A composite microbial fertilizer, a preparation method and application thereof

Abstract

The application provides a compound microbial fertilizer, a preparation method and application thereof. The compound microbial fertilizer comprises the following components in parts by weight: 10-30 parts of a compound microbial agent, 20-50 parts of an agent carrier, 30-50 parts of a compound fertilizer slow-release agent and 10-30 parts of modified urea aldehyde. The compound microbial fertilizer prepared by the application can be applied to growth tests of tomatoes, and higher yield, stem thickness growth value, vitamin C content and sugar acid ratio can be obtained. The compound microbial fertilizer has long-term effect, can release phosphorus, nitrogen and potassium and the like, has the effects of moisturizing and loosening soil, can increase the yield and quality of tomato fruits, promote the robustness of roots and stems and improve the eating taste.

Description

Technical Field

[0001] This invention belongs to the field of microbial fertilizer technology, and particularly relates to a compound microbial fertilizer, its preparation method and application. Background Technology

[0002] With a large population and limited arable land per capita, fertilizers play an increasingly important role in agricultural production in order to obtain more food from limited land. Improving soil fertility, promoting crop growth, and having a significant impact on soil quality evolution and sustainable agricultural development are crucial.

[0003] Traditional organic fertilizers are gradually being abandoned due to their time-consuming and labor-intensive production, unsanitary conditions, and slow fertilization effects. The increasing use of chemical fertilizers has also gradually revealed many drawbacks. Environmental protection and food safety issues have become the most concerning topics for people in recent years. For example, the overuse of chemical fertilizers has caused eutrophication of rivers and lakes, damaging ecosystems. Excessive nitrate content in groundwater threatens human health. Long-term use of chemical fertilizers leads to soil compaction, reduced organic humus content, and imbalance of soil microbial communities. In severe cases, it can lead to soil desertification, hindering the sustainable development of agriculture.

[0004] Because a large number of microorganisms exist in the soil and plant rhizosphere, the interaction between beneficial bacteria and plant roots can promote plant growth. Therefore, research on microbial fertilizers has been gradually carried out. Microbial fertilizers themselves do not contain nutrients, but they can improve the soil environment and stimulate crop growth through the activity of a large number of beneficial strains. They are considered to be one of the most promising tools for sustainably improving agricultural productivity. By regulating the function of soil microorganisms, it is hoped that the current over-reliance on chemical fertilizers in agriculture can be reduced.

[0005] The combined use of microbial fertilizers and compound fertilizers can further enhance soil fertility and reduce pollution. However, how to achieve long-term effects, continuously provide nutrients to crops, and reduce the frequency of fertilization are still problems that need to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide a bio-fertilizer, its preparation method, and its application, in order to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides a compound microbial fertilizer, characterized in that it comprises the following components in parts by weight: 10-30 parts of compound microbial agent, 20-50 parts of agent carrier, 30-50 parts of compound fertilizer slow-release agent, and 10-30 parts of modified urea aldehyde.

[0008] The compound fertilizer slow-release agent is a polyacrylic acid type compound fertilizer slow-release agent;

[0009] The modified urea aldehyde is sucrose-modified urea aldehyde.

[0010] As a further improvement, the composite microbial agent is prepared by mixing Bacillus subtilis, Bacillus mucilaginosus, Trichoderma harzianum, and Bacillus amyloliquefaciens in a mass ratio of 2-4:1-3:0.5-2:1, followed by inoculation, activation, and fermentation.

[0011] As a further improvement, the compound fertilizer slow-release agent contains at least phosphorus, nitrogen, potassium, and silicon as nutrients.

[0012] As a further improvement, the synthesis of the compound fertilizer slow-release agent includes the following steps:

[0013] (1) Add diatomaceous earth, ammonium dihydrogen phosphate and potassium humate to a flask equipped with a reflux condenser, add distilled water while stirring and heat to 70-90℃, react for 4-8 hours and then cool to 40-60℃.

[0014] (2) The pH of acrylic acid was adjusted to 4-5 with an inorganic alkaline solution under water bath conditions to obtain mixture A; the initiator and crosslinking agent were added to water and stirred to dissolve to obtain mixture B;

[0015] (3) Slowly add mixture A to step (1) and stir to mix. Then add mixture B to it. After the addition is complete, heat to 70-90℃. Stop the reaction when the reaction system becomes viscous and difficult to stir. After post-processing, obtain compound fertilizer slow-release agent.

[0016] As a further improvement, the inorganic alkaline solution is a micro-potassium hydroxide solution; the initiator is potassium persulfate; and the crosslinking agent is N,N-methylenebisacrylamide.

[0017] As a further improvement, the ammonium dihydrogen phosphate contains ≥60% phosphorus pentoxide and ≥12% nitrogen; the potassium humate contains ≥12% potassium oxide and ≥70% humic acid.

[0018] As a further improvement, the diatomaceous earth is of a size of 100-200 mesh.

[0019] As a further improvement, the synthesis of the modified urea aldehyde includes the following steps:

[0020] (1) Weigh urea and place it in a beaker, then add formaldehyde and stir to dissolve it. Then add inorganic alkali solution dropwise to adjust the pH of the system to 7-9. React in a water bath at 30-50℃ for 1-3 hours to obtain urea aldehyde solution.

[0021] (2) Add sucrose and catalyst to step (1) in sequence, then add inorganic acid solution to adjust the pH of the system to 4-6, and then react at 60-80℃ to obtain a paste, which is then extruded and granulated by an extruder, and then post-treated to obtain modified urea aldehyde.

[0022] As a further improvement, the inorganic alkaline solution is a potassium hydroxide solution; the catalyst is copper sulfate; and the inorganic acid solution is a phosphoric acid solution.

[0023] As a further improvement, the microbial agent carrier is biochar.

[0024] This invention provides a method for preparing a compound microbial fertilizer, characterized by comprising the following steps:

[0025] (1) The compound microbial agent is sprayed onto the agent carrier according to the weight parts, and then dried to obtain microbial powder;

[0026] (2) The microbial powder obtained in step (1) is mixed with compound fertilizer slow-release agent and modified urea aldehyde to obtain compound microbial fertilizer.

[0027] This invention also provides an application of compound microbial fertilizer in promoting crop fruit growth and improving crop quality.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] This invention provides a compound microbial fertilizer and its preparation method. When applied to the growth of tomatoes, it can achieve higher yield, stem diameter growth, vitamin C content, and sugar-acid ratio, indicating that the compound microbial fertilizer has a long-lasting effect, releases nutrients such as phosphorus, nitrogen, and potassium, and has the functions of moisturizing and loosening soil. It can increase the weight and yield of tomato fruits, promote the robustness of roots and stems, and improve the taste.

[0030] Among them, Trichoderma harzianum in compound microbial agents can inhibit fungal pathogens, improve the soil environment, and ferment together with Bacillus subtilis, Bacillus mucilaginosus, and Bacillus amyloliquefaciens to form dominant colonies. Living in or inside the roots of crops, it secretes a variety of functional enzymes, which play a role in nitrogen fixation, phosphorus solubilization, and potassium solubilization, promoting the absorption of nutrients by crops and improving crop quality. Detailed Implementation

[0031] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0032] In the following examples, except for the microbial inoculant, compound fertilizer slow-release agent, modified urea aldehyde, and urea aldehyde, all other compound monomers and related reagents used were commercially available. Specifically, Bacillus subtilis, Bacillus mucilaginosus, Trichoderma harzianum, and Bacillus amyloliquefaciens were purchased from Beijing Kezhan Biotechnology Co., Ltd., with product numbers CMCC(B)63501, BNCC335819, BNCC336568, and BNCC132483, respectively. Potassium humate was purchased from Xinjiang Longjia Humic Acid Co., Ltd., ammonium dihydrogen phosphate from Jinan Zhongcheng Chemical Co., Ltd., diatomaceous earth from Lingshou Zhuolei Building Materials Co., Ltd., sucrose and urea from Tianjin Kemio Chemical Reagent Co., Ltd., and biochar from Henan Xingnuo Environmental Protection Materials Co., Ltd. The commercially available compound fertilizer slow-release agent was purchased from Gansu Sudi Fertilizer Co., Ltd., model 8-12-5.

[0033] The preparation of microbial inoculants includes the following steps:

[0034] Bacillus subtilis, Bacillus mucilaginosus, Trichoderma harzianum, and Bacillus amyloliquefaciens strains were inoculated into NB medium (formula: 10g peptone, 3g beef extract, 5g NaCl, 1L distilled water, pH=7.2-7.4) and activated incubated at 150 rpm and 30℃ for 12 h in a shaker to obtain activated bacterial solutions. 50 mL of NB medium was brought to a final volume in a 100 mL volumetric flask, and 1 mL of the activated bacterial solution was inoculated into another 100 mL volumetric flask and incubated at 30℃ for 24 h in a shaker at 200 rpm to obtain seed culture.

[0035] (2) The seed culture was then inoculated into a 100L liquid fermenter for fermentation and culture until the absorbance of the suspension reached OD. 600 ≈1.0, to obtain fermentation broths of four strains, which were then mixed in a mass ratio of 3:2:1:1 to obtain microbial inoculants.

[0036] The synthesis of compound fertilizer slow-release agents includes the following steps:

[0037] (1) Add 10g of diatomaceous earth, 20g of ammonium dihydrogen phosphate and 20g of potassium humate to a flask equipped with a reflux condenser, add 200mL of distilled water while stirring and heat to 80℃. After reacting for 6h, cool down to 50℃.

[0038] (2) Adjust the pH of 100g acrylic acid to 4.5 with 1mol / L potassium hydroxide solution under 5℃ water bath conditions to obtain mixture A; add 2.2g potassium persulfate and 0.3g N,N-methylenebisacrylamide to 100mL water and stir to dissolve to obtain mixture B;

[0039] (3) Slowly add mixture A to step (1) and stir to mix. Then add mixture B to it. After the addition is complete, heat to 80°C. Stop the reaction when the reaction system becomes viscous and difficult to stir. Take out the reaction product, wash it repeatedly with anhydrous ethanol, and then dry and pulverize it at 80°C to obtain the compound fertilizer slow-release agent.

[0040] The synthesis of modified urea-formaldehyde includes the following steps:

[0041] (1) Weigh 50g of urea and place it in a beaker, then add 17.86g of formaldehyde. After the urea is completely dissolved, add 5% potassium hydroxide solution to adjust the pH of the system to 8. React in a 40℃ water bath for 1.5h to obtain urea aldehyde solution.

[0042] (2) 7.57g sucrose and 0.75g copper sulfate were added to step (1) in sequence, and then a 2% phosphoric acid solution was added to adjust the pH of the system to 5. The mixture was then reacted at 70℃ for 40min to obtain a paste, which was extruded and granulated using an extruder and dried at 80℃ to constant weight to obtain modified urea aldehyde.

[0043] The synthesis of urea-formaldehyde involves the following steps:

[0044] (1) Weigh 50g of urea and place it in a beaker, then add 17.86g of formaldehyde. After the urea is completely dissolved, add 5% potassium hydroxide solution to adjust the pH of the system to 8. React in a 40℃ water bath for 1.5h to obtain urea aldehyde solution.

[0045] (2) Add 2% phosphoric acid solution to urea aldehyde solution to adjust the pH of the system to 5, then react at 70°C for 40 min to obtain a paste, extrude and granulate it, and dry it at 80°C to constant weight to obtain urea aldehyde.

[0046] The preparation methods of Examples 1-3 and Comparative Examples 1-3 include the following steps:

[0047] (1) The compound microbial agent is sprayed onto the agent carrier according to the weight parts, and then dried naturally at room temperature to obtain microbial powder;

[0048] (2) The microbial powder obtained in step (1) is mixed with compound fertilizer slow-release agent and modified urea aldehyde to obtain compound microbial fertilizer.

[0049] The components and their contents used in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 below:

[0050] Table 1

[0051]

[0052] The compound microbial fertilizers prepared in Examples 1-3 and Comparative Examples 1-3 were used to conduct growth-promoting experiments on tomato seedlings. The experimental methods are as follows:

[0053] Experimental area setup: Seven different treatments were set up, including a blank control group, Examples 1-3, and Comparative Examples 1-3. Tomato seedlings (Zhefen 702 variety) were planted in the soil of the experimental area, with each sub-area having an area of ​​18.0 m². 2 Each treatment was repeated 3 times in a randomized block design. Planting was carried out using a raised bed method with a bed height of about 0.3m and a plant spacing of 0.3m. Each small area was separated from the adjacent small areas by a 50cm×20cm field ridge.

[0054] Fertilization method: Tomato seedlings were planted in each experimental area. During the planting period, the blank control group was watered only and no fertilizer was applied. The other areas were fertilized with the compound microbial fertilizers of Examples 1-3 and Comparative Examples 1-3 at a rate of 1000 kg / hm². 2 ;

[0055] Harvesting begins after the fruit matures, and records are kept according to regional settings. The yield of each region is obtained by weighing the fruit. The stem diameter before and after planting is measured using vernier calipers to obtain the stem diameter growth value. The content of organic acids (total acids) in tomato fruit is determined according to the method in the national standard "Determination of Total Acids in Food". The vitamin C content in tomato fruit is determined by the iodometric method. The soluble sugar content in tomato fruit is determined by the anthrone colorimetric method. The sugar-acid ratio is calculated based on the ratio of soluble total sugar to total acid.

[0056] The test results are shown in Table 2, as follows:

[0057] Table 2

[0058]

[0059] As can be seen from Example 2 and Comparative Examples 1-2 in Table 2, compared with the use of conventional compound fertilizers or commercially available compound fertilizer slow-release agents in the preparation of compound microbial fertilizers, the compound microbial fertilizers prepared using polyacrylic acid type compound fertilizer slow-release agents showed higher yield, stem diameter growth value, vitamin C content, and sugar-acid ratio in tomato growth experiments. This indicates that acrylic acid, as a coating material, can be grafted and copolymerized with substances containing nutrients such as phosphorus, nitrogen, and potassium to prepare polyacrylic acid type compound fertilizer slow-release agents that have a long-lasting effect, increasing the yield and quality of tomato fruits, promoting robust roots and stems, and improving the taste. Furthermore, since diatomaceous earth itself is water-absorbing and lightweight, it can play a role in moisturizing and loosening the soil. When used in conjunction with phosphorus, nitrogen, and potassium, it can serve as a long-acting silicon fertilizer, further promoting crop growth.

[0060] As can be seen from Example 2 and Comparative Example 3, compared with the compound microbial fertilizer prepared using unmodified urea aldehyde, the compound microbial fertilizer prepared using sucrose-modified urea aldehyde has higher yield, stem diameter growth value, vitamin C content and sugar-acid ratio in the tomato growth experiment. This indicates that the introduction of sucrose can improve the release efficiency of nitrogen and organic matter in the soil, stimulate soil urease activity, and provide favorable conditions for the growth and reproduction of microorganisms in the soil, thereby improving the production quality of crops.

[0061] The test results from Examples 1-3 show that the compound microbial fertilizer prepared by the method provided by the present invention, when applied to the growth experiment of tomatoes, can achieve higher yields, stem diameter growth, vitamin C content, and sugar-acid ratio. This indicates that the compound microbial fertilizer has a long-lasting effect, releases nutrients such as phosphorus, nitrogen, and potassium, and has the functions of moisturizing and loosening the soil. It can increase the yield and quality of tomato fruits, promote the robustness of roots and stems, and improve the taste.

[0062] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A compound microbial fertilizer, characterized in that, It contains the following components in parts by weight: 10-30 parts of compound microbial inoculant, 20-50 parts of inoculant carrier, 30-50 parts of compound fertilizer slow-release agent, and 10-30 parts of modified urea formaldehyde. The compound fertilizer slow-release agent is a polyacrylic acid type compound fertilizer slow-release agent; The modified urea aldehyde is sucrose-modified urea aldehyde; The synthesis of the compound fertilizer slow-release agent includes the following steps: (1) Add diatomaceous earth, ammonium dihydrogen phosphate and potassium humate to a flask equipped with a reflux condenser, add distilled water while stirring and heat to 70-90℃, react for 4-8 hours and then cool to 40-60℃. (2) The pH of acrylic acid was adjusted to 4-5 with an inorganic alkaline solution under water bath conditions to obtain mixture A; the initiator and crosslinking agent were added to water and stirred to dissolve to obtain mixture B; (3) Slowly add mixture A to step (1) and stir to mix. Then add mixture B to it. After the addition is complete, heat to 70-90℃. Stop the reaction when the reaction system becomes viscous and difficult to stir. Then process to obtain compound fertilizer slow release agent. The synthesis of the modified urea aldehyde includes the following steps: (1) Weigh urea and place it in a beaker, then add formaldehyde and stir to dissolve it. Then add inorganic alkali solution dropwise to adjust the pH of the system to 7-9. React in a water bath at 30-50℃ for 1-3 hours to obtain urea aldehyde solution. (2) Add sucrose and catalyst to step (1) in sequence, then add inorganic acid solution to adjust the pH of the system to 4-6, and then react at 60-80℃ to obtain a paste, which is then extruded and granulated by an extruder, and then processed to obtain modified urea aldehyde. The compound microbial agent is prepared by mixing Bacillus subtilis, Bacillus mucilaginosus, Trichoderma harzianum, and Bacillus amyloliquefaciens in a mass ratio of 2-4:1-3:0.5-2:1, followed by inoculation, activation, and fermentation.

2. The compound microbial fertilizer according to claim 1, characterized in that, The compound fertilizer slow-release agent contains at least phosphorus, nitrogen, potassium, and silicon as nutrients.

3. The compound microbial fertilizer according to claim 1, characterized in that, The ammonium dihydrogen phosphate contains ≥60% phosphorus pentoxide and ≥12% nitrogen; the potassium humate contains ≥12% potassium oxide and ≥70% humic acid.

4. The compound microbial fertilizer according to claim 1, characterized in that, The diatomaceous earth has a mesh size of 100-200.

5. The compound microbial fertilizer according to claim 1, characterized in that, The carrier for the microbial agent is biochar.

6. A method for preparing a compound microbial fertilizer according to any one of claims 1-5, characterized in that, Includes the following steps: (1) The compound microbial agent is sprayed onto the agent carrier according to the weight parts, and then dried to obtain microbial powder; (2) The microbial powder obtained in step (1) is mixed with compound fertilizer slow-release agent and modified urea aldehyde to obtain compound microbial fertilizer.

7. The application of a compound microbial fertilizer according to any one of claims 1-5 in promoting crop fruit growth and improving crop quality.

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