闽江河口淡水、半咸水沼泽土壤碳氮磷分布及计量学特征

以闽江河口区淡水、半咸水短叶茳芏沼泽湿地为研究对象,于2013年11月~2014年8月分季节采集表层土壤样品,研究土壤有机碳(SOC)、总氮(TN)、总磷(TP)含量时空变异格局及其计量学特征,并同步观测相关环境因子.结果表明,淡水、半咸水沼泽土壤SOC、TN、TP含量范围分别为(18.24~28.36,1.44~2.24,0.45~1.01)(14.96~26.19,1.55~2.45,0.67~1.18)g/kg.淡水沼泽土壤各元素含量均具有明显的垂直变化规律;而半咸水沼泽除TN含量垂直变异明显外,其他各指标则表现为波动变化的特征.淡水、半咸水沼泽土壤C/N、C/P、N/P均值分别为12.41±1.22,29.77±6.76,2.40±0.47以及10.89±1.09,24.92±3.80,2.29±0.25.方差分析显示,各指标含量在两个沼泽均存在显著空间差异.两个沼泽土壤SOC、TP、C/N、C/P均与土壤pH和EC呈显著相关关系,而与含水率和容重相关性不显著;土壤C/N均与粉砂粒和砂粒呈极显著相关关系;土壤SOC、TN、TP含量对C/N、C/P、N/P影响显著.淡水、半咸水沼泽土壤营养元素含量分布特征是水动力学作用、外源物质输入、植物生产力和人类活动等多因子综合作用的结果.

Spatiotemporal distribution and stoichiometry characteristics of carbon,nitrogen and phosphorus in surface soilsof freshwater and brackish marshes in the Min River estuary

During October 2013 to August 2014, the spatiotemporal distribution and stoichiometry characteristics of carbon, nitrogen and phosphorus in surface soils from the freshwater and brackish Cyperus malaccensis marshes were measured in different seasons, and examined the key environmental factors controlling the variation of nutrient elements simultaneously in Min River estuary. The contents of soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) in the freshwater and brackish marshes were greater variability, the ranges were (18.24~28.36, 1.44~2.24, 0.45~1.01)(14.96~26.19, 1.55~2.45, 0.67~1.18)g/kg, respectively. Overall, contents of SOC and TN showed increasing trends with depth in soil profiles, while TP exhibited decreasing gradually with depth in freshwater marsh. The nutrient element contents no significant vertical variation in the brackish marsh except TN. The average values of C/N、C/P and N/P in the freshwater and brackish marshes soils were 12.41±1.22,29.77±6.76,2.40±0.47 and 10.89±1.09,24.92±3.80,2.29±0.25, respectively. The ANOVA revealed that most element contents were significant spatial differences in two marshes. The values of SOC, TP, C/N and C/P in both freshwater and brackish marshes had a significant correlation with soil pH and conductivity, while there were not significant correlations with soil moisture and bulk density. The soil C/N was significantly correlated with silt and sand content. The soil C/N, C/P and N/P values were affected significantly by soil SOC, TN and TP. Spatiotemporal distributions of nutrient elements in two marshes were the result of the combined effects of multiple factors, such as hydrodynamics, exogenous input, vegetation production and human activity.