中文摘要：

研究三峡调蓄对长江河口土壤水盐动态和土壤盐渍化演变的影响情况,进行多年数据监测、土样采集和分析,通过对三峡运行前后河口土壤水盐动态变化的对比分析和对该区不同水文年土壤盐渍化状况和特点的主成分分析和聚类分析,探讨三峡工程对河口土壤水盐平衡影响的权重及规律。结果表明：三峡运行后的河口枯水年份北支江水位月均降幅20cm左右,咸潮入侵加剧,雨季地下水和土壤积盐加剧危及作物生产;三峡运行后的枯水年汛末秋季河口土壤盐渍化加剧,土壤呈Na质盐碱化趋势,土壤剖面盐分以表聚为主,丰水年份土壤盐渍化明显改善,土壤剖面盐分以底聚淋洗主;三峡调蓄后河口不同水文年土壤盐渍化演变的较大差异性表明该区土壤水盐平衡的影响因素中气候因素更显著,三峡1012月蓄水易增加河口枯水年份秋冬季咸潮入侵和土壤盐渍化风险,应采取合理的农耕灌排措施和Na质盐碱土改良措施防控河口枯水年份夏秋季土壤盐渍化风险。

英文摘要：

In order to study the impact on soil water-salt dynamics and soil salinization in Yangtze River estuary by the Three Gorges Project,a site monitoring program was conducted for many years and soil samples were collected and tested.By comparative study on the changes of soil water-salt dynamics in the estuary before and after the Three Gorges Project,and by principal component analysis and cluster analysis on the soil salinization in different hydrological years in the estuary,the weight and rule of the impact from the Three Gorges Project on soil water-salt balance in the estuary was investigated.Results show that in dry years after the Three Gorges Project the river level in the estuary fell 20 centimeters monthly on average,the saline water intrusion intensified,and the soil and groundwater salinization in rainy seasons were aggravated which endangered crop growth.In autumn of the dry year after the project the soil salinization in the estuary was aggravated,the sodium modification of saline soil was severe,and soil salt was accumulated upward in most soil profiles.However,in the autumn of wet years the soil salinization was ameliorated significantly,and soil salt was washed downward in most soil profiles.The great otherness of soil salinization between different hydrological years indicates that the climate factor plays a remarkable role than the factor of the Three Gorges Project on soil water-salt dynamics in the estuary.However,the water storage of the Three Gorges Project from October to December may increase the risk of saline water intrusion and soil salinization in the estuary in dry years.On such a basis,the authors call for rational irrigation,drainage and cultivation measures to leach salt and restrain the soil salinization trend in summer and autumn of dry year and to ameliorate Na＋ type saline soil.