双台河口四种类型湿地土壤中的碳、氮含量垂直分布特征

Vertical Distribution Characteristics of Carbon and Nitrogen Contents in Soils of 4 Types of Wetlands in Shuangtai River Estuary

2013年9月11日和12日,在双台河口的天然碱蓬盐沼、退化碱蓬盐沼、光滩和海水养殖塘中,分层采集0~100 cm深度的土壤样品,测定其有机碳含量、可溶解有机碳含量、全氮含量、铵态氮含量、硝态氮含量和碳氮比,并分析这些指标的垂直分布特征。研究结果表明,在天然碱蓬盐沼中,不同深度的土壤有机碳含量都显著高于其它类型湿地土壤(p<0.05);除养殖塘外,其它类型湿地土壤有机碳含量总体上随着土壤深度增加而减小,养殖塘不同深度土壤有机碳含量差异不明显;天然碱蓬盐沼不同深度土壤的全氮含量都显著高于退化碱蓬盐沼和光滩土壤(p<0.05),总体上,随着土壤深度增加,天然碱蓬盐沼和退化碱蓬盐沼土壤的全氮含量减小,养殖塘土壤的全氮含量波动变化。在0~10 cm深度,光滩土壤的碳氮比最高;养殖塘不同深度土壤碳氮比都较低。随着土壤深度增加,天然碱蓬盐沼、光滩和养殖塘土壤中的可溶性有机碳含量波动变化,且无显著差异;退化碱蓬盐沼土壤可溶性有机碳含量波动减小。随着土壤深度增加,退化碱蓬盐沼土壤铵态氮含量减小,养殖塘土壤中的铵态氮含量呈单峰曲线变化,峰值出现在30~50 cm深度土层;光滩土壤铵态氮含量波动减小。在土壤垂直方向上,各类型湿地土壤硝态氮含量都波动变化;与其它湿地类型相比,养殖塘不同深度土壤硝态氮含量都最低。

To analyze the vertical distribution characteristics of carbon and nitrogen in coastal wetland of Shuangtai River estuary, soil samples in 0-100 cm were gathered in the natural Suaeda salsa salt marshes, the degraded Suaeda salsa salt marshes, the mudflat and the aquaculture pond on 11 and 12 September, 2013. We measured the contents of soil organic carbon, dissolved organic carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen and ratios of carbon and nitrogen. The results showed that contents of soil organic carbon in the natural Suaeda salsa salt marshes were higher than other types of wetland soils significantly（p〈0.05）. Contents of soil organic carbon decreased with soil layer deepened in all types of wetlands except aquaculture pond, and there was no significant in soils of different depths in aquaculture pond. Contents of total nitrogen in soils of different depths in the natural Suaeda salsa salt marshes were higher than those in the degraded Suaeda salsa salt marshes and the mudflat（p〈0.05）. Contents of total nitrogen in soils of the natural Suaeda salsa salt marshes and the degraded Suaeda salsa salt marshes with soil layer deepened, which were fluctuate changed in the aquaculture pond. Ratios of carbon and nitrogen in soils of mudflat were highest in 0-10 cm,and they were lower in soils of different depths in the aquaculture pond. Contents of dissolved organic carbon in soils of the natural Suaeda salsa salt marshes, mudflat and the aquaculture pond were fluctuate changed with soil layer deepened, and there was no significant. Contents of dissolved organic carbon in soils of the degraded Suaeda salsa salt marshes were decreased with soil layer deepened. With soil layer deepened, contents of ammonium nitrogen decreased in soils of the degraded Suaeda salsa salt marshes. Contents of ammonium nitrogen fluctuate changed in soils of the natural Suaeda salsa salt marshes and the mudflat. In vertical direction, contents of nitrate nitrogen in soils of 4 types of wetlands fluctuate changed, and contents of nitrate nitrogen in soils of different depths of aquaculture pond were lowest.