[Desorption characteristics of phosphorus in tea tree rhizosphere soil]

In order to explore the phosphorus (P) release process and its supply mechanism in tea tree rhizosphere soil, an exogenous P adsorption and culture experiment was conducted to study the P desorption process and characters in the tea tree rhizosphere soils having been cultivated for different years and derived from different parent materials. The least squares method was used to fit the isotherms of P desorption kinetics. There was an obvious difference in the P desorption process between the rhizosphere soils and non-rhizosphere soils. The P desorption ability of the rhizosphere soils was significantly higher than that of the non-rhizosphere soils. As compared with non-rhizosphere soils, rhizosphere soils had higher available P content, P desorption rate, and beta value (desorbed P of per unit adsorbed P), with the average increment being 5.49 mg x kg(-1), 1.7%, and 24.4%, respectively. The P desorption ability of the rhizosphere soils derived from different parent materials was in the order of granite > quaternary red clay > slate. The average available P content and P desorption ability of the rhizosphere soils increased with increasing cultivation years.