the soil watersalt dynamics in different hydrological years in the eatuary changed seasonally that soil salinization is serious in spring and autumn，but more serious in summer in dry years，and there is good correlation among dynamic factors of soil watersalt.Aiming at the problem that how the impounding of the Three Gorges Reservoir influences upon the regime of river water and soil watersalt dynamics in the estuary，the practical changes of soil watersalt characteristics during the transitionperiod of impounding of the Three Gorges Reservoir after Jun.2003 and the causes were analyzed.The results showed that the influences of the impounding to soil watersalt dynamics in the estuary did not occurr in the three years after impounding of the Three Gorges Reservoir，climate played a leading factor on the soil watersalt dynamics in the estuary.The river level in the estuary fell 20 centimeters in average，the saline water intrusion in the estuary intensified，and the soil and groundwater salinization in rainy seasons in the estuary were serious which endangered the crops growth and production.So some irrigation and cultivation measures are suggested to control the disadvantages at the lowest level.

Key words: Yangtze River Estuary, characteristics of soil watersalt changes, Three Gorges Reservoir, transitionperiod of impounding