Abstract:Taking peach orchard as the research object, the effect of green manure on soil phosphorus fractions and phosphorus turnover characteristics were investigated by Tiessen’s phosphorus fractionation method. There were three treatments, including green manure utilization as surface cover (SC), buried underground (BU) and clean tillage control (CT). Soil samples from 0—20 and 20—40 cm were collected after green manure utilization for 1, 4, and 7 years, to measure the content of total phosphorus, labile phosphorus pool (Resin-Pi and NaHCO3—P), moderately stable phosphorus pool (NaOH—P) and stable phosphorus pool (Dil.HCl—Pi, Conc.HCl—P and Residual—P).The results showed that, compared with CT, SC and BU increased soil total phosphorus, Resin-Pi, NaHCO3—P, NaOH—P and Residual—P contents, and decreased Dil. HCl—Pi and Conc. HCl—P contents in each sampling year. These differences were more pronounced with the increase of green manure utilization time. And, the BU showed the higher phosphorus availability than SC and the green manure mainly affected 0—20 cm soil layer. After seven years of cultivation and utilization of green manure, compared with CT, the contents of Resin—Pi, NaHCO3—P, NaOH—P and Residual—P of BU were significantly increased by 48.82%~128.41%, 145.93%~231.16%, 206.26%~590.06% and 34.67%~37.66%, respectively, and the contents of Dil. HCl—Pi and Conc. HCl—P were significantly reduced by 12.37%~15.79% and 43.72%~91.39%, respectively. In summary, compared with CT, green manure utilization could significantly increase the proportion of soil labile and moderately stable phosphorus pool, and significantly decrease the proportion of stable phosphorus pool. Moreover, with the increasing green manure utilization years, the proportion of soil labile and moderately stable phosphorus pool also increased, while the proportion of stable phosphorus pool decreased. This study shows that the cultivation and utilization of green manure in orchards could effectively promote the mobilization and turnover of insoluble phosphorus and improve the bioavailability of soil phosphorus.