A composite soil conditioner and a method for preparing the same
By using a composite soil conditioner containing treated biochar-loaded microbial inoculum, the problem of reduced growth and activity of microbial soil conditioners under soil conditions was solved, thereby improving soil improvement effects and increasing crop yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTHWEST UNIV
- Filing Date
- 2024-04-17
- Publication Date
- 2026-07-03
AI Technical Summary
Microbial soil conditioners are easily affected by soil conditions and adverse environmental factors, which can reduce their growth and activity, thus affecting their effectiveness.
Using biochar as a carrier, a composite microbial inoculum is loaded after treatment with isoamyl acetate and L-erythritol, and D-mannitol and other raw materials are added to form a composite soil conditioner, which improves the loading rate and activity of microorganisms and enhances the soil improvement effect of the conditioner.
It increases the reproduction rate and activity of microorganisms in the soil, promotes the dissolution of insoluble phosphorus in the soil, improves the physical and chemical properties of the soil, inhibits the occurrence of diseases, and increases crop yield.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of soil conditioner preparation technology, and in particular to a composite soil conditioner and its preparation method. Background Technology
[0002] Soil is the most basic production material in agricultural production. Under the influence of human factors and parent material, many obstacles have also been generated, including poor soil structure and tilth, soil nutrient deficiency, and high disease incidence. Generally, obstacle soils have low productivity and are difficult to carry out agricultural activities. How to eliminate soil limiting obstacles and improve the basic soil fertility of arable land is an urgent problem to be solved in agricultural production.
[0003] Applying soil conditioners is one of the main measures to restore degraded soil and improve soil fertility. Soil conditioners mainly include organic soil conditioners, mineral soil conditioners, chemical soil conditioners, and microbial soil conditioners. Compared with other types of conditioners, microbial inoculants are non-toxic, harmless, require small amounts, and have good effects. Applying them to degraded soil can optimize the soil microbial community, increase soil organic matter content, control disease occurrence through microbial antagonism and the recruitment of beneficial bacteria, and have a positive effect on improving soil nutrient structure and promoting plant growth. Therefore, they have good application prospects in soil improvement.
[0004] However, when microbial soil conditioners are applied, the growth and reproduction rates and activity of microorganisms are easily limited by soil conditions and adverse environmental factors, resulting in reduced efficacy. Therefore, it is necessary to find a method for preparing microbial soil conditioners to address the problem that microorganisms in these conditioners are easily affected by soil conditions and adverse environmental factors, inhibiting their growth and activity and thus reducing the effectiveness of the conditioners. Summary of the Invention
[0005] Therefore, the purpose of this invention is to provide a composite soil conditioner and its preparation method, which solves the problem that microorganisms in current soil conditioners are easily restricted by soil conditions and environmental factors, inhibiting their reproductive performance and activity, thus reducing the effectiveness of the conditioner.
[0006] The present invention solves the above-mentioned technical problems through the following technical means:
[0007] A composite soil conditioner, the conditioner comprising the following raw materials in parts by weight:
[0008] 20-40 parts biochar, 1-2 parts compound microbial inoculum, 1-2 parts L-erythritol, 0.8-1.6 parts D-mannitol, 0.5-1 part isoamyl acetate, 7-15 parts humic acid, 20-30 parts straw residue, and 10-20 parts sawdust.
[0009] Furthermore, the modifier comprises the following raw materials in parts by weight:
[0010] 25-35 parts biochar, 1.3-1.6 parts compound microbial inoculum, 1.4-1.6 parts L-erythritol, 1-1.4 parts D-mannitol, 0.6-0.8 parts isoamyl acetate, 10-12 parts humic acid, 24-26 parts straw residue, and 14-16 parts sawdust.
[0011] Furthermore, the modifier comprises the following raw materials in parts by weight:
[0012] 30 parts biochar, 1.5 parts compound microbial inoculum, 1.5 parts L-erythritol, 1.2 parts D-mannitol, 0.7 parts isoamyl acetate, 10 parts humic acid, 25 parts straw residue, and 15 parts sawdust.
[0013] Furthermore, the composite microbial culture solution is obtained by mixing Pseudomonas aeruginosa, Bacillus subtilis, and Bacillus licheniformis in a mass ratio of 1:1:1 after activation and culture.
[0014] The present invention also discloses a method for preparing the composite soil conditioner, the specific preparation method of which is as follows:
[0015] (1) Dissolve isoamyl acetate in ethanol, then add biochar, inject water and heat to react, cool to room temperature and stand for 12-24 hours, then filter and take the solid and wash it with water 2-3 times to obtain the treated biochar.
[0016] (2) After dissolving L-erythritol in water, adjust the pH of the solution, add the treated biochar and stir for 1-2 hours, then let it stand at room temperature for 6-8 hours. Then add D-mannitol and mix evenly. Slowly heat to 35°C, add microbial inoculum and stir slowly for 3-5 minutes. Then keep it at a constant temperature of 35°C and let it stand for 6-12 hours. Filter to remove the filtrate to obtain the microbial-loaded biochar.
[0017] (3) Mix straw residue, humic acid and sawdust evenly, adjust the moisture content and pH, and then add biochar loaded with microorganisms and mix evenly to obtain a composite soil conditioner.
[0018] Microbial soil conditioners typically have specific application ranges, thus limiting their application scenarios. However, the composite soil conditioner prepared by this invention can be applied to improve soil under any different soil conditions, while providing a stable environment with temperature, humidity, and other factors to maintain high activity of microorganisms and accelerate their reproduction rate. Specifically, the composite microbial inoculum of this invention is composed of three bacteria: Pseudomonas aeruginosa, Bacillus subtilis, and Bacillus licheniformis. Pseudomonas aeruginosa and Bacillus licheniformis have high requirements for environmental humidity. To ensure the reproduction, growth, and activity of the microorganisms and improve soil amendment, this invention first uses isoamyl acetate to react with biochar under heating to obtain treated biochar. Then, L-erythritol is used to further treat the treated biochar under specific temperature and pH conditions before loading microorganisms. L-erythritol modifies the biochar to improve its affinity and adsorption for microorganisms, thereby increasing the loading rate. Furthermore, isoamyl acetate is incorporated into the biochar. During microbial loading, it promotes the adsorption of culture medium components in the composite inoculum by the biochar, allowing more microorganisms to enter the pores of the biochar. The biochar isolates the microorganisms from adverse external environments, and the presence of adsorbed culture medium components within the biochar allows for better growth and reproduction of the microorganisms, maintaining high activity. Subsequently, the microorganisms begin to be released from the biochar into the soil, thus efficiently amending the soil.
[0019] After microorganisms are loaded onto biochar, their metabolic products can further react with isoamyl acetate to form an adsorption film inside the biochar, increasing its adsorption capacity for water molecules. This ensures a higher level of humidity required for the loaded microorganisms for an extended period, thus better preserving their activity. However, the metabolic products produced by the microorganisms promote the release of reactive oxygen species (ROS). Combined with the ROS already present in the soil, this accelerates the aging of the biochar and shortens its effective lifespan. Therefore, D-mannitol is added to inhibit ROS damage to the biochar, thereby extending its effective lifespan. A soil conditioner is prepared by mixing raw materials such as straw residue and sawdust, adjusting the pH and moisture content, and then adding it to the microbially loaded biochar. The synergistic effect of the ingredients in the conditioner better conditions the soil and improves its physical and chemical properties.
[0020] Furthermore, the characteristic feature is that the bacterial cell concentration in the composite microbial solution is 10. 6 -10 8 cfu / mL.
[0021] Furthermore, in step (1), the heating reaction temperature is 60-80℃ and the heating reaction time is 2-4h.
[0022] Furthermore, in step (2), the pH of the L-erythritol solution is adjusted to 7.5-8.
[0023] Furthermore, in step (3), the water content is adjusted to 60-70%, and the pH is adjusted to 5-6.
[0024] Beneficial effects:
[0025] 1. This invention uses isoamyl acetate, L-erythritol, D-mannitol, etc. to treat biochar, which can improve the microbial load rate while ensuring the reproduction, growth and activity of microorganisms, thereby improving the soil improvement effect.
[0026] 2. This invention uses biochar as a carrier to load microorganisms, and then mixes it with raw materials such as straw and sawdust to prepare a soil conditioner. The components in the conditioner work together to promote the dissolution of insoluble phosphorus in the soil, improve nitrogen fixation, improve soil physicochemical properties, inhibit disease occurrence, and increase crop yield. It has good application prospects in soil improvement. Detailed Implementation
[0027] The present invention will be described in detail below with reference to specific embodiments:
[0028] The *Pseudomonas aeruginosa* strain of this invention was isolated from soil, and the specific experimental procedure is as follows:
[0029] (1) Inducing the formation of a healthy microbial microenvironment in the soil rhizosphere: An experiment was conducted at a field test site in Yuanlou Village, Taiping Town, Tongliang District, Chongqing. Bacillus subtilis and Trichoderma harzianum were mixed at a ratio of 1:2 and applied to the seedling substrate (peat, coconut coir, perlite, and humus in a mass ratio of 4:2:3:1). After mixing, the substrate was evenly placed into 96-cell seedling trays. Then, chili seeds were sown individually into the cells about 1.5 cm deep. After sowing, a layer of substrate was covered. After sowing, the chili seeds were thoroughly watered. During the chili growth period, water was added every two days. The growth of the chili seedlings was observed. The seedling trays were randomly rotated to keep the chili seedlings growing evenly and uniformly.
[0030] (2) Rhizosphere soil collection: At the end of the pepper harvest, clean up the debris and topsoil around the base of the pepper roots planted in the induced healthy soil. Use a shovel to vertically penetrate 10-30cm into the soil around the base of the pepper to separate the soil inside and outside the root system. Then dig to form a root soil column. Gently shake the root soil column to remove loose soil, place it on the prepared sampling cloth, and gently brush off the soil adhering to the root surface with a brush. After mixing, collect 250g of fresh soil sample. Three replicates are made at each sampling point. Take part of the soil sample for preliminary separation and purification, and place the remaining fresh sample in a 4℃ refrigerator for DNA extraction from the soil.
[0031] (3) Preliminary separation and purification: Weigh 10g of fresh soil sample and quickly pour it into a sterile 250mL Erlenmeyer flask. Add 20 sterile glass beads and 90mL of sterile distilled water. Place the flask on a shaker at 160r / min for 20min to break up the soil sample and shake it thoroughly to obtain soil bacterial solution. Use a pipette to take 1mL of soil bacterial solution into a 10mL sterile test tube, add 9mL of sterile water, mix well to obtain initial bacterial solution, and dilute it 10 times. Take 20uL of diluted bacterial solution and spread it evenly on Monkina agar plates, mark it, and incubate it upside down at 28℃ for 7 days. Observe the growth of colonies on the plates every 12h to screen for phosphate-solubilizing bacteria. Perform streak purification for 3 generations to obtain pure strains. Inoculate them onto LB slant agar and store them in a refrigerator at 4℃ for later use.
[0032] (4) Functional verification: The selected strains were tested on Assumption medium to verify their nitrogen fixation function and screen out strains that can solubilize phosphorus and fix nitrogen. The antagonistic activity of Fusarium graminearum and Rhizoctonia solani was verified on WA plates to screen out strains with the best phosphorus solubilization, nitrogen fixation and antibacterial effects.
[0033] (5) Strain identification: After DNA quality, concentration and purity were tested, primers ITS1F (5′-CTTGGTCATTTAGAGGAAGTAA-3′) and ITS2R (5′-GCTGCGTTCTTCATCGATG C-3′), 27F (5′-AGAGTTTGATCCTGGCTCAG-3′) and 1492R (5′-ACGGTTACCTTGTTACGACTT-3′) were used to amplify different regions of the genes of the screened strains by PCR, followed by high-throughput sequencing and subsequent analysis. Sequencing was performed at Sangon Biotech (Shanghai) Co., Ltd. to determine the strain classification.
[0034] (6) According to the sequencing results and functional verification experiments, the strain with good phosphorus solubilization, nitrogen fixation and antibacterial functions is Pseudomonas aeruginosa.
[0035] The components of the culture medium used in this process are as follows:
[0036] Monkina culture medium: 10g glucose, 5g magnesium chloride, 5g tricalcium phosphate, 0.25g magnesium sulfate heptahydrate, 0.2g potassium chloride, 0.1g ammonium sulfate, 20g agar, 1000mL distilled water;
[0037] LB medium: 10g tryptone, 5g yeast extract, 10g NaCl, 20g agar, 1000mL distilled water;
[0038] Assumption medium: potassium hydrogen phosphate 0.2g, magnesium sulfate heptahydrate 0.2g, calcium sulfate dihydrate 0.1g, sodium chloride 0.2g, calcium carbonate 5g, mannitol 10g, agar 20g, distilled water 1000mL;
[0039] WA medium: 5g peptone, 10g glucose, 3g beef extract, 5g sodium chloride, 20g agar, 1000mL distilled water.
[0040] The finally selected *Pseudomonas aeruginosa*, along with *Bacillus subtilis* and *Bacillus licheniformis*, were inoculated into LB liquid medium and cultured at 35°C and 180 rpm for 24 h on a shaker. Then, they were mixed at a bacterial concentration ratio of 1:1:1 to obtain a composite microbial culture, containing approximately 10 viable bacteria. 8 cfu / mL.
[0041] Of course, the compound microbial inoculum prepared in this invention is composed of Pseudomonas aeruginosa, Bacillus subtilis, and Bacillus licheniformis. Pseudomonas aeruginosa, Bacillus subtilis, and Bacillus licheniformis can also be purchased directly from the market.
[0042] After the preparation of the compound microbial inoculum solution, a modifier was further prepared, as shown below:
[0043] Example 1: Preparation of Modifier
[0044] Weigh out 30 kg of biochar, 1.5 kg of compound microbial inoculum, 1.5 kg of L-erythritol, 1.2 kg of D-mannitol, 0.7 kg of isoamyl acetate, 10 kg of humic acid, 25 kg of straw residue, and 15 kg of sawdust. The bacterial concentration in the compound microbial inoculum is 10%. 8 cfu / mL.
[0045] Preparation method:
[0046] (1) Dissolve isoamyl acetate in 3.5 kg of 60 wt% ethanol solution, then add biochar, pour water to cover the biochar, heat to 70 °C and react for 3 h, cool to room temperature and stand for 20 h, then filter and take the solid and wash it three times with water to obtain the treated biochar.
[0047] (2) Dissolve L-erythritol in 30kg of water and adjust the pH of the solution to 7.8. Add the treated biochar and stir for 1.5h. Let it stand at room temperature for 7h. Then add D-mannitol and mix evenly. Slowly heat to 35℃. Add microbial inoculum and stir slowly for 3min. Then keep it at 35℃ and let it stand for 10h. Filter to remove the filtrate to obtain microbial-loaded biochar.
[0048] (3) Mix straw residue, humic acid and sawdust evenly, adjust the moisture content to 65%, adjust the pH to 5.5, and then add biochar loaded with microorganisms and mix evenly to obtain a composite soil conditioner.
[0049] Example 2: Preparation of Modifier II
[0050] Weigh out 25 kg of biochar, 1.3 kg of compound microbial inoculum, 1.4 kg of L-erythritol, 1 kg of D-mannitol, 0.6 kg of isoamyl acetate, 10 kg of humic acid, 24 kg of straw residue, and 14 kg of sawdust. The bacterial concentration in the compound microbial inoculum is 10%. 8 cfu / mL.
[0051] Preparation method:
[0052] (1) Dissolve isoamyl acetate in 3 kg of 60 wt% ethanol solution, then add biochar, pour water to cover the biochar, heat to 70 °C and react for 3 h, cool to room temperature and stand for 18 h, then filter and take the solid and wash it with water 3 times to obtain the treated biochar.
[0053] (2) Dissolve L-erythritol in 28kg of water and adjust the pH of the solution to 7.5. Add the treated biochar and stir for 1.5h. Let it stand at room temperature for 6h. Then add D-mannitol and mix evenly. Slowly heat to 35℃. Add microbial inoculum and stir slowly for 3min. Then keep it at 35℃ and let it stand for 8h. Filter to remove the filtrate to obtain the microbial-loaded biochar.
[0054] (3) Mix straw residue, humic acid and sawdust evenly, adjust the moisture content to 65%, adjust the pH to 5, add biochar loaded with microorganisms and mix evenly to obtain a composite soil conditioner.
[0055] Example 3: Preparation of Modifier
[0056] The mixture consisted of 35 kg of biochar, 1.6 kg of compound microbial inoculum, 1.6 kg of L-erythritol, 1.4 kg of D-mannitol, 0.8 kg of isoamyl acetate, 12 kg of humic acid, 26 kg of straw residue, and 16 kg of sawdust. The bacterial concentration in the compound microbial inoculum was 10%. 8 The concentration of cfu / mL was obtained by activating and culturing Pseudomonas aeruginosa, Bacillus subtilis, and Bacillus licheniformis in the compound bacterial solution, which were all purchased from the market and then mixed.
[0057] Preparation method:
[0058] (1) Dissolve isoamyl acetate in 4 kg of 60 wt% ethanol solution, then add biochar, pour water to cover the biochar, heat to 80 °C and react for 3 h, cool to room temperature and stand for 20 h, then filter and take the solid and wash it with water 3 times to obtain the treated biochar.
[0059] (2) Dissolve L-erythritol in 32kg of water and adjust the pH of the solution to 8. Add the treated biochar and stir for 2 hours. Let it stand at room temperature for 8 hours. Then add D-mannitol and mix evenly. Slowly heat to 35℃, add microbial inoculum and stir slowly for 5 minutes. Then keep it at a constant temperature of 35℃ and let it stand for 12 hours. Filter to remove the filtrate to obtain the microbial-loaded biochar.
[0060] (3) Mix straw residue, humic acid and sawdust evenly, adjust the moisture content to 65%, adjust the pH to 5.5, add biochar loaded with microorganisms and mix evenly to obtain a composite soil conditioner.
[0061] Comparative Example 1: Preparation of Modifier
[0062] Compared with Example 1, the only difference is that the preparation of the modifier in Comparative Example 1 lacked the treatment of isoamyl acetate in step (1), as follows:
[0063] (1) Dissolve L-erythritol in 30kg of water and adjust the pH of the solution to 7.8. Add biochar and stir for 1.5h. Let stand at room temperature for 7h. Then add D-mannitol and mix evenly. Slowly heat to 35℃. Add microbial inoculum and stir slowly for 3min. Then keep at 35℃ and stand for 10h. Filter to remove the filtrate to obtain microbial-loaded biochar.
[0064] (2) Mix straw residue, humic acid and sawdust evenly, adjust the moisture content to 65%, adjust the pH to 5.5, add biochar loaded with microorganisms and mix well to obtain a composite soil conditioner.
[0065] Comparative Example 2: Preparation of Modifier
[0066] Compared with Example 1, the only difference is that L-erythritol was not added in step (2) of the preparation of the modifier in Comparative Example 2, as follows:
[0067] (1) Same as Example 1;
[0068] (2) Add the treated biochar and D-mannitol to 30kg of water and mix evenly. Slowly heat to 35℃, add microbial inoculum and stir slowly for 3min. Then keep it at a constant temperature of 35℃ for 10h and filter to remove the filtrate to obtain microbial-loaded biochar.
[0069] (3) Same as Example 1.
[0070] Comparative Example 3: Preparation of Modifier
[0071] Compared with Example 1, the only difference is that D-mannitol was not added during the preparation of the modifier in Comparative Example 3, as detailed below:
[0072] (1) Same as Example 1;
[0073] (2) Dissolve L-erythritol in 30kg of water and adjust the pH of the solution to 7.8. Add the treated biochar and stir for 1.5h. Let it stand at room temperature for 7h. Then slowly heat to 35℃, add microbial liquid and stir slowly for 3min. Then keep it at 35℃ and let it stand for 10h. Filter to remove the filtrate to obtain microbial-loaded biochar.
[0074] (3) Same as Example 1.
[0075] Comparative Example 4: Preparation of Modifier
[0076] In contrast to Example 1, the only difference is that in Comparative Example 4, the reaction in step (1) of the preparation of the modifier was carried out at room temperature, as detailed below:
[0077] (1) Dissolve isoamyl acetate in 3.5 kg of 60 wt% ethanol solution, then add biochar, pour water to cover the biochar, mix and react at room temperature for 3 h, let stand for 20 h, then filter and take the solid and wash it with water 3 times to obtain the treated biochar.
[0078] (2)-(3): Same as in Example 1.
[0079] Comparative Example 5: Preparation of Modifier
[0080] Compared with Example 1, the only difference is that in the preparation of the modifier in Comparative Example 5, the pH of the L-erythritol solution was adjusted to 6 in step (2).
[0081] Comparative Example 6: Preparation of Modifier
[0082] In contrast to Example 1, the only difference is that in Comparative Example 6, conventional biochar was directly used to load microorganisms during the preparation of the modifier, as detailed below:
[0083] (1) Add water to the biochar to cover the biochar and slowly heat it to 35°C. Then add the compound microbial liquid and stir slowly for 3 minutes. Keep it at a constant temperature of 35°C for 10 hours and then filter to remove the filtrate to obtain the biochar loaded with microorganisms.
[0084] (2) Mix straw residue, humic acid and sawdust evenly, adjust the moisture content to 65%, adjust the pH to 5.5, add biochar loaded with microorganisms and mix well to obtain a composite soil conditioner.
[0085] Experiment 1: Microbial Activity Detection Experiment
[0086] (1) Soil was dug from a farmland in Yuanlou Village, Taiping Town, Tongliang District, Chongqing. It was placed in a high-pressure sterilizer and sterilized at 121℃ and 0.1Mpa for 30 minutes. After cooling to room temperature, it was placed in an oven and dried at 60℃ to obtain sterilized soil.
[0087] (2) Weigh 100g of the microbial-loaded biochar prepared according to the methods of Examples 1, 3, and Comparative Examples 1-6, and mix it evenly with 3kg of sterilized soil to obtain mixed soils of Examples 1, 3, and 1-6. After standing for 12 hours, determine the initial value of the viable bacteria count in each group of mixed soils. Then, treat the soils according to the methods of Groups 1, 2, and 3 below, and then determine the viable bacteria count again, as follows:
[0088] Group 1: Weigh 1 kg of mixed soil from each of Example 1, Example 3, and Comparative Examples 1-6, adjust the humidity of the mixed soil to 40% and the pH to 7, and then place them in flower pots. After static culture at 30℃ and 2000 lx light for 3 days, the number of viable bacteria in the mixed soil of each group is measured.
[0089] Group 2: Weigh 1 kg of mixed soil from each of Example 1, Example 3, and Comparative Examples 1-6, adjust the humidity of the mixed soil to 10% and the pH to 4, and then place them in flower pots. After 3 days of static culture at 30℃ and 2000 lx light, the number of viable bacteria in the mixed soil of each group was measured.
[0090] Group 3: Weigh 1 kg of mixed soil from each of Example 1, Example 3, and Comparative Examples 1-6, adjust the humidity of the mixed soil to 60% and the pH to 9, and then place them in flower pots. After static incubation at 30℃ and 2000 lx light for 3 days, the number of viable bacteria in the mixed soil of each group is measured.
[0091] The data obtained from three repeated experiments are shown in Table 1:
[0092] Table 1 (Unit: CFU / g: viable bacteria count per gram of soil)
[0093] Example 1 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 initial value <![CDATA[8.6×10 4 ]]> <![CDATA[8.5×10 4 ]]> <![CDATA[6.6×10 3 ]]> <![CDATA[9.5×10 3 ]]> <![CDATA[8.4×10 4 ]]> <![CDATA[5.4×10 4 ]]> <![CDATA[3.2×10 4 ]]> <![CDATA[1.8×10 3 ]]> Group 1 <![CDATA[8.3×10 9 ]]> <![CDATA[8.2×10 9 ]]> <![CDATA[4.7×10 8 ]]> <![CDATA[7.4×10 7 ]]> <![CDATA[7.6×10 9 ]]> <![CDATA[9.8×10 8 ]]> <![CDATA[6.7×10 8 ]]> <![CDATA[8.4×10 6 ]]> Group 2 <![CDATA[3.1×10 9 ]]> <![CDATA[2.7×10 9 ]]> <![CDATA[1.9×10 8 ]]> <![CDATA[3.4×10 7 ]]> <![CDATA[1.8×10 9 ]]> <![CDATA[7.3×10 8 ]]> <![CDATA[3.2×10 8 ]]> <![CDATA[5.3×10 6 ]]> Group 3 <![CDATA[4.2×10 9 ]]> <![CDATA[4.5×10 9 ]]> <![CDATA[2.3×10 8 ]]> <![CDATA[4.2×10 8 ]]> <![CDATA[1.0×10 9 ]]> <![CDATA[5.4×10 8 ]]> <![CDATA[1.6×10 8 ]]> <![CDATA[2.7×10 6 ]]>
[0094] Based on the data analysis in Table 1, we can conclude that:
[0095] In Example 1, the initial values of the mixed soil were higher than those of Comparative Examples 1-6. In Group 1, the mixed soil moisture was adjusted to 40% and the pH to 7. These conditions were more suitable for the reproduction and growth of the loaded microorganisms. After 3 days of static culture, the microorganisms in Example 1 grew and multiplied rapidly, with a high viable count. In contrast, after 3 days of culture under conditions of low soil moisture and pH in Group 2 and high soil moisture and pH in Group 3, the viable count of the microorganisms in Example 1 remained high. This indicates that the biochar prepared in Example 1 can retain and fix more microorganisms and maintain their normal reproduction and growth, thus better improving the soil.
[0096] In Comparative Example 1, the biochar was not treated with isoamyl acetate, which reduced its adsorption capacity for microorganisms, resulting in a low loading rate and a low number of viable bacteria in the mixed soil. In Comparative Example 2, the lack of L-erythritol not only reduced the loading rate of microorganisms (low initial number of viable bacteria), but also significantly affected their proliferation and reproduction under the poor humidity and pH conditions of Groups 2 and 3, further reducing the number of viable bacteria.
[0097] Experiment 2: Soil Conditioner Application Experiment
[0098] 1. Soil improvement experiments were conducted using the composite soil conditioners prepared in Example 1 and Comparative Examples 1-6. The experiments were carried out in Yuanlou Village, Taiping Town, Tongliang District, Chongqing. A specific area was selected as the experimental zone. Before the experiment, the initial soil properties of the experimental zone were measured. The experimental zone was then divided into 8 equal areas, each with an area of 4×5m, corresponding to Example 1, Comparative Examples 1-6, and the blank control, respectively. Then, the soil conditioner was applied at a concentration of 200g / m². 2 The amendment was applied in the same amount every 6 months, while the blank control group was directly treated with water. The application frequency was the same as in Example 1 and Comparative Examples 1-6. Then, corn was planted, with 150 corn plants per group, and the corn was managed in the same way as in conventional methods. The corn yield and the incidence of damping-off disease in each group were recorded. The data were obtained by three replicates and are shown in Table 1.
[0099] Table 2
[0100]
[0101] Soil-related properties were measured again one year after the application of the amendment, and the data are shown in Table 3.
[0102] Table 3
[0103]
[0104]
[0105] According to the data analysis in Table 2, the incidence of damping-off disease in corn was significantly reduced after using the improver prepared in Example 1 compared with the blank control group. This indicates that the highly efficient loading of Pseudomonas aeruginosa as the main functional microorganism has a good inhibitory effect on pathogens, which can effectively reduce the incidence of disease and increase yield.
[0106] Based on the data analysis in Table 3, we can conclude that:
[0107] After applying the soil conditioner prepared in Example 1, the physical and chemical properties of the soil were better than those of the soil conditioners prepared in Comparative Examples 1-6. Microorganisms in the soil played a good role in phosphorus solubilization and nitrogen fixation, effectively increasing the content of soil organic matter, available phosphorus, and alkaline nitrogen, and the soil properties were significantly improved.
[0108] In Comparative Example 1, the modifier was not treated with isoamyl acetate; in Comparative Example 2, L-erythritol was not added, resulting in poor adsorption performance of microorganisms when loading them, leading to a reduction in the amount of microorganisms that could function with the final modifier and a decrease in its effectiveness; in Comparative Example 5, the pH of the L-erythritol solution was adjusted to 6 during the preparation of the modifier, which reduced the reactivity of L-erythritol with biochar and thus affected the adsorption loading rate of microorganisms.
[0109] In Comparative Example 6, the soil conditioner prepared using conventional methods had a low microbial loading rate and poor activity, resulting in poor efficacy and ineffective soil improvement. This indicates that the composite soil conditioner prepared according to the method of this invention can improve the microbial loading rate. At the same time, the synergistic effect of the raw materials has a good comprehensive improvement effect on the soil, effectively improving the soil's physical and chemical properties, inhibiting pathogens in the soil, reducing crop disease incidence, and increasing crop yield, showing good application prospects.
[0110] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.
Claims
1. A composite soil conditioner, characterized in that, The modifier comprises the following raw materials in parts by weight: 20-40 parts biochar, 1-2 parts compound microbial inoculum, 1-2 parts L-erythritol, 0.8-1.6 parts D-mannitol, 0.5-1 part isoamyl acetate, 7-15 parts humic acid, 20-30 parts straw residue, and 10-20 parts sawdust. The specific method for preparing the composite soil conditioner is as follows: (1) Dissolve isoamyl acetate in ethanol, then add biochar, inject water and heat to react, cool to room temperature and stand for 12-24 hours, then filter and take the solid and wash with water to obtain the treated biochar. (2) After dissolving L-erythritol in water, adjust the pH of the solution, add the treated biochar and stir for 1-2 hours, then let it stand at room temperature for 6-8 hours. Then add D-mannitol and mix evenly. Slowly heat to 35°C, add the composite microbial liquid and stir slowly for 3-5 minutes. Then keep it at a constant temperature of 35°C for 6-12 hours and filter to remove the filtrate to obtain the microbial-loaded biochar. (3) Mix straw residue, humic acid and sawdust evenly, adjust the moisture content and pH, and then add biochar loaded with microorganisms and mix evenly to obtain a composite soil conditioner.
2. The composite soil conditioner according to claim 1, characterized in that, The modifier comprises the following raw materials in parts by weight: 25-35 parts biochar, 1.3-1.6 parts compound microbial inoculum, 1.4-1.6 parts L-erythritol, 1-1.4 parts D-mannitol, 0.6-0.8 parts isoamyl acetate, 10-12 parts humic acid, 24-26 parts straw residue, and 14-16 parts sawdust.
3. The composite soil conditioner according to claim 2, characterized in that, The modifier comprises the following raw materials in parts by weight: 30 parts biochar, 1.5 parts compound microbial inoculum, 1.5 parts L-erythritol, 1.2 parts D-mannitol, 0.7 parts isoamyl acetate, 10 parts humic acid, 25 parts straw residue, and 15 parts sawdust.
4. The composite soil conditioner according to claim 3, characterized in that, The composite microbial culture solution is obtained by mixing Pseudomonas aeruginosa, Bacillus subtilis, and Bacillus licheniformis after activation and culture.
5. The method for preparing a composite soil conditioner according to claim 4, characterized in that, The concentration of the microbial cells in the complex microbial bacterial solution is 10 6 -10 8 cfu / mL.
6. The method for preparing a composite soil conditioner according to claim 5, characterized in that, In step (1), the heating reaction temperature is 60-80℃ and the heating reaction time is 2-4h.
7. The method for preparing a composite soil conditioner according to claim 6, characterized in that, In step (2), the pH of the L-erythritol solution is adjusted to 7.5-8.
8. The method for preparing a composite soil conditioner according to claim 7, characterized in that, In step (3), the water content is adjusted to 60-70%, and the pH is adjusted to 5-6.