武汉动物园人工湿地土壤氮素时空分布特征

以武汉动物园内人工湿地为例,采样测定了塘-湿地组合系统中土壤氮素的时空分布特征。结果表明:一阶湿地中土壤全氮随剖面层次向下而降低,碱解氮在0~40 cm层次变化不大,40 cm以下迅速降低;二阶湿地中土壤全氮和碱解氮在0~30 cm随剖面向下而下降,30 cm以下变化缓慢。一阶湿地中土壤碱解氮从2005年7月至2006年4月的变化为0~20 cm土层降低,20~40 cm土层呈倒“U”变化,40~60 cm土层变化缓和;二阶湿地中土壤碱解氮2005年7月至2006年4月的变化为0~10 cm土层递减,20~30 cm土层先降低后升高,其他土层先升后降,而2006年1月至4月含量变化不大。湿地土壤的全氮、碱解氮与有机质含量有显著线性相关。该结果可为利用塘-湿地组合系统调控城市水体面源污染提供科学依据。

Temporal and Spatial Distribution of N in Marsh Soils of Artificial Wetland of Wuhan Zoo

An investigation on temporal and spatial distribution of N in marsh soils of pond-wetlands system in the artificial wetland was conducted in a little experimental watershed of Wuhan Zoo,Hubei Prorince.Results showed that the contents of total nitrogen(TN) in marsh soil of the first wetland decreased with increasing depth at profiles.The content of alkaline hydrolysis N(AHN) changed slowly at 0~30 cm,as for the content of the soil below 40 cm changed rapidly.The concentrations of TN and AHN in soil of the second wetland decreased with increasing depth of the soil layers at 0~30 cm,and the content of the soil below 30 cm changed gently.The content of AHN in the surface soil of the first wetland decreased with the temporal variation during the period of investigation within a year.The changing tendency of AHN concentrations in the soil at 20~40 cm showed a shape of inverted "U",whereas the content of AHN at 40~60 cm changed gently.The content of AHN in the top soil of the second wetland decreased with the temporal variation,as for the content of the soil at 20~30 cm decreased at first,then increased with the temporal variation,as for other soil layers,the content of AHN first gradually increased,after decreased with the temporal variation,and changed gently with the temporal variation of January to April 2006.Wetland soil TN,AHN and organic matter content correlated linearly.The results reveal the characteristics of the temporal and spatial distribution of N in marsh soils of the pond-wetlands composite system,thus can serve for controlling the non-point pollution of urban water through pond-wetlands system.