| Straw is also known as straw straw,which is the remaining stems,stems and leaves after threshing of corn,wheat,rice and other grasses.The straw is rich in cellulose and lignin,which is an important source of organic matter.China is the largest straw producing country in the world.According to statistics,with the increase of agricultural comprehensive production capacity,the total output of straw in China is increasing continuously.With the development of agricultural modernization,straw returning has become an inevitable trend of agricultural production.But in the production process,on the effect of straw returning to disease remains controversial,some scholars believe that the straw after the growth and reproduction of pathogenic bacteria to provide a favorable environment,make the pathogen initial amount of bacteria increased,aggravating disease;but also some scholars believe that the straw will make the Soil Antagonistic Bacteria Number the material will produce a solution rot,enhance the resistance of plants,so as to reduce the disease.The main research of this paper is as follows:1.According to the principles of plant disease epidemiology,field survey showed that the index of maize sheath blight disease was straw returning to field,and no straw returning.The research showed that straw returning on the whole to pop corn sheath blight occurrence,display data from the survey of three years: the same year with the amount of straw of corn sheath blight disease was more aggravated,the same amount of straw of Corn Sheath Blight with increasing number of diseases with heavy returning.The field canopy meteorological monitoring showed that the average temperature and average humidity of the field canopy increased with the increase of the amount of straw returning.It can be seen that the reasons for the aggravation of Corn Sheath Blight are as follows: straw returning to the field improves the temperature and humidity of the canopy of the field.By using SPSS 19 software on time of Maize Sheath Blight epidemic curve simulation,Logistic model can better simulate the dynamic changes of Maize Sheath Blight Disease index of different amount of straw with time and three times through the Logistic model to calculate the prevalence of the disease(incubation period,growth period and recession period).2.The decomposition of corn stalks in soil was preliminarily discussed.PH measuring instrument and EC value measuring instrument were used to measure the soil of different straw returning field respectively.The results showed that the soil pH value decreased obviously with the increase of the amount of straw returning,the EC value of the straw returning amount 9000kg/hm2 treatment was higher than that of the straw returning to the field 4500kg/hm2,and the EC value of the two was more stable than the No Straw Recyclingtreatment.In this experiment,a pot experiment was conducted to convert the proportion of straw and corn field to field to the effect of straw content on straw decomposition in potted soil area.In the experiment,the maximum straw decomposition rate in third weeks after the total straw was returned to field was 1.12%,while the straw decomposition rate decreased gradually from the first week to the first week.The weightlessness rate(V)of straw returned to field was less than half of straw returning to field,and 1/4 returned to field.The effect of different concentration of the solution on mycelium growth and sclerotia of CORB solanae was proved by the effect of soil decomposition solution of straw returning field on the mycelium sclerotium of maize Solanum blight.3.The effect of straw soil decomposing solution on Rhizoctonia solani was preliminarily cleared.It was found that the concentration of straw decomposition solution was 0.041g/ml on the growth of mycelium and the number of Sclerotinia sclerotiorum of maize sheath blight,while the concentration of straw full amount of straw decomposing solution was 0.0184g/ml,which could promote the growth of mycelium and the number of sclerotia.The effects of phenolic acids and fulvic acid on the pathogen of corn sheath blight were studied.The results showed that phenolic acids and fulvic acids inhibited the growth of mycelium,the number of sclerotia and the weight inhibition rate of sclerotia.The concentration of benzoic acid1~0.0625mg/ml inhibited the growth of mycelia and sclerotia and the weight of Rhizoctonia solani,and the inhibition rate was 100%.The bacteriostasis effect of the other 5 substances:eugenic acid > vanillic acid > para hydroxy benzoic acid > fulvic acid > phthalic acid,of which phthalic acid 0.5mg/ml,0.125mg/ml of para hydroxy benzoic acid can promote the number of corns,and 0.5mg/ml,phthalic acid 0.5,0.25mg/ml can promote the weight of Sclerotinia sclerotiorum.4.The equivalent relationship between the occurrence of Maize Sheath Blight and the amount of sclerotia and the number of sclerotia increased.Through the field comparison test,it was found that the number of Sclerotinia Sclerotinia increased gradually with the increase of the amount of straw returning to the field,and the number of the pathogenic Sclerotinia overwintering under the same straw returning amount increased with the increase of the initial bacteria source.The results of the effect of straw returning to the Overwintering Rate of the pathogen of Corn Sheath Blight showed that the Overwintering Rate of the pathogenic bacteria under different treatments was obviously different,and the Overwintering Rate of the pathogenic bacteria was also significantly different under the treatment of different bacteria sources.The results showed that the number of leaf sheath,the number of diseases,the area of the disease spot,the disease index,the growth rate of the disease spot,the number of Sclerotium producing and the primary infection of the pathogen were gradually increasing,and the initial invasion of the same pathogenic bacteria under the same straw returning amount of Corn Sheath Blight under the same straw returning amount of corn sheath blight.The number of sheath of Maize Sheath Blight increased with the increase of straw returning.5.It relationship between Overwintering Rate and initial sclerotia of Rhizoctonia solani was established.SAS9.0 software is applied to build and verify its reliability and validity.The results showed that the Linear model had better fitting effect on the quantitative overwintering of Maize Sheath Blight under different straw returning amount.Through the test of dynamic model fitting effect,the test results show that the Linear model is relatively suitable for the number of primary infection of Corn Sheath Blight under different straw returning field.Through the test of dynamic model fitting effect,the test results show that the Logistic model has the best dynamic fitting effect on several measurement indexes of Corn Sheath Blight under different straw returning fields.The dynamic model Linear of the initial Sclerotinia of Corn Sheath Blight under different straw returning and the dynamic model of the yield of Maize Sheath Blight with the change of the initial dyed sclerotium and the dynamic model Logistic of the onset of the primary dyed sclerotium,and the dynamic model of the variation of Maize Sheath Blight with the initial Sclerotinia amount under different straw returning fields. |
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