三峡调蓄过渡期长江河口地区不同水文年土壤水盐变化特征

通过布置土壤水盐动态监测网开展长江河口地区土壤水盐动态数据监测、采集和统计分析，研究该区不同水文年土壤水盐变化特征及水盐动态因子关系，结果表明该区不同水文年土壤水盐变化都有春秋季土壤积盐的季节性特点，但其枯水年份夏季土壤积盐更剧，土壤水盐动态各因子间存在明显相关性。针对三峡调蓄如何影响河口水情及土壤水盐动态这一问题，分析2003年6月三峡进入调蓄过渡期后河口土壤水盐实际动态情况及其影响因素，结果表明蓄水试运行后的3年，三峡调蓄对河口土壤水盐动态的影响尚不明显，气候因素对河口土壤水盐动态影响占主导地位，河口江水位偏低20 cm左右，河口咸潮入侵势头加强，雨季土壤和地下水积盐严重，影响作物生产，为此需采取各种水利农耕措施将不利影响降至最低。

ON CHARACTERISTICS OF SOIL WATER-SALT CHANGES IN DIFFERENT HYDROLOGICAL YEARS IN YANGTZE RIVER ESTUARY DURING THE TRANSITION-PERIOD OF IMPOUNDING OF THE THREE GORGES RESERVOIR

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 eatu- ary 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 transi- tion-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 oc- curt 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 cul- tivation measures are suggested to control the disadvantages at the lowest level.