闽江口潮汐盐沼湿地土壤碳氮磷的空间变化

以闽江口区最大的鳝鱼滩潮汐盐沼湿地为研究对象,选择远、近潮沟区2个不同潮水水淹地段设置样线,采集3种优势植物芦苇(Phragmites australis)、咸草(Cyperus malac-censisvar.bervifolius)和藨草(Scirpus triqueter)下18个土壤剖面分层样品,分析土壤中DOC、TN和TP等含量和储量的空间分布规律及土壤物理特征对其的影响。结果表明:远、近潮沟区3种植物下土壤表层(0~10 cm)TN浓度范围为0.24~1.91g kg-1,TP为0.21~1.34 g kg-1,DOC为13.68~93.73 mg kg-1,无论是近潮沟区还是远潮沟区,芦苇和咸草下土壤DOC、TN和TP含量十分接近,且均大于藨草下土壤DOC、TN含量,藨草下土壤TN和TP含量和储量在近潮沟区均明显大于远潮沟区,而芦苇和咸草下土壤TN和TP含量在远、近潮沟区差距不大;土壤DOC、TN和TP含量与土壤粒径、容重和含水量呈显著相关,盐度对土壤中NH4+-N和NO3--N含量影响显著,与NH4+-N为正相关关系,与NO3--N为负相关关系。

Spatial variations of carbon, nitrogen and phosphorous in tidal salt marsh soils of the Minjiang River estuary

The Minjiang River estuary is a typical tidal estuary in the southeast of China, and the Shanyutan wetland (between 119°34'12″-119°40'40″E and 26°00'36″-26°03'42″N) is the largest estuarine wetland in the Minjiang River estuary area. The climate is relatively warm and wet, with a mean annual temperature of 19.6 ℃ and a mean annual precipitation of 1350 mm. The samples were collected in 18 soil profiles with a depth of 60 cm under three dominated macrophytes (Phragmites australis, Cyperus malacceusis var.bervifolius and Scirpus triqueter) in two different inundated districts far from and near a tide ditch in the middle of the Shanyutan wetland. These soil samples were divided into layers of 0-10, 10-20, 20-30, 30-40, 40-50 and 50-60 cm in depth. The soil properties and DOC, TN, TP, NH⁺₄-N and NO^-₃-N contents and storages were measured. The concentrations of DOC in a depth of 0-10 cm ranged from 13.68 to 93.73 mg kg^-1, TN from 0.24 to 1.91 g kg^-1, and TP, 0.21-1.34 g kg^-1. The DOC, TN and TP concentrations of the soils under P. australis and C. malacceusis were similar, which was higher than DOC and TN concentration under Scirpus triqueter in the area far from and near the tide ditch. The TN and TP contents and storages near the tide ditch were significantly higher than that far from the tide ditch for S.triqueter wetland, however, for the P. australis and C. malacceusis wetlands, the TN and TP contents in the area far from and near the tide ditch were similar. Besides, the DOC, TN and TP contents in soils were significantly correlated with the soil grain size, bulk density and moisture. The soil salinity values had a positive correlation with NH⁺₄-N content, and a negative correlation with NO⁺₃-N. The DOC, TN and TP contents in the Shanyutan tidal wetland were much similar with those in the Yangtze River and Pearl River estuaries, and some coastal regions across the world.