[目的]土壤氮素是湿地营养水平的重要指标,研究鄱阳湖双退区受损湿地土壤氮素空间分布特征及其影响因素,为开展鄱阳湖受损湿地植被生态恢复与重建提供科学依据.[方法]在鄱阳湖退田还湖区中的双退区选择位于江西省都昌县多宝乡的马影湖湿地4类受损湿地土壤,分别为沼泽土、草甸土、草甸沼泽土和次生草甸沼泽土,研究0～20 cm(表层土)、20～40 cm(中层土)和40～60 cm(深层土)3个土壤剖面的全氮(TN)、硝态氮(NO3--N)和氨态氮(NH4+-N)的空间分布特征,利用聚类推进树算法量化环境因子对氮素的相对贡献,利用Pearson相关性分析氮素与环境因子的关系、利用结构方程模型分析了环境因子对氮素的影响路径.[结果]除沼泽土NH4+-N以中层土最高及次生草甸沼泽土土壤TN、NO3--N、NH4+-N分别以中层土和深层土最高外,其余土壤类型皆以表层(0～20 cm)土壤氮素含量最高,分别为TN(0.35±0.03)g/kg、NH4+-N(4.02±0.38)mg/kg和NO3--N(4.84±0.53)mg/kg.土层深度、有效磷(AP)对氮素分布和积累具有重要影响,pH通过影响土壤有机碳(SOC)、AP、有效钾(AK)间接影响到氮素,阳离子交换量(CEC)通过影响SOC间接影响到氮素.[结论]与鄱阳湖天然湿地相比,区内4类受损湿地土壤氮素含量均处于极低水平,各氮素最高值多集中在土壤表层,其中TN以草甸土含量最高也最易淋失,其次为草甸沼泽土、次生草甸沼泽土,沼泽土最少且最易被流水冲洗,氮素的积累和分布受土层深度、AP、pH、CEC等影响较大.
[Objective]Soil nitrogen is an important indicator of wetland nutrient levels.Investigation on the spatial distribution characteristics and influencing factors of soil nitrogen in damaged wetlands in the double-returned areas of Poyang Lake could provide scientific basis for ecological restoration and reconstruction of damaged wetland vegetation in Poyang Lake.[Method]In the Maying Lake wetland located in Duobao Town,Duchang County,Jiangxi province,which is considered a typical double-returned area of returning farmland to lake area in Poyang Lake,four types of damaged wetland soils including marsh soil,meadow soil,meadow swamp soil and secondary meadow swamp soil were selected,and the total nitrogen(TN)and nitrate nitrogen(NO3--N)and ammoniacal nitrogen(NH4+-N)were investigated.The clustering tree algorithm were used to quantifying the relative contribution of environmental factors to nitrogen,Pearson correlation was used to analyze the relationship between soil nitrogen and environmental factors in the wetland,and structural equation model was used to analyze the impact of environmental factors on nitrogen.[Result]The highest content of NH4+-N was observed in the middle layer soil for swamp soil,and the highest contents of soil TN,NO3--N,and NH4+-N were observed in the middle layer soil and deep soil for secondary meadow swamp soil,respectively.The highest levels of nitrogen of the other soil types were observed in the surface layer,which were TN(0.35±0.03)g/kg,NH4+-N(4.02±0.38)mg/kg and NO3--N(4.84±0.53)mg/kg,respectively.Soil depth and available phosphorus(AP)had an important impact on nitrogen distribution and accumulation.Soil pH indirectly affected nitrogen by affecting soil organic carbon(SOC),AP,and available potassium(AK).Cation exchange volume(CEC)indirectly affected nitrogen by affecting SOC.[Conclusion]Compared with the natural wetlands of Poyang Lake,the soil nitrogen contents of the four types of damaged wetlands in the research area were at extremely low levels,and the highest level of nitrogen were concentrated in the soil surface.Among them,meadow soil had the highest TN content and it was the most vulnerable to leaching,followed by meadow marsh soil and secondary meadow swamp soil.Swamp soil had the least TN and it was easily washed by running water.The accumulation and distribution of nitrogen were affected by soil depth,AP,pH,CEC,etc.
于婷婷;钱海燕;周杨明;杨梅花
东华理工大学 地球科学学院,江西 南昌 330013江西师范大学 地理与环境学院,江西 南昌,330200豫章师范学院 生态与环境学院,330103
农业科学
湿地土壤氮素;影响因素;结构方程模型;双退区;鄱阳湖退化湿地
wetland soil nitrogen;influencing factors;the structural equation model;the double-returned areas;damaged wetland in Poyang Lake
《江西农业大学学报》 2024 (002)
530-542 / 13
国家自然科学基金项目(41561105)和江西省自然科学基金面上项目(20212BAB203002,20212BAB205022) Project supported by the National Natural Science Foundation of China(41561105)and Jiangxi Provincial Natural Science Foundation General Project(20212BAB203002,20212BAB205022) 东华理工大学博士科研启动基金项目(DHBK201909838)同时对本研究给予了资助,谨致谢意!
10.3724/aauj.2024048
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