Special alkaline biocontrol organic fertilizer for bananas and preparation method thereof

Abstract

The invention discloses a special alkaline biocontrol organic fertilizer for bananas and a preparation method thereof, and belongs to the technical field of biological organic fertilizers. The special alkaline biocontrol organic fertilizer for bananas is prepared from the following raw materials: 25-30 parts of modified tobacco straw carbonized powder, 20-25 parts of a moringa seed fermentation product, 5-10 parts of a cactus fermentation product, 10-14 parts of seaweed residues, 8-12 parts of humic acid powder and 3-5 parts of shell powder, moringa seeds are subjected to enzymolysis and microbial inoculum fermentation, macromolecular substances are effectively decomposed into micromolecular substances, and the micromolecular substances are decomposed into micromolecular substances; achromobacter sosoli and acinetobacter tuberosa secrete various active substances, and the effect of resisting diseases and promoting growth of bananas is remarkable. According to the organic fertilizer disclosed by the invention, various substances are synergistically matched, the use of chemical bactericides is reduced, the banana wilt is effectively inhibited, the soil acidity is neutralized, the banana yield is increased, and the economic and social benefits are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological organic fertilizers, and particularly relates to a special alkaline biocontrol organic fertilizer for bananas and a preparation method thereof. Background Art

[0002] Bananas are large perennial herbaceous fruit trees and are one of the important cash crops in tropical and subtropical regions, playing an important role in the development of the agricultural economy. Bananas have the attribute of perennial rootstocks, with a large biomass, rapid growth, a large demand for nutrients, and an obvious phased and seasonal pattern in the law of nutrient absorption and utilization.

[0003] In recent years, the problem of excessive application of chemical fertilizers for bananas has become prominent. A large amount and frequent application of chemical fertilizers has led to a series of problems such as low fertilizer utilization rate, high production cost, decline in fruit quality, soil compaction and acidification, serious soil-borne diseases, and environmental pollution. In addition, due to the high economic value of bananas, the amount of fertilizer applied in production has increased year by year, and long-term and large-scale application of acidic or physiologically acidic chemical fertilizers has led to an aggravation of soil acidification in banana orchards. Soil acidification not only causes damage to the soil structure, a decline in soil fertility, and a reduction in soil microbial diversity and activity, but also leads to the germination of Fusarium oxysporum and the harm to banana growth, causing the outbreak of banana wilt disease, resulting in a reduction or even a complete loss of banana production. The occurrence and spread of banana wilt disease seriously restrict the development of the banana industry. Banana wilt disease is a typical soil-borne disease caused by the infection of the Cuban special form of Fusarium oxysporum, which is prone to break out in an acidic environment. Conventional chemical agents are difficult to play a continuous disease control role, and the control effects of measures such as soil fumigation and crop rotation are also very limited. However, when the pH value of the soil is significantly increased, the disease index of banana wilt disease is significantly reduced.

[0004] The replacement of chemical fertilizers with organic fertilizers is an important way to achieve zero growth in the amount of chemical fertilizers used. The main ways to achieve this include applying livestock and poultry manure, returning straw to the field, planting green manure, and applying new functional fertilizers. New composite microbial fertilizers have functions such as promoting growth, biocontrol, and resisting abiotic stress, and the research on reducing chemical fertilizer input has been increasingly valued. However, there are few comprehensive evaluations of the effects of new organic fertilizers, especially alkaline organic fertilizers that increase the soil pH, on soil properties, crop growth, yield, banana wilt disease resistance, and economic benefits. In particular, there is a lack of research on the combined effects of functional organic fertilizers and facility irrigation in tropical cash crops such as bananas. Therefore, it is particularly important to explore new biocontrol organic fertilizers for preventing and controlling banana diseases and increasing banana yield. Summary of the Invention

[0005] The purpose of the present invention is to provide a special alkaline biocontrol organic fertilizer for bananas, which can effectively prevent and control banana wilt disease, neutralize soil acidity, and increase banana yield.

[0006] To achieve the above technical purpose, the technical solution adopted by the present invention is as follows:

[0007] A special alkaline biocontrol organic fertilizer for bananas is prepared from the following raw materials in parts by weight: 25-30 parts of modified tobacco straw carbonized powder, 20-25 parts of moringa seed ferment, 5-10 parts of cactus ferment, 10-14 parts of seaweed residue, 8-12 parts of humic acid powder, and 3-5 parts of shell powder.

[0008] Furthermore, the pH value of the biocontrol organic fertilizer is greater than 8.0.

[0009] Furthermore, the preparation method of the moringa seed ferment is as follows:

[0010] Step S1: Take dried and crushed moringa seeds to obtain moringa seed powder, add a composite hydrolysis enzyme solution containing papain and cellulase, enzymatically hydrolyze at 45-55 °C for 4-6 h, inactivate at high temperature, cool to room temperature, and reserve the mixture;

[0011] Step S2: Add Achromobacter solvens and Acinetobacter gandensis to the mixture, ferment at 30 °C for 24-48 h to obtain moringa seed ferment.

[0012] Furthermore, in step S1 of the preparation method of the moringa seed ferment, the mass-volume ratio of moringa seed powder to the composite hydrolysis enzyme solution is 1 kg: 2 L.

[0013] Even further, the composite hydrolysis enzyme solution contains 15-18 g / L of papain and 10-14 g / L of cellulase.

[0014] Furthermore, in step S2 of the preparation method of the moringa seed ferment, Achromobacter solvens is purchased from the China General Microbiological Culture Collection Center, with the preservation number CGMCC 1.4514 and the original preservation date of June 27, 2005; Acinetobacter gandensis is purchased from the China General Microbiological Culture Collection Center, with the preservation number CGMCC 1.15884 and the original preservation date of September 20, 2016; the addition amount of Achromobacter solvens is 18-22 g / L, and the addition amount of Acinetobacter gandensis is 25-30 g / L.

[0015] Even further, the preparation methods of Achromobacter solvens and Acinetobacter gandensis are as follows: Pick single colonies of Achromobacter solvens and Acinetobacter gandensis and inoculate them into LB liquid medium, culture at 30 °C and 200 r / min until OD 600 = 0.6 to obtain seed liquid, inoculate the seed liquid into 5 L of LB liquid medium at 1% amount and culture at 30 °C and 200 r / min. Culture Achromobacter solvens until the viable count is greater than 1×10 10 CFU / mL, and culture Acinetobacter gandensis until it is greater than 2×10 10CFU / mL, collect the bacterial sludge by centrifugation, and prepare freeze-dried powder by adding trehalose, skim milk, and ascorbic acid respectively, then detect the viable counts of Achromobacter solis and Acinetobacter gandensis.

[0016] Furthermore, the viable count of Achromobacter solis is 10 billion / g, and the viable count of Acinetobacter gandensis is 20 billion / g.

[0017] Further, the preparation method of the modified tobacco straw carbonized powder is as follows:

[0018] Wash the waste tobacco straw, dry it, crush it through a 100-mesh sieve, put it into a reaction kettle, introduce nitrogen to evacuate the air, carbonize it at 500 °C for 2 h, cool it to room temperature after carbonization, soak the carbonized powder in 5% calcium hydroxide solution, stir for 2 - 3 h, filter and dry it; then mix the carbonized powder with magnesium oxide and calcine it at 400 °C for 1.5 h, and finally stir it in 10% urea-formaldehyde nitrogen solution at 60 °C for 2 h and then dry it to obtain the modified tobacco straw carbonized powder.

[0019] Furthermore, the preparation method of the urea-formaldehyde nitrogen solution is: Mix the formaldehyde solution with 60% of the total amount of urea, add sodium hydroxide solution to adjust the pH to 8 - 9, react in a water bath at 60 - 80 °C for 1 h, slowly add the remaining urea, naturally cool to 50 °C, and continue to react for 30 - 60 min until the viscosity reaches a syrup-like state to prepare the urea-formaldehyde nitrogen solution; The molar ratio of urea to formaldehyde is 1:1.5 - 2.0, and the formaldehyde solution is a 37% aqueous formaldehyde solution.

[0020] Furthermore, in the preparation method of the modified tobacco straw carbonized powder, the solid-liquid ratio of the carbonized powder, magnesium oxide, 5% calcium hydroxide solution, and 10% urea-formaldehyde nitrogen solution is 100 g:15 g:500 mL:400 mL.

[0021] A preparation method of a special alkaline biocontrol organic fertilizer for bananas includes the following steps:

[0022] (1) Cut fresh cactus into slices, dry it at 60 °C until the water content is less than 10%, crush it through a 60-mesh sieve, remove fiber lumps, adjust the water content to 50 - 55%, add EM bacterial agent and ferment for 7 days, and spread it out to dry until the water content is less than 20% after fermentation to obtain cactus ferment.

[0023] (2) Mix the modified tobacco straw carbonized powder, humic acid powder, and shell powder evenly, add moringa seed ferment, cactus ferment, and seaweed residue, and stir until there are no lumps to obtain a mixture.

[0024] (3) Granulate the mixture using a disc granulator, spray 5% water to assist in forming, screen out particles with a particle size of 2 - 4 mm, and dry it at 50 °C until the water content is less than 10% to obtain the final product, the alkaline biocontrol organic fertilizer.

[0025] The raw materials used in the present invention are all commercially available.

[0026] The shell powder and calcium hydroxide modified tobacco stalk charcoal can neutralize acidic soil, especially suitable for acidified banana orchards caused by long-term application of chemical fertilizers. The modified tobacco stalk carbonized powder is rich in magnesium oxide, which further enhances the alkaline regulation ability of the carbonized powder, promotes the absorption of medium and trace elements such as calcium and magnesium by bananas, and avoids the yellow leaf disease caused by the easy magnesium deficiency in bananas. The modified tobacco stalk carbonized powder forms a porous structure through high-temperature carbonization, and the calcium hydroxide and magnesium oxide loaded in the pores slowly release alkaline substances. The slow-release nitrogen source of urea-formaldehyde nitrogen solution reduces nutrient loss. In addition, the tobacco stalk carbonized powder contains nicotine-like substances, which have a certain inhibitory effect on fungal diseases.

[0027] The biocontrol organic fertilizer of the present invention adds moringa seeds, and a variety of natural active substances are produced during the fermentation process, which enhances root development, improves nutrient absorption ability, releases nutrients at the same time, and improves fertilizer efficiency; in addition, its antioxidant components can relieve the oxidative stress of plants and enhance the stress resistance of plants to acidic soil stress.

[0028] Two microbial strains are screened in the present invention. The two strains can not only accelerate the decomposition of moringa seeds, but also secrete a variety of active substances. Among them, Acinetobacter gandensis has the functions of secreting indole acetic acid and decomposing potassium, and Achromobacter xylosoxidans has the function of producing siderophores; in addition, both strains have an antagonistic effect on banana wilt disease, and the inhibitory effect on the pathogen of banana wilt disease is the best when the two strains are used together. The two strains are used in combination, cooperate synergistically, and have a significant effect on disease resistance and growth promotion.

[0029] Beneficial effects

[0030] The alkaline biocontrol organic fertilizer of the present invention adds the fermented product of moringa seeds. The moringa seeds are fermented by enzymatic hydrolysis and microbial agents, effectively decomposing macromolecular substances into small molecular substances, which can be directly absorbed by banana plants, promoting the growth of banana plants. At the same time, Achromobacter xylosoxidans and Acinetobacter gandensis secrete a variety of active substances, which have a significant effect on disease resistance and growth promotion of bananas.

[0031] The alkaline biocontrol organic fertilizer of the present invention uses a large amount of agricultural wastes such as tobacco stalks, seaweed residues and shell powder, reducing production costs, meeting the requirements of ecological circular agriculture. At the same time, the biocontrol organic fertilizer of the present invention can gradually neutralize soil acidity, reduce the toxicity caused by soil acidification in banana orchards, and extend the planting years.

[0032] The alkaline biocontrol organic fertilizer of the present invention has various substances cooperating synergistically, reduces the use of chemical fungicides, effectively inhibits banana wilt disease, improves banana yield, and improves economic and social benefits. Brief description of the drawings

[0033] Figure 1 It is a diagram for measuring the compatibility of the two strains used in the present invention. Note: A is Acinetobacter gandensis, and B is Achromobacter xylosoxidans;

[0034] Figure 2 Graph showing the measured results of soil pH values after banana harvesting for each treatment group. Detailed implementation manners

[0035] The technical solutions of the present invention will be further described below in conjunction with specific embodiments, but not limited thereto.

[0036] Example 1

[0037] A special alkaline biocontrol organic fertilizer for bananas, comprising the following raw materials in parts by weight: 25 parts of modified tobacco straw carbonized powder, 20 parts of moringa seed ferment, 5 parts of cactus ferment, 10 parts of seaweed residue, 8 parts of humic acid powder, and 3 parts of shell powder.

[0038] The preparation method of the moringa seed ferment is as follows:

[0039] Step S1: Take dried moringa seeds, crush them to obtain moringa seed powder, add a composite hydrolysis enzyme solution containing papain and cellulase, enzymatically hydrolyze at 45 - 55 °C for 4 - 6 h, inactivate at high temperature, cool to room temperature, and reserve the mixture;

[0040] Step S2: Add Achromobacter solubilans and Acinetobacter gandensis to the mixture, ferment at 30 °C for 24 - 48 h to obtain moringa seed ferment.

[0041] In step S1 of the preparation method of the moringa seed ferment, the mass - volume ratio of moringa seed powder to the composite hydrolysis enzyme solution is 1 kg: 2 L.

[0042] The composite hydrolysis enzyme solution contains 15 g / L of papain and 10 g / L of cellulase.

[0043] In step S2 of the preparation method of the moringa seed ferment, the preservation number of Achromobacter solubilans is CGMCC1.4514; the preservation number of Acinetobacter gandensis is CGMCC1.15884; the addition amount of Achromobacter solubilans is 18 g / L, and the addition amount of Acinetobacter gandensis is 25 g / L.

[0044] The viable count of Achromobacter solubilans is 10 billion / g, and the viable count of Acinetobacter gandensis is 20 billion / g.

[0045] The preparation method of the modified tobacco straw carbonized powder is as follows:

[0046] Wash the waste tobacco straw, dry it, crush it through a 100 - mesh sieve, put it into a reaction kettle, introduce nitrogen to exhaust air, carbonize at 500 °C for 2 h, cool to room temperature after carbonization, soak the carbonized powder in 5% calcium hydroxide solution, stir for 2 - 3 h, filter and dry; then mix the carbonized powder with magnesium oxide and calcine at 400 °C for 1.5 h, and finally stir in 10% urea - formaldehyde nitrogen solution at 60 °C for 2 h and then dry to obtain the modified tobacco straw carbonized powder.

[0047] In the preparation method of the modified tobacco straw carbonized powder, the solid-liquid ratio of the carbonized powder, magnesium oxide, 5% calcium hydroxide solution and 10% urea-formaldehyde nitrogen solution is 100 g: 15 g: 500 mL: 400 mL.

[0048] A preparation method of a special alkaline biological control organic fertilizer for bananas comprises the following steps:

[0049] (1) Slice fresh cactus, dry it at 60 °C until the water content is less than 10%, crush it through a 60-mesh sieve, remove fiber lumps, adjust the water content to 50 - 55%, add EM bacterial agent and ferment for 7 days, and after fermentation, spread it out to dry until the water content is less than 20% to obtain cactus fermented product;

[0050] (2) Mix the modified tobacco straw carbonized powder, humic acid powder, and shell powder evenly, add the moringa seed fermented product, cactus fermented product, and seaweed residue, and stir until there are no lumps to obtain a mixture;

[0051] (3) Granulate the mixture using a disk granulator, spray 5% water to assist in forming, screen out particles with a particle size of 2 - 4 mm, and dry at 50 °C until the water content is less than 10% to obtain the final product, the alkaline biological control organic fertilizer.

[0052] The pH value of the organic fertilizer is greater than 8.

[0053] Compatibility determination between strains

[0054] After activating the cryopreserved Achromobacter solvens and Acinetobacter gandensis, streak them on an LB plate medium and culture at 30 °C for 3 - 5 d. Respectively pick single colonies of the two bacteria and streak them on one medium to prove whether there is mutual inhibition between the two strains.

[0055] The growth states of the two cultured bacteria are as Figure 1 shown, where A is Acinetobacter gandensis and B is Achromobacter solvens. There is no obvious inhibition zone between the two bacteria, indicating that there is no obvious inhibition between them and they can be compounded.

[0056] Example 2

[0057] A special alkaline biological control organic fertilizer for bananas comprises the following raw materials in parts by weight: 28 parts of modified tobacco straw carbonized powder, 22 parts of moringa seed fermented product, 8 parts of cactus fermented product, 12 parts of seaweed residue, 10 parts of humic acid powder, and 4 parts of shell powder.

[0058] The preparation method of the moringa seed fermented product is as follows:

[0059] Step S1: Take dried moringa seeds, crush them to obtain moringa seed powder, add a composite hydrolysis enzyme solution containing papain and cellulase, enzymatically hydrolyze at 45 - 55 °C for 4 - 6 h, inactivate at high temperature, cool to room temperature, and reserve the mixture;

[0060] Step S2: Add *Achromobacter solis* and *Acinetobacter gandensis* to the mixture, and ferment at 30 °C for 24 - 48 h to obtain the fermented moringa seeds.

[0061] In step S1 of the preparation method of the fermented moringa seeds, the mass - volume ratio of moringa seed powder to the complex hydrolytic enzyme solution is 1 kg: 2 L.

[0062] The complex hydrolytic enzyme solution contains 16 g / L of papain and 12 g / L of cellulase.

[0063] In step S2 of the preparation method of the fermented moringa seeds, the preservation number of *Achromobacter solis* is CGMCC 1.4514; the preservation number of *Acinetobacter gandensis* is CGMCC 1.15884; the addition amount of *Achromobacter solis* is 20 g / L, and the addition amount of *Acinetobacter gandensis* is 27 g / L.

[0064] The viable count of *Achromobacter solis* is 10 billion / g, and the viable count of *Acinetobacter gandensis* is 20 billion / g.

[0065] The preparation method of the modified tobacco straw carbonized powder is as follows:

[0066] Wash the waste tobacco straw, dry it, crush it through a 100 - mesh sieve, put it into a reaction kettle, introduce nitrogen to exhaust air, carbonize at 500 °C for 2 h, cool to room temperature after carbonization, soak the carbonized powder in 5% calcium hydroxide solution, stir for 2 - 3 h, filter and dry; then mix the carbonized powder with magnesium oxide and calcine at 400 °C for 1.5 h, and finally stir in 10% urea - formaldehyde nitrogen solution at 60 °C for 2 h and then dry to obtain the modified tobacco straw carbonized powder.

[0067] In the preparation method of the modified tobacco straw carbonized powder, the solid - liquid ratio of the carbonized powder, magnesium oxide, 5% calcium hydroxide solution and 10% urea - formaldehyde nitrogen solution is 100 g: 15 g: 500 mL: 400 mL.

[0068] A preparation method of a special alkaline biological control organic fertilizer for bananas includes the following steps:

[0069] (1) Cut fresh cactus into slices, dry at 60 °C until the water content is less than 10%, crush through a 60 - mesh sieve, remove fiber lumps, adjust the water content to 50 - 55%, add EM bacterial agent and ferment for 7 days, and after fermentation, spread it out to dry until the water content is less than 20% to obtain the fermented cactus;

[0070] (2) Mix the modified tobacco straw carbonized powder, humic acid powder, and shell powder evenly, add the fermented moringa seeds, fermented cactus, and seaweed residue, and stir until there are no lumps to obtain a mixture;

[0071] (3) The mixture is granulated using a disk granulator, 5% water is sprayed in to assist in forming, granules with a particle size of 2 - 4 mm are screened out, and dried at 50 °C until the water content is less than 10% to obtain the final product of the biocontrol organic fertilizer.

[0072] The pH value of the biocontrol organic fertilizer is greater than 8.

[0073] Example 3

[0074] A special alkaline biocontrol organic fertilizer for bananas, comprising the following raw materials in parts by weight: 30 parts of modified tobacco straw carbonized powder, 25 parts of moringa seed ferment, 10 parts of cactus ferment, 14 parts of seaweed residue, 12 parts of humic acid powder, and 5 parts of shell powder.

[0075] The preparation method of the moringa seed ferment is as follows:

[0076] Step S1: Take dried moringa seeds, crush them to obtain moringa seed powder, add a composite hydrolysis enzyme solution containing papain and cellulase, enzymolyze at 45 - 55 °C for 4 - 6 h, inactivate at high temperature, cool to room temperature, and reserve the mixture;

[0077] Step S2: Add Achromobacter solvens and Acinetobacter gandensis to the mixture, ferment at 30 °C for 24 - 48 h to obtain the moringa seed ferment.

[0078] In step S1 of the preparation method of the moringa seed ferment, the mass - volume ratio of the moringa seed powder to the composite hydrolysis enzyme solution is 1 kg: 2 L.

[0079] The composite hydrolysis enzyme solution contains 18 g / L of papain and 14 g / L of cellulase.

[0080] In step S2 of the preparation method of the moringa seed ferment, the preservation number of Achromobacter solvens is CGMCC1.4514; the preservation number of Acinetobacter gandensis is CGMCC1.15884; the addition amount of Achromobacter solvens is 22 g / L, and the addition amount of Acinetobacter gandensis is 30 g / L.

[0081] The viable count of Achromobacter solvens is 10 billion / g, and the viable count of Acinetobacter gandensis is 20 billion / g.

[0082] The preparation method of the modified tobacco straw carbonized powder is as follows:

[0083] Wash the waste tobacco straw, dry it, crush it through a 100 - mesh sieve, put it into a reaction kettle, introduce nitrogen to evacuate the air, carbonize at 500 °C for 2 h, cool to room temperature after carbonization, soak the carbonized powder in a 5% calcium hydroxide solution, stir for 2 - 3 h, filter and dry; then mix the carbonized powder with magnesium oxide and calcine at 400 °C for 1.5 h, and finally stir in a 10% urea - formaldehyde nitrogen solution at 60 °C for 2 h and then dry to obtain the modified tobacco straw carbonized powder.

[0084] In the preparation method of the modified tobacco straw carbonized powder, the solid-liquid ratio of the carbonized powder, magnesium oxide, 5% calcium hydroxide solution and 10% urea-formaldehyde nitrogen solution is 100 g: 15 g: 500 mL: 400 mL.

[0085] A preparation method of a special alkaline biological control organic fertilizer for bananas comprises the following preparation steps:

[0086] (1) After slicing fresh cactus, dry it at 60 °C until the water content is less than 10%, crush it through a 60-mesh sieve, remove fiber lumps, adjust the water content to 50 - 55%, add EM bacterial agent and ferment for 7 days, and after fermentation, spread it out to dry until the water content is less than 20% to obtain cactus fermented product;

[0087] (2) Mix the modified tobacco straw carbonized powder, humic acid powder and shell powder evenly, add the moringa seed fermented product, cactus fermented product and seaweed residue, and stir until there are no lumps to obtain a mixture;

[0088] (3) Granulate the mixture using a disk granulator, spray 5% water to assist in forming, screen out particles with a particle size of 2 - 4 mm, and dry at 50 °C until the water content is less than 10% to obtain the final product of biological control organic fertilizer.

[0089] The pH value of the biological control organic fertilizer is greater than 8.

[0090] Comparative Example 1

[0091] Compared with Example 1, in the preparation process of the moringa seed fermented product, only Acinetobacter gentes (43 g) is added, and the other raw materials and steps are the same as those in Example 1.

[0092] Comparative Example 2

[0093] Compared with Example 1, in the preparation process of the moringa seed fermented product, only Achromobacter solutus (43 g) is added, and the other raw materials and steps are the same as those in Example 1.

[0094] Comparative Example 3

[0095] Compared with Example 1, in the preparation process, the moringa seeds are not fermented with Acinetobacter gentes and Achromobacter solutus, and the other raw materials and steps are the same as those in Example 1.

[0096] Comparative Example 4

[0097] Compared with Example 1, in the preparation process, the moringa seed fermented product is not added, and the other raw materials and steps are the same as those in Example 1.

[0098] Comparative Example 5

[0099] Compared with Example 1, except that the tobacco straw carbonized powder is not modified with magnesium oxide and urea-formaldehyde nitrogen solution, the other raw materials and steps are the same as those in Example 1.

[0100] Performance test

[0101] Functional identification of Acinetobacter gandensis and Achromobacter solus

[0102] Determination of indole-3-acetic acid (IAA) production ability: The Salkowski colorimetric method was used to determine the IAA production ability of the strains. The deeper the red color after the reaction, the stronger the IAA production ability of the strains. The absorbance was measured at 530 nm, and then the IAA production amount was calculated according to the standard curve of IAA.

[0103] Determination of potassium-dissolving ability: The activated strains were inoculated into 50 mL of seed liquid medium and cultured for 48 h, then centrifuged at 6000 r / min for 10 min to discard the supernatant. The cells without medium were collected and suspended in deionized water to prepare a cell suspension (OD 600 = 0.6). The cell suspension was inoculated into potassium-dissolving liquid medium at an inoculation amount of 5%, and cultured for 7 d. An equal amount of inactivated cell suspension was used as a control treatment. Take 10 mL of the fermentation broth of the potassium-dissolving liquid medium, add 2 mL of H2O2, digest it in a boiling water bath for 1 h, and make up to 10 mL with deionized water. Centrifuge at 10000 r / min for 5 min, and take the supernatant to measure the potassium content by flame spectrophotometry. Compare with the blank control and calculate the decomposition rate of the strain to potassium feldspar ore powder.

[0104] Determination of siderophore production ability: The CAS detection method was used. Record the color and size of the orange halo. Use a vernier caliper to measure the diameter (D) of the orange siderophore halo of a single colony and the colony diameter (d), and judge the siderophore production ability of the strain by the ratio of D / d.

[0105] Determination of the ability to inhibit pathogenic bacteria:

[0106] The antagonistic effect of microbial inoculants against banana wilt was determined by the plate confrontation culture method. A 5-mm-diameter bacterial cake of the banana wilt pathogen was inoculated in the center of a petri dish. A 5-mm-sterilized filter paper was pasted about 2 cm to the left and right of the center of the pathogen. 5 μL of the fermentation broth of the two strains prepared in Example 1 of the present invention was added dropwise to the filter paper. The treatment of only inoculating the pathogen bacterial cake without inoculating the microbial inoculant of the present invention was used as a control, and each treatment was repeated 3 times. The inoculated petri dishes were placed in an incubator at 30 °C for culture. The colony diameter of the pathogen in each treatment was measured, and the inhibition rate was calculated by the mycelial growth rate method.

[0107] The measurement results are as follows:

[0108] Table 1 Identification of the abilities of two strains

[0109] Strain IAA production (mg / L) Potassium solubilization rate (%) Siderophore production ability Fusarium wilt inhibition rate (%) Acinetobacter gandensis 42.4 22.53 1.16 52.3 Achromobacter guttatus — 1.85 3.71 65.2

[0110] Note: — indicates that the test reaction is negative.

[0111] Through the confrontation experiment on flat plates, it was found that the two strains added in the present invention had obvious inhibitory effects on the pathogen of banana wilt disease.

[0112] Planting experiment

[0113] Banana variety for test: Brazilian banana.

[0114] Test field: Conducted in Danzhou City, Hainan Province. The soil is laterite, the soil pH value is 5.1, and continuous banana planting has led to severe incidence of banana wilt disease.

[0115] The test was set with 9 treatment groups: a conventional fertilization group (CK) and the biocontrol organic fertilizers T1 - T8 prepared in Examples 1 - 3 and Comparative Examples 1 - 5 of the present invention. The fertilization amount of the conventional fertilization group was pure N 600 kg / hm 2 , P2O5 300 kg / hm 2 , K2O 900 kg / hm 2 , and the fertilizers were applied in 10 times; the fertilization method for treatment groups T1 - T8 was to be applied once as the base fertilizer, and the application amount was 1 t / hm 2 . Each treatment group had 3 replicates, the test plots were arranged in a randomized block design, the row spacing was 2.3 m, the plant spacing was 2 m, and each plot had 20 banana plants. The daily management measures for each treatment were the same.

[0116] Data statistics: Statistics were made on indicators such as yield and control effect, the incidence situation was investigated, and the disease level was determined based on the proportion of the brown - stained area in the longitudinal section of the banana seedling corm: level 0 was no brown stain on the corm; level 1 was the brown - stained area of the corm ≤ 25%; level 3 was 25% < the brown - stained area of the corm ≤ 50%; level 5 was 50% < the brown - stained area of the corm ≤ 75%; level 7 was the brown - stained area of the corm > 75%. The disease index and control effect of each treatment were calculated. Disease index = ∑(number of diseased plants at each level × representative value of that level) / (total number of plants × representative value of the highest level) × 100; Control effect = (control disease index - treatment disease index) / control disease index × 100%. After the banana harvest was completed, the plough layer soil of each test plot was collected for pH value measurement, and the statistical results are shown in Figure 2 .

[0117] Table 2 Planting effects

[0118] Disease index Control effect (%) Yield (t / mu) Yield increase rate (%) CK 20.5 — 2.93 — Example 1 3.9 80.98 4.07 38.91 Example 2 5.7 72.19 4.01 36.86 Example 3 6.1 70.24 3.98 35.87 Comparative Example 1 10.8 47.32 3.62 23.55 Comparative Example 2 8.5 58.54 3.74 27.65 Comparative Example 3 17.3 15.61 3.25 10.92 Comparative Example 4 18.2 11.22 3.19 8.87 Comparative Example 5 7.4 63.9 3.82 30.38

[0119] It can be seen from the data in Table 2 that the biocontrol organic fertilizer of the present invention can effectively control banana wilt disease and increase the banana yield. For Comparative Examples 1 - 5 where the composition of the organic fertilizer was changed, the synergistic effect of each substance was broken, the disease resistance of bananas was significantly reduced, and thus the yield was decreased.

[0120] It should be noted that the above embodiments are only some of the embodiments of the preferred ways to implement the present invention, rather than all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

Claims

1. A special alkaline biological control organic fertilizer for bananas, characterized in that, It is prepared from the following raw materials in parts by weight: 25-30 parts of modified tobacco straw carbonized powder, 20-25 parts of moringa seed ferment, 5-10 parts of cactus ferment, 10-14 parts of seaweed residue, 8-12 parts of humic acid powder, and 3-5 parts of shell powder.

2. The special alkaline biocontrol organic fertilizer for bananas according to claim 1, characterized in that, The preparation method of the moringa seed ferment is as follows: Step S1: Take dried moringa seeds, crush them to obtain moringa seed powder, add a composite hydrolysis enzyme solution containing papain and cellulase, enzymatically hydrolyze at 45-55°C for 4-6 hours, inactivate at high temperature, cool to room temperature, and reserve the mixture; Step S2: Add Achromobacter solubilans and Acinetobacter gandensis to the mixture, ferment at 30°C for 24-48 hours to obtain moringa seed ferment.

3. The banana-specific alkaline biocontrol organic fertilizer according to claim 2, wherein In step S1 of the preparation method of the moringa seed ferment, the mass-volume ratio of the moringa seed powder to the composite hydrolysis enzyme solution is 1 kg: 2 L.

4. The special alkaline biocontrol organic fertilizer for bananas according to claim 3, wherein The composite hydrolysis enzyme solution contains 15-18 g / L of papain and 10-14 g / L of cellulase.

5. The banana-specific alkaline biocontrol organic fertilizer according to claim 2, wherein In step S2 of the preparation method of the moringa seed ferment, the preservation number of Achromobacter solubilans is CGMCC 1.4514, and the preservation number of Acinetobacter gandensis is CGMCC 1.15884; the addition amount of Achromobacter solubilans is 18-22 g / L, and the addition amount of Acinetobacter gandensis is 25-30 g / L.

6. The special alkaline biocontrol organic fertilizer for bananas according to claim 5, wherein The viable count of Achromobacter solubilans is 10 billion / g, and the viable count of Acinetobacter gandensis is 20 billion / g.

7. The special alkaline biological organic fertilizer for bananas according to claim 1, characterized in that, The preparation method of the modified tobacco straw carbonized powder is as follows: Wash the waste tobacco straw, dry it, crush it through a 100-mesh sieve, put it into a reaction kettle, introduce nitrogen to evacuate the air, carbonize at 500°C for 2 hours, cool to room temperature after carbonization, soak the carbonized powder in 5% calcium hydroxide solution, stir for 2-3 hours, filter and dry; then mix the carbonized powder with magnesium oxide and calcine at 400°C for 1.5 hours, and finally stir in 10% urea-formaldehyde nitrogen solution at 60°C for 2 hours and dry to obtain the modified tobacco straw carbonized powder.

8. The banana-special alkaline biocontrol organic fertilizer according to claim 7, wherein In the preparation method of the modified tobacco straw carbonized powder, the solid-liquid ratio of the carbonized powder, magnesium oxide, 5% calcium hydroxide solution, and 10% urea-formaldehyde nitrogen solution is 100 g: 15 g: 500 mL: 400 mL.

9. A preparation method of the special alkaline biological control organic fertilizer for bananas described in claims 1-8, characterized in that, It is prepared by the following steps: (1) Cut fresh cactus into slices, dry at 60°C until the water content is less than 10%, crush through a 60-mesh sieve, remove fiber lumps, adjust the water content to 50-55%, add EM bacterial agent and ferment for 7 days, and after fermentation, spread it out to dry until the water content is less than 20% to obtain cactus ferment; (2) Mix the modified tobacco straw carbonized powder, humic acid powder, and shell powder evenly, add the moringa seed ferment, cactus ferment, and seaweed residue, and stir until there are no lumps to obtain a mixture; (3) Granulate the mixture using a disk granulator, spray 5% water to assist in forming, screen out particles with a particle size of 2-4 mm, and dry at 50°C until the water content is less than 10% to obtain the final product of alkaline biocontrol organic fertilizer.

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