Abstract: [Objective] Through the analysis of soil chemical properties in hydro-fluctuation belt without flooding and after four times of water level fluctuation in the Three Gorges Reservoir, we hope to provide a scientific basis for revealing the changes in water and soil conditions and for vegetation restoration.[Method] Permanent sample plots were established in typical hydro-fluctuation belt of Three Gorges Reservoir and were monitored in 2008 (without flooding) and 2012 (after four times of water level fluctuation) to study the changing characteristics of soil chemical elements.[Result] The results showed that the pH of different soil layers in 2012 increased significantly as compared to 2008, and tended to be neutral. As compared to 2008, the contents of soil organic matter, total N, total P, total K, available N, available P and available K in different soil layers decreased by 36.9%-53.3%, 12.0%-23.5%, 42.0%-52.3%, 39.7%-43.8%, 12.3%-17.5%, 78.5%-91.4%,and 41.1%-57.9%, respectively. Among them the decrease of N content was relatively smaller and the decrease of P content was the largest. The soil nutrients were in a very poor condition after four times of water level fluctuation, and the change of K content was the most obvious. The soil metal elements were all increased due to the impacts by the water level fluctuation, and in 2012 the largest increases were found in the total Mg and the total Na which were significantly different from those in 2008. The total Ca was somehow increased, but not different significantly from that in 2008.[Conclusion] With the long-time water level fluctuation of the reservoir, the problem of soil depletion and water eutrophication will gradually become more apparent, and a long-time monitoring of the changes of soil chemical properties in this area is needed.

Key words: Three Gorges Reservoir, hydro-fluctuation belt, water level fluctuation, soil pH, soil organic matter, soil total nutrients, soil available nutrients, soil metallic elements