向海芦苇沼泽湿地土壤硝态氮含量的季节动态变化

以付老文泡湿地和二百方子湿地为研究对象,对比研究了封闭性湿地和开放性湿地土壤中硝态氮含量的季节动态变化特征,结果表明封闭性湿地除表层土壤硝态氮的季节动态变化呈不规则的倒"V"字型外,其它各层都较平缓;开放性湿地土壤硝态氮含量除在生长初期以前呈显著的下降趋势外,在以后各物候期内变化都较平缓;但两典型区土壤硝态氮含量的季节动态变化也表现出一定的共性特征,各层土壤硝态氮含量的季节动态过程均可采用三次多项式来模拟其动态变化,模拟效果都较理想,基本上反映了向海沼泽湿地硝态氮的季节动态变化规律。与封闭性湿地相比,开放性湿地土壤硝态氮的季节动态变化的规律性更强。图2,表1,参9。

Seasonal dynamic variations in nitrate nitrogen in marsh soils from Phragmites wetlands in Xianghai National Natural Reserve

The typical sites such as Fulaowenpao wetland and Erbaifangzi wetland were chosen to study the characteristics of seasonal dynamics of nitrate nitrogen in soils from"close" wetlands and"open" wetlands.The results showed that except that the changing tendency of nitrate nitrogen concentrations in surface soils appears the shape of anomalous"V"in"close" wetlands,but as for other soil layers,the contents of nitrate nitrogen change gently.The contents of nitrate nitrogen in soils from"open" wetlands significantly decrease from December in last year to May,and change gently from May to October.There is similarity of the characteristics of seasonal dynamic of nitrate nitrogen for the two sites,the changing processes of nitrate nitrogen contents in soils from each soil layer can be fitted by three order polynomial,and these models give a good fit,reflecting the changing laws of seasonal dynamic of the contents of nitrate nitrogen in soils.