关键词: 三峡库区, 消落带下部区域, 受淹土壤, 底泥, 氮磷释放

Abstract:

The sediment of Jialing River was chosen to simulate nitrogen and phosphorus releasing rules of submerged soil in the bottom part (145~155 m) of the shorearea of Three Gorges Reservoir，which will be submerged for a rather long time every year.The results showed that during the submerging period，nitrogen and phosphorus were released to the overlying water from submerged soit.The nitrate nitrogen was dominant in total nitrogen under aerobic conditions while ammonia was the dominant form under the anaerobic conditions.The release ratio of nitrogen and phosphorus was high at beginning time，then went down with time and the release ability of total phosphorus in anaerobic conditions was better than aerobic conditions.The equilibrium concentration of total nitrogen in overlying water was little influenced by the aeration rates under aerobic conditions.However，the concentration of total nitrogen changed because the releasing process of nitrate nitrogen and ammonia was greatly influenced by aeration rate.The drying process of soil affected the release of nitrogen positively but the release of phosphorus negatively.The risks of eutrophication and pollution would increase if the bottom part of the shorearea was agriculturally utilized in short drying period.

Key words: Three Gorges Reservoir, bottom part of shore area, submerged soil, sediment, release of N and P