Distribution characteristics and driving factors of phosphorus in the water-level-fluctuating wetland soil of the Poyang Lake
The water-level-fluctuating area is an active area of material and energy transport and transformation between aquatic and terrestrial ecosystems.In this paper,different landscape belts(mudflat belt,Carex cinerascens belt and Triarrhena lutarioriparia belt)were selected in the wetland of the Poyang Lake to evaluate the relationship between soil phosphorus forms and soil physicochemical properties.The results showed that the content of phosphorus forms in different wetland soils was followed as C.HCl-Pi>NaOH-Pi>NaOH-Po>D.HCl-Pi>NaHCO3-Pi>NaHCO3-Po>C.HCl-Po>Residual-P>H2O-Pi.The content of organic phosphorus(Po)was significantly lower in the mudflat belt than it was in the vegetation belt,while inorganic phosphorus(Pi)showed the opposite result,which possibly drived the uptake of inorganic phosphorus by vegetation growth and the accumulation of organic phosphorus due to the input of litter.Except C.HCl-Pi,there was no significant difference in content of soil phosphorus forms between the Carex cinerascens and Triarrhena lutarioriparia belt.The results of RDA showed that content of soil phosphorus forms was mainly affected by soil pH;total nitrogen,organic matter and pH showed the significant negative correlation with NaHCO3-Po and NaOH-Po.Soil phosphorus forms in the mudflat belt was mainly affected by the soil total nitrogen level,and the total nitrogen and organic matter positively correlated with NaHCO3-Pi and D.HCl-Pi.The correlation analysis indicated that the content of Fe and Mn positively correlated with NaOH-Pi content.The variation of phosphorus forms in wetland soil was regulated by landscape difference,metal content and soil physicochemical properties.In addition,compared with mudflat belt,vegetation belt increased the level of medium active phosphorus in wetland soil and decreased the stable phosphorus level,indicating that vegetation promoted the circulation of phosphorus in wetland soil.The results are helpful to clarify the soil phosphorus conversion process in freshwater wetland under the alternation of wetting and drying,and provide the scientific basis for freshwater wetland protection and water environment management.
the Poyang Lakewater-level-fluctuating areaphosphorus formsdistributiondriving factor
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