Soil Hydrolase And The Interaction With Available Nitrogen And Phosphorus At Quanzhou Bay Wetland

The soil samples collected from 0～10 cm,10～20 cm,20～30 cm,30～40 cm and 40～50 cm layers in spring and autumn were taken to study the activities of soil urease and phosphatase and the content of available nitrogen and phosphorus upon different plots(upstream,midstream and downstream) at Quanzhou Bay estuarine wetland,while the new alluvial soil without plants and Bared land were collected under five mangrove plants(Centenary Aegiceras corniculatum,Aegiceras corniculatum, Kandelia candel,Avicennia marina,Spartina alterniflora)as comparison.The seasonal, regional and vertical distributive properties of soil urease,phosphatase,available nitrogen and phosphorus under five different mangrove plants were studied.By correlation analysis,regression analysis and coefficient of variation analysis to discuss the relationships of soil urease,phosphatase,phosphate,ammonium,nitrate and sub-nitrate.With a view to provide necessary data and theoretical basis of all mangrove plants research on the environmental adaptation at Quanzhou Bay wetland.It had a positive significance for further development of ecological restoration and environmental protection of Quanzhou Bay wetland.The results are as follows:There was significant difference between soil urease and phosphatase in different seasons.Both were higher in spring than autumn,which showed no significant difference upon different plots.Vegetation types and root growth conditions have a significant influence on soil enzyme activities that were all higher under mangrove plants than those in the New alluvial soil without plants and Bared land.Soil urease activity exhibited no significant difference under different mangrove species.The phosphatase activity in the soil of Centenary Aegiceras corniculatum and Spartina alterniflora was the highest,which was the higher in the soil of Kandelia candel and Avicennia marina.The two soil enzyme activities generally decreased with increasing soil depth.There was significant difference upon different plots between available nitrogen and phosphorus,which showed significant difference under different plants.Their contents were all higher under mangrove plants than those in the New alluvial soil without plants and Bared land.Phosphate and ammonium exhibited higher in spring than autumn,but nitrate and sub-nitrite exhibited no significant difference in two seasons.Phosphate and ammonium generally decreased with increasing soil depth,but nitrate and sub-nitrate were not so.By variation analysis,there was significant variability under different plants and in different seasons of soil hydrolase activities,available nitrogen and phosphorus.Among which the urease and phosphatase had a larger coefficient variation in different factors. The soil of Avicennia marina and Spartina alterniflora had a larger coefficient variation under different plants.The soil hydrolase activities and available nitrogen and phosphorus contents changed greater in the rate of different seasons than in different layers.Correlation and regression analysis showed that there was significant positive correlation between the soil urease and phosphatase activities,the correlation coefficient was 0.935(n=195),they exhibited significant positive correlation with phosphate, ammonium,nitrate and sub-nitrate.The urease exhibited greater positive effect with nitrogen and phosphorus.The multiple regression coefficient of urease and phosphatase to available nitrogen and phosphorus were respectively 0.882,0.844(P＜0.005).