关键词: 集约化蔬菜地, 磷吸附饱和度, 最大缓冲容量, 流失风险

Abstract: In order to study accumulation and leaching risk of soil phosphorus, soil sampleswere collected from vegetable fields, different in intensive vegetable cultivation history (3 - 5, 15 - 20 and 25 - 30 years) in the suburbs ofNanjing for assay of concentrations of total phosphorus ( TP) , available phosphorus (Olsen-P) , dissolved reactive phosphorus (CaCl2-P) and bio2available phosphorus (NaOH-P) , and Padsorption in 0 - 20 cm soil layer, and for assessment of soil phosphate leaching risk through determination of degree of phosphorus saturation (DPS) and maximum buffer capacity (MBC)of the soils. Results show that the longer the history of intensive vegetable cultivation, the higher the accumulation of phosphorus for all Pfractions, except forNaOH-P, which was higher in soils of 3 - 5 a than in the other two groups. TP, Olsen-P, CaCl2-P and NaOH-P accumulatedmainly in the 0 - 20 cm soil layer, and decreased in concentration with the dep thin profile. DPS increased with the history. In the 0 - 5 cm soil layers of soils of 25 - 30 a, the concentration of DPS was even higher than 25% , the environmental sensitive index for soil P loss, while MBC was the lowest, suggesting that the leaching risk of soil phosphorus riseswith the cultivation history, particularly in 0 - 5 cm soil layer.

Key words: vegetable soil, phosphorus adsorption, degree of phosphorus saturation, maximum buffering capacity, leaching risk