鄱阳湖湿地剖面土壤铁结合态有机碳沿高程的分布特征  

Distribution characteristics of soil iron-bound organic carbon in profiles along the elevation in Poyang Lake wetland

作　　者：徐晨瀛 胡启武[1,2] 张桂华 梁金凤 薛文婧 叶雨欣 陈珂 吴菡 尧波[1,2] XU Chenying;HU Qiwu;ZHANG Guihua;LIANG Jinfeng;XUE Wenjing;YE Yuxin;CHEN Ke;WU Han;YAO Bo(School of Geography and Environment,Jiangxi Normal University,Nanchang 330022,China;Ministry of Education Key Laboratory of Poyang Lake Wetland and Watershed Research,Jiangxi Normal University,Nanchang 330022,China;Zhejiang Forestry Academy,Hangzhou 310023,China)

机构地区：[1]江西师范大学地理与环境学院,南昌330022 [2]鄱阳湖湿地与流域研究教育部重点实验室,南昌330022 [3]浙江省林业科学研究院,杭州310023

出　　处：《应用生态学报》2024年第12期3488-3496,共9页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(32360302,32060275);江西省自然科学基金重点项目(20212ACB203006)资助。

摘　　要：铁氧化物的矿物保护被认为是土壤有机碳长期稳定的关键机制之一。为探明湿地剖面尺度土壤铁结合态有机碳(Fe-OC)的分布规律及其调控机制,本研究选择在鄱阳湖南矶湿地国家级自然保护区,沿高程设置高滩、中滩、低滩和泥滩采集土壤样品,测定了不同高程0~100cm剖面土壤基础理化性质、不同土壤铁组分及Fe-OC含量。结果表明:不同高程0~100cm剖面土壤Fe-OC平均含量为(0.9±0.1)g·kg^(-1),其对土壤有机碳的贡献率(f_(Fe-OC))为11.6%±1.4%。沿高程降低,0~10和50~100cm深度的Fe-OC及0~100cm深度的f_(Fe-OC)均呈先增加后下降的趋势,而10~50cm深度的Fe-OC在不同高程间无显著差异。不同高程0~100cm剖面土壤碳铁摩尔比(OC/Fe)平均为0.1±0.0,所有土层的OC/Fe均<1,土壤铁-碳耦合关系以吸附方式为主。土壤Fe-OC分别与土壤亚铁、非晶质氧化铁、络合态铁、土壤有机碳、全氮、全磷、土壤水分、铵态氮、硝态氮、有效磷呈显著正相关,而与容重和pH呈显著负相关。结构方程模型表明,高程通过改变土壤水分、pH和土壤有机碳驱动土壤氧化还原状态的转变和不同类型铁氧化物之间的转化,从而调控土壤Fe-OC。The mineral protection of iron oxides is considered as one of the key mechanisms for the long-term stability of soil organic carbon.To investigate the distribution patterns and regulatory mechanisms of soil iron-bound organic carbon(Fe-OC)at the soil profile scale,we collected soil samples of high beach,middle beach,low beach and mud flat along the elevation gradient in Nanji Wetland National Nature Reserve of Poyang Lake,and measured soil basic physicochemical properties,the different soil iron fractions,and the Fe-OC content in the 0-100 cm profiles.The resuls showed hat the average contents of Fe-OC at diferent clevalions was(O.9+0.1)g·kg^(-1).accounting for 11.6%±1.4%of total soil organic carbon(f_(Fe-OC)).Along the elevation gradient,both Fe-OC at depths of 0-10 cm and 50-00 cm,as well as f_(FE-OC)across the entire 0-100 cm depth,showed a trend of first increase and then decline.However,there was no significant difference in Fe-OC content at depths of 10-50 cm across different elevations.The average soil carbon-iron molar ratio(OC/Fe)in the O-100 cm profiles at different elevations was 0.1±0.0,and the OC/Fe in all soil layers was less than 1,indicating that adsorption was the primary mode of iron-carbon coupling.Fe-OC was significantly positively correlated with ferrous iron,amorphous iron oxide,complexed iron,soil organic carbon,total nitrogen,total phosphorus,soil moisture,ammonium nitrogen,nitrate nitrogen,and available phosphorus,but negatively correlated with soil bulk density and soil pH.The structural equation modelling showed that elevation regulates Fe-OC by driving the transformation between soil redox state and iron oxides morphology via changing soil moisture,pH,and soil organic carbon.

关 键 词：铁结合态有机碳 剖面分布 高程 湿地 鄱阳湖 

分 类 号：X144[环境科学与工程—环境科学] S153.6[农业科学—土壤学]