Complex microbial inoculant suitable for straw organic fertilizer fermentation and method for improving and fertilizing soil by using complex microbial inoculant

Abstract

The invention relates to the technical field of soil improvement, in particular to a complex microbial inoculant suitable for straw organic fertilizer fermentation and a method for improving and fertilizing soil through the complex microbial inoculant. The complex microbial inoculant is formed by compounding a functional microbial inoculant and a carrier according to the mass ratio of 1: (3-5); the functional microbial agent is prepared by mixing lignin degrading bacteria, cellulose decomposing bacteria and functional auxiliary bacteria; all the components of the complex microbial inoculant have a synergistic effect, the fermentation function of the complex microbial inoculant can be greatly improved, the lignin degrading bacteria specifically break ether bonds (-O-) and carbon-carbon bonds (C-C) in a lignin three-dimensional network structure by secreting laccase, manganese peroxidase and the like, lignin is degraded into low-molecular aromatic compounds, and the low-molecular aromatic compounds can be used for degrading the lignin into low-molecular aromatic compounds. Physical wrapping on cellulose is removed, so that a straw fiber structure is converted into a loose structure which is easy to decompose from a lignin-cellulose complex.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soil improvement, in particular to a composite microbial agent suitable for straw organic fertilizer fermentation and a method for improving and fertilizing soil. BACKGROUND

[0002] With the expansion of agricultural production scale, a large amount of straw waste is generated in China every year. According to statistics, the annual output of straw of the three major crops of rice, wheat and corn exceeds 700 million tons.

[0003] In the traditional treatment method, open-air burning of straw will produce a large amount of PM2.5, nitrogen oxides and volatile organic compounds, resulting in serious air pollution and easily causing fire hazards. Although the conventional direct soil burial can partially return the nutrients to the field, the lignin and cellulose in the straw have stable structure and long natural degradation period, usually about 6 months, which can easily cause soil pore blockage, breeding of pests and diseases, and low release efficiency of nitrogen, phosphorus and potassium nutrients, thus being difficult to meet the demand of modern agriculture for soil fertility.

[0004] In addition, the traditional straw composting process relies on natural fermentation, which has the defects of long fermentation period, more than 60 days, unstable temperature control and large loss of organic matter.

[0005] The present application provides a composite microbial agent suitable for straw organic fertilizer fermentation, which can rapidly decompose the straw through the synergistic effect of functional microbial agents and porous carriers, and then combine with the soil to improve and fertilize the soil, thereby realizing efficient recycling of agricultural waste. SUMMARY

[0006] In view of the problems in the prior art, the present application provides a composite microbial agent suitable for straw organic fertilizer fermentation and a method for improving and fertilizing soil.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0008] A composite microbial agent suitable for straw organic fertilizer fermentation, which is composed of functional microbial agents and carriers at a mass ratio of 1:3-5; the functional microbial agents include lignin-degrading bacteria, cellulose-degrading bacteria and functional auxiliary bacteria.

[0009] The lignin-degrading bacteria include Trametes versicolor and Pycnoporus cinnabarinus, the cellulose-degrading bacteria include Clostridium thermocellum and Bacillus subtilis, and the functional auxiliary bacteria include Azotobacter chroococcum, Bacillus methylotrophicus and Pseudomonas putida.

[0010] As a further technical solution, the effective viable cell content of each bacterial species in the functional bacterial agent is:

[0011] Lignin-degrading bacteria: Trametes versicolor 1×10 8 -5×10 8 CFU / g, Pycnoporus cinnabarinus 5×10 7 -3×10 8 CFU / g;

[0012] Cellulose-degrading bacteria: Clostridium thermocellum 2×10 8 -4×10 8 CFU / g, Bacillus subtilis 3×10 8 -1×10 8 CFU / g;

[0013] Functional auxiliary bacteria: Azotobacter chroococcum 1×10 8 -4×10 8 CFU / g, Bacillus methylotrophicus 2×10 8 -5×10 8 CFU / g, Pseudomonas putida 1×10 8 -5×10 8 CFU / g.

[0014] As a further technical solution, the carrier is prepared by the following method: sodium alginate and chitosan are dissolved in a citric acid buffer solution with a pH of 5.5-6.5 at a mass ratio of 2:1-3, then montmorillonite powder is added to form a mixed colloid, the montmorillonite powder is added in an amount of 16-20% of the mass of the mixed colloid, and the porous spherical carrier is prepared by spray drying;

[0015] The average particle size of the carrier is 0.3-0.8mm, and the specific surface area is ≥35m 2 / g;

[0016] The inlet air temperature of the spray drying is 160-180℃, and the outlet air temperature is 80-90℃.

[0017] As a further technical solution, the complexing process of the functional bacterial agent and the carrier is:

[0018] The functional bacteria agent is made into a bacteria suspension, mixed with a carrier at a mass ratio of 3-5:1, adsorbed at 28-32°C for 6-8 hours, then 0.1-0.3% proline is added as a protective agent, accounting for 0.1-0.3% of the total mass of the bacteria suspension, mixed uniformly, and then adsorbed for another 4 hours, filtered, and dried at low temperature to a water content of ≤8%;

[0019] The concentration of the bacteria suspension is 1×10 9 -5×10 9 CFU / mL.

[0020] The low-temperature drying temperature is ≤40°C.

[0021] As a further technical solution, the porosity of the carrier is 45-60%, and the average pore size is

[0022] 1-5μm, which can make the functional bacteria agent in the straw compost have a slow-release period of 15-20 days.

[0023] As a further technical solution, the carrier contains 3-5% attapulgite by mass;

[0024] The attapulgite is added together with the montmorillonite powder when the carrier is prepared.

[0025] As a further technical solution, the complex bacteria agent is used for straw organic fertilizer fermentation, and the specific method comprises:

[0026] The straw is crushed to a length of 1-3cm, mixed at a mass ratio of straw: livestock and poultry manure: wood ash of 6-8:2-3:1, and the water content of the mixture is adjusted to 60-65%;

[0027] 2-3kg of the complex bacteria agent is added per ton of mixture, and then uniformly stirred and stacked into a strip pile with a height of 1.2-1.5m and a width of 2-2.5m;

[0028] Three-stage temperature control is adopted for fermentation treatment, and after fermentation is completed, a complex bacteria agent fermented fertilizer is obtained.

[0029] As a further technical solution, the three-stage temperature control specifically comprises: a warming period of 2-3

[0030] days, ventilation and warming to 55-60°C; a high-temperature period of 6-7 days, intermittent anaerobic-aerobic switching, maintaining a temperature of 55-60°C; a maturation period of 8-10 days, maintaining a low temperature of 40-45°C.

[0031] As a further technical solution, the intermittent anaerobic-aerobic switching frequency during the high-temperature period is once every 12 hours, and each anaerobic duration is 4 hours and each aerobic duration is 8 hours;

[0032] The oxygen volume concentration of the aerobic oxygen is maintained at 8-10%.

[0033] The method for improving and fertilizing soil by the composite microbial agent comprises the following steps: preparing the composite microbial agent, and applying the composite microbial agent into the soil as the fermentation fertilizer, wherein the application amount is 200-300 kg per mu, and the relative water content of the soil is kept at 60-70% within 7 days after the application.

[0034] Compared with the prior art, the method has the following beneficial effects:

[0035] The components of the composite microbial agent in the application have synergistic effect, and can greatly improve the fermentation function of the composite microbial agent, wherein the lignin-degrading bacteria: through secreting laccase, manganese peroxidase and the like, specifically breaking ether bond (-O-) and carbon-carbon bond (C-C) in the three-dimensional network structure of lignin, degrading lignin into low-molecular aromatic compounds, relieving the physical wrapping of cellulose, and converting the straw fiber structure from lignin-cellulose complex into loose structure which is easy to be decomposed. The cellulose-decomposing bacteria: using cellulase complex to adsorb to the cellulose surface, through endoglucanase to randomly cut beta-1,4 glycosidic bond to generate oligosaccharide, and through exoglucanase to further hydrolyze into cellobiose, and finally through beta-glucosidase (BG) to be converted into glucose. The organic acid generated in the process can reduce the pH value of the fermentation system and promote the dissolution of mineral nutrients. The functional auxiliary bacteria: nitrogen-fixing bacteria: through nitrogenase catalysis, converting nitrogen in the air into ammonia nitrogen, directly improving the nitrogen content of the fermentation fertilizer. Phosphorus and potassium solubilizing bacteria: secreting organic acids such as citric acid and oxalic acid, dissolving the insoluble phosphorus and potassium minerals in the soil through proton exchange, releasing effective phosphorus and potassium ions, and improving the total phosphorus and total potassium content of the fermentation fertilizer.

[0036] Meanwhile, the porous carrier has obvious synergistic effect; the physical structure advantage of the porous carrier: the sodium alginate-chitosan gel network and the montmorillonite-attapulgite layered mineral form a "double adsorption system", the functional bacteria are adsorbed through hydrogen bond and ionic bond, the porosity and average pore size of the carrier match the size of the microorganisms, a micro anaerobic-aerobic micro area is formed, and different metabolic type microorganisms, such as cellulose-decomposing bacteria, are coexistent in the micro area. The bacteria are released through pore diffusion, the slow-release period is long, and the corresponding functional bacterial groups are planted in the fermentation temperature rising period (dominated by thermophilic bacteria), the high temperature period (dominated by mesophilic bacteria) and the maturation period (dominated by humification bacteria), so that the problem of activity attenuation caused by the one-time release of traditional bacteria is avoided.

[0037] The composite microbial agent fermentation fertilizer has a great improvement effect on soil improvement and fertilization. The humic acid in the fermentation fertilizer forms water-stable aggregates by hydrogen bond and cation bridging effect, so that the soil porosity and the aeration porosity are increased, and the water permeability and aeration performance of the soil are improved. The polysaccharide (such as β-glucan) produced by the degradation of straw fiber as a biological cementing agent is adsorbed on the surface of soil particles, so that the friction coefficient between soil particles in the plowing process is reduced, and the compaction problem caused by mechanical compaction is reduced. The montmorillonite in the carrier and the organic acid (such as humic acid) produced by fermentation form a buffer system, so that the pH value of the soil deviates to the neutral side, and the activation of toxic ions (such as Al 3+ , Mn 2+ and the like) in the acidic soil is effectively alleviated. The functional bacteria (such as nitrogen-fixing bacteria and phosphorus-dissolving bacteria) introduced by the composite microbial agent inhibit the colonization of pathogenic bacteria (such as fusarium) through competitive exclusion, and at the same time, the exopolysaccharide is secreted to provide carbon source for indigenous beneficial bacteria, so that the soil microbial diversity index is improved, and the soil health state is improved. The microbial metabolites (such as coenzyme and vitamin) in the fermentation fertilizer can activate the hydrolytic enzyme activities of soil urease, acid phosphatase and invertase, accelerate the mineralization of organic nitrogen, and promote the decomposition of organic phosphorus.

[0038] Drawings

[0039] Figure 1 is a soil pH statistical diagram after each group of treatments in the examples and comparative examples. DETAILED DESCRIPTION

[0040] The technical solutions in the examples of the present application will be described clearly and completely below. Obviously, the described examples are only a part of the examples of the present application, rather than all the examples. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0041] The present application provides a composite microbial agent suitable for straw organic fertilizer fermentation, which is composed of functional microbial agents and carriers at a mass ratio of 1:3-5. The functional microbial agents include lignin-degrading bacteria, cellulose-degrading bacteria and functional auxiliary bacteria. The lignin-degrading bacteria include Trametes versicolor and Pycnoporuscinnabarinus, the cellulose-degrading bacteria include Clostridium thermocellum and Bacillus subtilis, and the functional auxiliary bacteria include Azotobacter chroococcum, Bacillus methylotrophicus and Pseudomonas putida.

[0042] In the present application, the effective viable cell content of each bacterial species in the functional bacterial agent is as follows: lignin-degrading bacteria: Trametes versicolor 1 x 10 8 -5 x 10 8 CFU / g, Pycnoporus cinnabarinus 5 x 10 7 -3 x 10 8 CFU / g; cellulose-degrading bacteria: Clostridium thermocellum 2 x 10 8 -4 x 10 8 CFU / g, Bacillus subtilis 1 x 10 8 -3 x 10 8 CFU / g; functional auxiliary bacteria: Azotobacter chroococcum 1 x 10 8 -4 x 10 8 CFU / g, Bacillusmethylotrophicus 2 x 10 8 -5 x 10 8 CFU / g, Pseudomonas putida 1 x 10 8 -5 x 10 8 CFU / g.

[0043] The carrier is prepared by the following method: dissolving sodium alginate and chitosan in a citric acid buffer solution at pH 5.5-6.5 at a mass ratio of 2:1-3, then adding montmorillonite powder to form a mixed colloid, the montmorillonite powder is added in an amount of 16-20% of the mass of the mixed colloid, and the porous spherical carrier is prepared by spray drying; the average particle size of the carrier is 0.3-0.8 mm, and the specific surface area is ≥ 35 m 2 / g; the inlet air temperature of the spray drying is 160-180°C, and the outlet air temperature is 80-90°C.

[0044] The compounding process of the functional bacterial agent and the carrier is as follows: the functional bacterial agent is prepared into a bacterial suspension, mixed with the carrier at a mass ratio of 3-5:1, adsorbed at 28-32°C for 6-8 hours, then proline is added as a protective agent in an amount of 0.1-0.3% of the total mass of the bacterial suspension, mixed uniformly, then adsorbed for another 4 hours, then filtered, and dried at low temperature to a water content of ≤8%; the concentration of the bacterial suspension is 1 x 10 9 -5 x 10 9 CFU / mL; the low-temperature drying temperature is ≤40°C.

[0045] The porosity of the carrier is 45-60%, the average pore size is 1-5 μm, and the functional bacteria agent can be released in the straw compost for 15-20 days. The carrier contains 3-5% of the palygorskite by mass; and the palygorskite is added together with the montmorillonite powder when the carrier is prepared.

[0046] The complex bacteria agent is used for straw organic fertilizer fermentation, and the specific method comprises the following steps: straw is crushed to a length of 1-3 cm, and then mixed according to a mass ratio of 6-8:2-3:1 of straw: livestock and poultry manure: wood ash, and the water content of the mixture is adjusted to 60-65%; 2-3 kg of the complex bacteria agent is added per ton of the mixture, and then uniformly stirred and stacked into a strip pile with a height of 1.2-1.5 m and a width of 2-2.5 m; three-stage temperature control is adopted for fermentation treatment, and after the fermentation is completed, the complex bacteria agent fermented fertilizer is obtained.

[0047] The three-stage temperature control specifically comprises the following steps: the temperature is raised for 2-3 days, and ventilation is performed to raise the temperature to 55-60℃; the temperature is kept at 55-60℃ for 6-7 days through intermittent anaerobic-aerobic switching; and the temperature is kept at 40-45℃ for 8-10 days. The intermittent anaerobic-aerobic switching frequency is once every 12 hours during the high-temperature period, the anaerobic time is 4 hours, and the aerobic time is 8 hours; and the oxygen volume concentration during the aerobic stage is kept at 8-10%.

[0048] The complex bacteria agent fermented fertilizer prepared by the complex bacteria agent is applied to the soil, the application amount is 200-300 kg per mu, and the relative water content of the soil is kept at 60-70% within 7 days after the application.

[0049] The complex bacteria agent provided by the application can effectively improve the straw organic fertilizer fermentation efficiency, enhance the fertilizer efficiency of the fermented fertilizer, and improve the soil environment through specific strain combination and carrier design. The following examples and comparative examples are used for detailed description.

[0050] Example 1

[0051] The functional bacteria agent comprises: the effective viable count of Trametes versicolor is 3×10 8 CFU / g, the effective viable count of Pycnoporus cinnabarinus is 2×10 8 CFU / g, the effective viable count of Clostridium thermocellum is 3×10 8 CFU / g, the effective viable count of Bacillus subtilis is 2×10 8 CFU / g, the effective viable count of Azotobacter chroococcum is 2×10 8 CFU / g, and the effective viable count of Bacillus methylotrophicus is 3×10 8CFU / g, Pseudomonas putida 1 x 10 8 CFU / g.

[0052] Carrier preparation: sodium alginate and chitosan were dissolved in pH 6.0 citric acid buffer at a mass ratio of 2:2, 18% montmorillonite powder and 4% attapulgite were added, spray drying inlet temperature 170℃, outlet temperature 85℃, the carrier was prepared, the porosity was 52%, the average pore size was 3μm, the average particle size was 0.5mm, the specific surface area was 38m 2 / g.

[0053] Composite process: functional bacteria agent and carrier were compounded at a mass ratio of 1:4, the concentration of bacteria suspension was 3 x 10 9 CFU / mL, first adsorbed for 7 hours at 30℃, then 0.2% proline was added and adsorbed for 4 hours, and then low-temperature drying was carried out to a water content of 6%.

[0054] Fermentation method: straw, livestock and poultry manure, wood ash were mixed at a ratio of 7:2.5:1, 2.5kg of composite bacteria agent was added per ton, and the three-stage temperature control met the requirements.

[0055] Example 2

[0056] Functional bacteria agent composition: Trametes versicolor 1 x 10 8 CFU / g, Pycnoporus cinnabarinus 5 x 10 7 CFU / g, Clostridium thermocellum 2 x 10 8 CFU / g, Bacillus subtilis 3 x 10 8 CFU / g, Azotobacter chroococcum 1 x 10 8 CFU / g, Bacillus methylotrophicus 2 x 10 8 CFU / g, Pseudomonas putida 1 x 10 8 CFU / g.

[0057] Carrier preparation: sodium alginate and chitosan were dissolved in pH 5.5 citric acid buffer at a mass ratio of 2:1, 16% montmorillonite powder and 3% attapulgite were added, spray drying inlet temperature 160℃, outlet temperature 80℃, carrier porosity 45%, average pore size 1μm, average particle size 0.3mm, specific surface area 35m 2 / g.

[0058] Composite process: functional bacteria agent and carrier are compounded according to the mass ratio of 1:3, the concentration of bacteria suspension is 1x10 9 CFU / mL, adsorbed for 8 hours at 28℃, 0.1% proline is added, adsorbed for 4 hours, and dried at low temperature to the water content of 7%.

[0059] Fermentation method: same as example 1.

[0060] Example 3

[0061] Functional bacteria agent composition: Trametes versicolor is 5x10 8 CFU / g, Pycnoporus cinnabarinus is 3x10 8 CFU / g, Clostridium thermocellum is 4x10 8 CFU / g, Bacillus subtilis is 1x10 8 CFU / g, Azotobacter chroococcum is 4x10 8 CFU / g, Bacillus methylotrophicus is 5x10 8 CFU / g, Pseudomonas putida is 5x10 8 CFU / g.

[0062] Carrier preparation: sodium alginate and chitosan are dissolved in pH 6.5 citric acid buffer according to the mass ratio of 2:3, 20% montmorillonite powder and 5% attapulgite are added, spray drying inlet temperature is 180℃, outlet temperature is 90℃, carrier porosity is 60%, average pore size is 5μm, average particle size is 0.8mm, specific surface area is 40m 2 / g.

[0063] Composite process: functional bacteria agent and carrier are compounded according to the mass ratio of 1:5, the concentration of bacteria suspension is 5x10 9 CFU / mL, adsorbed for 6 hours at 32℃, 0.3% proline is added, adsorbed for 4 hours, and dried at low temperature to the water content of 5%.

[0064] Fermentation method: same as example 1.

[0065] Example 4

[0066] Same as example 1, the difference is that attapulgite is not added in the carrier.

[0067] Example 5

[0068] The three-stage temperature control is substantially the same as that in Example 1, except that the temperature control is as follows: 2 days for the temperature rising period, ventilation and temperature rising to 58 DEG C; 6 days for the high temperature period, intermittent anaerobic-aerobic switching, maintaining the temperature at 55 DEG C; 8 days for the maturation period, maintaining the temperature at 42 DEG C; and the adsorption temperature in the composite process is 25 DEG C.

[0069] Comparative Example 1

[0070] The difference from Example 1 is that the functional bacteria agent does not contain functional auxiliary bacteria (Azotobacter chroococcum, Bacillus methylotrophicus, Pseudomonas putida), and the content of other bacteria is the same as that in Example 1.

[0071] Comparative Example 2

[0072] The difference from Example 1 is that:

[0073] Carrier preparation: ordinary clay is used as the carrier, the porosity is 30%, and the average pore size is 0.5 μm.

[0074] Test

[0075] The improvement effect of the composite bacteria agent fermentation fertilizer on the physicochemical properties of soil pH, organic matter, total nitrogen, total phosphorus, total potassium, etc. is verified.

[0076] Soil sample collection: the surface soil (0-20 cm) of the same farmland is selected, mixed uniformly, and divided into 8 parts, of which 1 part is used as the initial control group, and the remaining 7 parts correspond to the treatment groups of Example 1-5 and Comparative Example 1-2.

[0077] Initial index determination:

[0078] pH value: according to GB / T6920-1986 "Determination of Soil pH Value", the pH value is determined by glass electrode method.

[0079] Organic matter: according to NY / T1121.6-2006 "Soil Testing Part 6: Determination of Soil Organic Matter", the potassium dichromate oxidation method is used for determination.

[0080] Total nitrogen: according to HJ717-2014 "Determination of Soil Quality Total Nitrogen by Kjeldahl Method".

[0081] Total phosphorus: according to LY / T1232-1999 "Determination of Forest Soil Total Phosphorus", acid dissolution-molybdenum antimony anti-spectrophotometric method is used for determination.

[0082] Total potassium: according to NY / T889-2004 "Determination of Soil Available Potassium and Slowly Available Potassium Content", flame photometry is used for determination.

[0083] Treatment method:

[0084] The compound microbial agent fermentation fertilizer of the corresponding example / contrastive example was applied to each treatment group of soil, the application amount was 250 kg per mu (converted according to the soil weight), the relative water content of the soil was adjusted to 65% after uniform mixing, and the soil was cultured for 30 days under the cover of film.

[0085] After the culture, the pH value, the content of organic matter, total nitrogen, total phosphorus and total potassium of the soil in each treatment group were determined again.

[0086] Table 1

[0087]

[0088]

[0089] As can be seen from Table 1, the pH values of the soils treated by examples 1-5 all deviated to the neutral, and the effect of example 3 was the best; the pH values of the soils treated by contrastive examples 1-2 changed little, which indicated that the synergistic effect of the functional microbial agent and the carrier could improve the soil acidification.

[0090] Organic matter: the content of organic matter of the examples was increased by 34.4%-53.6%, which was significantly higher than that of the contrastive examples, indicating that the compound microbial system of the functional microbial agent accelerated the decomposition and accumulation of the straw organic matter.

[0091] Total nitrogen / total phosphorus / total potassium: the content of nitrogen, phosphorus and potassium of the examples was increased by 29.4%-55.3%, while the content of the contrastive examples was only increased by 3.9%-15.3%, which indicated that the slow-release effect of the functional auxiliary bacteria (such as nitrogen-fixing bacteria, phosphorus-solubilizing bacteria and potassium-solubilizing bacteria) and the carrier effectively enhanced the supply of soil nutrients.

[0092] The preferred embodiments of the above disclosed application are only used to help explain the application. The preferred embodiments do not describe all the details, and the application is not limited to the specific embodiments described. Obviously, according to the content of the specification, many modifications and changes can be made.

Claims

1. A compound microbial agent suitable for straw organic fertilizer fermentation, characterized in that, The complex microbial agent is compounded by a functional microbial agent and a carrier in a mass ratio of 1:3-5; the functional microbial agent comprises lignin-degrading bacteria, cellulose-decomposing bacteria and functional auxiliary bacteria; The lignin-degrading bacteria comprise Trametes versicolor and Pycnoporus cinnabarinus, the cellulose-decomposing bacteria comprise Clostridium thermocellum and Bacillus subtilis, and the functional auxiliary bacteria comprise Azotobacter chroococcum, Bacillus methylotrophicus and Pseudomonas putida.

2. The complex bacterial agent according to claim 1, characterized by, The effective viable count of each bacterial species in the functional microbial agent is: Lignin-degrading bacteria: Trametes versicolor 1 x 10 8 -5 x 10 8 CFU / g, Pycnoporus cinnabarinus 5 x 10 7 -3 x 10 8 CFU / g; Cellulolytic bacteria: Clostridium thermocellum 2 x 10 8 -4 x 10 8 CFU / g, Bacillus subtilis 3 x 10 8 -1 x 10 8 CFU / g; Functional helper bacteria: Azotobacter chroococcum 1 x 10 8 -4 x 10 8 CFU / g, Bacillus methylotrophicus 2 x 10 8 -5 x 10 8 CFU / g, Pseudomonas putida 1 x 10 8 -5 x 10 8 CFU / g.

3. The complex bacterial agent according to claim 1, characterized by, The carrier is prepared by the following method: sodium alginate and chitosan are dissolved in a citric acid buffer solution with a pH of 5.5-6.5 in a mass ratio of 2:1-3, and then montmorillonite powder is added to form a mixed colloid, the addition amount of the montmorillonite powder being 16-20% of the mass of the mixed colloid, and the mixed colloid is spray-dried to obtain a porous spherical carrier; The average particle size of the carrier is 0.3-0.8mm, the specific surface area is ≥35m 2 / g; The inlet air temperature of the spray drying is 160-180℃, and the outlet air temperature is 80-90℃.

4. The complex bacterial agent according to claim 1, characterized by, The compounding process of the functional microbial agent and the carrier is as follows: The functional microbial agent is prepared into a bacterial suspension, mixed with the carrier in a mass ratio of 3-5:1, adsorbed for 6-8 hours at 28-32℃, then 0.1-0.3% proline is added as a protective agent, the mixture is uniformly mixed, and then adsorbed for another 4 hours, and then filtered and dried at low temperature to a water content of ≤8%; The bacterial suspension concentration is 1 x 10 9 -5 x 10 9 CFU / mL; The low-temperature drying temperature is ≤40℃.

5. The complex bacterial agent according to claim 1, characterized by, The porosity of the carrier is 45-60%, and the average pore size is 1-5μm, so that the functional microbial agent can be released slowly in the straw compost for 15-20 days. 6.The complex bacterial agent according to claim 1, characterized in that, The carrier contains 3-5% attapulgite by mass; The attapulgite is added together with the montmorillonite powder when the carrier is prepared.

7. The complex bacterial agent according to claim 1, characterized by, The complex microbial agent is used for fermentation of straw organic fertilizer, and the specific method comprises the following steps: The straw is crushed to a length of 1-3cm, mixed with livestock and poultry manure and wood ash in a mass ratio of 6-8:2-3:1, and the water content of the mixture is adjusted to 60-65%; 2-3kg of the complex microbial agent is added per ton of the mixture, and then uniformly stirred and stacked into a strip pile with a height of 1.2-1.5m and a width of 2-2.5m; Three-stage temperature control is adopted for fermentation treatment, and after the fermentation is completed, a complex microbial agent fermented fertilizer is obtained. 8.The complex bacterial agent according to claim 7, characterized in that, The three-stage temperature control is specifically as follows: 2-3 days for the warming-up period, ventilation and temperature rising to 55-60℃; 6-7 days for the high-temperature period, intermittent anaerobic-aerobic switching, and maintaining the temperature at 55-60℃; and 8-10 days for the maturation period, low-temperature maintaining at 40-45℃. 9.The complex bacterial agent according to claim 8, characterized in that, The frequency of the intermittent anaerobic-aerobic switching during the high-temperature period is once every 12 hours, and the anaerobic time is 4 hours and the aerobic time is 8 hours each time; The oxygen volume concentration during the aerobic stage is maintained at 8-10%.

10. The method for improving and fertilizing soil with the complex microbial agent according to claim 9, characterized in that, The complex microbial agent fermented fertilizer prepared by the complex microbial agent is applied to the soil, and the application amount is 200-300kg per mu, and the relative water content of the soil is maintained at 60-70% within 7 days after the application.

Images