Preparation method of straw biomass fertilizer

Abstract

The invention provides a preparation method of a straw biomass fertilizer, and relates to the technical field of biomass fertilizers. The straw biomass fertilizer is obtained by mixing straw ash and crushed straw subjected to steam explosion and microwave treatment, performing fermentation treatment by adopting virona and clostridium butyricum in sequence, and performing sterilization treatment after the virona is fermented. According to the method, the defects in the prior art are overcome, the straw and plant ash mixture is subjected to fermentation treatment through selected strains, the fertility of the final biological fertilizer is effectively and comprehensively improved, and on the basis of reducing addition of other fertilizers, the soil fertility is comprehensively improved, plant growth is promoted, the straw utilization rate is increased, and the planting cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of biomass fertilizers, and in particular to a method for preparing straw biomass fertilizers. Background Art

[0002] Straw is the general term for the stems, leaves, and ears of mature crops, typically the remaining portion of wheat, rice, corn, potatoes, rapeseed, cotton, sugarcane, and other crops (usually coarse grains) after the seeds are harvested. Straw is derived from a wide range of crops and is an inevitable byproduct of agricultural production.

[0003] In the past, most ways of dealing with straw were to burn it directly in the fields and use the ash from the burning as fertilizer for the farmland. However, with the development of green planting, burning of straw in the fields has been strictly prohibited. Based on this, straw has become debris that needs to be dealt with in the fields after the crops are harvested. In order to improve the utilization rate of straw and reduce waste, there are various ways to reuse straw at this stage, and it is generally made into fertilizer and feed.

[0004] Straw fertilizer is generally divided into two types: one is to return the straw to the field after simple shredding, and the other is to compost and ferment the straw into fertilizer. While direct straw crushing and returning to the field can improve soil fertility, the insect eggs and pathogens contained in the straw can increase the risk of pests and diseases in subsequent crops. Furthermore, the straw takes a long time to decompose, making it prone to diseased seedlings and seed dieback, which affects the germination and rooting of the next season's seeds. Straw composting, on the other hand, often uses high-temperature fermentation or the addition of complex bacterial agents to accelerate straw decomposition, which takes a long time. Furthermore, the composted fertilizer, when not fully decomposed, may carry insect eggs, harmful viruses, and bacteria. Standard organic fertilizers used in composting often require fermentation at temperatures above 55°C for at least three days before safe use. However, existing composts are poorly standardized and may not meet these safety standards. Furthermore, composted straw fertilizers often have poor fertility and require the addition of a large number of other fertilizers for actual use, making them uneconomical for overall planting costs. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a method for preparing straw biomass fertilizer. By fermenting and treating the straw and wood ash mixture separately with selected bacterial strains, the fertility of the final biofertilizer is effectively and comprehensively improved. On the basis of reducing the addition of other fertilizers, the soil fertility is comprehensively improved, plant growth is promoted, the straw utilization rate is increased, and the planting cost is reduced.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for preparing straw biomass fertilizer, comprising the following steps: S1. Burning straw to obtain straw ash for future use; S2, crushing the fresh straw and performing steam explosion treatment, and then microwave drying to obtain straw shreds for later use; S3. Mix the chopped straw and straw ash in a mass ratio of 9-11:1, and spray with sugar water until the moisture content is 18%-20%, to obtain a mixture for later use; S4, spraying 1%-2% of the total mass of the mixture into the mixture, controlling the viable bacteria content of the Verona fermentation liquid to 10 8 -10 10 / mL, stir evenly, ferment for 5-8 days to obtain the preliminary fermentation material; S5, after sterilizing the above-mentioned preliminary fermentation material, spray 1%-2% of the total mass of the mixed material with Clostridium butyricum fermentation liquid, and control the content of live bacteria of Clostridium butyricum fermentation liquid to be 10 8 -10 10 After stirring evenly, ferment for 9-11 days to obtain the final fermentation material for use; S6. Drying and crushing the final fermented material to obtain straw biomass fertilizer.

[0007] Preferably, the steam explosion treatment in step S2 is carried out at a pressure of 1-2 MPa, with the steam temperature controlled at 120° C., for 1-2 seconds.

[0008] Preferably, the microwave power of the microwave drying in step S2 is 800-1000W, and the moisture content of the dried straw shreds is ≤8%.

[0009] Preferably, the sugar water in step S3 is a white sugar aqueous solution with a mass concentration of 12%-15%.

[0010] Preferably, the Verona fermentation broth in step S4 is prepared by inoculating Verona into SCMB liquid culture medium and fermenting, and the formula of the SCMB liquid culture medium is: 0.5g sodium butyrate + 0.1g pecan shell powder + 3g maltose + 0.4g beef powder + 100mL water.

[0011] Preferably, the sterilization method in step S5 is high-pressure steam sterilization, with a pressure of 0.2-0.3 MPa, a steam temperature of 121° C., and a sterilization treatment time of 20 minutes.

[0012] Preferably, the Clostridium butyricum fermentation broth in step S5 is obtained by inoculating Clostridium butyricum into RCM medium and fermenting, and the formula of RCM medium is: peptone 10.0 g / L + beef powder 10.0 g / L + yeast powder 3.0 g / L + glucose 5.0 g / L + soluble starch 1.0 g / L + sodium chloride 5.0 g / L + sodium acetate 3.0 g / L, L-cysteine ​​hydrochloride 0.5 g / L + agar 0.5 g / L, and the balance is water.

[0013] Preferably, the fermentation material is dried in step S6 by constant temperature drying at 45-50° C. until the moisture content is ≤8%.

[0014] Preferably, the powder is crushed through a 20-mesh sieve in step S6.

[0015] The present invention provides a method for preparing straw biomass fertilizer, which has the following advantages over the prior art: The present invention adopts plant ash obtained by burning straw and steam-exploded dried fresh straw as raw materials, and adopts Verona mycelium and Clostridium butyricum to carry out fermentation treatment respectively, so as to effectively promote the decomposition of straw while releasing a variety of organic components and substances, thereby promoting plant growth. In addition, the present invention carries out sterilization treatment after the Verona mycelium fermentation, effectively killing the Verona mycelium while inactivating miscellaneous bacteria and insect eggs in the straw, thereby improving the use safety of the biofertilizer, effectively preventing the Verona mycelium from inhibiting the subsequent Clostridium butyricum fermentation treatment, comprehensively improving the fertility of the fertilizer, reducing the addition of other fertilizers in plant growth, and comprehensively improving the utilization rate of the straw. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the microscopic morphology of the biomass fertilizer of Example 1 of the present invention; Figure 2 Schematic diagram of the microscopic morphology of the biomass fertilizer of Comparative Example 1 of the present invention; Figure 3 Schematic diagram of the microscopic morphology of the biomass fertilizer of Comparative Example 2 of the present invention; Figure 4 Schematic diagram of the microscopic morphology of the biomass fertilizer of Comparative Example 3 of the present invention; Figure 5 Schematic diagram of the microscopic morphology of the biomass fertilizer of Comparative Example 4 of the present invention; Figure 6 Schematic diagram of the microscopic morphology of the biomass fertilizer of Comparative Example 5 of the present invention; Figure 7 Schematic diagram of fermentation with Verona spp. for 7 days at different ratios of chopped straw and straw ash in the embodiment of the present invention; Figure 8 Schematic diagram of fermentation with Clostridium butyricum for 10 days at different ratios of chopped straw and straw ash in an embodiment of the present invention; Figure 9 Schematic diagram of the microscopic morphology of biomass fertilizer prepared with a ratio of chopped straw to straw ash of 1:0 in an embodiment of the present invention; Figure 10 Schematic diagram of the microscopic morphology of biomass fertilizer prepared with a ratio of chopped straw to straw ash of 5:0 in an embodiment of the present invention; Figure 11 Schematic diagram of the microscopic morphology of the biomass fertilizer prepared with the ratio of chopped straw and straw ash being 1:1 in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0018] The Verona mycoides used in the following examples was obtained from the Yunnan Academy of Forestry and Grassland Sciences, with a deposit number of CCTCC NO: M 2024291 (the strain has been disclosed in the patent application number CN202410591938.9 filed on May 14, 2024); Clostridium butyricum was obtained from South China University of Technology, with a deposit number of GDMCC NO: 60623 (the strain has been disclosed in the patent application number CN201910510790.0 filed on June 13, 2019); and the Verona mycoides fermentation broth was prepared by inoculating Verona mycoides into SCMB liquid medium (0.5 g sodium butyrate + 0.1 g pecan shell powder + 3 g maltose + 0.4 g beef powder + 100 mL water) and fermenting until the number of viable Verona mycoides cells reached 10 9 The fermentation broth of Clostridium butyricum was prepared by inoculating the fermentation broth of Clostridium butyricum into RCM medium (peptone 10.0 g / L + beef powder 10.0 g / L + yeast powder 3.0 g / L + glucose 5.0 g / L + soluble starch 1.0 g / L + sodium chloride 5.0 g / L + sodium acetate 3.0 g / L, L-cysteine ​​hydrochloride 0.5 g / L + agar 0.5 g / L, the balance being water) and culturing until the viable count of Clostridium butyricum reached 10 9 pieces / mL.

[0019] The straw used in the following examples is corn straw harvested from the same batch. Example 1:

[0020] Preparation of straw biomass fertilizer: Step (1): drying fresh straw and then burning it to obtain straw ash; Step (2): crush the fresh straw and place it under a pressure of 1.5 MPa, use 120°C high-temperature steam explosion treatment for 2 seconds, then take it out and dry it under a microwave power of 800 W to a moisture content of ≤8%, to obtain straw shreds; Step (3): the chopped straw and straw ash are mixed and stirred evenly in a mass ratio of 10:1, and then sugar water (a white sugar aqueous solution with a mass concentration of 14%) is sprayed until the water content reaches 20%, thereby obtaining a mixture; Step (4): spraying 1.5% of the total mass of the mixture with Verona fermentation liquid into the mixture, stirring evenly, and fermenting at a constant temperature of 26±2°C for 7 days to obtain a preliminary fermentation material; Step (5): sterilize the preliminary fermentation material with steam at 121°C for 20 min under a pressure of 0.25 MPa, take it out, cool it to room temperature, and spray it with 1.5% of the total mass of the preliminary fermentation material of Clostridium butyricum fermentation liquid, stir it evenly, and ferment it at a temperature of 36±2°C for 10 days to obtain the final fermentation material; Step (6): The final fermented material is dried at a constant temperature of 45°C to a moisture content of ≤8%, and then crushed and passed through a 20-mesh sieve to obtain straw biomass fertilizer. Comparative Example 1:

[0021] Referring to the preparation method of Example 1 above, only the operation method of step (2) is different: Step (2): crush the fresh straw and dry it at 50°C until the moisture content is ≤8% to obtain straw shreds; Comparative Example 2:

[0022] Refer to the preparation method of Example 1 above, only the operation method of step (5) is different: Step (5): spraying the preliminary fermentation material with 1.5% of the total mass of the preliminary fermentation material with Clostridium butyricum fermentation liquid, stirring evenly, and fermenting at a temperature of 36±2°C for 10 days to obtain the final fermentation material; Comparative Example 3:

[0023] Referring to the preparation method of Example 1 above, step (1), step (2), and step (3) are the same as those in Example 1, and the remaining steps are: Step (4): spraying 1.5% of the total mass of the mixture with Verona fermentation liquid and 1.5% of the total mass of the mixture with Clostridium butyricum fermentation liquid into the mixture, stirring evenly, and fermenting at a constant temperature of 30°C for 17 days to obtain a fermentation material; Step (5): The fermented material is dried at a constant temperature of 45°C to a moisture content of ≤8%, and then crushed and passed through a 20-mesh sieve to obtain straw biomass fertilizer. Comparative Example 4:

[0024] Referring to the preparation method of Example 1 above, steps (1), (2), (3), and (4) are the same as those of Example 1, and the remaining steps are: Step (5): The preliminary fermented material is dried at a constant temperature of 45°C to a moisture content of ≤8%, and then crushed and passed through a 20-mesh sieve to obtain straw biomass fertilizer. Comparative Example 5:

[0025] Referring to the preparation method of Example 1 above, step (1), step (2), and step (3) are the same as those in Example 1, and the remaining steps are: Step (4): spraying 1.5% of the total mass of the mixture with Clostridium butyricum fermentation liquid into the mixture, stirring evenly, and fermenting at a constant temperature of 36±2°C for 10 days to obtain a fermentation material; Step (5): The fermented material is dried at a constant temperature of 45°C to a moisture content of ≤8%, and then crushed and passed through a 20-mesh sieve to obtain straw biomass fertilizer. Comparative Example 6:

[0026] The contents of C, H, O, and D in the straw biomass fertilizers prepared in Example 1 and Comparative Examples 1-5 were detected (CHON organic element analyzer). The specific results are shown in Table 1 below: Table 1

[0027] The microscopic morphology of the biomass fertilizers prepared in Example 1 and Comparative Examples 1-5 is as follows: Figure 1-6 As shown, as an organic fertilizer, the C / N ratio is generally best when it is 20-30:1. If the ratio is greater than 30:1, the accumulation of carbon in the soil will increase, affecting the nitrogen balance of the soil. If the ratio is less than 20:1, the nutrient release is too concentrated, resulting in nutrient loss or waste, and may also increase the volatilization loss of nitrogen in the soil. As can be seen from the above table, the C content of the biomass fertilizer in Example 1 is relatively low, indicating that a large amount of carbon source is consumed in the microbial fermentation stage, and the fermentation is relatively sufficient, and the subsequent C / N ratio is more appropriate. In the comparative examples, there is no sterilization treatment after Verona fermentation (Comparative Example 2), Verona and Clostridium butyricum are co-fermented (Comparative Example 3), and only Verona / Clostridium butyricum fermentation is used (Comparative Example 4 / Comparative Example 5). The final C content and C / N ratio are also high. This may be due to the growth antagonism between the two bacteria during co-fermentation, which limits the decomposition of straw.

[0028] 2. Detect the relevant properties of straw biomass fertilizer prepared by fermentation of straw crushed straw and straw ash at different proportions: The ratio of straw shreds to straw ash was controlled to be 0:1, 1:0, 5:1, 10:1, and 1:1, and fermentation was performed using the preparation method of Example 1. Figure 7As shown in Figure 2, after 10 days of fermentation with Clostridium butyricum, Figure 8 As shown; The C, H, O, and D contents of the final product at various ratios were detected (CHON organic element analyzer). When the ratio of crushed straw to straw ash was 0:1, i.e., fermentation with straw ash was used, the overall fermentation effect was poor, with essentially no fermentation change. Furthermore, since the C content in the straw ash itself was relatively low, no detection was performed. The specific results are shown in Table 2 below (Group 3 is the same group as Example 1): Table 2

[0029] The microscopic morphology of the biomass fertilizers in Group 1, Group 2 and Group 4 is as follows: Figure 9-11 As shown in Table 2 above, it can be seen that when the ratio of straw shreds to straw ash is too high or when no straw ash is added, it is easy to cause the C / N ratio to increase, which is not conducive to the soil's utilization of organic fertilizer.

[0030] Potted plant experiment: Ordinary garden soil was selected as the planting soil, and after high-temperature steam sterilization, it was mixed evenly with the straw biomass fertilizer prepared in Example 1, Comparative Examples 1 to 5 and Groups 1, 2, and 4 at a mass ratio of 5:1 as the experimental group. A blank control group (garden soil without fertilizer) and a conventional fertilizer control group (garden soil and conventional fertilizer were mixed at a mass ratio of 5:1) were set up. The conventional fertilizer was a mixture of decomposed cow dung fertilizer and ecological compound fertilizer 17-20-5 (brand is Kailong) at a mass ratio of 5:1. The same batch of summer corn seedlings (18-20 cm) were transplanted into each group of substrates (5 pots per group, one plant per pot), and watered according to routine management. The growth of the corn seedlings in the blank control group was used as a benchmark. The height and stem diameter of the corn seedlings in each experimental group 15 days after transplanting were recorded and calculated. The specific results are shown in Table 3 below (no diseases or insect pests occurred or affected during the growth period of all corn seedlings): Table 3

[0031] As can be seen from Table 3 above, the seedling height in experimental group 5 is the highest, but the stem thickness is relatively thin, that is, the fertilizer in experimental group 5 is overall unbalanced, resulting in excessive growth of corn, no corresponding thickening of the stem, and poor overall growth performance. Comprehensive comparison shows that the fertilizer prepared in Example 1 in experimental group 1 has the best overall growth-promoting effect.

[0032] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing straw biomass fertilizer, characterized in that: The preparation method comprises the following steps: S1. Burning straw to obtain straw ash for future use; S2, crushing the fresh straw and performing steam explosion treatment, and then microwave drying to obtain straw shreds for later use; S3. Mix the chopped straw and straw ash in a mass ratio of 9-11:1, and spray with sugar water until the moisture content is 18%-20%, to obtain a mixture for use; S4, spraying 1%-2% of the total mass of the mixture into the mixture, controlling the viable bacteria content of the Verona fermentation liquid to 10 8 -10 10 / mL, stir evenly, ferment for 5-8 days to obtain the preliminary fermentation material; S5, after sterilizing the above-mentioned preliminary fermentation material, spray 1%-2% of the total mass of the mixed material with Clostridium butyricum fermentation liquid, and control the content of live bacteria of Clostridium butyricum fermentation liquid to be 10 8 -10 10 After stirring evenly, ferment for 9-11 days to obtain the final fermentation material for use; S6. Drying and crushing the final fermented material to obtain straw biomass fertilizer.

2. The preparation method according to claim 1, wherein: The steam explosion treatment in step S2 is performed at a pressure of 1-2 MPa, with the steam temperature controlled at 120° C., for 1-2 seconds.

3. The preparation method according to claim 1, wherein: The microwave power of the microwave drying in step S2 is 800-1000W, and the moisture content of the dried straw shreds is ≤8%.

4. The preparation method according to claim 1, wherein: The sugar water in step S3 is a white sugar aqueous solution with a mass concentration of 12%-15%.

5. The preparation method according to claim 1, wherein: The Verona fermentation broth in step S4 is prepared by inoculating Verona into SCMB liquid culture medium and fermenting the culture medium. The formula of the SCMB liquid culture medium is: 0.5g sodium butyrate + 0.1g pecan shell powder + 3g maltose + 0.4g beef powder + 100mL water.

6. The preparation method according to claim 1, wherein: The sterilization method in step S5 is high-pressure steam sterilization, with a pressure of 0.2-0.3 MPa, a steam temperature of 121° C., and a sterilization treatment time of 20 minutes.

7. The preparation method according to claim 1, wherein: The Clostridium butyricum fermentation broth in step S5 is obtained by inoculating Clostridium butyricum into RCM medium for fermentation, and the formula of the RCM medium is: peptone 10.0 g / L + beef powder 10.0 g / L + yeast powder 3.0 g / L + glucose 5.0 g / L + soluble starch 1.0 g / L + sodium chloride 5.0 g / L + sodium acetate 3.0 g / L, L-cysteine ​​hydrochloride 0.5 g / L + agar 0.5 g / L, and the balance is water.

8. The preparation method according to claim 1, wherein: The fermentation material is dried in step S6 by constant temperature drying at 45-50° C. until the moisture content is ≤8%.

9. The preparation method according to claim 1, wherein: In the step S6, the powder is crushed and passed through a 20-mesh sieve.

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