Effects Of Silicate Soil Conditioner On Morphology Of Cadmium In Flue-Cured Tobacco Rhizosphere Soil And Absorption And Accumulation Of Cadmium By Tobacco

This experiment researched the effect of silicate soil conditioner on morphology of cadmium in rhizosphere soil and the absorption and accumulation of cadmium by tobacco.Systematically analyzed the changes of rhizosphere soil pH and cadmium morphology,the biomass,cadmium content and cadmium accumulation of various parts of flue-cured tobacco.The results showed:1.Silicate soil conditioner can improve rhizosphere soil pH,the increase rate of up to15.07~29.13%.The increase of rhizosphere soil pH of Zhongyan 101 and Yunyan 87 was higher than that of Xiangyan No.3 and K326 in each period.2.Silicate soil conditioner can reduce the content and proportion of acid-soluble cadmium and reducible cadmium,Increase the content and proportion of oxidizable cadmium and residual cadmium in rhizosphere soil.Compared with the control group,acid-soluble cadmium and reducible cadmium's content can be reduced by 22.30%and23.62%,oxidizable cadmium and residual cadmium's content can be increased by 91.43%and 41.32%after transplanted for 90 days.3.Silicate soil conditioner can improve the biomass of various parts of flue-cured tobacco and the distribution of cadmium in roots and shoots,reduce cadmium content and cadmium accumulation in various parts and the distribution of cadmium in leaves.The biomass of roots,stems and leaves of tobacco can be increased by 28.45%,22.42%and14.28%.The cadmium content and cadmium accumulation in tobacco leaves decreased the most,up to 55.58%and 50.49%,the distribution rate of leaves up to 7.61%.4.The responses of different varieties to the silicate soil conditioner were different,specific performance as,with the increase in the amount of conditioner applied,the size relationship under different varieties treatment was not consistent.And there were significant differences among some cultivars,but generally were not significant.5.The effect of silicate soil conditioner on the indexes in this experiment was related to the level of application:In general,there was no significant effect on the indexes when the application level was 1500 kg/hm~2.The indicators under the application amount of4500kg/hm~2 had significant difference with control group,but had no significant difference with the application amount of 3000kg/hm~2.When the application amount was3000kg/hm~2,rhizosphere soil pH can be increased by 26.64%,acid-soluble cadmium and reducible cadmium's content can be reduced by 22.30%and 21.37%,total cadmium,oxidizable cadmium and residual cadmium's content can be increased by6.21%,55.56%and 41.32%.As to roots,stems and leaves of tobacco,the biomass can be increased by 38.82%,44.81%and 24.69%,the cadmium content can be reduced by 34..81%,34.83%and 59.48%,the cadmium accumulation can be reduced by 16.70%,28.70%and51.52%.The differences were significantly between 3000kg/hm~2 and control group.In combination,the 3000kg/hm~2 application had lower cost and the overall effect was the best.