Impacts of Nitrogen (Urea) Fertilization on Cadmium Accumulation Nitrate Contents and Nutritive Values in Chinese Cabbage

Abstract

Pot-mode cultivation experiments were carried out to study the impacts of nitrogen（urea）fertilization in different level on Cadmium (Cd) accumulation, nitrate contents and nutritive values in Chinese cabbage, The results showed that: at different level of Cd artificial enriched soil, with applied urea increased, the accumulation of Cd in edible part of Chinese cabbage gradually decreased. Nitrate Contents in edible part have a positive correlation with the concentration of Cd in soil and the nitrogen fertilizer applied. In the natural soil (with contaminated Cd in concentration of 0.18 mg/kg), when the urea was fertilized by 255 kg/hm2 to 330 kg/hm2, Cd and nitrate contents of edible parts of cabbage were within the national food security limits, which could guarantee the food security of Chinese cabbage. Increasing nitrogen fertilization in the form of urea has a certain effect on amino acids contents but little effect on soluble sugar contents in Chinese cabbage, when the concentration of urea was 320 kg/hm2, amino acids contents of cabbage reached the highest level of 355 mg/kg1. Increasing nitrogen fertilization could lower down the contents of water-soluble Cd and the available Cd in soil, thereby reduce the absorption of Cd by Chinese cabbage. To a certain extent, increasing nitrogen fertilization could increase the food security of Chinese cabbage.