天津滨海湿地土壤盐分空间演变规律研究

天津滨海的天然湿地主要起源于全新世中、晚期以来的海陆变迁,后来的海陆交互作用以及人类活动使其产生了不同程度的盐渍化.为研究湿地土壤盐分自潮间带向内陆演进的演变规律,依据距海距离,选取潮间带(0 km)、北大港(24 km)、七里海(38 km)和大黄堡(70 km)4个典型滨海湿地,对其土壤盐分的演变规律进行分析.结果显示:(1)土壤含盐量和电导率自潮间带向内陆呈显著指数递减趋势,并表现出表层(0~5 cm)聚集特征.(2)除(HCO3-+CO32-)外,离子含量与距海距离之间呈极显著指数负相关关系.潮间带、七里海和大黄堡湿地的土壤阳离子均以Na+为主,而北大港湿地以Na+和Ca2+组成占绝对优势.从潮间带到内陆湿地,土壤中阴离子从以Cl-为主过渡到以Cl-、SO42-和HCO3-+CO32-为主.(3)除大黄堡湿地,各湿地含盐量均与Cl-呈极显著正相关,与SO42-从潮间带湿地到内陆湿地由不相关过渡到极显著正相关,HCO3-+CO32-与含盐量仅在北大港湿地呈极显著正相关.(4)潮间带湿地土壤表层(0~5 cm)和中间层(20~50 cm)为弱碱化土,次表层(5~20 cm)和深层(50~100 cm)为中度碱化;北大港和大黄堡湿地整个1 m土层均为弱碱化;七里海湿地为中度碱化.

Research on the spatial evolvement regulations of soil salt of the coastal natural wetlands in Tianjin

The coastal natural wetlands in Tianjin were mainly formed from the sea-land changes since the middle-late Holocene, the different degrees of salinity of coastal wetlands were generated by the later land-sea interaction and human ac-tivities. In order to research the evolvement of salt characteristics of coastal wetland soils from intertidal zone to inland, the evolvement of the soil salinity of the coastal natural wetlands were analyzed by choosing four typical coastal natural wetlands which were intertidal wetland （0 km）, Beidagang wetland （24 km）, Qilihai wetland （38 km） and Dahuangpu wetland （70 km ） according to the distance from the seashore. The results show that ： （ 1 ） the soil salt content and electric conductivity （EC） exponentially decreased from intertidal zone to inland, and the profile distribution of soil salinity and EC are obviously accu- mulated at surface soil layer （0-5 cm）. （2） There are negative correlations between the ions content and the distance except HCO3^＋CO3^2-. Na^＋ is the predominant cation in the intertidal, Qilihai and Dahuangpu wetland, and Na^＋ and Ca^2＋ are the pre dominant cations in the Beidagang wetland. The predominant anion in soil transferred from Cl^- in the intertidal wetland to Cl^-, SO4^2- and HCO^3-＋CO3^2- in the inland wetlands. （3） Salt content is significantly positive correlation with the content of Cl^- in the wetlands except Dahuangpu wetland, SO42- shows no correlation with salt content in the intertidal wetland but signifi-cantly positive correlation in the inland wetlands. HCO^3-＋CO3^2- significantly relates with salt content in the Qilihai wetland. （4） The soil of the intertidal wetland is weak alkalization in the 0-5 cm and 20-50 cm layers, and mild alkalization in the 5-20 cm and 50-100 cm layers. The 1 m soil layer of Beidagang and Dahuangpu wetland are weak alkalization. The 1 m soil layer of Qilihai wetland is mild alkalization.