Abstract: 【Objective】Excessive application of phosphorus fertilizer is commonly observed in vegetable production in China. The purpose of this study was to investigate the potential of phosphorus fertilization reduction in vegetable production and recommend appropriate phosphorus rates for cucumber and tomato.【Method】Cucumber and tomato were widely cultivated in North China, and thus were taken as the research objects. In this study, cropping model was the winter-spring cucumber and autumn-winter tomato double cropping system. The basic Olsen-P level was 40.2 mg·kg^-1. Three treatments were designed in this experiment, including a non-phosphorus control (P₀), a reduced phosphorus rate (P₁) and a farmers’ conventional phosphorus rate (P₂). In cucumber season, the amounts of P₂O₅ applied in P₀, P₁ and P₂ treatments were 0, 300, 675 kg·hm^-2, respectively. The corresponding phosphorus amounts in the tomato season were P₂O₅ 0, 225, 675 kg·hm^-2, respectively. The apparent phosphorus balances, soil phosphorus availability and movement and yield changes among 3 years were collected and analyzed to find out the appropriate phosphorus rates.【Result】(1) Phosphorus surplus was P 480.0 kg·hm^-2·a^-1 and the average Olsen-P content in 0-20 cm soil was 70.2 mg·kg^-1 in P₂ treatment during 3 years. Due to the surplus application, the Olsen-P in 0-20 cm soil increased by 2.7 mg·kg^-1 when phosphorus surplus increased by P 100 kg·hm^-2. The DPS_M3 was 80% at 0-20 cm depth in P₂ treatment and phosphorus leached obviously to deeper soil. (2) Compared to P₂ treatment, the phosphorus application rate decreased by 61.1% and the phosphorus surplus among 3 years reduced by 71.0%-77.3% in P₁ treatment; the Olsen-P contents decreased by 18.6%-43.5% with the average of 49.3 mg·kg^-1 among 3 years, which was close to the critical value of the fruit vegetable production; the average of Olsen-P content decreased by 9.3%-30.1% at 20-60 cm soil depth, and the DPS_M3 decreased by 21 percentage point, which indicated lower phosphorus leaching in P₁ treatment, and no yield reduction was observed. (3) The Olsen-P in 0-20 cm soil decreased by 3.4 mg·kg^-1 when phosphorus uptake increased by P 100 kg·hm^-2 in P₀ treatment. The average Olsen-P content in 0-20 cm soil was 30.5 mg·kg^-1 in P₀ treatment. Although no yield decrease was observed, the phosphorus uptake in 2008 tomato season decreased by 19.8%-30.0% in P₀ treatment. (4) Based on this results, when the soil Olsen-P was above 40 mg·kg^-1, less than 300 kg·hm^-2 P₂O₅ was recommended for cucumber with yield level of 170 t·hm^-2, and not more than 225 kg·hm^-2 P₂O₅ was recommended for tomato with yield level of 100 t·hm^-2.【Conclusion】The reduction of phosphorus fertilizer exhibited a great potential in the greenhouse vegetable production in North China Plain. For greenhouse planted for more than 3 years, 60% phosphorus could be saved and significantly decrease the phosphorus surplus, lessen available phosphorus accumulation, reduce phosphorus leaching and keep vegetable yield at high level.

Key words: greenhouse vegetable, reducing phosphorus rate, soil available phosphorus, phosphorus balance, yield