Effect of Different Levels N Application on the Nitrate Accumulation in Cucumber and Soil in Sunlight Greenhouse

The effect of different levels N application(225,450,675 and 900 kg/ha)on cucumber growth and NO3——N changes in fruit and soil was studied in sunlight greenhouse with cucumber.The result showed that high nitrogen fertilizer improved the growth and yield of cucumber,but the yield decreased at 675 kg/ha;Correlation between N levels and NO3——N in soil and cucumber was significant positive,NO3——N in soil became lower with the cucumber growing developing and then increased after fruiting stage in the whole growth stage,while NO3——N in fruit increased and then became lower.