Vegetable green straw adaptive complex microbial inoculant and preparation method thereof

Abstract

The invention discloses a vegetable green straw adaptive complex microbial inoculant and a preparation method thereof, and belongs to the technical field of vegetable straw decomposition. The vegetable green straw complex microbial inoculant with high moisture adaptability comprises 0.2-2 parts of a microbial component, 20-30 parts of straw charcoal, 10-15 parts of a diatomite-polyglutamic acid complex, 5-10 parts of hydrophobic modified rice hull powder, 30-40 parts of a nutrition buffer agent, 1-5 parts of a detoxification synergist and 1-5 parts of a biofilm inducer. Through the synergistic effect of the composite flora, the functional material and the nutrition buffer system, the three technical bottlenecks of hypoxia suffocation, rancidity inhibition and physical barrier in a high-moisture (70-85%) environment of the green vegetable straws are systematically overcome, the degradation rate of dry matters within 60 days is over 69%, the degradation rate of toxins within 60 days is over 73%, and the degradation rate of organic matters within 60 days is over 70%. The straw decomposition efficiency and the resource utilization level are remarkably improved, and an efficient solution is provided for green treatment of agricultural wastes.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vegetable straw rotting, and particularly relates to a vegetable green straw adaptive composite microbial inoculant and a preparation method thereof. BACKGROUND

[0002] The horticulture industry in China is booming, leading to a sustained increase in vegetable production. As a result, the production of vegetable straw has also increased significantly, and its total amount has now ranked fourth among crop straw resources, only next to rice, corn and wheat straw. However, a large amount of vegetable straw has not been effectively utilized and is generally randomly piled up or discarded. This extensive treatment method has brought multiple problems: not only does it provide a breeding ground for pathogenic bacteria, threatening crop health, but it also pollutes the surrounding water and soil environment, and most importantly, it leads to the waste of valuable nutrients contained in the straw.

[0003] The root cause is that vegetable straw itself contains abundant available substances. Studies have shown that about half of the photosynthetic products of plants are stored in these straws. In terms of composition, the cellulose content in the dry matter can reach about 30%, providing an important carbon source; it also contains about 5% protein and various essential mineral elements such as calcium and phosphorus. If the value of vegetable straw can be fully tapped, it will be of great significance.

[0004] Vegetable green straw after harvesting has characteristics such as high water content (usually 70%-85%), complex physical structure (containing gum mucilage), and low carbon-nitrogen ratio (C / N about 10-20:1), which makes it difficult for conventional straw rotting microbial inoculants to effectively function. Most of the existing commercially available microbial inoculants are designed for low-moisture (15%-30%) straws such as wheat and corn.

[0005] Vegetable straw has a water content of 70%-85%, which squeezes the pores of the material and hinders the diffusion of oxygen. Corn / wheat straw, on the other hand, has a water content of only 15%-30% and a loose structure, which is conducive to the colonization of aerobic bacteria. Green vegetable straw has a high nitrogen content (C / N about 10-20:1), while the optimal C / N for microorganisms is 25-35:1. A high-nitrogen environment can accelerate acidification (pH <5.5), inhibit cellulose-decomposing bacteria, and promote the production of organic acids by anaerobic bacteria, further reducing pH and releasing NH3, which is toxic to microorganisms. Vegetable straw often contains gum and mucilage, which form a physical barrier around the fibers. While the waxy layer of corn straw is hydrophobic, it is more easily invaded by microbial inoculants after mechanical crushing. Therefore, there are three major technical bottlenecks in the application of current microbial inoculants to vegetable green straw: oxygen deprivation of microorganisms, inhibition of spoilage, and physical barriers.

[0006] Therefore, there is an urgent need for a microbial inoculant suitable for high-moisture vegetable green straw. SUMMARY

[0007] Therefore, the present application aims to provide a vegetable green straw adaptive composite microbial inoculant and a preparation method thereof.

[0008] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0009] In a first aspect, the present application provides a vegetable green straw high-moisture adaptive composite microbial inoculant, comprising the following components by mass fraction:

[0010] The microbial component is 0.2-2 parts, the straw biochar is 20-30 parts, the diatomite-polyglutamic acid complex is 10-15 parts, the hydrophobically modified rice husk powder is 5-10 parts, the nutrient buffer is 30-40 parts, the detoxification synergist is 1-5 parts, and the biological membrane inducer is 1-5 parts.

[0011] Preferably, the microbial component is composed of Trichoderma pseudokoningii, Aspergillus niger, Penicillium oxalicum, Pseudomonas putida and Acinetobacter lwoffi in a mass ratio of (30-40):20:10:(20-30):15.

[0012] The total viable bacterial count of the microbial component is greater than or equal to 2 billion CFU / g.

[0013] By using the above technical solution, the strains are selected for vegetable green straw, Trichoderma pseudokoningii still maintains high activity under the condition of 80% moisture content, secretes extracellular pectinase and cellulase, and specializes in cracking the physical barrier of the green straw skin gum layer of vegetables such as tomatoes and cucumbers. At the same time, the strain can effectively degrade alkaloid toxins such as alpha-tomatin secreted by solanaceous crops, reducing the toxicity to other strains. Aspergillus niger can further select acid-resistant varieties, tolerate acidic environments with pH 3.5-5.0, and still maintain more than 80% enzyme activity at pH≤5.0, while secreting citric acid to neutralize the ammonia nitrogen produced in the high-nitrogen environment and simultaneously dissolving the insoluble phosphate in the straw. Penicillium oxalicum can effectively decompose aromatic compounds in soft straws such as lettuce and spinach under the condition of 85% moisture content, with a lignin degradation rate increased by 40%.

[0014] Pseudomonas putida maintains activity at 10℃ low temperature and 80% moisture content, secretes low-temperature cellulase, and solves the problem of straw decomposition in winter agriculture at low temperature. Acinetobacter lwoffi can efficiently degrade cellulose, and the extracellular polysaccharide product promotes the formation of bacterial biofilm, enhancing environmental adaptability. Acinetobacter lwoffi can decompose hemicellulose through fermentation pathways in anoxic microenvironments, and simultaneously degrade organic acids to eliminate rancid odors.

[0015] The fungi are responsible for breaking down the fiber structure by secreting extracellular enzymes, and the bacteria are responsible for degrading small molecules and acid metabolism, thereby synergistically degrading the green vegetable straw.

[0016] Preferably, the specific surface area of the straw biochar is greater than or equal to 350 m 2 / g, and the porosity is greater than or equal to 90%. The honeycomb structure forms micro-oxygen channels, and even under the condition of a water content of 80%, the oxygen content in the pores is still greater than or equal to 15%, thereby providing a living space for aerobic bacteria.

[0017] Preferably, the preparation method of the diatomite-polyglutamic acid composite is as follows: diatomite is crushed to pass through a 200-mesh sieve, is baked at 500 DEG C for 2 hours to remove organic impurities, polyglutamic acid powder is mixed with the diatomite at a weight ratio of 1:1, 5 times the volume of deionized water is added, and stirring is performed to form a slurry, constant-temperature stirring is performed at 60 DEG C for 2 hours, then a 0.1M CaCl2 solution is added dropwise, and after solidification, washing and drying at 40 DEG C are performed, the composite particles with a particle size of 1-3 mm are obtained. The diatomite is surface-modified by polyglutamic acid, and the water holding capacity is 8 times the weight of the diatomite; when the moisture content is greater than 85%, free water is adsorbed; and when the moisture content is less than 70%, water is released in a slow-release manner, so that the moisture content of the pile is stably maintained in an optimal range of 75% plus or minus 5%.

[0018] Preferably, the preparation method of the hydrophobically modified rice husk powder is as follows: the rice husk is washed and dried at 60 DEG C until the water content is less than or equal to 5%, and then is crushed to pass through an 80-mesh sieve; then the rice husk powder is immersed in a 5-10wt% silane coupling agent solution, the ratio of the rice husk powder to the solution is 1:10 (w / v), constant-temperature stirring is performed at 45 DEG C for 6-12 hours, so that the silane is uniformly coated, and then is filtered and dried at 100 DEG C for 2 hours, so that the silane is crosslinked into a film. In the present application, the rice husk is treated by silanization to form a hydrophobic barrier, thereby constructing a drainage channel at the bottom of the pile and preventing the formation of an anaerobic zone, and the air permeability of the pile is effectively improved.

[0019] Preferably, the nutrient buffer is composed of a C / N regulator, trace elements and an acid-base buffer at a mass ratio of 10:1:2.

[0020] Preferably, the C / N regulator is a mixture of corn cob powder and mature chicken manure at a mass ratio of 3:1.

[0021] The trace element activator is composed of ammonium molybdate, manganese sulfate and boric acid at a mass ratio of 2:1:1.

[0022] The acid-base buffer is composed of dipotassium hydrogen phosphate and magnesium oxide at a mass ratio of 2:1.

[0023] In the present application, the corn cob powder-mature chicken manure compound is used to increase the overall C / N ratio to an ideal range of 30-35:1. The corn cob powder (C / N approximately equal to 80:1) provides a slow-decomposing carbon source, and the mature chicken manure (C / N approximately equal to 15:1) contains thermophilic actinomycete spores, and the temperature is increased to above 55 DEG C during fermentation, thereby promoting the dissolution of gelatin.

[0024] Trace elements containing ammonium molybdate, manganese sulfate, boric acid, activate lignin peroxidase, manganese peroxidase and other key enzyme system activity. Among them, molybdenum element promotes nitrate reduction, reduces the risk of nitrite accumulation.

[0025] Acid-base buffer potassium phosphate-dicitrate buffer pair: maintain the pH 6.0-7.5 enzyme optimum activity interval, especially protect the neutral bacterial activity. Magnesium oxide neutralizes organic acids while providing a source of magnesium, promoting chlorophyll-degrading bacteria proliferation.

[0026] As preferred, the detoxification synergist is oyster shell powder, tea polyphenol. Oyster shell powder CaCO3 content ≥ 90%, is a slow-release alkaline substance, the dissolution rate is 60% lower than limestone, avoiding local pH sudden rise; tea polyphenol can antioxidant scavenge free radicals, passivate heavy metal activity, reduce toxicity to strains.

[0027] As preferred, the biofilm inducer is chitosan oligosaccharide. Can further enhance the ability of microbial colonization.

[0028] The application also provides a preparation method of the compound microbial agent.

[0029] S1. The raw materials are weighed according to the weight parts;

[0030] S2. The microbial components are activated to obtain an activated solution;

[0031] S3. The activated solution, straw biochar and biofilm inducer are uniformly mixed, and then diatomite-polyglutamic acid complex, hydrophobically modified rice husk powder, nutrient buffer and detoxification synergist are sequentially added and uniformly mixed to obtain the compound microbial agent.

[0032] As preferred, the amount of the compound microbial agent is 5-15 kg / acre.

[0033] At least the following beneficial technical effects are achieved:

[0034] The application solves the three technical bottlenecks of anoxic asphyxia, rancid inhibition and physical barrier in the environment of high moisture (70%-85%) of green straw of vegetables through the synergistic effect of compound microbial flora (Trichoderma reesei, Aspergillus niger and the like), functional materials (straw biochar to construct micro-aerobic channels, diatomite-polyglutamic acid complex to dynamically regulate water) and nutrient buffer system, realizes the dry matter degradation rate of more than 69% and the toxin degradation rate of more than 73% within 60 days, significantly improves the straw composting efficiency and resource utilization level, and provides an efficient solution for green treatment of agricultural waste. DETAILED DESCRIPTION

[0035] The following detailed description of various exemplary embodiments of the application will not be considered limiting of the application, but rather a description of certain aspects, features and embodiments of the application.

[0036] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Additionally, for a range of values of a parameter, unless otherwise stated, each intervening value of the parameter is also specifically included within the scope of the present application. The intervening values of the parameter are combined with a stated value of the parameter in range form. These are only exemplary of the various preferred embodiments and are not intended to be limiting of the application. Other embodiments will occur to those skilled in the art upon consideration of this description. Modifications and variations are considered within the scope of the application as those skilled in the art will understand in light of the teachings.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All publications mentioned in this specification are herein incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The citation of any reference is not construed as an admission that it is prior art with respect to the present application.

[0038] Many modifications and variations of this application can be made in the light of the above teachings without departing from the spirit and scope thereof. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The examples in the specification and examples are illustrative only and not restrictive of the application.

[0039] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional, unrecited elements or method steps.

[0040] The raw materials or instruments used in the following examples of the present application are commercially available unless otherwise specified.

[0041] Raw material description:

[0042] The specific surface area of the straw biochar is 378 m 2 / g, and the porosity is 93%.

[0043] The preparation method of the diatomite-polyglutamic acid composite is as follows: diatomite is crushed to pass through a 200-mesh sieve, is baked at 500°C for 2 hours to remove organic impurities, polyglutamic acid powder is mixed with the diatomite at a weight ratio of 1:1, 5 times the volume of deionized water is added, and stirring is performed to form a slurry, constant temperature stirring is performed at 60°C for 2 hours, then 0.1M CaCl2 solution is added dropwise, after solidification, washing and drying at 40°C, a composite particle with a particle size of 2 mm is obtained.

[0044] The rice husk is washed and dried at 60 DEG C to a moisture content of less than or equal to 5%, and is crushed to pass through an 80-mesh screen; then the rice husk powder is immersed in a 5-10 wt% silane coupling agent solution, the ratio of the rice husk powder to the solution being 1:10 (w / v), and the solution is stirred at a constant temperature of 45 DEG C for 6-12 hours to allow the silane to uniformly coat the rice husk powder; the coated rice husk powder is filtered and dried at 100 DEG C for 2 hours to allow the silane to crosslink and form a film.

[0045] The nutrient buffer is composed of C / N regulator, trace elements and acid-base buffer in a mass ratio of 10:1:2, wherein the C / N regulator is a mixture of corn cob powder and decomposed chicken manure in a mass ratio of 3:1; the trace element activator is composed of ammonium molybdate, manganese sulfate and boric acid in a mass ratio of 2:1:1; and the acid-base buffer is composed of dipotassium hydrogen phosphate and magnesium oxide in a mass ratio of 2:1.

[0046] Example 1

[0047] The application further provides a preparation method of the composite microbial agent, comprising the following steps:

[0048] S1. The microbial component, straw biochar, diatomite-polyglutamic acid complex, hydrophobically modified rice husk powder, nutrient buffer, detoxification synergist and biofilm inducer are weighed according to the mass ratio of 1:25:12:8:35:3:3, wherein the microbial component is composed of Trichoderma pseudokoningii, Aspergillus niger, Penicillium oxalicum, Pseudomonas putida and Acinetobacter lwoffi in a mass ratio of 35:20:10:25:15; and the total viable bacterial count of the microbial component is 2.2 billion CFU / g.

[0049] S2. The microbial component is activated to obtain an activated solution.

[0050] S3. The activated solution, straw biochar and biofilm inducer are uniformly mixed, and then the diatomite-polyglutamic acid complex, hydrophobically modified rice husk powder, nutrient buffer and detoxification synergist are sequentially added and uniformly mixed again to obtain the composite microbial agent.

[0051] Example 2

[0052] The application further provides a preparation method of the composite microbial agent, comprising the following steps:

[0053] S1. The microbial component, straw biochar, diatomite-polyglutamic acid complex, hydrophobically modified rice husk powder, nutrient buffer, detoxification synergist and biofilm inducer are weighed according to the mass ratio of 0.2:20:10:5:30:1:1, wherein the microbial component is composed of Trichoderma pseudokoningii, Aspergillus niger, Penicillium oxalicum, Pseudomonas putida and Acinetobacter lwoffi in a mass ratio of 30:20:10:20:15; and the total viable bacterial count of the microbial component is 23.5 billion CFU / g.

[0054] S2. The microbial component is activated to obtain an activated solution.

[0055] S3. The activated liquid, straw biochar, biofilm inducer are mixed uniformly, then diatomite-polyglutamic acid complex, hydrophobically modified rice husk powder, nutrient buffer, detoxification synergist are added in turn and mixed again to obtain the compound microbial inoculant.

[0056] Example 3

[0057] The application further provides a preparation method of the compound microbial inoculant, comprising the following steps:

[0058] S1. Microbial components 2 parts, straw biochar 30 parts, diatomite-polyglutamic acid complex 15 parts, hydrophobically modified rice husk powder 10 parts, nutrient buffer 40 parts, detoxification synergist 5 parts and biofilm inducer 5 parts are weighed according to the mass ratio; wherein the microbial components are composed of Trichoderma pseudokoningii, Aspergillus niger, Penicillium oxalicum, Pseudomonas putida and Acinetobacter lwoffi according to a mass ratio of 40:20:10:30:15; and the total viable bacterial count of the microbial components is 2.08 billion CFU / g.

[0059] S2. The microbial components are activated to obtain an activated liquid;

[0060] S3. The activated liquid, straw biochar and biofilm inducer are mixed uniformly, then diatomite-polyglutamic acid complex, hydrophobically modified rice husk powder, nutrient buffer and detoxification synergist are added in turn and mixed again to obtain the compound microbial inoculant.

[0061] Comparative Example 1

[0062] The preparation method of the comparative example is the same as that of Example 1, except that the microbial components are composed of Trichoderma pseudokoningii and Aspergillus niger according to a mass ratio of 35:20; and the total viable bacterial count of the microbial components is 2.23 billion CFU / g.

[0063] Comparative Example 2

[0064] The preparation method of the comparative example is the same as that of Example 1, except that the microbial components are composed of Penicillium oxalicum, Pseudomonas putida and Acinetobacter lwoffi according to a mass ratio of 10:25:15; and the total viable bacterial count of the microbial components is 2.27 billion CFU / g.

[0065] Comparative Example 3

[0066] The preparation method of the comparative example is the same as that of Example 1, except that the raw materials do not contain diatomite-polyglutamic acid complex.

[0067] Comparative Example 4

[0068] The preparation method of the comparative example is the same as that of Example 1, except that the raw materials do not contain hydrophobically modified rice husk powder.

[0069] Comparative Example 5

[0070] The preparation method of the present comparative example is the same as that of Example 1, except that the C / N regulator is not contained in the nutrient buffer.

[0071] Experimental Example

[0072] The same tomato planting plot is selected, the planting density of which is 1800 plants per mu, and after the last batch of tomatoes is harvested, the water content of the tomato plants is detected to be 76.8%, and the tomato plants are crushed and returned to the field by using a returning machine.

[0073] The returning plot is divided into 10 areas, each of which is spaced 2 meters apart, and then numbered 1-10; the No. 1 area is a blank control; the No. 2 area is applied with a commercially available straw microbial agent; the No. 3-5 areas are respectively applied with the compound microbial agents prepared in Examples 1-3; and the No. 6-10 areas are respectively applied with the compound microbial agents prepared in Comparative Examples 1-5. Among them, the No. 2 area is applied according to the method in the instruction manual of the commercially available straw microbial agent, and the No. 3-10 areas are applied with a dosage of 12 kg per mu, and all the plots are tilled by using a tiller.

[0074] After 50 days, 3 samples are taken from each plot for detection and calculation of the average value.

[0075] Dry matter weight loss rate: (initial dry weight-residual dry weight) / initial dry weight x 100%.

[0076] Tomatine degradation rate: HPLC detection of tomatine.

[0077] The detection results are shown in Table 1

[0078] Table 1

[0079]

[0080] According to Table 1, the compound microbial agent prepared by the present application can greatly improve the degradation speed of tomato straw, can adapt to the high-moisture vegetable crop straw environment, and has a good effect on the degradation of toxins; at the same time, it coordinates the nutrients in the field. The use of diatomite-polyglutamic acid complex will significantly affect the degradation capacity, and the C / N regulator also has a significant effect.

[0081] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A compound microbial agent with high moisture adaptability for vegetable green straw, characterized in that, The components include the following parts by weight: Microbial components 0.2-2 parts, straw biochar 20-30 parts, diatomaceous earth-polyglutamic acid complex 10-15 parts, hydrophobically modified rice husk powder 5-10 parts, nutrient buffer 30-40 parts, detoxification synergist 1-5 parts, biofilm inducer 1-5 parts.

2. The compound microbial agent according to claim 1, characterized in that, The microbial components consist of Trichoderma synergae, Aspergillus niger, Penicillium oxalate, Pseudomonas stolonifera, and Acinetobacter rumeni in a mass ratio of (30-40):20:10:(20-30):

15. The total viable count of the microbial components is ≥2 billion CFU / g.

3. The compound microbial agent according to claim 1, characterized in that, The preparation method of the diatomaceous earth-polyglutamic acid composite is as follows: diatomaceous earth is pulverized and passed through a 200-mesh sieve, calcined at 500℃ for 2 hours to remove organic impurities, polyglutamic acid powder and diatomaceous earth are mixed at a weight ratio of 1:1, 5 times the volume of deionized water is added and stirred into a slurry, stirred at 60℃ for 2 hours, and then 0.1M CaCl2 solution is added dropwise. After solidification, the mixture is washed and dried at 40℃ to obtain composite particles with a particle size of 1-3 mm.

4. The compound microbial agent according to claim 1, characterized in that, The preparation method of the hydrophobic modified rice husk powder is as follows: after washing the rice husks, dry them at 60℃ until the moisture content is ≤5%, and then crush them through an 80-mesh sieve; then immerse the rice husk powder in a 5-10wt% silane coupling agent solution, with the ratio of rice husk powder to solution being 1:10 (w / v), stir at a constant temperature of 45℃ for 6-12 hours to uniformly coat the silane, filter, and then dry at 100℃ for 2 hours to crosslink the silane into a film.

5. The compound microbial agent according to claim 1, characterized in that, The nutrient buffer is composed of a C / N regulator, trace elements, and an acid-base buffer in a mass ratio of 10:1:

2.

6. The compound microbial agent according to claim 5, characterized in that, The C / N regulator is made by mixing corn cob powder and well-rotted chicken manure at a mass ratio of 3:

1. The trace element activator is composed of ammonium molybdate, manganese sulfate, and boric acid in a mass ratio of 2:1:

1. The acid-base buffer is composed of dipotassium hydrogen phosphate and magnesium oxide in a mass ratio of 2:

1.

7. The compound microbial agent according to claim 1, characterized in that, The detoxification enhancer is oyster shell powder and tea polyphenols.

8. The compound microbial agent according to claim 1, characterized in that, The biofilm inducer is chitosan oligosaccharide.

9. The method for preparing the compound microbial agent according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Weigh the raw materials according to the stated weight proportions; S2. Activate the microbial components to obtain an activated solution; S3. After mixing the activation solution, straw biochar, and biofilm inducer evenly, add the diatomaceous earth-polyglutamic acid complex, hydrophobic modified rice husk powder, nutrient buffer, and detoxification synergist in sequence and mix evenly again to obtain the compound microbial agent.

10. The preparation method according to claim 9, characterized in that, The dosage of the compound microbial agent is 5-15 kg / mu.

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