施用氮肥对蔬菜中硝酸盐积累的影响

用硝酸盐快速检测法———改进的镉粉法 ,以小白菜为材料 ,采用田间试验和室外盆栽试验相结合的方法 ,研究了化肥及土壤对蔬菜中硝酸盐含量的影响。结果表明 :蔬菜中硝酸盐的含量依施用氮肥的种类而异 ,磷、钾配施有利于降低NO3 含量 ,且随着土壤中的氮素和有机质含量的增高而增多 ;随着采收期的延长 ,蔬菜中硝酸盐的含量逐渐降低。提出减少蔬菜中硝酸盐含量的有关控制措施 ,为发展无公害蔬菜及绿色食品提供了科学依据

Effect of nitrogen fertilizer on nitrate accumulation in vegetables

The nitrate content in vegetables by conducting field and outside potted plant experiments on Chinese cabbage is researched with a rapid analysis of nitrate in vegetablesimproved powder cadmium method. The results show that the nitrate contents in vegetables vary with different nitrogen fertilizers and increase with the raise of dosage in nitrogen and organism in the field. The application of phosphorus together with potash is helpful to lower nitrate content, the later harvest vegetables have the lower nitrate level. And the controlling measures on reducing the nitrate content in vegetables are presented, which establishes the science basis for development of nonpolluted vegetables and green food.