The effects of longterm different fertilization practices(initiated in 1981)and resultant changes in soil properties on phosphorus(P)sorption characteristics were studied using P sorption isotherm experiment.We selected 12 soil samples at depth of 0～15 cm from a longterm field trial with four fertilization practices including no fertilizer(CK),only application of chemical fertilizer,straw retention,and biogas slurry incorporation.The results showed that the amount of sorbed P increased with initial added P concentration increasing.The Langmuir equation was more ideal than Freundlich and Temkin equations in fitting the P sorption isotherm,which had determination coefficients greater than 0.99 for all treatments.Biogas slurry incorporation had the greatest Langmuir P sorption maximum(Xm),which was significantly higher than the other three treatments(P<0.05),followed by straw retention and chemical fertilization treatments,and the lowest in CK.In addition,biogas manure treatment had the highest value of degree of P saturation.However,there were no significant differences in the constant related to the bonding strength and maximum buffer capacity among the four treatments.Oxalateextracted Fe,Al,and P(Feox,Alox,and Pox,respectively),and Mehlich 3extracted Ca and Mg(CaM3 and MgM3)were positively correlated with Xm,especially for Pox and Feox,for which the correlation coefficient was 0.95(P<0.01)and 0.64(P<0.05),respectively.Principal component analysis showed that Feox,Alox,CaM3 and MgM3 contributed mostly to the variation of P sorption characteristics among the four fertilization regimes.Compared with CK and chemical fertilizer application treatments,longterm incorporation of biogas manure increased the contents of amorphous Fe and Al minerals in paddy soil,and thus enhanced soil P sorption capacity.