闽江福州下游段水体N含量季节变化及对湿地土壤N含量的影响

选取闽江福州下游段水体及河口短叶茳芏湿地土壤水作为研究对象,采用SAN++连续流动分析仪测试样品中NO-3—N,NO-2—N和NH+4—N含量,以揭示河流水体N含量的季节差异和对土壤水N含量的影响。研究结果表明:(1)闽江福州下游段秋季河流水NH+4—N和NO-3—N含量高于春季,NO-2—N含量低于春季;秋季短叶茳芏湿地土壤水NH+4—N和NO-2—N含量也明显高于春季,土壤水NO-3—N含量低于春季;春、秋季土壤水NH+4—N含量皆高于河流水,而NO-3—N和NO-2—N含量皆明显低于河流水。(2)河流水的浸淹对土壤N含量影响较大,说明河流水是湿地土壤的主要N源。(3)闽江福州下游段河流水3种形态的N含量表现为秋季大于春季,存在较明显的季节差异。(4)与2007—2008年的观测值相比较,闽江河口河流水体N含量呈大幅上升趋势,水体富营养化加剧。

Seasonal Variations of N Content in Fuzhou Downstream Section of Minjiang River and Its Influence on N Content in Wetland Soil

Water-body in Fuzhou downstream section of Minjiang River and soil water of wetland growing Cyperus malaccensis in intertidal region of estuary were selected as object of study. The contents of nitrate nitrogen(NO₃-N), nitrite nitrogen(NO₂-N) and ammonium nitrogen(NH₄⁺-N) in the samples were measured by SAN⁺⁺ Continuous Flow Analytical System for showing the difference of their contents between spring and autumn, and the influence of N contents in river water on the contents of soil water. The result showed that:(1) The contents of NH₄⁺-N and NO₃-N in river water in autumn are higher than in spring, and the content of NO₂-N was opposite; In the soil water, the contents of NH₄⁺-N and NO₂-N in autumn were higher than in spring, and the content of NO₃-N was invers; the content of NH₄⁺-N in soil water was higher than that in river water, on the contrary, the contents of NO₃-N and NO₂-N in soil water were less than that in river water;(2) River water was the main source for N in wetland soil water due to submersion of river water influencing on N content of the soil water significantly;(3) The total contents of NO₃-N, NO₂-N and NH₄⁺-N in river water in autumn were more than in spring, there was a obvious seasonal difference;(4) Compared with the contents in river water from Minjiang River in 2007-2008, the N contents in river water increased sharply in recent years, as a result, the river water eutrophication was aggravated.