Effects of Lanthanum Different Application Methods on Cadmium and Chromium Absorption and Biomass of Absorption Difference Chinese Cabbage Varieties

The authors investigated the growth and development effects and biological effects against heavy metal stress in crops under Cd/Cr combined contaminated soil by light rare earth La, and further provided the basic theoretical guidance for scientific application of rare earth fertilizers. The effects of La on the Cd and Cr absorption and biomass in absorption difference Chinese cabbage varieties (low absorption and high absorption accumulation) were evaluated using soil potting methods and different fertilization techniques (soil mix application, soil irrigation application and foliar spray application). The results indicated that the effect of La treatment on the yield increase effect of biomass of absorption of difference Chinese cabbage varieties was significantly lower than that of high absorption accumulation type. Among them, the low absorption accumulation type showed significant yield-increasing effects by foliar application and soil irrigation application. The high absorption cumulative type did not show an increase in yield. The inhibitory effect of three fertilization treatments on the heavy metal absorption of Cd/Cr combined absorption Chinese cabbage varieties showed that the Cd low absorption accumulation type was higher than the high absorption accumulation type. The Cr high absorption accumulation type is higher than the low absorption accumulation type. Among them, foliar application and soil irrigation application treatment showed significant effects on the absorption of Cd and Cr on the low absorption accumulation type. However, the three fertilization methods showed no significant or no inhibition on the Cd absorption inhibition of high absorption accumulation vegetables, but significantly inhibited the absorption of Cr in stems and leaves. The effect of La treatment on the reduction of Cd and Cr transport coefficients of Cd/Cr composite cultivars with different cultivars was consistent with the inhibitory effects of Cd and Cr. The greater the effect of reducing the transport coefficient, the more significant the inhibition of the absorption of heavy metals Cd and Cr. Exogenous La significantly affects La absorption and distribution in Chinese cabbage, root absorption and accumulation are the main factors in mixed soil application and soil irrigation, foliar spraying is mainly based on the absorption and accumulation of stems and leaves. These findings found that the anti-stress effects of light rare earth La treatment on heavy metals in Cd/Cr combined contaminated soil is closely related to heavy metal absorption and difference of fertilization mechanism. © 2020, Editorial Office of Journal of the Chinese Society of Rare Earths. All right reserved.