Passivation Effect of Biochar on Soil Cadmium Pollution and Rape Growth
In order to explore the remediation technology of biochar and rape seedlings for heavy metal cadmium(Cd)contamination of soil in the southern border area,the yellow rape,black rape and Indian mustard(Brassica juncea)were used as test materials,the mass fraction of biochar addition was set as 0%(T0),2%(T2),4%(T4),6%(T6)and 8%(T8),respectively.The effects of biochar addition on the growth and Cd accumulation of rapeseed seedlings under cadmium(Cd)stress were elucidated by measuring and analyzing the soil physicochemical properties and Cd morphology,seedling biomass and enrichment transport of each site in different treatments.The results showed that the pH,organic matter content and oilseed rape biomass(dry weight)in the soil increased significantly with the increase of biochar addition;meanwhile,the content of the more active exchangeable Cd gradually decreased,and the content of carbonate-bound Cd,Fe-Mn oxide-bound Cd,organic matter and sulfide Cd,which were not easily absorbed by the crop,gradually increased.When the soil Cd content was certain,the Cd activity index decreased gradually,and the passivation effect of T8 treatment was the most significant.Biochar effectively reduced the root enrichment coefficient and above-ground transport coefficient of rapeseed,and the best effect was achieved with 8%biochar application.The best response effects of pH,organic matter content,rapeseed biomass,Cd morphology changes and root enrichment coefficient and above-ground transport coefficient in yellow rape soil were observed under different biochar treatments.Overall,the best passivation effect and growth characteristics of rapeseed were selected for 8%biochar application,and yellow rape showed the best response to biochar treatment.By adding biochar,the heavy metal Cd was effectively mitigated on the growth of rape seedlings in South Xinjiang region,which provided technical and theoretical support for oilseed rape cultivation in South Xinjiang region.
biocharrapesoil heavy metal Cdpassivation effectgrowth characteristics
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