Effects Of Modifiers On Cadmium Contentand Soil Microbial Community Structure Inrice

Rice is the main grain crop in China.Food security has a direct impact on the future development of the country.Therefore,it is an urgent problem to solve the problem of heavy metal pollution in rice and to ensure food security for the people's livelihood.In this paper,we studied the migration and transport of cadmium in Rice by different soil amendments and the effect of soil amendments on soil microorganisms.The results of the study are as follows:(1)The effects of eight amendments on the migration and accumulation of available cadmium from soil to rice,as well as on soil pH value,rice yield and cadmium content in rice were studied in paddy soil polluted by heavy metal cadmium.The results showed that the application of amendments could significantly reduce the transport of cadmium from soil to rice,achieve the goal of reducing cadmium in rice,and increase yield and efficiency of rice.Compared with CK,soil pH value was increased by 1.3-4.3% and the activity of cadmium was decreased by applying amendments.Among the available cadmium in soil,nano-chelated iron was the most obvious,and the best treatment could significantly reduce the soil cadmium availability by 76.5%.In rice yield,the application of amendments could increase rice yield by 1.01-9.43%.As for the content of cadmium in rice,nano-chelated iron could significantly reduce the content of cadmium in Rice by 66.98-78.56%.The results showed that among the 8 kinds of amendments,treatment 1~treatment 4 had good potential in controlling cadmium contaminated farmland.(2)In the field experiment,the improved soil bacterial community structure of early rice and late rice was compared by using high-throughput sequencing with 8 medium soil improvement methods,and the results were compared with those of conventional methods(adding lime).The results of reads length frequency distribution,OUT analysis,richness sparse curve,Shannon index sparse curve,cluster analysis and principal component analysis showed that the soil microbial diversity was similar and the biomass was similar.Principal component 1(PC1)and principal component 2(PC2)in late rice explained 47.94% of the total variance variables respectively.And 23.7%.Treatment 12(58-1)and 18(10-1)were close to each other and distributed in the positive end of principal component 2.When Euclidean distance was 0.17,the soil treated with different amendments could be divided into two groups,while CK and residual treatment methods were in the second group,indicating that the soil microbial diversity was similar and the biomass was similar.