| The application of organic fertilizer for the control of heavy metal pollution has drawn a lot of attention owing to the severe heavy metal pollution problem in soil and introduction of policy for fertilizer reduction..However,the study of the effects of black soldier fly feces on the growth of rice which plant in contaminated soil and the accumulation-migration of heavy metal anwas rarely reported.In this study,rice pot experiments were conducted to investigated the effects of black soldier fly feces on rice growth,yield and plant accumulation of Cd,Pb,Zn in contaminated soil,and soil physical and chemical properties in two years after treated with various amounts of black soldier fly feces.And further explored the mechanism of black soldier fly feces on rice growth and migration-accumulation of Cd,Pb,Zn in soil and rice.The following conclusions were summarized as follows:（1）The application of insect feces organic fertilizer increased the chlorophyll content of rice by 7.00%-59.90%,the enzyme activity of SOD and POD were increased by10.20%-45.22%and 16.87%-48.99%,respectively.And the contents of nitrogen,phosphorus and potassium in plant were increased in the range of 8.62%-439.05%.In 2018,rice plant height,the enzyme activity of CAT,aboveground dry matter quality and yield with application of 4% concentration insect feces were increased by 5.82%,42.26%,40.20% and 43.66%,respectively.In 2019,the indicators of rice with the 8% concentration insect feces application rate were the highest,the output was increased by 195.48% compared with CK and increased by 214.70% compared with the CK in 2018.（2）The application of insect feces organic fertilizer increased by 2.15%-10.26% of the soil p H value,13.56%-99.92% of the EC value,25.18%-195.40% of ammonium nitrogen content,effective phosphorus content of 45.67%-312.03%,available potassium content of372.47%-2014.50%,organic matter content of 7.06%-32.46%,soil urease activity of21.64%-109.49%,phosphatase activity of 14.50%-45.44%,sucrase activity of25.21%-286.54%,respectively.The indicators of rice treated with 8% concentration insect feces were the highest in both two years.Compared with 2018,the EC value,ammonium nitrogen content,available phosphorus content,available potassium content,and organic matter content were reduced by 23.45%,46.21%,and 23.10%,27.39%,10.34%,respectively.（3）The application of insect feces organic fertilizer reduced the Cd,Pb and Zn contents of the rice at the tillering stage by 33.04%-85.24%,by 6.37%-67.06% and5.77%-42.76%,respectively.And it reduced the Cd content and enrichment coefficient of rice at the mature stage by 8.28%-66.44 % and 9.57-66.77%,respectively.Andreduced Pb content of rice by6.38%-61.85% and its enrichment coefficient by 8.01%-63.76% I;Zn content by 5.01%-51.57% and its enrichment coefficient by 5.02%-52.27%.The Cd,Pb and Zn content and relevant enrichment coefficients of mature rice which was treated with 4% concentration insect feces in 2018 were the lowest,while in 2019 the indicators of rice treated with 8%concentration insect feces was the lowest.In addition,the Cd,Pb and Zn contents and relevant enrichment coefficients of rice in the second year after the same treatment were lower than those in the first year.With the application of insect feces in two years,the content of weak acid soluble state of Cd,Pb,Zn in soil were reduced by 57%-18.17%,and increased the content of its oxidizable state by 0.68%-9.58%.In conclusion,the application of insect feces organic fertilizer could improve the soil fertility and increase the rice yield,while reduce the activity of heavy metals in the soil,inhibit the transfer of heavy metals into the rice,and reduce the accumulation of heavy metals in rice plant. |
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