A modified Hedley phosphorus (P) fractionation was used to study the P distribution seaward in the newly formed wetlands soils of Yellow River Delta. In addition, the adsorption-desorption experiments were performed to evaluate the ability of P retention and release in the sampled soils. The results showed that inorganic P remained the largest portion of total P (TP), accounting for more than 93% of TP. Due to the lower content of organic matter, the organic P was relatively low in these soils. Among the inorganic P, Dilute HCl-P was the dominated form, related with the content of Ca in soils. The content of available P was 18.6~33.4 mg/kg, accounting for only 3.2%~5.9% of TP in soils, which might restrict the growth of plants in the wetland system. Furthermore, it was found that the content of available P in the sampling site covered with plants was higher than that in the beach soils, indicating that the vegetation cover may enhance the accumulation of soil available P. According to the adsorption-desorption experiments, when the concentration of initial P addition was in the range of 0.05~5 mg/L, the P adsorption increased with the increase of initial P concentration. Moreover, the percentage of adsorption was 70%~99%while desorption rate was less than 7%. It could be concluded that in these soils, the capacity of P retention was high and the release potential was relatively low.
; 邵宏波
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