三峡入库河流大宁河回水区浸没土壤及消落带土壤氮形态及分布特征

利用分级浸取分离法首次对三峡入库河流大宁河回水区表层浸没土壤、消落带土壤不同形态氮含量进行了测定,分析了各形态氮之间以及各形态氮与环境参数之间的相关性.结果表明,①浸没土壤总氮含量在436.0~921.6 mg/kg,消落带土壤总氮含量在1 253.5~2 439.8 mg/kg,与长江中下游浅水湖泊表层浸没土壤总氮含量相比,大宁河回水区表层浸没土壤总氮含量处于偏低水平.②浸没土壤可转化态氮含量在289.7~511.3 mg/kg,消落带土壤可转化态氮含量在271.6~595.1 mg/kg,有机态和硫化物结合态氮是可转化态氮的优势组分,离子交换态氮是可转化态无机氮的优势组分.③浸没土壤与消落带土壤中总氮、可转化态氮含量与有机态和硫化物结合态氮显著相关,表明样品中的可转化态氮含量的增加主要来源于有机态和硫化物结合态氮.

Nitrogen Forms and Its Distribution Character in Immerged and Water-level-fluctuating Zone Soils of the Backwater Reach from Input River of Three Gorges Reservoir

This study measures the contents of different nitrogen forms in the immerged soils and the soils of water-level-fluctuating zone of the backwater area from input river of Three Gorges Reservoir, and analyzes the relationship between nitrogen forms and environmental parameters. The results indicates that:①Content of TN in the surface immerged soils ranged from 436.0 to 921.6 mg/kg, and that in the soils of water-level-fluctuating zone ranged from 1 253.5 to 2 439.8 mg/kg. Compared with the TN content in surface immerged soils from the shallow lakes in the middle and lower reaches of Yangtze River, content of TN in the Surface immerged soils is in the mid-lower level and the TN content in the soils of water-level-fluctuating zone is higher than that in the surface immerged soils.②Content of transferable nitrogen in the surface immerged soils ranged from 289.7 to 511.3 mg/kg, and that in the soils of water-level-fluctuating zone ranged from 271.6 to 595.1 mg/kg·Organic matter-sulfide form nitrogen(OSF-N) is the predominant form of the transferable nitrogen, whereas ion-exchangeable form nitrogen (IEF-N) is predominant in the transferable inorganic nitrogen.③Correlation coefficients between nitrogen forms and environmental parameters show that OSF-N is the main impact factor to increase the concentrations of total nitrogen and transferable nitrogen in the surface immerged soils and the soils of water-level-fluctuating zone. The increasing of the concentration of the transferable nitrogen is mainly from OSF-N.