| Pepper is the largest vegetable crop in China,and it is also one of the most popular vegetables by the whole people.Capsici is one of the main diseases in pepper production.It may occur in the whole growth and development period of pepper,and the yield can be reduced by 30%to 100%.In recent years,livestock and poultry manure and other agricultural waste resources and materials are widely used,but the utilization rate is low.In view of the prevention and control of major diseases of pepper,it is of great practical significance to research and develop biological cultivation matrix with the functions of promoting growth and biological control,so as to realize the resource utilization of agricultural organic wastes such as livestock manure,which is of great practical significance to improve the production efficiency of pepper.In this experiment,the decomposed grassland sheep dung and grass charcoal were used as raw materials,and a pot experiment was used to screen out suitable cultivation substrates for pepper growth.At the same time,based on the selected suitable ratio substrates,it will have an antagonistic effect on the pathogen of pepper blight.The biocontrol Bacillus polymyxa K4 was expanded and cultured and inoculated into it to make a disease-preventing cultivation substrate to study its growth-promoting effect on pepper growth and its biocontrol effect on pepper blight.The main results are as follows:1.The optimum substrate for pepper cultivation was M7（sheep manure:peat=4:6）.The plant height,stem diameter and leaf area were higher than those of other treatments;the aboveground dry weight,underground dry weight,root activity and rhizosphere substrate microbial quantity increased by 4.73%,12.24%,5.28%and 9.73%respectively compared with the commercial substrate,and the bulk density was 0.249 g·cm-1.The results showed that the total porosity was 63.698%,the aeration porosity was 2.440%,the water holding porosity was 61.258%,p H value was 7.00,EC value was 3.49 m S·cm-1,organic matter content was598.20 g·kg-1,total phosphorus content was 8.61 g·kg-1,total potassium content was 7.72g·kg-1,total nitrogen was 13.93%The comprehensive score of M7 was 3.773,which was higher than that of commercial substrate and other treatments,so it was an ideal substrate ratio for pepper substrate cultivation.2.The disease-preventing cultivation substrate（LMK47）developed has a significant effect on pepper growth.The plant height,leaf area,dry matter above ground,dry matter underground,root vitality,total root length,total root surface area,total root volume,average root diameter and number of root tips in LMK47 treatment were significantly higher than those of the most suitable substrate（M7）.Treatment,the increase was 19.93%,53.23%,39.12%,14.89%,17.35%,44.18%,56.27%,34.65%,27.5%and 27.16%.3.The developed disease-preventing cultivation substrate（LMK47）has a significant effect on pepper blight.The morbidity and disease index of LMK47+LZWS1805（inoculation of Phytophthora capsici in the disease-preventing cultivation substrate）treatment were lower than that of M7+LZWS1805（the most suitable than the treatment of Phytophthora capsici in the substrate）treatment,and the treatment of LMK47+LZWS1805 had lower effects on pepper blight.The disease prevention rate is 32.62%.4.The biodefense mechanism of LMK47 was initially proved.The targeted center strain Bacillus polymyxa（K4）added in LMK47 has a direct inhibitory effect on the pathogen of pepper blight,with an inhibition rate of 59.54%;LMK47 substrate cultivation pepper can significantly activate the defense enzyme system in pepper leaves,and LMK47 treatment is better compared with M7 treatment,the activity of superoxide dismutase（SOD）in pepper leaves was increased by 624.77%,and the activity of PAL and the content of MDA decreased by 34.27%and 70.63%respectively,which improved the disease resistance of pepper.In conclusion,sheep manure and peat were used as raw materials to screen out the most suitable proportion of cultivation media（sheep manure:peat=4:6,volume ratio）,and then the expanded Bacillus polymyxa K4 was added to the substrate to prepare the disease control culture medium.Through the exploration of pot application effect,it was found that the disease control culture medium had good biocontrol effect on Pepper Blight,and could significantly promote the growth of pepper.The results provide a theoretical basis for the development and application of the special substrate for disease control of pepper. |
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