Contents of nitrate and mineral elements and their relationships in leafy-vegetables
叶类蔬菜硝酸盐与矿质元素含量及其相关性研究

The contents of nitrate,mineral nutrient elements and their relationships are studied in twenty-three leafy-vegetables in Chongqing. The results show that the content variations of nitrate and mineral elements are very great in the different vegetables and the different varieties; other vegetables especially celery are polluted by nitrate except asparagus lettuce ,west-romaine lettuce,pack-choi.The significant or very significant positive correlation in N,P and K and other mi-neral nutrient elements.In fresh leafy-vegetables,the correlation is significantly or very significantly positive in NO~-_3 and K,Na,Ca and Fe, and is negative in NO~-_3 and P,S,Mn,Zn,B and Mo in the dry vegetables,moreover there is a significantly negative relationship between NO~-_3 and B and P.