| Livestock farming waste is one of the sources of agricultural surface pollution.Organic fertilizer production based on aerobic composting is one of the most widespread and effective ways to treat and apply livestock manure,and organic fertilizer will become the new normal for fertilizer application in agriculture in the future.However,organic fertilizer has weak function,poor effect,difficult to promote,lack of functional products and other problems;and long-term soil crop,chemical fertilizer indiscriminate application,pesticide indiscriminate use of the soil structure has been damaged,soil acidification,salinization,caking,sticky and other problems,crops appear wilt,green wilt,blight,root rot and a series of problems,crop production quality seriously reduced.Compound microbial organic fertilizer is a ternary compound of microbial bacteria,inorganic nutrients and organic fertilizer,which will have a better role and application prospect in water retention and fertilization of soil,improving quality and yield,preventing and controlling soil-borne diseases,and improving fertilizer utilization.It will have a better role and application prospect in improving the function and value of organic fertilizer,in water retention and fertilization of soil,improving quality and yield,preventing and controlling soil-borne diseases,and improving the utilization rate of fertilizer.Based on this,this study screened functional strains of disease prevention,developed compound microbial organic fertilizer,and investigated the effects of compound microbial organic fertilizer on growth indexes and soil physicochemical properties of tomato and cucumber,laying the foundation for high value utilization of animal manure and disease prevention and growth promotion of tomato and cucumber.The main research results are as follows:(1)Screening and identification of functional strains for disease prevention and growth promotion.The 51 functional strains preserved in the laboratory were re-screened using the plate standoff method,and six strains with good bacterial inhibitory effect on pathogenic bacteria were obtained.The sequencing analysis showed that 8 were Bacillus amyloliquefaciens,17 were Bacillus velezensis,21 were Paenibacillus polymyxa,25 were Bacillus siamese),45 Bacillus subtilis,51 Bacillus velezensis,respectively,against five common pathogens such as Phytophthora capsici,Aspergillus and Fusarium.These six strains of functional bacteria have significant inhibition effect on the five common pathogens,and have the potential to be developed into a compound bacterial agent for disease prevention and growth promotion,as well as a compound microbial organic fertilizer.(2)Inhibition effect of functional bacteria and bioactive substance detection.The perforation inhibition test showed that all six strains of functional bacteria were highly inhibitory to five common pathogenic bacteria of tomato and cucumber,which could lead to changes such as reduction of survival sites of pathogenic bacteria,deterioration of survival environment and hindrance of mycelial growth,and their fermentation supernatant had the best inhibition effect on pathogenic bacteria.Meanwhile,the six functional strains were determined to be able to secrete gelatinase to liquefy and decompose the insoluble gelatin into amino acids.And Bacillus amylolyticus(8),Bacillus belleus(17),Bacillus polymyxa(21),Bacillus siamensis(25),Bacillus subtilis(45)and Bacillus belleus(51)all had the ability to secrete protease with the hyaline circle width(D value)of 3mm,12 mm,5mm,15 mm,8mm and 5mm,respectively.(3)Formulation of compound bacterial agent.The plate confrontation test showed that there was no antagonism between Bacillus belleus(17),Bacillus polymyxa(21)and Bacillus siamensis(25)in complex I.Similarly,there was no antagonism between Bacillus amyloliquefaciens(8),Bacillus subtilis(45)and Bacillus belleus(51)in complex II.The volume ratio of Bacillus subtilis(45): Bacillus subtilis(51): Bacillus amyloliquefaciens(8)= 1:2:2,and the volume ratio of Bacillus subtilis(45): Bacillus amyloliquefaciens(51): Bacillus amyloliquefaciens(8)= 1:2:2.The combination of strains can not only improve the stability of The strain combination can not only improve the stability of each functional bacteria,but also make the functional bacteria function efficiently,which can provide more theoretical basis for its production application.(4)Study on the growth promotion effect of compound bacterial agent on tomato and cucumber.After 45 and 60 days of treatment in different experimental groups of tomato,the height of tomato plants in the treatment group with the application of Fungicide Complex II was extremely significantly higher than the control group CK,increasing by 10.30% and12.16%,respectively;after 17 days of treatment,the leaf width of tomato in the treatment group with Fungicide Complex II was extremely significantly higher than that in the treatment group with CK,increasing by 17.69%,and the concentration of chlorophyll a in tomato in the treatment group with the addition of Fungicide Complex II was extremely The concentration of tomato chlorophyll a in the treatment group with the addition of Fungicide II was significantly higher than that in the CK treatment group,increasing by19.05%;both Fungicide I and Fungicide II promoted the growth of tomato root system,increasing the root weight of tomato by 30.13% and 27.30%,respectively,compared to the control group.After 15 days of treatment in different experimental groups of cucumber,the leaf width of cucumber in the treatment group with the addition of Fungicide Complex II was extremely significantly higher than that of the control group CK,which increased by6.13%.Comprehensive tomato and cucumber throughout the planting cycle,the compound bacterial agent can promote the growth of tomato and cucumber to different degrees,with good growth promoting effect.(5)Study on the effect of compound microbial organic fertilizer on the growth promotion of tomato.After 17 days of treatment in different experimental groups of tomatoes,the height and leaf width of tomato plants in the treatment group with compound microbial organic fertilizer I were extremely significantly higher than those in the inorganic fertilizer application group,increasing by 35.65% and 59.07%,respectively;after 45,60 and 75 days of treatment,the stem thickness of tomatoes in the treatment group with compound microbial organic fertilizer I was extremely significantly higher than those in the inorganic fertilizer treatment group,increasing by 18.17%,20.77% and 16.03% respectively.After 17 days of treatment in different experimental groups of tomatoes,the height and leaf width of tomato plants in the treatment group with compound microbial organic fertilizer II were extremely significantly higher than those in the inorganic fertilizer treatment group,with an increase of 42.62% and 70.21%,respectively;after 45,60 and 75 days of treatment,the stem thickness of tomatoes in the treatment group with compound microbial organic fertilizer II was extremely significantly higher than those in the inorganic fertilizer treatment group,with an increase of 18.61%,13.70% and 11.74%,respectively.and 11.74%,respectively.Both Compound Microbial Organic Fertilizer I and Compound Microbial Organic Fertilizer II significantly improved the growth indexes of tomato plant height,leaf width and stem thickness and were better than inorganic fertilizers,which have the potential to replace inorganic fertilizers.(6)Study on the effect of compound microbial organic fertilizer on the growth promotion of cucumber.After 40 days of treatment in different experimental groups of cucumber,the height of cucumber plants in the treatment group with compound microbial organic fertilizer I was extremely significantly higher than that in the inorganic fertilizer application group,with an increase of 11.30%;after 5 and 10 days of treatment,the leaf width of cucumber in the treatment group with compound microbial organic fertilizer I was extremely significantly higher than that in the inorganic fertilizer treatment group,with an increase of 20.33% and17.06%,respectively.After 5 and 10 days of treatment,the leaf width of cucumber in the group treated with compound microbial organic fertilizer II was extremely significantly higher than that in the group treated with inorganic fertilizer,which increased by 25.20%and 19.41%,respectively.(7)Effect of compound microbial organic fertilizer on soil index of tomato and cucumber.The fast-acting phosphorus content of tomato soil in the treatment group of compound microbial organic fertilizer I was highly significantly higher than that of organic fertilizer treatment group and inorganic fertilizer treatment group,with an increase of 14.68%and 35.88%,respectively;the fast-acting potassium content of tomato soil in the treatment group of compound microbial organic fertilizer I was highly significantly higher than that of organic fertilizer and inorganic fertilizer treatment group,with an increase of 56.92%and 240.00%,respectively.Meanwhile,the fast-acting phosphorus content in the soil of cucumber in the compound microbial organic fertilizer II treatment group was extremely significantly higher than that in the inorganic fertilizer treatment group,with an increase of9.00%,and the fast-acting potassium content in the soil of cucumber in the compound microbial organic fertilizer II treatment group was extremely significantly higher than that in the organic fertilizer treatment group and the inorganic fertilizer treatment group,with an increase of 21.91% and 42.67%,respectively.In summary,the six strains of biocontrol bacteria had good inhibition effect on the pathogenic bacteria of five crops.Compound Fungicide I could significantly promote the growth of tomato and cucumber roots compared with CK treatment;compared with Compound Fungicide I,Compound Fungicide II could significantly promote the plant height,leaf width,stem thickness and chlorophyll synthesis of tomato.The tomato and cucumber planting tests showed that compound microbial organic fertilizers I and II could improve soil fast-acting phosphorus and fast-acting potassium content and soil environment while promoting the growth of tomato and cucumber.It further verified the efficacy of compound microbial organic fertilizers,which have the potential to replace inorganic fertilizers and broad application prospects. |
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