Compound microbial fertilizer for soil improvement and green preparation method thereof

Abstract

The invention relates to the technical field of microbial fertilizers, in particular to a compound microbial fertilizer for soil improvement and a green preparation method thereof.The compound microbial fertilizer is prepared from screened and purified compound bacteria, EM bacteria, bacillus megatherium, bacillus mucilaginosus, photosynthetic bacteria, mesoporous silica, humic acid and fermented cottonseed meal; screened and purified compound bacteria are introduced, are obtained by screening and purifying cow dung, and contain a plurality of microbial strains with specific functions. The bacterial strains can form dominant bacterial communities in soil, inhibit growth of harmful microorganisms through a competitive effect, regulate a soil microbial community structure and improve a soil micro-ecological environment, and the compound microbial fertilizer can improve a soil physical structure, regulate soil chemical properties and a microbial environment and improve the soil micro-ecological environment through synergistic cooperation of all the components, so that the compound microbial fertilizer has the advantages of low cost and high efficiency. The problems of soil hardening, physicochemical property reduction and the like caused by long-term use of chemical fertilizers are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of microbial fertilizers, in particular to a composite microbial fertilizer for soil improvement and an environmentally friendly preparation method thereof. Background Art

[0002] During the growth of crops, sufficient nutrients are needed to maintain normal physiological metabolism and growth and development. Fertilizer, as a key substance for supplementing soil nutrients, plays an irreplaceable role in agricultural production.

[0003] Traditional chemical fertilizers, with their high nutrient content and rapid effectiveness, have played an important role in increasing crop yields and are widely used in agricultural production. However, the long-term and extensive use of chemical fertilizers has also brought about a series of serious problems.

[0004] On the one hand, excessive application of chemical fertilizers disrupts the soil's original nutrient balance, leading to salt accumulation, soil structure destruction, and compaction. This reduces soil air and water permeability, restricts root growth space, and hinders crop roots' absorption of water and nutrients. On the other hand, the irrational use of chemical fertilizers can also degrade the soil's physical and chemical properties, reduce the number and activity of beneficial microorganisms, and disrupt the structure of soil microbial communities, thereby affecting soil biological activity and ecological functions.

[0005] The decline in soil quality has inhibited the growth and development of subsequently planted crops, increased the frequency of pests and diseases, and ultimately led to a significant reduction in crop yields, seriously affecting the sustainable development of agriculture.

[0006] Therefore, developing a new type of fertilizer that can improve soil quality and promote crop growth has become an urgent problem to be solved in the agricultural field. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a compound microbial fertilizer for soil improvement and an environmentally friendly preparation method thereof.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A composite microbial fertilizer for soil improvement is composed of the following raw materials in parts by weight: 6-10 parts of screened and purified composite bacteria, 3-5 parts of EM bacteria, 2-3 parts of Bacillus megaterium, 2-4 parts of Bacillus mucilaginosus, 1-2 parts of photosynthetic bacteria, 15-20 parts of mesoporous silica, 4-6 parts of humic acid, and 30-40 parts of fermented cottonseed meal.

[0010] As a further technical solution, the specific surface area of the mesoporous silica is 600-700m 2 / g, average pore diameter of 5-8nm, pore volume of 0.8-1.2cm 3 / g, this parameter range can increase the adsorption and fixation efficiency of mesoporous silica on microorganisms and nutrients by 30-50%, significantly enhancing the stability and slow-release properties of the fertilizer.

[0011] As a further technical solution, the preparation method of the fermented cottonseed meal is:

[0012] High-quality cottonseed meal without mildew, with a crude protein content of 42% or more and an impurity content of less than 1% was selected and crushed to 100-110 mesh using a hammer mill; the crushed cottonseed meal was placed in a clean stainless steel container, deionized water (1.2-1.5 times the weight of the cottonseed meal) was added, and the mixture was stirred at a speed of 100-110 r / min for 18-20 minutes to form a paste; a composite fermentation agent composed of lactic acid bacteria, yeast, and bacillus in a weight ratio of 1:1:2 was prepared and mixed with sterile water to prepare an agent concentration of 1.2×10 8 -1.5×10 8 The method comprises the following steps: a bacterial liquid containing 0.6-0.8% CFU / mL of bacterial liquid is added to a paste material in an amount of 0.6-0.8% by weight of cottonseed meal, and the mixture is stirred again for 8-10 minutes; the inoculated material is transferred to a fermentation tank with a sealed lid, the temperature is controlled at 32-34°C, and the temperature fluctuation does not exceed ±0.5°C; the material is stirred every 7 hours to a depth of 2 / 3 of the material layer; the pH value, temperature and odor of the material are tested every day; and the fermentation ends after 4 days when the pH value drops to 4.2-4.4; and the fermented material is placed in a belt dryer for drying to produce fermented cottonseed meal.

[0013] As a further technical solution, the drying in the belt dryer is:

[0014] Dry at 52-55℃, keep the material layer thickness at 4cm, and reduce the moisture content to 8-9%.

[0015] As a further technical solution, the method for screening and purifying the composite bacteria is as follows: collecting a fresh cow dung sample, adding it to a triangular flask containing beef extract peptone culture medium, and oscillating and culturing it for 36 hours at 32-34°C and 180r / min for enrichment culture; using the dilution spread plate method to inoculate the enriched cultured bacterial liquid onto the beef extract peptone solid culture medium, and culturing it in a constant temperature incubator at 32-34°C for 36 hours; after the colonies grow, selecting single colonies with different morphologies, colors, sizes, etc., and mixing them to obtain the composite bacteria.

[0016] As a further technical solution, the beef extract peptone culture medium includes: 3g beef extract, 10g peptone, 5g sodium chloride, 1000mL distilled water, pH 7.0-7.2.

[0017] The preparation method of compound microbial fertilizer comprises the following steps:

[0018] Screening and purification of bacteria: screening and purifying the purified composite bacteria from cow dung according to the above method;

[0019] Bacterial culture: Bacillus megaterium, Bacillus mucilaginosus, and photosynthetic bacteria were inoculated into the corresponding liquid culture medium, and cultured at 32-34°C and 180 r / min for 36 h until the bacterial solution concentration reached 1.4×10 8 -1.6×10 8 CFU / mL, EM bacteria were commercially available;

[0020] Raw material mixing: mesoporous silica, humic acid, and fermented cottonseed meal were mixed in a double-shaft paddle mixer at a speed of 80-100 r / min for 15 minutes to obtain a solid mixed raw material;

[0021] Adding the bacterial agent: add the cultured Bacillus megaterium, Bacillus mucilaginosus, photosynthetic bacteria liquid, EM bacteria and screened and purified composite bacteria to the solid mixed raw materials according to the weight ratio and stir thoroughly;

[0022] Drying and molding: Dry the mixed materials at 50-55°C to reduce the moisture content to below 8-10%, and then granulate them through a disc granulator. The particle size of the granulated particles is 2.5-3.5mm. Granular compound microbial fertilizer is made and vacuum-sealed for packaging.

[0023] As a further technical solution, the liquid culture medium of Bacillus megaterium is composed of: 10 g glucose, 5 g yeast powder, 2 g potassium dihydrogen phosphate, 0.5 g magnesium sulfate, and 1000 mL distilled water, with a pH of 7.0-7.2; the liquid culture medium of Bacillus mucilaginosus is composed of: 12 g sucrose, 3 g sodium nitrate, 2 g dipotassium hydrogen phosphate, 0.2 g magnesium sulfate, 0.01 g manganese sulfate, and 1000 mL distilled water, with a pH of 7.2-7.4; and the liquid culture medium of photosynthetic bacteria is composed of: 1 g ammonium chloride, 0.6 g potassium dihydrogen phosphate, 0.2 g magnesium sulfate, 2 g sodium chloride, 2 g sodium bicarbonate, 0.1 g yeast extract, and 1000 mL distilled water, with a pH of 7.0-7.5.

[0024] As a further technical solution, before the raw material mixing step, the mesoporous silica is surface modified by immersing it in a 3-4% by mass silane coupling agent ethanol solution, stirring it at 50-55°C for 2-3h, and then filtering, washing, and drying it to constant weight.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The composite microbial fertilizer of the present invention exhibits significant advantages in improving soil and promoting crop growth through the synergistic effect of its components:

[0027] The introduction of mesoporous silica, with its specific specific surface area, average pore size, and pore volume, allows for efficient adsorption and fixation of microorganisms and nutrients, significantly enhancing the stability and slow-release properties of the fertilizer. This allows for the slow release of nutrients into the soil, preventing rapid nutrient loss, improving fertilizer utilization, and continuously providing nutrients for crop growth.

[0028] By introducing humic acid, a natural organic macromolecular substance, it can improve soil aggregate structure, increase soil porosity, and enhance soil water and fertilizer retention. It can also react with metal ions in the soil to reduce the toxic effects of heavy metal ions on crops, while stimulating crop root growth and enhancing crop resistance.

[0029] Through a specific fermentation process, cottonseed meal is enriched with nutrients such as amino acids and protein, as well as a large number of beneficial microbial metabolites. These substances provide a rich source of carbon and nitrogen for soil microorganisms, promoting their growth and activity and improving the microbial environment. Furthermore, organic acids and other substances produced during the fermentation process can regulate soil pH, making the soil more suitable for crop growth.

[0030] The combined use of EM bacteria, Bacillus megaterium, Bacillus mucilaginosus and photosynthetic bacteria can decompose organic matter in the soil, release nutrients such as nitrogen, phosphorus and potassium, and improve the effectiveness of soil nutrients; inhibit the growth and reproduction of pathogens in the soil, reduce the occurrence of soil-borne diseases; enhance the biological activity of the soil and improve the soil ecological environment.

[0031] By introducing a screened and purified composite bacteria, obtained by screening and purification from cow dung, the bacteria contain multiple microbial strains with specific functions. These strains can form dominant bacterial communities in the soil, inhibiting the growth of harmful microorganisms through competition, regulating the soil microbial community structure, and improving the soil microecological environment. Furthermore, the screened and purified composite bacteria can produce a variety of extracellular enzymes, such as cellulases and proteases, which accelerate the decomposition and transformation of organic matter in the soil, promote the formation of humus, and improve soil fertility. They can also secrete plant hormones and growth regulators, stimulating crop root growth, enhancing the crop's ability to absorb nutrients, and improving the crop's stress resistance and yield.

[0032] The composite microbial fertilizer of the present invention improves the soil from multiple aspects through the synergistic cooperation of various components. It can not only improve the physical structure of the soil, but also regulate the chemical properties and microbial environment of the soil. It effectively solves the problems of soil compaction and deterioration of physical and chemical properties caused by long-term use of chemical fertilizers, and significantly improves soil quality and crop yields. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0034] The present application provides a compound microbial fertilizer for soil improvement and a preparation method thereof.

[0035] The composite microbial fertilizer of the present application is composed of 6-10 parts of screened and purified composite bacteria, 3-5 parts of EM bacteria, 2-3 parts of Bacillus megaterium, 2-4 parts of Bacillus subtilis, 1-2 parts of photosynthetic bacteria, 15-20 parts of mesoporous silica, 4-6 parts of humic acid, and 30-40 parts of fermented cottonseed meal.

[0036] The specific surface area of mesoporous silica is 600-700m 2 / g, average pore diameter of 5-8nm, pore volume of 0.8-1.2cm 3 / g, this parameter range can increase the adsorption and fixation efficiency of mesoporous silica on microorganisms and nutrients by 30-50%, significantly enhancing the stability and slow-release properties of the fertilizer.

[0037] The preparation method of fermented cottonseed meal is as follows:

[0038] High-quality cottonseed meal without mildew, with a crude protein content of 42% or more and an impurity content of less than 1% was selected and crushed to 100-110 mesh using a hammer mill; the crushed cottonseed meal was placed in a clean stainless steel container, deionized water (1.2-1.5 times the weight of the cottonseed meal) was added, and the mixture was stirred at a speed of 100-110 r / min for 18-20 minutes to form a paste; a composite fermentation agent composed of lactic acid bacteria, yeast, and bacillus in a weight ratio of 1:1:2 was prepared and mixed with sterile water to prepare an agent concentration of 1.2×10 8 -1.5×10 8 The method comprises the following steps: preparing a bacterial liquid having a CFU / mL content, adding a paste material in an amount of 0.6-0.8% by weight of cottonseed meal, and stirring again for 8-10 minutes; transferring the inoculated material to a fermentation tank with a sealed lid, controlling the temperature at 32-34°C with a temperature fluctuation of no more than ±0.5°C, stirring the material every 7 hours to a depth of 2 / 3 of the material layer, monitoring the pH value, temperature, and odor of the material daily, and ending the fermentation after 4 days when the pH value drops to 4.2-4.4; and drying the fermented material in a belt dryer at 52-55°C with a material layer thickness of 4 cm, thereby reducing the moisture content to 8-9%, thereby producing fermented cottonseed meal.

[0039] The method for screening and purifying composite bacteria is as follows: collect fresh cow dung samples, add them to a conical flask containing beef extract peptone medium (3g beef extract, 10g peptone, 5g sodium chloride, 1000mL distilled water, pH7.0-7.2), and shake culture for 36 hours at 32-34°C and 180r / min for enrichment culture; use the dilution spread plate method to inoculate the enriched culture liquid onto beef extract peptone solid medium, and culture it in a constant temperature incubator at 32-34°C for 36 hours; after the colonies grow, select single colonies with different morphology, color, size, etc., mix them to obtain composite bacteria, and the total number of selected single colonies accounts for not less than 95%.

[0040] The preparation method of compound microbial fertilizer comprises the following steps:

[0041] Screening and purification of bacterial strains: Screening and purification of the bacterial strains from cow dung were performed according to the above method to obtain the screened and purified composite bacteria.

[0042] Bacterial culture: Bacillus megaterium, Bacillus mucilaginosus, and photosynthetic bacteria were inoculated into the corresponding liquid culture medium, and cultured at 32-34°C and 180 r / min for 36 h until the bacterial solution concentration reached 1.4×10 8 -1.6×10 8 CFU / mL, EM bacteria were commercially available. The liquid culture medium for Bacillus megaterium consisted of: 10g glucose, 5g yeast powder, 2g potassium dihydrogen phosphate, 0.5g magnesium sulfate, 1000mL distilled water, pH 7.0-7.2; the liquid culture medium for Bacillus mucilaginosus consisted of: 12g sucrose, 3g sodium nitrate, 2g dipotassium hydrogen phosphate, 0.2g magnesium sulfate, 0.01g manganese sulfate, 1000mL distilled water, pH 7.2-7.4; the liquid culture medium for photosynthetic bacteria consisted of: 1g ammonium chloride, 0.6g potassium dihydrogen phosphate, 0.2g magnesium sulfate, 2g sodium chloride, 2g sodium bicarbonate, 0.1g yeast extract, 1000mL distilled water, pH 7.0-7.5.

[0043] Raw material mixing: Prior to the raw material mixing step, the mesoporous silica is surface-modified and immersed in a 3-4% by weight silane coupling agent ethanol solution. The mixture is stirred at 50-55°C for 2-3 hours, then filtered, washed, and dried to a constant weight. The treated mesoporous silica, humic acid, and fermented cottonseed meal are mixed in a twin-shaft paddle mixer at 80-100 rpm for 15 minutes according to a weight ratio to obtain a solid mixed raw material.

[0044] Adding the bacterial agent: adding the cultured Bacillus megaterium, Bacillus mucilaginosus, photosynthetic bacteria liquid, EM bacteria and screened and purified composite bacteria to the solid mixed raw materials according to the weight ratio, and stirring thoroughly.

[0045] Drying and molding: Dry the mixed materials at 50-55°C to reduce the moisture content to below 8-10%, and then granulate them through a disc granulator. The particle size of the granulated particles is 2.5-3.5mm. Granular compound microbial fertilizer is made and vacuum-sealed for packaging.

[0046] The following are specific embodiments

[0047] Example 1

[0048] Screening and purification of composite bacteria: fresh cow dung samples were collected and added to a triangular flask containing beef extract peptone medium, and the samples were shaken and cultured at 32°C and 180 rpm for 36 hours for enrichment culture; the enriched cultured bacterial liquid was inoculated onto beef extract peptone solid medium using the dilution spread plate method, and cultured in a constant temperature incubator at 32°C for 36 hours; after the colonies grew, single colonies with different morphology, color, size, etc., accounting for 98% of the total number, were selected to obtain the composite bacteria.

[0049] Fermented cottonseed meal: Select high-quality cottonseed meal without mildew, with a crude protein content of 42% and an impurity content of 0.8%, and crush it to 100 mesh using a hammer mill; place the crushed cottonseed meal in a clean stainless steel container, add deionized water 1.2 times the weight of the cottonseed meal, and stir at a speed of 100 r / min for 18 minutes to form a paste; prepare a composite fermentation agent composed of lactic acid bacteria, yeast, and Bacillus in a weight ratio of 1:1:2, and mix it with sterile water to prepare an agent concentration of 1.2×10 8 The method comprises the following steps: a bacterial liquid with a CFU / mL content is added to a paste material in an amount of 0.6% by weight of cottonseed meal, and the mixture is stirred for another 8 minutes; the inoculated material is transferred to a fermentation tank with a sealed lid, the temperature is controlled at 32°C, the temperature fluctuation does not exceed ±0.5°C, the material is stirred every 7 hours, and the stirring depth reaches 2 / 3 of the material layer; the pH value, temperature and odor of the material are tested every day, and the fermentation is terminated after 4 days when the pH value drops to 4.2; the fermented material is placed in a belt dryer and dried at 52°C, the material layer thickness is maintained at 4 cm, and the moisture content is reduced to 8%, thereby producing fermented cottonseed meal.

[0050] Preparation of compound microbial fertilizer:

[0051] Bacterial culture: Bacillus megaterium, Bacillus mucilaginosus, and photosynthetic bacteria were inoculated into the corresponding liquid culture medium, and cultured at 32°C and 180 rpm for 36 h until the bacterial solution concentration reached 1.4 × 10 8 CFU / mL, EM bacteria were commercially available products.

[0052] Raw material mixing: mesoporous silica (specific surface area 600m 2 / g, average pore diameter 5nm, pore volume 0.8cm3 / g) was surface-modified and immersed in a 3% by mass silane coupling agent ethanol solution, stirred at 50°C for 2 hours, then filtered, washed, and dried to constant weight. 15 parts of the treated mesoporous silica, 4 parts of humic acid, and 30 parts of fermented cottonseed meal were mixed in a twin-shaft paddle mixer at 80 rpm for 15 minutes to obtain a solid mixed raw material.

[0053] Addition of bacterial agent: add 6 parts of screened and purified composite bacteria, 3 parts of EM bacteria, 2 parts of Bacillus megaterium liquid, 2 parts of Bacillus mucilaginosus liquid, and 1 part of photosynthetic bacteria liquid to the solid mixed raw materials and stir thoroughly.

[0054] Drying and molding: The mixed materials are dried at 50°C to reduce the moisture content to 8%, and then granulated by a disc granulator. The particle size of the granulated particles is 2.5 mm. Granular compound microbial fertilizer is made and vacuum-sealed for packaging.

[0055] Example 2

[0056] Screening and purification of composite bacteria: The culture temperature was 33° C., and the rest was the same as in Example 1.

[0057] Fermented cottonseed meal: Cottonseed meal crude protein content 43%, impurity content 0.9%, crushed to 105 mesh, added 1.3 times deionized water, stirring speed 105r / min, stirring time 19min, bacterial agent concentration 1.3×10 8 CFU / mL, the inoculation amount was 0.7%, and the mixture was stirred for another 9 minutes. The fermentation temperature was 33°C, and the fermentation was terminated when the pH dropped to 4.3. The drying temperature was 53°C, and the moisture content dropped to 8.5%. The rest was the same as in Example 1.

[0058] Preparation of compound microbial fertilizer:

[0059] Bacteria culture: culture temperature 33 ° C, the rest is the same as Example 1.

[0060] Raw material mixing: mesoporous silica with a specific surface area of 650m 2 / g, average pore diameter 6nm, pore volume 1cm 3 / g, 3.5% mass fraction of silane coupling agent ethanol solution, stirring temperature 52°C, stirring time 2.5h, 17 parts of mesoporous silica, 5 parts of humic acid, 35 parts of fermented cottonseed meal, mixer speed 90r / min, and other parameters are the same as in Example 1.

[0061] The bacterial agent added: 8 parts of screened and purified composite bacteria, 4 parts of EM bacteria, 2.5 parts of Bacillus megaterium liquid, 3 parts of Bacillus mucilaginosus liquid, 1.5 parts of photosynthetic bacteria liquid, and the rest are the same as in Example 1.

[0062] Drying and molding: drying temperature 52° C., moisture content reduced to 9%, particle size 3 mm, and other aspects are the same as in Example 1.

[0063] Example 3

[0064] Screening and purification of composite bacteria: The culture temperature was 34° C., and the rest was the same as in Example 1.

[0065] Fermented cottonseed meal: Cottonseed meal crude protein content 44%, impurity content 0.9%, crushed to 110 mesh, added 1.5 times deionized water, stirring speed 110r / min, stirring time 20min, bacterial concentration 1.5×10 8 CFU / mL, the inoculation amount was 0.8%, and the mixture was stirred for 10 min again. The fermentation temperature was 34°C, and the fermentation was terminated when the pH dropped to 4.4. The drying temperature was 55°C, and the moisture content dropped to 9%. The rest was the same as in Example 1.

[0066] Preparation of compound microbial fertilizer:

[0067] Bacteria culture: culture temperature 34 ° C, the rest is the same as Example 1.

[0068] Raw material mixing: mesoporous silica with a specific surface area of 700m 2 / g, average pore diameter 8nm, pore volume 1.2cm 3 / g, silane coupling agent ethanol solution mass fraction 4%, stirring temperature 55 ° C, stirring time 3h, 20 parts of mesoporous silica, 6 parts of humic acid, 40 parts of fermented cottonseed meal, mixer speed 100r / min, the rest are the same as Example 1.

[0069] The bacterial agent added: 10 parts of screened and purified composite bacteria, 5 parts of EM bacteria, 3 parts of Bacillus megaterium liquid, 4 parts of Bacillus mucilaginosus liquid, 2 parts of photosynthetic bacteria liquid, and the rest are the same as in Example 1.

[0070] Drying and molding: drying temperature 55°C, moisture content reduced to 10%, particle size 3.5 mm, other aspects are the same as in Example 1.

[0071] Example 4

[0072] Screening and purification of composite bacteria: The culture conditions were the same as in Example 2.

[0073] Fermented cottonseed meal: Preparation conditions are the same as in Example 2.

[0074] Preparation of compound microbial fertilizer:

[0075] Bacteria culture: The culture conditions are the same as those in Example 2.

[0076] Raw material mixing: the parameters of mesoporous silica are the same as those in Example 2, the silane coupling agent treatment conditions are the same as those in Example 2, 16 parts of mesoporous silica, 4.5 parts of humic acid, 32 parts of fermented cottonseed meal, the mixer speed is 85 r / min, and the rest are the same as in Example 1.

[0077] The bacterial agent added: 7 parts of screened and purified composite bacteria, 3.5 parts of EM bacteria, 2.2 parts of Bacillus megaterium liquid, 2.5 parts of Bacillus mucilaginosus liquid, 1.2 parts of photosynthetic bacteria liquid, and the rest are the same as in Example 1.

[0078] Drying and molding: drying temperature is 51° C., moisture content is reduced to 8.2%, particle size is 2.7 mm, and the rest is the same as in Example 1.

[0079] Comparative Example

[0080] Comparative Example 1

[0081] Based on Example 1, no screened and purified composite bacteria were added.

[0082] Comparative Example 2

[0083] On the basis of Example 1, the mesoporous silica was replaced by ordinary silica.

[0084] Comparative Example 3

[0085] Based on Example 1, unfermented cottonseed meal was used.

[0086] test

[0087] Soil organic matter content improvement test

[0088] The test was conducted in the same test area, which was divided into several test blocks of equal area. After the soil organic matter content was detected and recorded, the fertilizers of the embodiment and the comparative example were applied respectively, with the same parameters for 3 months. The soil after using the fertilizers of the embodiment and the comparative example was tested with reference to GB9834-1988 "Determination of Soil Organic Matter":

[0089] Table 1

[0090] Group Increase in soil organic matter content (%) Example 1 12.3 Example 2 13.5 Example 3 14.2 Example 4 12.8 Comparative Example 1 7.2 Comparative Example 2 8.9 Comparative Example 3 9.3

[0091] As can be seen from Table 1, the composite microbial fertilizer prepared by the present invention can greatly increase the organic matter content of the soil.

[0092] Test on increasing available phosphorus content in soil

[0093] Continuing the above test, the soil after using the fertilizers of the embodiment and the comparative example was tested with reference to GB / T10303-2001 "Determination of available phosphorus content in fertilizers" for a period of 3 months.

[0094] Table 2

[0095]

[0096]

[0097] As can be seen from Table 2, the composite microbial fertilizer prepared by the present invention can significantly increase the content of available phosphorus in the soil.

[0098] Crop yield increase test

[0099] Crops of the same variety and the same growth conditions (corn and Jingke 968) were selected for planting, and a group of blank untreated soil test plots were set up for identical planting. Then, the soil test plots treated with the fertilizers of the embodiment and the comparative example were used for planting, and the yield increase rate was calculated after the planting cycle.

[0100] Table 3

[0101]

[0102]

[0103] It can be seen from Table 3 that the composite microbial fertilizer of the present invention can improve soil and increase crop yield.

[0104] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. The preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification.

Claims

1. A compound microbial fertilizer for soil improvement, characterized in that: The invention is composed of the following raw materials in parts by weight: 6-10 parts of screened and purified composite bacteria, 3-5 parts of EM bacteria, 2-3 parts of Bacillus megaterium, 2-4 parts of Bacillus mucilaginosus, 1-2 parts of photosynthetic bacteria, 15-20 parts of mesoporous silica, 4-6 parts of humic acid and 30-40 parts of fermented cottonseed meal.

2. The compound microbial fertilizer according to claim 1, characterized in that The specific surface area of the mesoporous silica is 600-700m 2 / g, average pore diameter of 5-8nm, pore volume of 0.8-1.2cm 3 / g, this parameter range can increase the adsorption and fixation efficiency of mesoporous silica on microorganisms and nutrients by 30-50%, significantly enhancing the stability and slow-release properties of the fertilizer.

3. The compound microbial fertilizer according to claim 1, characterized in that The preparation method of the fermented cottonseed meal is: High-quality cottonseed meal without mildew, with a crude protein content of 42% or more and an impurity content of less than 1% was selected and crushed to 100-110 mesh using a hammer mill; the crushed cottonseed meal was placed in a clean stainless steel container, deionized water (1.2-1.5 times the weight of the cottonseed meal) was added, and the mixture was stirred at a speed of 100-110 r / min for 18-20 minutes to form a paste; a composite fermentation agent composed of lactic acid bacteria, yeast, and bacillus in a weight ratio of 1:1:2 was prepared and mixed with sterile water to prepare an agent concentration of 1.2×10 8 -1.5×10 8 The method comprises the following steps: a bacterial liquid containing 0.6-0.8% CFU / mL of bacterial liquid is added to a paste material in an amount of 0.6-0.8% by weight of cottonseed meal, and the mixture is stirred again for 8-10 minutes; the inoculated material is transferred to a fermentation tank with a sealed lid, the temperature is controlled at 32-34°C, and the temperature fluctuation does not exceed ±0.5°C; the material is stirred every 7 hours to a depth of 2 / 3 of the material layer; the pH value, temperature and odor of the material are tested every day; and the fermentation ends after 4 days when the pH value drops to 4.2-4.4; and the fermented material is placed in a belt dryer for drying to produce fermented cottonseed meal.

4. The compound microbial fertilizer according to claim 1, characterized in that The drying in the belt dryer is as follows: Dry at 52-55℃, keep the material layer thickness at 4cm, and reduce the moisture content to 8-9%.

5. The compound microbial fertilizer according to claim 1, characterized in that The method for screening and purifying the composite bacteria comprises the following steps: collecting a fresh cow dung sample, adding the sample to a triangular flask containing a beef extract peptone culture medium, and performing an enrichment culture by shaking culture at 32-34°C and 180 rpm for 36 hours; inoculating the enriched cultured bacterial solution onto a beef extract peptone solid culture medium using a dilution spread plate method, and culturing the culture in a constant temperature incubator at 32-34°C for 36 hours; and after colonies grow, selecting single colonies with different morphologies, colors, sizes, etc. to obtain the composite bacteria.

6. The compound microbial fertilizer according to claim 5, characterized in that The beef extract peptone culture medium comprises: 3g beef extract, 10g peptone, 5g sodium chloride, 1000mL distilled water, and a pH value of 7.0-7.

2.

7. A method for preparing the composite microbial fertilizer according to any one of claims 1 to 6, characterized in that: The following steps are involved: Screening and purification of bacteria: Screening and purifying the purified composite bacteria from cow dung according to the method of claim 5; Bacterial culture: Bacillus megaterium, Bacillus mucilaginosus, and photosynthetic bacteria were inoculated into the corresponding liquid culture medium, and cultured at 32-34°C and 180 r / min for 36 h until the bacterial solution concentration reached 1.4×10 8 -1.6×10 8 CFU / mL, EM bacteria were commercially available; Raw material mixing: mesoporous silica, humic acid, and fermented cottonseed meal were mixed in a double-shaft paddle mixer at a speed of 80-100 r / min for 15 minutes to obtain a solid mixed raw material; Adding the bacterial agent: add the cultured Bacillus megaterium, Bacillus mucilaginosus, photosynthetic bacteria liquid, EM bacteria and screened and purified composite bacteria to the solid mixed raw materials according to the weight ratio and stir thoroughly; Drying and molding: Dry the mixed materials at 50-55°C to reduce the moisture content to below 8-10%, and then granulate them through a disc granulator. The particle size of the granulated particles is 2.5-3.5mm. Granular compound microbial fertilizer is made and vacuum-sealed for packaging.

8. The preparation method according to claim 6, characterized in that The liquid culture medium of the Bacillus megaterium comprises: 10 g of glucose, 5 g of yeast powder, 2 g of potassium dihydrogen phosphate, 0.5 g of magnesium sulfate, and 1000 mL of distilled water, with a pH of 7.0-7.2; the liquid culture medium of the Bacillus mucilaginosus comprises: 12 g of sucrose, 3 g of sodium nitrate, 2 g of dipotassium hydrogen phosphate, 0.2 g of magnesium sulfate, 0.01 g of manganese sulfate, and 1000 mL of distilled water, with a pH of 7.2-7.4; and the liquid culture medium of the photosynthetic bacteria comprises: 1 g of ammonium chloride, 0.6 g of potassium dihydrogen phosphate, 0.2 g of magnesium sulfate, 2 g of sodium chloride, 2 g of sodium bicarbonate, 0.1 g of yeast extract, and 1000 mL of distilled water, with a pH of 7.0-7.

5.

9. The preparation method according to claim 6, characterized in that Before the raw material mixing step, the mesoporous silica is surface modified by immersing it in a 3-4% by mass silane coupling agent ethanol solution, stirring it at 50-55° C. for 2-3 hours, and then filtering, washing, and drying it to a constant weight.

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