中文摘要：

模拟三峡库区消落带土壤淹水变化特征设置了常规生长水分条件（CK组）、轻度干旱水分胁迫（T1组）、土壤水饱和（1、2组）以及水淹（T3组）4个不同处理组，研究池杉幼苗实生土壤营养元素含量变化机制。研究结果表明，不同水分处理对池杉幼苗土壤营养元素含量影响程度有所差异。在整个试验期间，T3组土壤有机质含量平均值极显著地分别高于CK、T1、T2组9．2％、5．6％和6．4％，而T1、T2以及CK组土壤有机质含量平均值之间却无显著差异。T2、T3组土壤在整个试验期间的pH值分别显著高出CK组3．0％-10．8％与4．1％-7．5％，而T2、T3组土壤pH平均值相互之间并无显著差异。T3组土壤全N含量整体平均值极显著高于CK、T1、T2组8．9％、5．8％和9．0％；而T1、T2、CK组土壤全N含量平均值相互之间则无显著差异存在。各处理组土壤全P含量平均值之间、全K含量平均值之间均无显著差异存在。T3组水解N含量分别显著高于CK、T1、T2组13．5％、7．1％和6．7％；然而，T1、T2组的水解N含量平均值相互之间却并无显著差异性，但二者均显著高于CK组平均值。土壤速效P含量整体平均值T2与T3组均分别显著低于T1与CK组；与此不同的是，土壤速效K含量平均值T1与T2组均分别显著高于T3与CK组。相关性分析发现，土壤有机质含量与全N、全P以及水解N成极显著正相关，而与速效P含量成极显著负相关。本试验中，池杉幼苗实生土壤在不同水分条件下的营养元素含量变化规律，显示出将池杉选择为三峡库区消落带防护林体系建设的造林树种是可行的。

英文摘要：

Through simulating soil dynamic submergence in the hydro-fluctuation belt of the Three Gorges Reservoir Region,four different kinds of water treatments were applied to examine the mechanism of the nutrient change in soils of Taxodium ascendens seedlings. The water treatments were normal growth water treatment （CK）, light drought water stress （T1）, soil water saturation treatment （T2） and soil submersion treatment （33）. Different water treatments had different effects on nutrient contents in soils of T. ascendens seedlings. During the entire experimental period, the mean content of organic matter in 33 was 9.2 %, 5.6 % and 6.4 %, which was significantly higher than that in CK, T1 and T2, respectively, while no significant differences were found among T1, T2 and CK. Mean pH value in T2 and 33 was significantly higher than that in CK with 3.0%-10.8 % and 4.1%-7.5 % respectively, however,T2 did not differ from 33 in mean pH value. Mean content of total nitrogen in 33 over the study period was significantly increased by 8.9% ,5.8% and 9.0% compared with that in CK, T1 and T2, respectively,in wich the latter three groups did not exhibit significant difference between each other. There was no significant difference found among the four groups either in mean content of total phosphorus or mean content of total potassium. Likewise, mean content of alkali hydrolysable nitrogen in 33 exceeded by 13.5% ,7.1% and 6.7% over that in CK,T1 and T2.T1 did not demonstrate a significant difference with T2, but both T1 and T2 showed a significantly higher content compared to CK, in mean content of alkali hydrolysable nitrogen. T2 and 33 showed significantly lower value than T1 and CK in mean content of available phosphorus, in contrast, TI and T2 were significantly higher than 33 and CK in mean content of available potassium. Content of soil organic matter showed a highly positive relationship with the content of total nitrogen, content of total phosphorus and content of alkali hydrolysable nitrogen,in contrast to its