Study On The Mechanism And Application Of Optimized Continuous Cropping Chrysanthemum

Chrysanthemum morifolium is the traditional medicinal plant in China. Yancheng is the main source of this plant. From the 1960s, C. morifolium have been planted in the area. It’s a long period for some fields planting this plant, and it resulted in lower fertility, nutrient unbalance of the soil, dropping of growth potential, aggravating of plant diseases, declining of flowers yield and quality. We confront with the problem to relieve the continuous cropping obstacles of C. morifolium, and increased the flower output and quality for C. morifolium planted in the area continuously. The previously studies show that endophtic fungi C4 can improve the yield and enhance the resistance stress ability of C. morifolium. Endophtic fungi C4 was been added into continues cropping soil, to approach the effect of fungi C4 on the soil environment and C. morifolium in continues cropping soil. It was a new pattern of remove the obstacles of C. morifolium’s continuous cropping.The reason and mechanism of the obstacle of C. morifolium’s continuous cropping were researched firstly. The soil samples were collected from four adjacent continuous cropping C. morifolium fields in Yancheng which were continuously cropped for 1,3,7 and 15 yeras respectively. The results show that with the increasing of continuous cropping system, the output of C. morifolium gradually reduced and incidence of diseases increased gradually. The output of C. morifolium planted 15 years was only 19.80% of the one just planted 1 year, and incidence of diseases of C. morifolium planted 15 years was 100%. The content of boron in the rhizosphere soil decreased with the increasing years of C. morifolium continuous cropping, while other elements and pH had no significant changes with continuous cropping years. The content of every element in C. morifolium which planted 15 years had significant difference with other treatments. Although the CFU of soil bacteria and actinomycete showed a trend with a saddle shaped curve while the CFU of fungi increased obviously with the increasing continuous cropping years, and continuous cropping soil microflora shifed from bacteria type to fungi type. The content of p-coumaric acid in the siol increased with the increasing years of C. morifolium continuous cropping, while coumarins appeared in the soil after C. morifolium planted 7 years. However, biomass and the root of C. morifolium were significantly inhibited by coumarins and high concentration of p-coumaric acid. The cropping obstacle of C. morifolium may be related to phenolic acids, microflora’s changes and the lack of microelement, which affected the microenvironment and the growth of C. morifolium.A pot experiment of adding litters and endophytic Chaetomium globosum (strain C4) to the continuous cropping soil which have planted C. morifolium for a long time was carried out, which was to study the effect of C4 on the microflora and the degrading of litters. Soil bacteria were more sensitive to C4 than soil fungi, and the CFU of bacteria in DC treatment (added C4) and DCF treatment (added C4 and its fermentation broth) were higher than the control in the first 30 days after treatment, meanwhile the bacterial community of every treatment were different. DC treatment and DCF treatment significantly accelerated decomposition of litters, and increased the activity of saccharase, but had no effect on urase of the soil. The cellulase of DC treatment was always higher than other treatments. When the experiment dealed with 70 days, the cellulase of DC treatment had no different changes with dealing with 20 or 30 days, while other treatments were all lower than before. Fungi C4 can affect the degradation of litters, which prompted litter degradation in advance into the mid-late stage compared with the natural degradation, and accelerated the material circulation of the soil.Fungi C4 was added to the soil which planted C. morifolium for 3 years to verify whether it can affect the output and quality of C. morifolium in the continuous cropping land. The number of endophytic fungi which was separated from C. morifolium in our study was different, and CK treatment was significantly lower than other treatments, while fungi C4 can not be isolated from every treatment in this study. The biomass of flowers and plant in JC treatment (added C4) and JCY treatment (added C4 and its fermentation broth) were significantly higher than CK. Compared to that of the control, the disease index of JC, JCY treatments decreased 28.13%, 31.25%, respectively. Disease index of JC, JCY treatments were significantly lower than that of CK’s. Total flavonoids content of the JC treatment was higher than that of the control remarkably, and total flavonoids content in JC、JCY treatments increased 87.42%,41.64% compared to CK respectively. In conclusion, fungi C4 can reduce the disease index, enhance the output and quality of C. morifolium in the continuous cropping land.