三峡入库河流大宁河回水区消落带土壤氨氮释放动力学研究

在室内模拟条件下,通过消落带土壤氨氮释放动力学实验,研究了三峡入库河流大宁河消落带土壤氨氮释放动力学特征,并分析了样品组成特征对释放动力学的影响,结果表明:一级动力学方程可以很好地拟合大宁河回水区消落带土壤样品氨氮释放动力学特征,前120 m in为快反应,氨氮释放速度较大,随后进入慢反应,逐渐达到最大氨氮释放量;土壤样品释放动力学特征与总氮、总磷呈现较好的相关性,与有机质、样品氧化物组成、颗粒组成理化指标相关性较弱;土壤样品释放动力学特征与可转化态氮呈现极显著正相关关系,与非可转化态氮的相关性较弱,这说明样品中氨氮的释放量主要受其可转化态氮含量控制.研究结果可为三峡库区支流大宁河回水区富营养化治理提供参考和理论依据.

Ammonia-Nitrogen Release Kinetics of Soils at Water-Level-Fluctuating Zone from Input River of Three Gorges Reservoir

Ammonia-nitrogen release kinetics characteristics of the soils at water-level-fluctuating zone from input river of Three Gorges Reservoir were determined in laboratory simulating condition through the release kinetic experiments;and the relationship between the sediment composition and its ammonia-nitrogen release characteristics was also investigated.The results indicate that：（1） The first-order kinetic equation can be used to fit the ammonia-nitrogen release characteristics of the soils at water-level-fluctuating zone;the process of ammonia-nitrogen release from the studied samples mainly occurs within 0-120min;and then the amount of released ammonia-nitrogen attends to a dynamic equilibrium gradually.（2） The parameters of the ammonia-nitrogen release kinetics of the studied samples were related to their composition;there is significant positive correlation with the content of total nitrogen（TN）,total phosphorus（TP）;the relationship with the content of organic matter（OM）,composition of the oxide,sand size fraction is not significant.（3） The parameters of ammonia-nitrogen release kinetics of the soils at water-level-fluctuating zone were related to nitrogen forms;there is significant positive correlation with the content of transformed nitrogen;and the relationship with non-transformed nitrogen is not significant.The results of this investigation can provide the evidences to illuminate the water-level-fluctuating zone of Daning River eutrophic mechanisms systemically.