Abstract: In 2009, a field experiment was conducted at the demonstration base of vegetable production in Damintun town of Shenyang City, Liaoning Province to study the effects of different rotation regime on the reduction of soil nitrogen and phosphorus downward translocation and of vegetable nitrate and nitrite accumulation. After one year planting, as compared with background values, the soil pH decreased by 0.09-0.47, surface soil total phosphorus (TP) content increased significantly, surface soil available phosphorus (AP) content was 86.80-161.04 mg·kg^-1, being significantly higher than the warning index (60 mg·kg^-1), and soil nitrate content was rather high, with an obvious downward translocation. Under the test three rotation regimes, the planted vegetables except spinach had the nitrate and nitrite concentrations accorded with the National safety standards for green vegetables. Among the rotation regimes tested, rape-cucumber-cowpea had the smallest variation range of soil pH, weaker downward translocation of soil nitrate, and higher nitrogen and phosphorous recovery, but less effect on the reduction of soil phosphorous downward translocation and of vegetable nitrate and nitrite accumulation. It was suggested that appropriate management practices should be taken to prevent the acidification, phosphorus accumulation, and nitrate downward translocation of facility vegetable soils.

Key words: Disease resistance, Growth, Trifolium repens, Uromyces trifolii-repentis