Abstract: Understanding the change of cabbage biomass and nitrate accumulation process in cabbage under conditions of different irrigation schemes and nitrogen fertilization provides the framework for reasonable irrigation and fertilization to achieve efficient utilization of nitrogen and nitrate security vegetable products.Cabbage,main vegetable varieties planted in Beijing,was studied by field split block experiment.1 800,3 000 and 4 800 m³/ha,three levels of the main irrigation rate were applied,followed by 0,150,300,and 450 kg/ha nitrogen treatments.The yield of harvest period was evaluated,and nitrate content in Cabbage at rosette stage,heading stage harvesting time was analysed.Result shows,Cabbage yields under the irrigation levels in the lower(1 800 m³/ha)or the higher(4 800 m³/ha)in the interactions of different amount of nitrogen were significantly lower than the one in 3000 m³/ha irrigation;yield increased with the first increase of nitrogen amount,and declined under the higher nitrogen treatment(450kg/ha),even which was lower than thatof the treatment of 150 kg/ha.Growth of the first half of the cabbage is more nitrogen absorption period,nitrate content of cabbage at rosette stage under the treatments of the interactions of different amount of irrigation and nitrogen fertilizer are much higher than national limit standards of nitrate((3000 mg/kg.FW,GB1933822003),are relatively lower level under the conditions of the lower irrigation or higher irrigation in the interaction of different amount of nitrogen,and are relatively higher under the irrigation of 3000 m³/ha in the interactions of 300,450kg/ha.With Cabbage developing stages extended the nitrate content was significantly decreased to the national limit standards of nitrate when it was 60 d,which there were no significant differences among the different amount of nitrogen fertilizer.The conditions of lower,or higher consumption of water in the interactions of nitrogen were not conducive to the growth and the absorption and utilization of nitrogen,there was an increase of nitrogen loss of environmental pollution risks;While the irrigation of 3 000 and 300 kg/ha nitrogen fertilizer were conducive to the growth of cabbage,nitrogen absorption and utilization,and reduce the risk of nitrate pollution of groundwater in vegetable field;increase output,and can provide the vegetable products up to the national standard of nitrate at the appropriate period of harvest and obtain a better product economic benefits.

Key words: Cabbage, Yields, Nitrate accumulation, Irrigation, Nitrogen fertilizer

CLC Number: 

• S143.1