Biochar-based composite organic fertilizer for improving soil structure and preparation method thereof
By using biochar-based compound organic fertilizer to improve the soil of the Loess Plateau, the problems of fragile soil structure and nutrient imbalance have been solved, resulting in increased organic matter, enhanced erosion resistance, and increased crop yield, while reducing the amount of chemical fertilizer used and carbon emissions.
Patent Information
- Application Number
- CN202511412468.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-29
- Publication Date
- 2026-01-23
AI Technical Summary
The soils of the Loess Plateau suffer from a lack of organic matter, fragile structure, nutrient imbalance, and micronutrient deficiency. Traditional organic fertilizers decompose slowly and release nutrients unevenly. The application of biochar alone leads to an imbalance in the soil carbon-nitrogen ratio and inhibits microbial activity.
The biochar-based compound organic fertilizer contains biochar, microbial agents, crop straw powder, ammonium sulfate, silicate mineral powder, and zinc sulfate and borax. Biochar is prepared by pyrolysis at a specific temperature. Combined with composting treatment and coating agents, it forms a microporous-macroporous structure, which enhances the stability of soil aggregates and nutrient release, and is adapted to the Loess Plateau environment.
It significantly increases soil organic matter, reduces erosion resistance index, increases crop yield and overall income, reduces fertilizer use, and reduces carbon emissions throughout the entire life cycle.
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Figure CN121377896A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of organic fertilizer, in particular to a biochar-based composite organic fertilizer for improving soil structure and a preparation method thereof. BACKGROUND
[0002] The soil of the loess high slope has the following soil problems due to its particularity, for example, lack of organic matter: the surface soil organic matter content is generally less than 1.5% (national standard ≥ 2%); fragile structure: poor erosion resistance, with an average annual soil loss of 20-50 t / km²; nutrient imbalance: nitrogen, phosphorus and potassium ratio imbalance (1:0.3:0.2), lack of trace elements (zinc, boron), etc.
[0003] At present, for the soil problems of the loess high slope, traditional organic fertilizers, such as livestock and poultry manure, have slow decomposition and uneven nutrient release, and the separate application of biochar leads to imbalance of soil carbon and nitrogen ratio and inhibition of microbial activity. SUMMARY
[0004] The present application provides a biochar-based composite organic fertilizer for improving soil structure and a preparation method thereof, in order to solve the above technical problems.
[0005] The first aspect of the present application provides a biochar-based composite organic fertilizer for improving soil structure, which comprises: 30-50% of biochar, 5-10% of microbial inoculum, 20-30% of crop straw powder, 3-5% of ammonium sulfate, 5-8% of silicate mineral powder and 0.2-0.5% of zinc sulfate borax.
[0006] In one possible implementation, the biochar is prepared by pyrolysis of corn straw at 550°C for 3 hours.
[0007] In one possible implementation, the specific surface area of the biochar is >120 m² / g.
[0008] In one possible implementation, the microbial inoculum comprises Bacillus subtilis and lignin-degrading bacteria, and the viable bacterial count is ≥1×10 CFU / g.
[0009] In one possible implementation, the silicate mineral powder comprises hydromica-type minerals, wherein the Si content is ≥65%.
[0010] In one possible implementation, the survival rate of the microbial inoculum at a temperature of 50°C is >80%.
[0011] The second aspect of the present application provides a preparation method of the biochar-based composite organic fertilizer for improving soil structure as in any one of the first aspect, which comprises: Step 1: preparing biochar from corn stalks, and preparing crop straw powder by crushing and sterilizing the corn stalks; Step 2: mixing the biochar, crop straw powder, microbial agent, ammonium sulfate, silicate mineral powder, and zinc sulfate borax according to the formula proportion to obtain an initial mixture; Step 3: composting the initial mixture to obtain an organic fertilizer raw material; Step 4: adding a coating agent to the organic fertilizer raw material and using a granulator to form a biochar-based composite organic fertilizer for improving soil structure.
[0012] In one possible implementation, the biochar is prepared from corn stalks, and the crop straw powder is prepared by crushing and sterilizing the corn stalks, including: The biochar is prepared by selecting corn stalks and pyrolyzing the corn stalks at a high temperature of 550 DEG C for 3 hours; The corn stalks are crushed to 80-100 mesh, and a sterilizing agent is used to sterilize the corn stalks at a temperature of 60 DEG C for 2 hours to obtain the crop straw powder.
[0013] In one possible implementation, the composting of the initial mixture to obtain the organic fertilizer raw material includes: The composting is performed at a temperature of 50 DEG C for 72 hours, and then at a temperature of 50 DEG C for 14 days to obtain the organic fertilizer raw material, wherein the composting is performed once every three days; and the water content in the organic fertilizer raw material is less than or equal to 30%.
[0014] In one possible implementation, the coating agent includes attapulgite clay, and the mass ratio of the attapulgite clay is 3%.
[0015] Implementing the embodiments of the present application has at least the following beneficial effects: 1. The biochar-based composite organic fertilizer for improving soil structure is used for the soil of the loess high slope, the soil organic matter is improved by 3 times that of the conventional organic fertilizer, and the corrosion resistance index is reduced by 50%.
[0016] 2. The biochar-based composite organic fertilizer for improving soil structure has a biochar fixed C potential of 2.1 t C / ton of fertilizer, and the carbon emission of the whole life cycle is reduced by 45%.
[0017] 3. After using the biochar-based composite organic fertilizer for improving soil structure, the fertilizer use per mu is reduced by 30%, but the crop yield is increased by 15-20%, and the comprehensive income is increased by 28%. BRIEF DESCRIPTION OF DRAWINGS
[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only represent some of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without any creative effort.
[0019] Figure 1 A flowchart of a preparation method of a biochar-based composite organic fertilizer for improving soil structure is provided for the embodiments of the present application. DETAILED DESCRIPTION
[0020] The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.
[0021] The terms "first", "second", and the like in the specification of the present application, the claims, and the above-mentioned drawings are used to distinguish different objects, and are not used to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include other steps or units not listed or can optionally include other steps or units inherent to the process, method, product or device.
[0022] In the present application, the phrase "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.
[0023] In order to better understand the improved soil structure of the biochar-based composite organic fertilizer provided by the embodiments of the present application, the application scenarios of the improved soil structure of the biochar-based composite organic fertilizer are briefly introduced. The improved soil structure of the biochar-based composite organic fertilizer is applied to the soil of the loess high slope. Due to the particularity of the loess high slope soil, for example, the loess plateau soil is mainly silty loam, the structure is loose, the porosity is high but the stability is poor, the organic matter content is low (usually <1%), the water and fertilizer retention capacity is weak, and it is easy to be eroded. When improving it, a variety of technical problems need to be solved at the same time to achieve a good effect. However, using traditional organic fertilizer, such as livestock and poultry manure, the decomposition is slow, the nutrient release is uneven, it is difficult to quickly improve the soil structure, and it is difficult to meet the demand of quickly improving the soil.
[0024] Therefore, in order to solve the above technical problems, the embodiments of the present application provide an improved soil structure of a biochar-based composite organic fertilizer, which can make the soil organic matter increase by 3 times of the conventional organic fertilizer, and the erosion resistance index decrease by 50%.
[0025] The embodiments of the present application provide an improved soil structure of a biochar-based composite organic fertilizer, the composite organic fertilizer comprising: biochar 30-50%, microbial inoculum 5-10%, crop straw powder 20-30%, ammonium sulfate 3-5%, silicate mineral powder 5-8% and zinc sulfate borax 0.2-0.5%.
[0026] Among them, the selection of strains in microbial inoculum needs to match the target function and environmental adaptability, specifically: If the target is nitrogen fixation, Klebsiella pneumoniae (high-efficiency nitrogen fixation, but poor salt tolerance) can be selected; if it is phosphorus solubilization, Pseudomonas putida (secreting organic acid to dissolve insoluble phosphorus) is preferred.
[0027] But the strains in this scheme may be screened for the characteristics of the loess plateau (such as drought resistance and stress resistance), and their functions need to be verified. Scene specificity: Drought environment: drought-resistant strains (such as Bacillus subtilis) need to be selected, and their spores can hibernate in the absence of water and activate when water is encountered.
[0028] Poor soil: arbuscular mycorrhizal fungi (AMF) symbiotic with plants to improve phosphorus absorption efficiency (such as Glomus mosseae).
[0029] Data support: field test data of strains in the loess plateau (such as yield increase ≥15%, soil available phosphorus increase 20%) need to be provided.
[0030] Specifically, the composite organic fertilizer designs the following beneficial mechanisms: (1) synergistic mechanism Biochar (porosity > 85%) combined with crop straw powder forms a "micro-macroporous" structure, and the water holding capacity is increased by 40%.
[0031] The bacterial agent (containing Bacillus subtilis and lignin-degrading bacteria) secretes exopolysaccharides, which combine with the hydroxyl groups on the surface of biochar, enhancing the stability of soil aggregates (> 30%).
[0032] Si in silicate mineral powder reacts with Ca²+ to form a colloidal substance, reducing the soil bulk density (from 1.6 g / cm³ to 1.2 g / cm³).
[0033] Among them, Ca mainly comes from biochar ash and exogenous additives: endogenous sources: Calcium carbonate (CaC ) or calcium hydroxide (Ca(OH ) in biochar ash, generated by calcium elements in raw materials (such as wheat straw) through high-temperature pyrolysis.
[0034] Ash content is related to pyrolysis temperature (ash content is about 5-10% at 500°C).
[0035] Exogenous addition: Gypsum (CaS 2 O) or limestone powder (CaC ) can be added to adjust the soil Ca concentration, neutralize Al toxicity (in acidic soils) or supplement calcium nutrition (if trees need calcium to prevent cracking and fruiting).
[0036] Detection method: Atomic absorption spectroscopy (AAS) or ICP-OES quantitative analysis of Ca content, chemical titration method (EDTA complex titration) to determine the total calcium amount.
[0037] (2) Environmental adaptability design
[0038] pH buffer system (biochar pH 7.5-8.5 + ammonium sulfate adjustment) adapts to the alkaline soil of the Loess Plateau (pH 8.0-9.5).
[0039] The bacterial agent is resistant to high temperature (survival rate > 80% at 50°C), and adapts to the high temperature environment of the Loess Plateau in summer.
[0040] Among them, the biochar is prepared by pyrolysis of corn straw at 550°C for 3 hours.
[0041] Among them, the specific surface area of biochar is > 120 m² / g.
[0042] The microbial agent includes Bacillus subtilis and lignin-degrading bacteria, with a viable count ≥ 1×1 CFU / g.
[0043] The silicate mineral powder includes hydromica-type minerals, wherein Si Content ≥65%.
[0044] Among them, the survival rate of microbial agents is >80% at a temperature of 50℃.
[0045] like Figure 1 As shown in the embodiments of this application, a method for preparing a biochar-based compound organic fertilizer for improving soil structure as described in any of the foregoing embodiments is also provided, the method comprising: Step 1: Biochar is produced from corn stalks, and crop straw powder is produced by crushing and sterilizing corn stalks. Step 2: Mix biochar, crop straw powder, microbial agent, ammonium sulfate, silicate mineral powder and zinc sulfate borax according to the formula ratio to obtain the initial mixture; Step 3: Compost the initial mixture to obtain organic fertilizer raw materials; Step 4: After adding a coating agent to the organic fertilizer raw material, use a granulator to form a granulated product to obtain a biochar-based compound organic fertilizer that improves soil structure.
[0046] Specifically, the production of biochar from corn stalks, and the production of crop straw powder from corn stalks after crushing and sterilizing, include: Biochar was prepared by pyrolyzing corn stalks at 550℃ for 3 hours. After crushing the corn stalks to 80-100 mesh, sterilize them with a sterilizing agent at 60℃ for 2 hours to obtain crop straw powder.
[0047] Among these, porosity and pore size distribution are key indicators for the prepared biochar. Specifically: Porosity requirements: Micropores (<2 nm): adsorb small molecule nutrients (such as N) N However, excessive amounts may limit microbial activity.
[0048] Mesopores (2-50 nm): Balance nutrient adsorption and microbial colonization.
[0049] Macropores (>50 nm): promote water penetration and root extension.
[0050] The Loess Plateau requires a high proportion of mesopores (30-50%) and macropores (>20%) to alleviate drought and nutrient loss.
[0051] Determination method: Both biochar and straw powder need to be determined: BET nitrogen adsorption method (ISO 15901) is used to analyze specific surface area and pore size distribution, and SEM-EDS is used to observe microstructure.
[0052] Technical difference: If the crop straw powder is not carbonized at high temperature, its porosity may be lower than that of biochar (biochar needs to be pyrolyzed at 400-600℃ to form stable pores).
[0053] Compared with the existing scheme which focuses more on biochar yield, the present scheme needs to additionally control pyrolysis temperature and raw material particle size (such as crop straw is crushed to below 1 mm) to optimize the pore structure.
[0054] Specifically, the initial mixture is subjected to composting to obtain the organic fertilizer raw material, which comprises: The composting is carried out at a temperature of 50℃ for 72h, and then at a temperature of 50℃ for 14 days to obtain the organic fertilizer raw material, wherein the composting is turned every three days; the water content in the organic fertilizer raw material is ≤30%.
[0055] Specifically, the coating agent comprises attapulgite clay, and the mass ratio is 3%.
[0056] The biochar-based composite organic fertilizer for improving soil structure provided by the embodiments of the present application is used for comparative experiments, and the specific experimental data are as follows:
[0057] The crop yield-related experimental data are as follows: Wheat: yield increased by 32.7% (application amount 5 t / ha), and protein content increased by 15.2%.
[0058] Apple: fruit sugar content increased to 14.3°Brix (control 12.1°Brix).
[0059] The embodiments of the present application also provide the following test data and comparative analysis: 1. Comparison test of soil physical and chemical properties
[0060] 2. Microbial activity detection data
[0061] 3. Crop growth and yield data (taking wheat as an example)
[0062] 4. Erosion resistance index (simulated rainfall test)
[0063] Specifically, after analyzing the data, the cation exchange capacity (CEC) of the biochar-straw composite is 128 meq / 100g, which is significantly higher than that of single biochar (85 meq / 100g); the Si The dissolution rate is 7.3% at pH 8.5, effectively supplementing soil silicon elements.
[0064] The above has carried out the detailed introduction to the embodiment of the application, the principle and implementation mode of the application have been described in the text by applying specific examples; the above embodiment explanation is only for helping to understand the method of the application and its core idea; at the same time, for the general technical personnel in the art, according to the idea of the application, the specific implementation mode and application range will have changes; in view of the above, the content of the specification should not be understood as the limitation of the application.
Claims
1. A biochar-based compound organic fertilizer for improving soil structure, characterized in that, The compound organic fertilizer comprises: 30-50% biochar, 5-10% microbial inoculant, 20-30% crop straw powder, 3-5% ammonium sulfate, 5-8% silicate mineral powder, and 0.2-0.5% zinc sulfate and borax.
2. The biochar-based compound organic fertilizer for improving soil structure according to claim 1, characterized in that, The biochar was prepared by pyrolyzing corn stalks at 550°C for 3 hours.
3. The biochar-based compound organic fertilizer for improving soil structure according to claim 2, characterized in that, The specific surface area of biochar is >120 m² / g.
4. The biochar-based compound organic fertilizer for improving soil structure according to any one of claims 1-3, characterized in that, The microbial agent includes Bacillus subtilis and lignin-degrading bacteria, with a mass ratio of Bacillus subtilis to lignin-degrading bacteria of 2:1 to 1:1, and a viable count ≥1×10⁻⁶. CFU / g.
5. The biochar-based compound organic fertilizer for improving soil structure according to claim 4, characterized in that, The silicate mineral powder includes hydromica-type minerals, wherein Si Content ≥65%.
6. The biochar-based compound organic fertilizer for improving soil structure according to claim 5, characterized in that, The survival rate of microbial inoculants is >80% at 50℃.
7. A method for preparing a biochar-based compound organic fertilizer for improving soil structure as described in any one of claims 1-6, characterized in that, The method includes: Step 1: Biochar is produced from corn stalks, and crop straw powder is produced by crushing and sterilizing corn stalks. Step 2: Mix biochar, crop straw powder, microbial agent, ammonium sulfate, silicate mineral powder and zinc sulfate borax according to the formula ratio to obtain the initial mixture; Step 3: Compost the initial mixture to obtain organic fertilizer raw materials; Step 4: After adding a coating agent to the organic fertilizer raw material, use a granulator to form a granulated product to obtain a biochar-based compound organic fertilizer that improves soil structure.
8. The method for preparing biochar-based compound organic fertilizer for improving soil structure according to claim 7, characterized in that, Biochar production from corn stalks, and crop straw powder produced by pulverizing and sterilizing corn stalks, include: Biochar was prepared by pyrolyzing corn stalks at 550℃ for 3 hours. After crushing the corn stalks to 80-100 mesh, sterilize them with a sterilizing agent at 60℃ for 2 hours to obtain crop straw powder.
9. The method for preparing biochar-based compound organic fertilizer for improving soil structure according to claim 8, characterized in that, The process of composting the initial mixture to obtain organic fertilizer raw materials includes: The composting process begins with composting at 50℃ for 72 hours, followed by composting at 50℃ for 14 days to obtain organic fertilizer raw materials. The compost is turned over every three days. The moisture content of the organic fertilizer raw materials is ≤30%.
10. The method for preparing biochar-based compound organic fertilizer for improving soil structure according to any one of claims 7-9, characterized in that, The coating agent comprises attapulgite clay at a mass ratio of 3%.