Characteristics of phosphorus contents in the rhizosphere soil of different shrubs on sandy grassland in Maqu

Three native shrubs inhabiting in Maqu county, including Salix oritrepha, Amorpha fruticosa and Hippophae rhamnoides, were used as materials to investigate the differences of total P content, available P content and P fractions between rhizosphere and nonrhizosphere soils. It was found that there was a higher available P concentration in the rhizosphere soil comparing to that in the nonrhizosphere soils of A.fruticosa and S.oritrepha.The total P content in the rhizosphere soil was higher than that in the nonrhizosphere soil of the three shrubs. The concentrations of total P and H2OP were lower in the nonrhizosphere soil than that in the rhizosphere soil except H.rhamnoides. The contents of NaOHPi and NaOHPo were higher in the rhizosphere soil than that in the nonrhizosphere soil of the three shrubs. The concentration of HHClPi in the rhizosphere soil was lower than that in the nonrhizosphere soil except A.fruticosa. The concentration of HHClPo in the rhizosphere soil was higher than that in nonrhizosphere soil except S.oritrepha. Regression analysis indicated that there was a negative significant relationship between available P concentration and pH in both soils of S.oritrepha and A.fruticosa, but no relationship was found between total P and available P concent in both of the rhizosphere and nonrhizosphere soils.