互花米草入侵对闽江口湿地土壤磷形态及释放风险的影响

Influences of Spartina alterniflora Invasion on Phosphorus Forms and Releasing Risk in Min River Estuarine Wetlands

选取闽江河口鳝鱼滩裸滩湿地和互花米草入侵裸滩湿地土壤为研究对象,测定其磷形态以及吸附特性,探讨互花米草入侵下裸滩湿地土壤磷赋存形态、吸附特性及其潜在释放风险的变化。结果表明:无机磷(IP)是2种湿地类型土壤磷的主要形态,分别占裸滩和互花米草湿地土壤总磷(TP)含量的61.40%和61.01%;互花米草入侵裸滩湿地后,土壤中总磷、无机磷、铁铝磷(Fe/A1-P)和钙磷(Ca-P)含量总体上显著增加,其增加比例分别为12.58%,9.49%,11.11%和5.32%,而有机磷(Org P)含量无显著变化;互花米草入侵对土壤无定形态铁(Feox)、铝(Alox)、磷(Pox)、吸附指数(PSI)和吸附饱和度(DPS)影响不一致,其中Feox和DPS总体上变化不明显,Alox有所降低,而Pox和PSI显著增加;裸滩湿地土壤磷潜在释放风险指数(ERI)为12.69,属于中度风险,而互花米草入侵后,土壤ERI降为9.98,表现为较低风险,说明互花米草入侵对土壤磷潜在释放风险具有一定削弱作用。

In order to study the variation of phosphorus forms,sorption capacity and the potential releasing risks,the phosphorus forms and sorption index were analyzed in the barren wetland and Spartina alterniflora invasion wetland of Min River estuary.The results indicated that inorganic phosphorus（IP）was the main form of soil phosphorus,which accounted for 61.40% and 61.01% of total phosphorus（TP）in soils of the barren wetland and Spartina alterniflora invasion wetland,respectively.The concentrations of TP,IP,iron and aluminum-bound phosphorus（Fe/A1-P）and calcium-bound phosphorus（Ca-P）were all significantly higher than those of the barren wetland,and the increase percentage were 12.58%,9.49%,11.11% and5.32%in turn,while the organic phosphorus（Org P）had no significant change.Furthermore,Spartina alterniflorainvasion had different impacts on the amorphous phosphorus（Pox）,iron（Feox）,aluminum（Alox）,the phosphorus adsorption index（PSI）and the degree of phosphorus saturation（DPS）,and the Feox and DPS were not significantly changed.However,the Poxand PSI were increased significantly,while the Alox was significantly decreased.The potential releasing risk（ERI）of the barren wetland was 12.69,which was belonged to middle risk,nevertheless,the ERI of the Spartinaalterniflorainvasion wetland was reduced to 9.98,which was belonged to low risk,indicating that Spartina alterniflorainvasion could lower the releasing risk of soil phosphorus in wetland.