施肥对菜薹硝酸盐含量的影响

在深圳市 6个蔬菜生产场抽样调查结果表明 ,菜薹硝酸盐含量在 3 0 0 0mg·kg-1以上。采用生物菌肥部分或全部取代复合肥 ,可使硝酸盐含量下降 2 5 %和 40 % ,在采收前第 7天叶面喷施锰、钼、锌及其混合微肥 ,硝酸盐下降 35 %、2 1%、12 %和 39% ,生物菌肥和微肥配合使用 ,可使硝酸盐下降 5 5 %～ 6 7%。同一菜薹品种处理中硝酸盐和亚硝酸盐呈极显著负相关 (r=- 0 .783 4,P =0 .0 1,n =13)。

Effect of Fertilization on the Content of Nitrate in Flowering Chinese Cabbage

The result of base line survey conducted in six vegetable production sites in shenzhen showed that the content of nitrate in flowering chinese cabbage (Brassica Campestris L. ssp Chinensis Var. Utilis) was higher than 3　000　mg*kg-1. Half or all chemical fertilizer was replaced by EM-organic fertilizer，then the contents of nitrate were reduced by 25　% and 40　% respectively. At sevent days before harvesting，spraying microelements of Mn，Mo，Zn and the mixture of them reduced the nitrate contents by 35　%，24　%，12　% and 39　% respectively. Using both EM-organic fertilizer and the microelements reduced the contents by 55　% to 67　%. The relation between the contents of nitrate and nitrite was shown to be significant negative (r=-0.7834，P=0.01，n=13) in the same variety of flowering chinese cabbage.