氮负荷增强条件下闽江河口芦苇湿地土壤磷赋存形态及其动态变化特征  

Impacts of enhanced nitrogen load on dynamic variations of phosphorus forms in marsh soils of the Minjiang estuary

作　　者：李尔恒 孙志高[1,2,3] 宋振阳 贺攀霏 武慧慧 方冠荣 LI Erheng;SUN Zhigao;SONG Zhenyang;HE Panfei;WU Huihui;FANG Guanrong(Fujian Provincial Key Laboratory for Subtropical Resources and Environment,Fujian Normal University,Fuzhou 350117;Key Laboratory of Humid Subtropical Eco˗geographical Process(Fujian Normal University),Ministry of Education,Fuzhou 350117;Fujian Minjiang Estuary Wetland Ecosystem National Observation and Research Station,National Forestry and Grassland Administration,Fuzhou 350215)

机构地区：[1]福建师范大学福建省亚热带资源与环境重点实验室,福州350117 [2]福建师范大学湿润亚热带生态地理过程教育部重点实验室,福州350117 [3]国家林业和草原局,福建闽江河口湿地生态系统国家定位观测研究站,福州350215

出　　处：《环境科学学报》2025年第3期427-440,共14页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金面上项目(No.42371105);福建省自然科学基金重点项目(No.2023J02012);福建省“闽江学者奖励计划”项目。

摘　　要：选择闽江河口鳝鱼滩的芦苇湿地为研究对象,基于野外氮负荷增强模拟试验(输氮形态为NH_(4)^(+)-N和NO_(3)^(-)-N,NH_(4)^(+)-N∶NO_(3)^(-)-N=1∶3.3),对比研究了输氮6个月(T6)和18个月(T18)后不同氮负荷水平下(对照处理,N0,0 g·m^(-2)·a^(-1);低氮负荷处理,NL,12.5 g·m^(-2)·a^(-1);中氮负荷处理,NM,25.0 g·m^(-2)·a^(-1);高氮负荷处理,NH,75.0 g·m^(-2)·a^(-1))湿地土壤磷赋存形态及其动态变化特征.结果表明,不同时期各氮负荷处理下的土壤TP含量相比N0处理均呈增加趋势,其值在T6时期的NL、NM、NH处理下分别增加了6.96%、1.42%和0.34%,而在T18时期的相应处理下分别增加了12.89%、4.83%和9.07%.尽管氮负荷增强整体提高了土壤TP含量,但其值随氮负荷时间的延长呈降低趋势.相较于T6时期,T18时期的TP含量在NL、NM和NH处理下分别下降了7.98%、9.89%和5.23%.T6和T18时期不同氮负荷处理下的土壤TP组成均以IP为主(54.20%~64.20%),OP占比介于35.80%~45.80%.氮负荷增强整体提高了T6和T18时期不同处理下的Ca-P含量,但相比T6时期,T18时期的Ca-P含量在NL、NM和NH处理下分别降低了10.87%、8.70%和12.39%.与之不同,氮负荷增强提高了T6时期不同处理下的Fe/Al-P含量,但却降低了T18时期相应处理下的Fe/Al-P含量.氮负荷增强条件下湿地土壤IP、Ca-P和Fe/Al-P含量的动态变化主要取决于土壤关键因子(pH和NO_(3)^(-)-N)的明显改变.研究发现,随着氮负荷时间的延长,NL和NM处理下的IP、Ca-P及Fe/Al-P含量均呈降低趋势,说明中低氮负荷水平下的土壤P养分限制程度可能较高.本研究将有助于明晰湿地土壤磷赋存及其主要转化过程对于氮负荷增强的响应,并可为该区湿地生态保育提供重要科学依据.This study investigated typical Phragmites australis marsh in the Minjiang estuary and conducted field nitrogen(N)load experiment(N forms,NH_(4)^(+)-N and NO_(3)^(-)-N;NH_(4)^(+)-N∶NO_(3)^(-)-N=1∶3.3)with four N load levels(no N treatment,N0,0 g N·m^(-2)·a^(-1);low N treatment,NL,12.5 g·m^(-2)·a^(-1);medium N treatment,NM,25 g·m^(-2)·a^(-1);and high N treatment,NH,75 g·m^(-2)·a^(-1)).The dynamic variations of phosphorus(P)forms in marsh soils with different N load levels after 6(T6)and 18 months(T18)of N import were comparatively investigated.Results showed that,compared to the N0 treatment,the total phosphorus(TP)contents in soils of different N load treatments at T6 or T18 showed an increasing trend and the values in the NL,NM and NH treatments increased by 6.96%,1.42%,0.34%(T6)and 12.89%,4.83%,9.07%(T18),respectively.Although enhanced N load generally increased the TP contents in soils of different N load treatments,its values decreased with prolonged N load time.Compared to T6,the TP contents in soils in the NL,NM and NH treatments at T18 period decreased by 7.98%,9.89%and 5.23%,respectively.The TP contents in soils of different N load treatments at T6 and T18 were dominated by inorganic phosphorus(IP)and its proportions varied between 54.20%and 64.20%.in comparison,the proportions of organic phosphorus(OP)ranged from 35.80%to 45.80%.Enhanced N load generally increased the Ca-P contents in soils of different N treatments at T6 or T18.However,compared to T6,the Ca-P contents in the NL,NM and NH treatments at T18 decreased by 10.87%,8.70%and 12.39%,respectively.In contrast,enhanced N load markedly increased the Fe/Al-P contents in soils of different N treatments at T6,but greatly decreased at T18.Under enhanced N load conditions,the dynamic variations of IP,Ca-P and Fe/Al-P contents primarily depended on the alterations of the key variables(e.g.,pH and nitrate nitrogen(NO_(3)^(-)-N))in mash soils.This study found that,with prolonged N load time,the IP,Ca-P and Fe/Al-P contents in the NL and NM treat

关 键 词：磷赋存形态 氮负荷水平 动态变化 芦苇湿地 闽江河口 

分 类 号：X171[环境科学与工程—环境科学]