Migration And Transformation Mechanism Of Arsenic In Pteris Vittata-Citrus Intercropping Repair System

At present,heavy metal pollution in farmland soils is becoming more and more serious in China.The application of phytoremediation technology with plant extraction as the core has achieved preliminary results.However,due to the high cost of remediation,its further industrial application is limited.It is one of the main directions to reduce the cost of phytoremediation to a certain extent through the model of super-enriched plant-cash crop intercropping,which restricts the popularization and application of phytoremediation technology.Based on the current research situation,this study proposed an intercropping method between fruit trees(citrus)with high economic value and hyper-enriched plants(Pteris vittata)to remediate arsenic-contaminated soil.Field and pot experiments were carried out to study the changes of arsenic content in citrus and Pteris vittata under the citrus-Pteris vittata intercropping restoration mode.2.The changes of soil properties and arsenic content in different forms under the citrus-Pteris vittata intercropping restoration mode.3.The transformation mechanism of arsenic in citrus-Pteris vittata-soil under the citrus-Pteris vittata intercropping restoration mode.In addition,economic parameters were obtained through field experiments to evaluate the feasibility of industrialized application of Pteris vittata-citrus intercropping remediation model,and to provide a new remediation model for arsenic-contaminated soil remediation.The main conclusions are as follows:(1)Intercropping remediation can increase arsenic content in Pteris vittata grass,reduce arsenic content in citrus leaves,increase available arsenic content in soil,reduce total arsenic content in soil,and is more conducive to remediation and purification of contaminated soil.It is a very effective remediation method for contaminated soil.(2)All three citrus cultivars have low accumulation of arsenic in soil and can be planted on arsenic-contaminated farmland,which has great application value.Intercropping remediation model changed the soil environment,was conducive to the growth of citrus and Pteris vittata grass,and promoted the uptake of arsenic by Pteris vittata grass in soil,and reduced the arsenic content of citrus.Among them,the effect of Citrus intercropping model Aiyuan 38 was the most obvious.(3)In addition,the arsenic content of three citrus varieties(local citrus,Aiyuan 38,Dayagan citrus)in the intercropping mode was not exceeded the standard,and the taste quality of the fruit was excellent.(4)Under the intercropping restoration model,the rhizosphere environment of Citrus Root changed the correlation between the original soil properties,thus promoting the transformation of Available Arsenic in the soil,thereby enhancing the accumulation of arsenic in Pteris vittata.(5)Through the evaluation of investment cost,economic income and ultimate economic benefit,this study found that different citrus intercropping restoration models have obvious benefits,of which Aiyuan 38 is the best planting variety.