Abstract: An open field experiment was conducted to study the effects of applying controlled-release fertilizer blended with rapidly available chemical N fertilizer on Chinese cabbage yield and quality as well as nitrogen losses, including ammonia volatilization and NO₃^--N accumulation and leaching in Beijing suburb. The results showed that a combined application of 2：1 controlled-release fertilizer and urea fertilizer (total N rate 150 kg·hm^-2) did not induce the reduction of Chinese cabbage yield, and decreased the leaf nitrate and organic acid contents significantly, compared with conventional urea N application (300 kg·hm^-2), and had no significant difference in the cabbage yield and leaf nitrate content, compared with applying 150 kg·hm^-2 of urea N. The combined application of 2：1 controlledrelease fertilizer and urea fertilizer improved the N use efficiency of Chinese cabbage, and reduced the ammonia volatilization and NO₃^--N leaching. At harvest, the NO₃^--N concentrations in 20-40, 60-80 and 80-100 cm soil layers were significantly lower in the combined application treatment than in urea N treatment.

Key words: spring Chinese cabbage, controlled-release fertilizer, ammonia volatilization, soil nitrate