Distribution of inorganic phosphorus and its response to the physicochemical characteristics of soil in Yeyahu Wetland, China

This research investigated spatial and vertical distribution of total phosphorus (TP), inorganic phosphorus (IP) and IP fractions as well as its responses to corresponding physicochemical properties in Yeyahu Wetland. The results shown that TP concentration varied from 335.37 to 683.32 mg kg−1, it was irregularly distributed in horizontal direction but decreased with the soil depth in vertical direction. The IP concentration varied from 249.43 to 387.49 mg kg−1, accounting for 60%–85% of TP. The order of contents were as follows: Ca-P > Fe-P > Ex-P > Al-P > Oc-P. In vertical direction, the Ca-P distributed roughly with IP because Ca-P was found to be the major species (up to 370 mg kg−1). Other forms were found to decrease with soil depth. According to redundancy analysis (RDA), Ex-P was positively correlated to organic matter content (r=0.637, P < 0.001), indicating that organic matter might be of the importance in maintaining P availability in soils. Anew, the TP correlated with the content of soil fine particles (2–20 μm) (r=0.629, P < 0.01), which suggested that fine particles were suitable for P adsorption in soils from Yeyahu Wetland. This study provided data support for sustainable development of wetland ecosystem.