鄱阳湖湿地土壤铁沿水位梯度的分布特征  

Distribution characteristics of soil iron along the water level gradient in Poyang Lake Wetland

作　　者：徐晨瀛 邹素珍 任琼[3] 廉欣 叶家飞 简正军 胡启武[1,2] 尧波[1,2] XU Chenying;ZOU Suzhen;REN Qiong;LIAN Xin;YE Jiafei;JIAN Zhengjun;HU Qiwu;YAO Bo(School of Geography and Environment,Jiangxi Normal University,Nanchang 330022;Key Laboratory of Poyang Lake Wetland and Watershed Research Ministry of Education,Jiangxi Normal University,Nanchang 330022;Jiangxi Academy of Forestry,Nanchang 330032)

机构地区：[1]江西师范大学地理与环境学院,南昌330022 [2]江西师范大学鄱阳湖湿地与流域研究教育部重点实验室,南昌330022 [3]江西省林业科学院,南昌330032

出　　处：《环境科学学报》2024年第6期340-349,共10页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金项目(No.32360302,32060275);2022年中央财政湿地保护与恢复补助江西省湖泊湿地固碳增汇关键技术示范项目;鄱阳湖湿地与流域研究教育部重点实验室(江西师范大学)开放基金资助项目(No.PK2021001);江西省研究生创新基金(No.YC2023-S220)。

摘　　要：湿地被认为是快速铁循环的热点区域,但当前对湿地土壤铁分布规律的认知仍不充分且存在分歧.为探明湿地土壤铁沿水位梯度的分布及机制,本研究在鄱阳湖南矶湿地国家级自然保护区设置了湖滨高滩至浅水域的代表性水位梯度观测样带,测定了不同水位梯度下土壤基本理化性状、全铁及组分含量.结果表明:①土壤全铁(FeT)、二价铁(Fe(Ⅱ))和三价铁(Fe(Ⅲ))含量变化范围分别为43.57~66.89 g·kg^(-1)、119.12~692.74 mg·kg^(-1)和213.45~793.52 mg·kg^(-1),不同土层FeT沿水位梯度有不同程度的下降趋势,而Fe(Ⅱ)表现为不同程度的增加,Fe(Ⅲ)除表层0~10 cm显著下降外其他土层则显著增加;②沿水位梯度,土壤游离氧化铁(Fed)、非晶质氧化铁(Feo)和络合态氧化铁(Fep)的变化范围分别为20.48~36.74、4.97~15.75和0.93~7.71 g·kg^(-1),所有土层Fed呈不同程度的下降而Feo呈不同程度的上升,Fep则除0~10 cm土层先增加后减少外,其余土层表现出增加趋势;③土壤铁及组分含量与土壤基本理化性状均显著相关,冗余分析显示土壤水分、pH、有机碳和全氮等是调控鄱阳湖湿地土壤铁沿水位梯度分布的关键因子.综上,不同水位的水文情势通过改变土壤理化性状、土壤氧化还原条件及铁-碳耦合关系等,影响湿地土壤铁及组分的含量与分布,本结果进一步拓展了对亚热带湖泊湿地土壤铁分布特征的现状认知。Wetlands are considered as hotspots for rapid iron cycling,but the current knowledge on soil iron distribution in wetlands is still unavailable.To investigate the distribution and mechanism of wetland soil iron along water level gradient,a representative sampling zone was established from high beach to shallow water at the lakeshore of Nanji Wetland National Nature Reserve of Poyang Lake.Subsequently,soil basic physicochemical properties,total iron(FeT)and its component contents were measured along the water level gradients.The results showed that the FeT,ferrous iron(Fe(Ⅱ))and ferric iron(Fe(Ⅲ))content varied from 43.57 to 66.89 g·kg^(-1),119.12 to 692.74 mg·kg^(-1)and 213.45 to 793.52 mg·kg^(-1),respectively.The iron content in different soil layers decreased with water gradient for FeT,but increased for Fe(Ⅱ).However,Fe(Ⅲ)decreased significantly at 0~10 cm depth,but increased significantly at other soil depths.Along the water level gradient,the free iron(Fed),amorphous iron(Feo)and complexed iron(Fep)content ranged from 20.48 to 36.74 g·kg^(-1),4.97 to 15.75 g·kg^(-1)and 0.93 to 7.71 g·kg^(-1),respectively.The iron content in all soil depths decreased with water gradient for Fed,but increased for Feo.Whereas,Fep increased except the top 0~10 cm soil depth.Soil iron and its components were significantly correlated with soil basic physicochemical properties.Redundancy analysis further identified soil moisture,pH,soil organic carbon and soil total nitrogen as key factors regulating the distribution of soil iron along the water level gradient.In conclusion,changes in hydrological conditions at different water levels alter soil physicochemical properties,resulting in changes in redox conditions and iron-carbon coupling relationships,thereby affecting the content and distribution of soil iron and its components in wetlands.The present results further expand the current knowledge of the distribution characteristics of soil iron in subtropical lake wetlands.

关 键 词：土壤铁 铁形态 剖面分布 水位梯度 湿地 鄱阳湖 

分 类 号：X53[环境科学与工程—环境工程]