| Biochar has the characteristics of porosity,adsorption capacity,and abundant surface functional groups.It improved the physical and chemical soil properties,changed the structure of organic pollutants,and reduced its bioavailability.It had became a research hotspot in the field of soil pollution amendment.At this stage,the pollution remediation of biochar was often used in the pollution control of heavy metals and persistent organic pollutants,while less attention has been paid to the pollution status and remediation of new pesticides such as kasugamycin.New pesticides,such as kasugamycin,often had the characteristics of high bactericidal efficiency,fast degradation rate and low residue,and had broad application prospects.The effect of biochar on seed germination was analyzed through the experiment of biochar extract;the adsorption and degradation behavior of the pesticide kasugamycin under the condition of the addition of biochar in the field were analyzed through indoor simulated cultivation and adsorption test conditions.The specific research conclusions were as follows:（1）The low-concentration biochar extract mainly promoted the growth of rice roots and the germination of corn seeds.The low-concentration biochar extract promoted seed germination,while the high-concentration biochar extract inhibited the growth of crops.Biochar extract contained a variety of small molecular organic substances and inorganic nutrients,such as triethyl phosphate,2,4-bisphenol,alkane,etc.,which had positive effects on plant root growth and elongation at low concentrations.Many organic substances,such as polycyclic aromatic hydrocarbons,promote crop growth at lower concentrations.The water-soluble organic matter of biochar helped to improve seed germination rate,promote crop growth,and provide a prerequisite for increasing yield.（2）Rice and wheat biochar has a good removal effect on solution kasugamycin,and the higher the solution temperature,the better the adsorption effect.The removal efficiency of kasugamycin from rice biochar was higher than that of wheat straw biochar.Biochar was modified with 0.1 mol L-1ferric chloride.Different temperatures had a significant effect on the adsorption of kasugamycin before and after the modification,and the adsorption curves were all in line with the Freundlich model,which also showed that the biochar before and after modification had a significant effect on the adsorption of Kasugamycin.The adsorption of the element was physical or chemical adsorption,and the adsorption capacity also increases with the increase of the concentration.The biochar-based Fenton-like photocatalytic system significantly improved the degradation effect of Kasugamycin in solution,indicating that ultraviolet light and biochar promoted the generation of free radicals and accelerated the degradation of Kasugamycin.（3）Biochar effectively reduced the concentration of available kasugamycin in the soil,and with the increase of depth,the content of available kasugamycin gradually decreased,effectively preventing the downward migration of pesticides.The application of biochar can increase the biomass of plants,increase the yield of plants,and reduce the content of kasugamycin in plants.Experiments show that spinach leaves absorb most of the kasugamycin in the whole plant.The kasugamycin in the soil is mainly distributed in the topsoil of 0-10 cm,and the content of kasugamycin in the deep soil>10 cm was very small,and the content of kasugamycin in the soil was also reduced after the addition of biochar.It was shown that biochar had a significant effect on reducing kasugamycin concentration in soil and plants.Kasugamycin in plant samples was mainly found in leaf tissue,and application ratio of biochar could effectively reduce the concentration of kasugamycin in plant tissue,indicating that biochar effectively degraded kasugamycin and inhibited the migration. |
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