施肥对蔬菜硝酸盐累积的影响研究

Effect of applying fertilizer on nitrate accumulation in vegetables

  • 摘要: 试验研究施肥对福州市多种蔬菜硝酸盐含量影响结果表明,农户传统施肥方式蔬菜硝酸盐含量为59.5~3743.1mg/kg,平均硝酸盐含量为绿叶菜类> 白菜类>葱蒜类>根茎类>瓜类>豆类>茄果类,且同类不同品种蔬菜硝酸盐含量也存在差异。以WHO/FAO规定的允许值为标准评价绿叶菜类超标最重,其次为白菜类和葱蒜类,其他4类未超标。化肥纯N施用量为450kg/hm2时,化学N 肥对蔬菜硝酸盐累积的贡献率>85% ,其中不同品种N肥贡献率依次为NH4NO3>NH4HCO3>CO(NH2)2>(NH4) SO4>NH4C1。N肥施用量与蔬菜硝酸盐累积量呈正相关,双氰胺施用量与蔬菜硝酸盐累积量呈负相关。等N量下蔬菜硝酸盐累积量随基肥所占比例减少、追肥所占比例增大而增大,且随追肥后时间推移呈直线下降。配施有机氮可降低蔬菜硝酸盐含量,降幅施厩肥>土杂肥。调整与优化蔬菜品种及施肥结构,采用“重头、稳中、控尾”施N 方式,根据蔬菜食用卫生要求选择N 肥用量及其使用安全期与双氰胺用量,可降低蔬菜硝酸盐含量。

     

    Abstract: The nitrate content in vegetables in Fuzhou City was studied in this experiment.The results show that the content of nitrate in vegetables are between 59.5 and 3743.1 mg/kg under the condition of common applying fertilizers.The order of nitrate content in defferent vegetables is leaf vegetable> Chinese cabbage>onion> rhizome> melon>bean>eggplant.According to the evaluation standard of WHO/FAO,the nitrate content of leaf vegetable,Chinese cabbage,and onion exceed the quota.Under the condition of applying pure nitrogen of 450 kg/hm2.85% nitrate accumulated in vegetables comes from nitrogen fertilizers,the contributive order of different kinds of nitrogen fertilizers to nitrate accumulated in vegetables is NH4NO3>NH4HCO3>CO(NH2)2>(NH4)2SO4>NH4C1.The doses and ways of applying nitrogen fertilizers are greatly relative to nitrate accumulated in vegetables.On the one hand,the positive relations are shown on applying nitrogen fertilizers and negativity one are shown on applying dicyan diamide.At the same dose of nitrogen fertilizers applied,the nitrate accumulated in vegetables is decreased with the reducing of the amount of base manure and in crea sing of the addition manure,and applying organic fertilizers cooperated may reduce the nitrate content in vegetable.With the results of the above statements,the following countermeasures are put forward including regulating breeds of vegetable and structures of fertilizer;adding proper dicyandiamide and preventing from applying exceeding amount of nitrogen fertilizers;applying high ratio nitrogen fertilizers in early stage,and low ratio nitrogen fertilizers in middle and late stages.

     

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