Abstract: The dynamic variations of nitrate contents in the asparagus greenhouse soil at different growth stages of asparagus in Chongming Island were measured. The result showed that contents of nitrate in the soils of 10-year, 4-year, and 1-year old asparagus greenhouses ranged from 248.3 to 651.0 mg N·kg^-1, from 18.4 to 928.4 mg N·kg^-1 and from 52.4 to 556.2 mg N·kg^-1, respectively. Generally, nitrate accumulated in the soils of all the three greenhouses. Both nitrogen fertilizer applications and plant uptakes of nitrogen caused significant variations of soil nitrate contents at different growth stages. The nitrate was most seriously accumulated in soil at late growth stage of asparagus in summer, which also resulted in heavy leach of nitrogen to the deeper layer. Soil acidifications and salinizations were found in all the three greenhouses. Nitrate accumulation was one of the important factors that caused soil salinization in the 10-year old asparagus greenhouse.

Key words: asparagus greenhouse, nitrate, soil acidification, soil salinization