三峡库区消落带下部区域土壤氮磷释放规律模拟实验研究

三峡库区消落带形成后其下部区域（145~155 m）由于长期处于淹没状态，其表层土壤将类似底泥状态，研究选择嘉陵江江底沉积物模拟其在好氧及厌氧淹水条件下N、P向上覆水体的释放规律。结果表明：土壤处于淹水期间，均向上覆水释放N、P，其中好氧状态下上覆水中TN以硝态氮为主，厌氧环境下上覆水中TN以氨氮形式为主；淹水前期，N、P释放速率均较快，随时间增加逐渐减缓，且在厌氧环境下TP释放能力较好氧环境强。好氧淹水中曝气量对上覆水中TN平衡浓度无显著影响，但对氨氮、硝态氮释放过程有影响，从而影响TN浓度变化；底泥状土壤落干过程对N素释放有正影响，对P素释放有负影响；在短暂的落干期间，如果进行农业利用，将增加库区水环境污染和水体富营养化的风险.

RELEASE OF N,P FROM SUBMERGED SOIL IN THE BOTTOM PART OF SHORE-AREA IN THREE GORGES RESERVOIR

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.