Analysis Of Influencing Factors On Fumigation Effect Of Chloropicrin In Panax Notoginseng Planting Soil

Panax notoginseng(Burk)F.h.Chen has strict requirements on growth environment and is easy to produce continuous cropping obstacles.Chloropicrin,as a soil fumigant,can kill pathogenic bacteria,pests,nematodes and other pests in the soil.It is widely used in strawberry,ginger,tomato,eggplant,pepper,ginseng,yam and other crops,effectively alleviating the continuous cropping obstacles and ensuring the quality and yield of crops.However,the application of chloropicrin in Panax notoginseng is rarely reported.In this study,the effects of chloropicrin fumigation on Panax notoginseng planting soil and the remediation technology,and the effects of plastic film on the fumigation effect of chloropicrin were explored.The main results are as follows:(1)Effects of chloropicrin treatment on Soil and growth of Panax notoginsengChloropicrin can solve the continuous cropping obstacle of Panax notoginseng,increase the nitrogen content in soil and provide nitrogen for the growth of Panax notoginseng.Chloropicrin can activate the activity of soil protease,and reduce the activity of acid phosphatase and urease during fumigation.Among them,when the dosage of chloropicrin was 40kg/666.7m~2,the growth state of leaves,roots and stems of Panax notoginseng was the best,and the contents of nutrient elements in Panax notoginseng plant and five main saponins in Panax notoginseng root were the best,with the order of CP40>CP50>CP30.When the dosage of chloropicrin was40kg/666.7m~2,the continuous cropping obstacle of Panax notoginseng could be effectively solved,and the yield and quality of Panax notoginseng could be increased.(2)Effect of microbial organic fertilizer on the remediation of chloropicrin fumigated soil microorganisms and the growth and development of Panax notoginsengMicrobial organic fertilizer can increase microbial diversity and improve species composition structure.Chloropicrin fumigation reduced the species richness of dominant and beneficial bacteria,while microbial organic fertilizer could repair some microbial species,such as gemmatimonadota,Basidiomycota,clathrosphaerina,Chrysosporium,and increase the species richness in soil.At the same time,the application of microbial organic fertilizer can increase the content of soil organic matter,improve soil physical and chemical properties,increase the yield and quality of Panax notoginseng,and increase the content of five main saponins in the taproot of Panax notoginseng.The results showed that chloropicrin fumigation could reduce soil microbial diversity,and microbial organic fertilizer could repair and promote the growth of Panax notoginseng.(3)Effect of film mulching on fumigation of chloropicrinThe results showed that the soil fumigation of chloropicrin covered with different thickness plastic film,and the duration of chloropicrin under 6S thickness plastic film was longer.From the first day of fumigation to the seventh day of fumigation,the content of chloropicrin in the soil decreased by 89.00%-90.53%,and the content of chloropicrin in the soil under 6S film was always higher than that under8s film.At the same time,the number of microbial colonies decreased first and then increased during fumigation,and the abundance of Fusarium under 6S film was more conducive to reduce.After fumigation with chloropicrin,the appearance,physical properties(light transmittance,weight,thickness,tensile strength at break)and chemical properties of the film changed,showing that 8S was corroded more than 6S.Therefore,film 6S is more conducive to soil fumigation of chloropicrin,and is better for chloropicrin retention,microbial killing and film corrosion.