Effects of Combined Application of N,P and K on the Nitrate Content in Different Kinds of Chinese Cabbage

An optimized regression design with quadratic saturation D(311B project) was conducted to study the effects of N,P and K fertilizers on the nitrate content in Chinese cabbage,and to find the models which can demonstrate the relations between fertilization and nitrate content.The results showed that there were certain relations between nitrate content and fertilization for different Chinese cabbage' varieties,but there were great differences among the Chinese cabbage varieties.With the same fertilization treatments,the nitrate content of Blue star 80 was lower than that of Wu Fu-cai.Moreover,there was a significant correlative relationship between the content of nitrate and NR of different Chinese cabbage varieties,thus,NR may be used as an index of nitrate accumulation in the Chinese cabbage.