| In this study,Dongshan Village,Chengguan Town,Kaiyang County,Guiyang City,Guizhou Province was selected as the research area,and the effects of 12 kinds of conditioners on soil pH,organic matter,Cd forms,migration and transportation of rice and rape,and yield of Cd contaminated paddy field were studied through the field experiment of rice oil rotation.The purpose of this study was to screen out the conditioners that can effectively prevent and control the migration and transportation of available Cd in soil and rice and rape,so as to provide reference for Guizhou Province,the main results are as follows:(1)The application of 12 conditioners could significantly increase the soil pH value in rice season and rape season.Compared with CK,soil pH value increased by 0.25?1.02 units during rice harvest.Soil pH increased by 0.02?0.81 units during the rape harvest period.However,compared with the changes before and after rice tanker cropping,the soil pH value in rapeseed season decreased by 0.02?0.54 units,and OSA conditioner had a relatively good effect on the improvement of soil pH in a short time.(2)Soil organic matter content in rice season and rape season could be significantly increased by applying conditioner.Soil organic matter content in rice season reached 45.56?51.68 g·kg-1,with an increase of 4.84%?18.94%.Soil organic matter content in rapeseed season reached44.58?50.58 g·kg-1,with an increase of 0.96%?14.55%.However,there was no significant change in the content of soil organic matter in Amms,Lime,Fertilizer and OSA conditioner.After applying most conditioners,the soil organic matter content in rapeseed season decreased by0.48%?8.60%.However,Wedikang conditioner further increased by 0.71%,indicating that Wedikang conditioner had a continuous improvement effect on soil organic matter in a short period of time.(3)The application of conditioner had no significant effect on soil total Cd content in two seasons,compared with rice season,soil total Cd content in rape season decreased by16.35%?26.42%.The soil available Cd content was decreased by all the conditioners applied in the two seasons,but the results showed that the soil available Cd content was decreased by 3.11%and 3.37%after SAX1 and OSA treatment,respectively.The other 10 conditioners increased the soil available Cd content by 0.94%?8.95%.(4)The content of Cd in different parts of rice could be effectively reduced by applying conditioner.Cd content in roots,stems,leaves,cobs,husks and rice decreased by 1.01%?70.75%,7.48%?94.35%,27.01%?78.40%,0.38%?85.12%,17.22%?77.36%and 19.18%?85.27%,respectively.At the same time,the enrichment coefficient of Cd in different parts of rice was decreased.The contents of Cd in roots,stems,shells and seeds of rapeseed were decreased by20.70%?42.39%,0.65%?46.16%,18.80%?32.86%and 11.83%?35.86%,respectively.The results showed that the soil had a strong ability to transport Cd to the root of rapeseed.(5)The application of conditioners had a certain effect on the forms of Cd in the soil at the mature stage of rice and rape seasons.The soil Cd in rice season was mainly residue.The second is the commutative state.The content of reducible state and oxidizable state is low.The soil Cd in rapeseed season was mainly exchangeable.The second is the residue state.The content of reducible state and oxidizable state is low.(6)The rice yield was increased by 1.56%?18.75%after the application of the conditioner.The yield of rapeseed was reduced by 0.84%?11.68%and increased by 1.58%?7.43%by other treatments except Amus,Tianxiang No.1,SAX1 and lime conditioner.Before and after the comprehensive analysis of the rice oil tanker for soil pH,organic matter,passivation,drop Cd effect and yield changes,visible OSA conditioner in a short time,it is better to improve soil pH,soil organic matter content has no obvious change,can continue to reduce the activity of soil Cd,can effective standard lower Cd content in rice and rape seeds,and increase yield.Therefore,under the rice tanker cultivation mode,OSA conditioning agent has the best effect,which can provide a reference for the remediation of Cd contaminated soil in the karst area of Guizhou. |
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