Carbon-based bio-organic fertilizer with phosphorus immobilization and biological activation functions and application of carbon-based bio-organic fertilizer

Abstract

The invention discloses a carbon-based bio-organic fertilizer with phosphorus immobilization and biological activation functions and application, and belongs to the technical field of agricultural environments and novel fertilizers. The organic fertilizer is prepared by compounding a high-performance phosphorus adsorption carbon-based material, a low-phosphorus leaching-loss organic fertilizer carrier, a composite functional microbial agent and fulvic acid, wherein the carbon-based material is fir sawdust carbon or rice hull carbon with the specific surface area being larger than or equal to 19 m < 2 > / g and the micropore proportion being larger than or equal to 60%, and the organic fertilizer carrier is decomposed sheep manure organic fertilizer; the microbial agent is prepared from trichoderma viride Tv41 and trichoderma longibrachiatum TB2; according to the organic fertilizer, a'carbon-fertilizer-bacterium 'ternary synergistic system is constructed, so that the bio-availability of the organic fertilizer is enhanced while soil phosphorus is effectively immobilized, the problem that immobilization and activation are difficult to cooperate in the traditional technology is solved, phosphorus loss is synchronously controlled and the absorption and utilization efficiency of crops on phosphorus is improved under the condition of reducing the dosage of a phosphate fertilizer, and the yield of the crops is increased. The method is suitable for application of crops such as cabbages and hot peppers in phosphorus-enriched vegetable fields.

Description

Technical Field

[0001] This invention belongs to the field of agricultural environment and new fertilizer technology, and in particular to a carbon-based bio-organic fertilizer with both phosphorus retention and bio-activation functions and its application. Background Technology

[0002] Commercial organic fertilizers play a vital role in improving soil structure and increasing organic matter. However, in vegetable cultivation systems, due to the short growing season and high multiple cropping index, excessive application of high-phosphorus organic fertilizers is often used in the field to pursue yield, leading to rapid accumulation of available phosphorus in the topsoil. Long-term application of high-phosphorus organic fertilizers easily leads to the accumulation of available phosphorus in the soil, which is prone to forming weakly bound phosphorus and increasing its migration risk. Related studies have pointed out (Chen et al., 2022, Long-term excessive phosphorus fertilization alters soil phosphorus fractions in the acidic soil of pomelo orchards; Pizzeghello et al., 2016, Relationship between soil test phosphorus and phosphorus release to solution in three soils after long-term mineral and manure application) that this type of phosphorus is easily lost through preferential flow and substrate flow pathways under heavy rainfall or irrigation conditions, becoming an important source of agricultural non-point source pollution and forming a typical "pulse pollution".

[0003] In recent years, biochar has been widely used in soil remediation and phosphorus fixation research due to its well-developed pore structure, abundant surface functional groups, and rich mineral components such as calcium, magnesium, and silicon. "Phosphorus fixation" specifically refers to the process of rapidly capturing and stably fixing easily leached dissolved phosphorus in the soil through physicochemical means (such as adsorption and precipitation) to control its migration via runoff or leaching. "Bioactivation" specifically refers to the process of converting insoluble phosphorus in the soil and fixed into available phosphorus that can be absorbed by crops through microbial action. Numerous studies have shown that biochar can effectively fix phosphate ions through various mechanisms such as micropore filling, electrostatic adsorption, surface coordination, and precipitation reactions, reducing the migration capacity of phosphorus in the soil environment. However, existing phosphorus management technologies have significant functional limitations: they focus on a single pathway. For example, while biochar-based phosphorus retention technologies (such as CN118812304A) can adsorb phosphorus, they can easily lead to a decrease in the bioavailability of the fixed phosphorus, resulting in a situation of "fixation without effectiveness." On the other hand, microbial activation technologies (such as CN117778023A), while activating soil phosphorus, pose a risk of exacerbating leaching in high-phosphorus soils. Existing technologies, including carbon-based soil conditioners (such as CN116640580B) and carbon-based compound fertilizers for specific crops (such as CN117069541B), mostly focus only on the comprehensive supply of nutrients, waste utilization, or general soil improvement. The microbial agents they use have broad functions or do not involve phosphorus conversion, failing to synergistically design for the contradictory relationship between "phosphorus retention" and "bioactivation." Overall, existing technologies for phosphorus utilization have the following problems: 1) High risk of phosphorus loss from organic fertilizers: The large-scale application of high-phosphorus organic fertilizers leads to the accumulation of available phosphorus in the soil, which easily forms weakly bound phosphorus, which enters water bodies through runoff and leaching driven by rainfall or irrigation; 2) Insufficient bioavailability after phosphorus fixation by biochar: Traditional biochar has a strong ability to fix phosphorus, but the fixed phosphorus is difficult for crops to absorb and utilize; 3) Single function and lack of synergy: Existing technologies mostly focus on a single pathway in physical adsorption, chemical fixation or biological activation, and lack systematic synergistic regulation schemes.

[0004] Therefore, providing a systematic solution that can simultaneously coordinate "retention" and "activation"—that is, a product that can physically adsorb and fix easily lost phosphorus while continuously activating it through a specific microbial community for crop absorption and utilization—has become a pressing technical challenge in this field. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a carbon-based bio-organic fertilizer with both phosphorus retention and bio-activation functions, along with its preparation method and application, to synergistically achieve "phosphorus retention" and "bio-activation." Specifically, it is a functional fertilizer that achieves intelligent regulation of phosphorus in farmland through a ternary synergistic system of "carbon-fertilizer-microorganism," and is suitable for non-point source pollution control and green production in phosphorus-rich farmland such as vegetable fields.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: First, this application provides a carbon-based bio-organic fertilizer with both phosphorus retention and bio-activation functions. The organic fertilizer is composed of the following components in parts by weight: 1 part of high-performance phosphorus adsorption carbon-based material; 6 parts of low-phosphorus leaching organic fertilizer carrier; 0.6~1.3 parts of fulvic acid; and compound functional microbial agent; The high-performance phosphorus adsorption carbon-based material has a specific surface area ≥19 m². 2 / g, the proportion of micropore volume to total pore volume is ≥60%; its composition is fir wood chip charcoal or rice husk charcoal; The low-phosphorus leaching organic fertilizer carrier is sheep manure organic fertilizer, with a total phosphorus content of 16-18 g / kg (P2O5). The preparation method of this organic fertilizer is a conventional technology in the field, as recorded in "Organic Fertilizer" (NY / T 525-2021) and "Practical Handbook of Composting Engineering". In specific implementation, commercially available products can also be used.

[0007] The compound functional microbial agent includes one of a fungal phosphate-solubilizing agent or a bacterial compound agent. The fungal phosphate-solubilizing agent comprises *Trichoderma viride* Tv41 and *Trichoderma longicornis* TB2; in the prepared carbon-based bio-organic fertilizer, the viable concentration of each bacterium is not less than 1 × 10⁻⁶. 7 CFU / g; The above-mentioned *Trichoderma viride* Tv41 was deposited on June 12, 2014, at the China General Microbiological Culture Collection Center (CGMCC), with accession number CGMCC NO.9293, and its taxonomic name is *Trichoderma viride* (…). Trichoderma viride The depositary address is No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, Postcode: 100101; *Trichoderma longicornis* TB2 was deposited on April 25, 2019, at the China General Microbiological Culture Collection Center (CGMCC), accession number CGMCC NO. 17663, taxonomically named *Trichoderma longicornis* (…). Trichoderma longibrachiatum The address for this application is No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, Postcode: 100101. In one embodiment of this application, the bacterial count ratio of *Trichoderma viride* Tv41 to *Trichoderma longifolia* TB2 is 1:1.

[0008] Bacterial compound inoculants contain Bacillus megaterium (Betaminaria) Bacillus megaterium ), gelatinous spore-forming bacteria ( Paenibacillus mucilaginosus ), Bacillus licheniformis ( Bacillus licheniformis ), Bacillus amyloliquefaciens ( Bacillus amyloliquefaciens ) and Bacillus laterosporus ( Bacillus laterosporus At least three of the bacteria must be present; and the viable bacterial concentration of each bacteria in the prepared carbon-based bio-organic fertilizer must be no less than 1×10⁻⁶.7 CFU / g.

[0009] The core function of fungal inoculants (Trichoderma viride TV41 and Trichoderma longifolia TB2) lies in enhancing the direct activation ability of microorganisms for phosphorus. Their hyphae can penetrate deep into the pores of the carbon matrix, directly colonizing phosphorus-fixing sites. By secreting large amounts of potent organic acids such as citric acid and oxalic acid, they specifically and efficiently dissolve phosphorus fixed by the carbon material and the original insoluble phosphorus pools in the soil, thus achieving a crucial transformation from "physical fixation" to "bioavailable phosphorus." Although many Trichoderma species can secrete organic acids, TV41 and TB2 used in the examples have been screened to have higher efficiency in secreting key phosphorus-solubilizing organic acids such as citric acid and oxalic acid. Furthermore, their secretion activity is more stable in the "carbon-fertilizer" composite system and less susceptible to inhibition by environmental fluctuations, thus ensuring sustained and potent phosphorus-solubilizing activity. As shown in Example 4 and Table 9 of the instruction manual, after applying the carbon-based bio-organic fertilizer (BOF1) containing the combination of TV41 and TB2, the available phosphorus content in the soil increased to 52.0 mg / kg, significantly higher than other treatments. This data directly demonstrates that the combination of Tv41 and TB2 exhibits the strongest bioactivation ability of the soil phosphorus pool in this system, effectively converting fixed phosphorus into available phosphorus. Simultaneously, the BOF1 treatment showed a 17.2% increase in crop phosphorus uptake compared to the control, the highest increase among all treatments. This is directly related to the highly efficient phosphorus solubilization function of Tv41 and TB2, proving that the activated phosphorus can be efficiently absorbed and utilized by crops, achieving a highly efficient transformation from "activation" to "absorption."

[0010] The core function of the aforementioned bacterial compound inoculant (various Bacillus species) lies in systematically constructing and maintaining a rhizosphere microenvironment conducive to phosphorus absorption. In addition to assisting phosphorus solubilization, it focuses on systematically protecting crop health by promoting root development through the secretion of plant growth hormones, producing antibacterial substances to inhibit soil-borne diseases, and rapidly colonizing to form a stable beneficial microbial community, thereby improving the efficiency of crop absorption and utilization of activated phosphorus.

[0011] Preferably, the fulvic acid, as a natural binder and microbial growth promoter, can enhance the colonization and activity of the microbial agent on the carbon-based carrier, and synergistically activate fixed phosphorus by microorganisms.

[0012] Secondly, the present invention also provides a method for preparing the carbon-based bio-organic fertilizer, comprising the following steps: a) Preparation of high-performance phosphorus adsorption carbon-based materials; b) Mix the carbon-based material with well-rotted sheep manure organic fertilizer at a mass ratio of 1:6; c) Add fulvic acid and continue stirring to mix; d) Inoculate with a compound functional microbial agent to ensure that the final concentration of the target strains is ≥1×10⁻⁶. 7 CFU / g; Preferably, the preparation of the high-performance phosphorus adsorption carbon-based material in step 1 includes: a) The raw materials are selected from one or both of cedar wood chips or rice husks; b) Differentiated pyrolysis based on raw material characteristics: cellulose-dominant raw materials are pyrolyzed at 400±10 °C for 2 hours, lignin-rich raw materials are pyrolyzed at 600±10 °C for 6 hours, and high-silica hard raw materials are pyrolyzed at 800±10 °C for 8 hours. The pyrolysis method is conventional in this field, as disclosed in the literature “Wei Siyue. Effects of different biomass raw materials and preparation temperature on the physicochemical characteristics of biochar [D]. University of Chinese Academy of Sciences (Guangzhou Institute of Geochemistry, Chinese Academy of Sciences), 2017.” and “Li Ying. Study on the characteristics of Chinese fir biochar and its influence on soil carbon stability [D]. Fujian Agriculture and Forestry University, 2018.”

[0013] c) The pyrolysis product was ball-milled and passed through a 40-mesh sieve. It was then acid-washed with 0.1 mol / L hydrochloric acid solution at a ratio of 1:10 (w / v) for 6 hours. The supernatant was removed by centrifugation. The centrifuged pyrolysis product was further washed with deionized water until neutral (pH 6.5–7.5), and then vacuum-dried at 60±2 °C to constant weight. Products with a specific surface area ≥19 m² were selected. 2 Carbon materials with a micropore volume ratio of ≥60% of the total pore volume are considered high-performance phosphorus adsorption carbon-based materials.

[0014] Third, this application provides the application of the above-mentioned carbon-based bio-organic fertilizer in retaining phosphorus in soil (such as farmland). That is, before transplanting vegetables, the carbon-based bio-organic fertilizer is applied together with chemical fertilizer as base fertilizer to the field (such as a phosphorus-rich vegetable field with soil available phosphorus content >40 mg / kg) to retain phosphorus in the soil.

[0015] Fourth, this application provides the application of the above-mentioned carbon-based bio-organic fertilizer in increasing the phosphorus content of vegetable crops and improving the phosphorus utilization rate of vegetable crops; that is, before transplanting vegetables, the carbon-based bio-organic fertilizer and chemical fertilizer are applied together as base fertilizer to the field (such as phosphorus-rich vegetable fields with soil available phosphorus content >40 mg / kg), and the application rate is 1.5~3.0 tons / hectare; the above-mentioned vegetables are preferably cabbage, pepper or tomato, etc.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This application strictly limits the carbon-based material to fir wood chip charcoal or rice husk charcoal. This component is a preferred raw material that has been systematically screened through the examples (Table 1) and can be stably prepared to meet the high-performance index of "specific surface area ≥19 m² / g, micropore ratio ≥60%". It is the key to achieving efficient phosphorus physical adsorption.

[0017] In this application, the low-phosphorus leaching organic fertilizer is well-rotted sheep manure organic fertilizer with a total phosphorus content of 16-18 g / kg (calculated as P2O5). This is because the purpose of this application is to solve the synergistic problem of "controlling leaching" and "promoting absorption" in phosphorus-rich vegetable fields. Therefore, the core requirements for the organic fertilizer carrier are "moderate phosphorus content" and "low leaching risk". After systematic leaching tests and screening, the examples (Table 2) found that only sheep manure organic fertilizer with this phosphorus content had the lowest cumulative phosphorus leaching, and its release curve was best synchronized with the crop's phosphorus requirement period. This is significantly better than other organic fertilizers such as mushroom residue (high leaching) and traditional Chinese medicine residue (delayed release). Its "low leaching characteristic" is specific and excellent, and not common to all well-rotted manure, thus meeting this dual standard and controlling phosphorus load from the source.

[0018] 3. This application achieves a synergistic unity of phosphorus "retention" and "activation": High-performance carbon-based materials rapidly adsorb and fix easily lost active phosphorus in the soil, thus controlling phosphorus loss during the process; simultaneously, specific composite microbial agents (TV41, TB2, etc.) continuously activate the insoluble phosphorus fixed by the carbon materials and present in the soil, converting it into available phosphorus for crop use. Data from Example 4 shows that this synergistic effect increased crop phosphorus uptake by 17.2% while reducing runoff phosphorus loss by 36.7%, successfully resolving the technical contradiction of simultaneously achieving "retention" and "activation."

[0019] 4. The organic fertilizer in this application provides a complete chain solution of "source reduction - process control - bio-enhancement": by selecting sheep manure organic fertilizer with low phosphorus leaching characteristics to reduce phosphorus load at the source, compounding high-performance carbon-based materials to control phosphorus loss during the process, and introducing functional microorganisms to improve the bioavailability of phosphorus, a complete technology chain of synergistic enhancement is formed.

[0020] 5. The organic fertilizer application of this application has significant effects, emphasizing both environmental and agronomic benefits: Field trials show that, without additional phosphate fertilizer input, the product of this invention can significantly reduce phosphorus loss load (32.9%~36.7%) compared with conventional fertilization, and promotes the absorption of phosphorus by crops through biological activation, thereby achieving a significant increase in crop yield (cabbage yield can be increased by up to 33.6%), achieving a win-win goal of green agricultural production and environmental pollution control. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a soil phosphorus leaching simulation monitoring device.

[0022] Figure 2 These are photographs from irrigation simulation and sample analysis experiments, serving as examples.

[0023] Figure 3 These are photographs from irrigation simulation and sample analysis experiments, serving as examples.

[0024] Figure 4 Photos show the field application of carbon-based bio-organic fertilizer.

[0025] Figure 5 The results show the spread and plant height of cabbage during the rosette stage.

[0026] Figure 6 This is a statistical result of the growth of cabbage during the rosette stage. Detailed Implementation

[0027] The present invention will be further illustrated by the following examples, but they are not intended to limit the scope of the invention.

[0028] In the embodiments, straw organic fertilizer was purchased from Nanjing Mingzhu Fertilizer Co., Ltd., mushroom residue organic fertilizer was purchased from Nanjing Ningliang Bioengineering Co., Ltd., and traditional Chinese medicine residue organic fertilizer was purchased from Jiangsu Haolais Fertilizer Co., Ltd.; sheep manure organic fertilizer was composted by the applicant at the organic fertilizer plant in Liuhe Base (the composting raw materials were sheep manure and straw, with a mass ratio of 98:2). The preparation method was carried out in accordance with the literature "Han Dayong, Li Yongjun, Liu Haixia, et al. Effects of rice straw on the physicochemical properties and nitrogen conversion of aerobic composting of sheep manure [J]. Journal of Agricultural Environmental Science, 2024, 43(8): 1896-1906." In specific implementation, pure sheep manure compost or commercially available sheep manure organic fertilizer can also be used, ensuring that its total phosphorus content (calculated as P2O5) is in the range of 16~18 g / kg, which can achieve the purpose of the invention.

[0029] Example 1: Directed preparation, characterization and screening of high-performance phosphorus adsorption carbon-based materials To achieve efficient capture and stable fixation of dissolved phosphates in vegetable field runoff, this embodiment provides a targeted preparation method based on the synergistic regulation of raw material characteristics, pyrolysis kinetics, and surface chemistry. By systematically integrating multi-source raw material screening, differentiated pyrolysis pathways, and targeted post-treatment processes, the pore structure and surface active sites of carbon-based materials are optimized, thereby enhancing their selective adsorption capacity for phosphate ions and their environmental stability.

[0030] 1. Directional preparation of carbon-based materials

[0031] (1) Raw material selection and pretreatment Six typical agricultural and forestry wastes were selected as raw materials, including fruit trees (apple and pear trees), fir sawdust, corn stalks, rice straw, rice husks, and bamboo, covering different lignin, cellulose, and ash composition characteristics. All raw materials were crushed to a particle size of 1–3 cm and dried at 105 °C to constant weight (moisture content <5%) to ensure uniform heat and mass transfer during pyrolysis.

[0032] (2) Differentiated pyrolysis process Based on the chemical composition and pyrolysis characteristics of the raw materials, the following pyrolysis conditions are set: Cellulose-dominant raw materials (corn straw, rice straw): Pyrolysis at 400±10 °C for 2 hours to effectively retain a large number of oxygen-containing functional groups (such as –COOH, –OH). These polar groups can preferentially recognize and bind phosphate ions through ligand exchange or hydrogen bonding, thereby enhancing the chemical affinity for phosphate ions. Lignin-rich raw materials (fruitwood, fir sawdust): Pyrolysis at 600±10 °C for 6 h. High lignin structure is dense and has a strong tendency to aromatization, requiring higher energy to drive the cleavage of cross-linked networks, thereby fully developing microporous and mesoporous systems and forming a multi-level porous structure that is conducive to the diffusion and physical adsorption of small molecules; High-silicon hard raw materials (rice husk, bamboo): Pyrolysis at 800±10 °C for 8 hours utilizes the mineral phase rearrangement and partial melting etching effect at high temperature to generate abundant nanoscale pores in situ; at the same time, it promotes the transformation of SiO2, K2O and other substances into amorphous active mineral phases, providing reaction sites for subsequent chemical precipitation or surface coordination of phosphorus.

[0033] All pyrolysis processes were carried out under the protection of high-purity nitrogen (purity ≥99.999%), with the temperature programmed to rise to the target temperature at a rate of 10 °C / min to avoid interference from oxidation side reactions.

[0034] (3) Post-pickling treatment The pyrolysis products were ball-milled through a 40-mesh sieve and then soaked in 0.1 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:10 (w / v, g / mL) for 6 hours to remove soluble ash, clear pores, enhance surface protonation, and improve the electrostatic adsorption capacity for phosphate. After acid washing, the samples were washed with distilled water until neutral (pH 6.5–7.5) and then vacuum-dried at 60 °C to constant weight to obtain surface-functionalized phosphorus-adsorbing carbon-based materials.

[0035] 2. Structural Characterization and Structure-Property Relationship Analysis To verify the effectiveness of the targeted design strategy and to reveal the fundamental reasons for the performance differences of carbon-based materials, a comprehensive analysis of six carbon-based materials was conducted.

[0036] (1) Low-temperature nitrogen adsorption / desorption test and detailed analysis of pore structure The sample was subjected to high vacuum (<10) at 110°C. -2 After degassing for 12 hours under conditions of 100 Pa, the N2 adsorption-desorption isotherm at 77 K was determined using a fully automated specific surface area and porosity analyzer. Micropore analysis and physicochemical adsorption were performed using an Autosorb-1 (Quantachrome, USA) analyzer, and the data were analyzed using the following model at multiple scales: The BET model (P / P0 = 0.05~0.30) is used to calculate the total specific surface area; HK method for calculating micropore volume and micropore surface area; BJH method for analyzing mesopore size distribution and pore volume; DFT theory fits the full range (0.3~50 nm) pore size distribution, improving resolution and accuracy.

[0037] The above detection methods are all conventional methods in this field. This embodiment refers to the methods disclosed in the references "Li Ying. Study on the characteristics of Chinese fir biochar and its influence on soil carbon stability [D]. Fujian Agriculture and Forestry University, 2018.", "Li Kunquan, Li Ye, Zheng Zheng, Sang Dazhi. Preparation, characterization and adsorption performance of high specific surface area biochar [J]. Environmental Science, 2023, 34(01)", and "Wei Siye. Influence of different biomass raw materials and preparation temperature on the physicochemical characteristics of biochar [D]. University of Chinese Academy of Sciences (Guangzhou Institute of Geochemistry, Chinese Academy of Sciences), 2017".

[0038] (2) Key findings and performance prediction The test results are summarized in Table 1, revealing a clear pattern of structural differentiation: Table 1. Pore structure characteristics of biochar from different raw materials Types of biochar <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[External surface area (m 2 / g)]]> <![CDATA[Micropore surface area (m 2 / g)]]> <![CDATA[Total pore volume (cm 3 / g)]]> <![CDATA[Mesoporous pore volume (cm 3 / g)]]> <![CDATA[Micropore pore volume (cm 3 / g)]]> Average pore size (nm) Corn stalk charcoal 0.80 0.80 0.00 0.003 0.002 0.002 12.63 Rice straw charcoal 0.54 0.54 0.00 0.002 0.001 0.001 11.20 Coconut shell charcoal 1.65 1.65 0.00 0.006 0.006 0.005 13.81 Cedar wood chip charcoal 23.17 14.27 8.90 0.018 0.008 0.008 3.13 Rice husk charcoal 19.42 5.74 13.67 0.016 0.009 0.009 3.28 Bamboo charcoal 11.63 3.34 8.29 0.009 0.005 0.005 3.11 The cedar wood chip charcoal exhibited the highest specific surface area (23.17 m²) under optimized pyrolysis at 600°C. 2 The phosphate hydrate ion has a well-developed microporous system (micropores account for 38.4%), with an average pore size of only 3.13 nm, which is well matched with the diameter of the phosphate hydrate ion (about 0.4 nm), making it suitable for physical adsorption dominated by the micropore filling mechanism. Although rice husk charcoal has a slightly lower specific surface area than cedar sawdust charcoal, its microporous surface area is as high as 13.67 m². 2 / g (accounting for 70.4% of the total surface area) and rich in amorphous silicate phase, possessing both physical adsorption and chemical precipitation potential; In contrast, straw-based materials suffer from rapid cellulose decomposition leading to intense volatile matter release, poor pore structure development, and a specific surface area of ​​less than 1 m². 2 / g has no practical value.

[0039] 3. Material selection and functional positioning Through extensive screening experiments, this embodiment discovers for the first time that the specific surface area of ​​carbon-based materials (≥19 m²) 2 The ratio of phosphorus volume (g / g) and the micropore volume fraction (≥60%) are key structural parameters for achieving efficient phosphorus adsorption and retention. As shown in Table 1, cedar wood chip charcoal and rice husk charcoal are preferred materials that meet this standard and achieve efficient phosphorus retention through different dominant mechanisms (physical adsorption and chemical precipitation).

[0040] Example 2: Screening and Synergistic Potential Assessment of Low-Leaching Organic Fertilizers Based on Phosphorus Release Kinetics Based on the preparation of high-performance phosphorus adsorption carbon-based materials in Example 1, this example focuses on screening organic fertilizer varieties with low phosphorus release characteristics, good slow-release performance, and matching the phosphorus requirements of crops, so as to control the risk of phosphorus migration from the source.

[0041] 1. Dynamic simulation of leaching (1) Construction of test soil and leaching device The experimental soil was collected from a typical vegetable planting base in Huai'an, Jiangsu Province (33°38′N, 118°57′E). The soil was silty loam with a pH of 6.2 and an initial available phosphorus content of 18.7 mg / kg, classifying it as farmland with moderate phosphorus levels. To accurately represent the longitudinal migration pathway of phosphorus in the field, soil samples were collected from 0–20 cm (topsoil, phosphorus-rich zone) and 20–40 cm (subsurface, migration pathway), air-dried, and sieved through a 2 mm sieve for later use.

[0042] The leaching device uses PVC columns with an inner diameter of 25 cm and a height of 48 cm. A 3 cm layer of acid-washed quartz sand is laid at the bottom as a drainage layer, based on the original soil bulk density (top layer 1.32 g / cm³). 3 Subsurface layer 1.45 g / cm 3 Layered filling, with a 5 cm irrigation space reserved at the top, and a liquid inlet at the bottom for connecting to a collection bottle (see...). Figure 1 The soil phosphorus leaching simulation monitoring device under organic fertilizer is a conventional detection device, as disclosed in publications such as "Niyungeko, C., Liang, X., Liu, C., Liu, Z.-w., Sheteiwy, M., Zhang, H., Zhou, J., Tian, ​​G., 2018. Effect of biogas slurry application rate on colloidal phosphorus leaching in paddy soil: A column study. Geoderma 325, 117-124." and "Teutscherova, N., Houška, J., Navas, M., Masaguer, A., Benito, M., Vazquez, E., 2018. Leaching of ammonium and nitrate from Acrisol and Calcisolamended with holm oak biochar: A column study. Geoderma 323, 136-145."

[0043] (2) Experimental treatment and physicochemical characteristics of organic fertilizer The experiment included five treatments: ① chemical fertilizer control (CK), ② straw organic fertilizer, ③ mushroom residue organic fertilizer, ④ traditional Chinese medicine residue organic fertilizer, and ⑤ sheep manure organic fertilizer. Each treatment was replicated four times using a completely randomized block design. All organic fertilizers underwent commercial composting stabilization treatment, and their basic physicochemical properties are shown in Table 2.

[0044] Table 2 Basic Physicochemical Properties of Organic Fertilizer

[0045] (3) Irrigation simulation and sample analysis Simulated chili peppers ( Capsicum annuum Irrigation was conducted during three key growth stages: seedling stage (week 1 after transplanting), flowering and fruit setting stage (week 5, peak water demand), and fruiting stage (week 9, fruit enlargement). After each irrigation, all leachate was collected, the volume was recorded, and a representative sample was frozen for preservation. Total phosphorus concentration was determined using the potassium persulfate high-temperature oxidation-molybdenum antimony spectrophotometric method (referencing "Routine Analysis Methods in Soil Agricultural Chemistry," Lu Rukun, 2000). Cumulative phosphorus leaching loss = ∑(single leachate volume × total phosphorus concentration), used to comprehensively assess the environmental risk of each treatment. Experimental photos are shown below. Figure 2 , Figure 3 As shown.

[0046] 2. Analysis and Scientific Screening of Release Behavior A thorough analysis of the data in Table 3 leads to the following key conclusions: (1) The mushroom residue organic fertilizer treatment showed the most severe phosphorus leaching during the entire experiment, with a cumulative leaching of up to 228.92 mg P throughout the entire growth period, which was nearly 70% higher than the chemical fertilizer control. In particular, an abnormally high leaching peak (69.27 mg P) appeared in the seedling stage, indicating that it rapidly released a large amount of soluble phosphorus after application, far exceeding the short-term adsorption capacity of the soil. This is directly related to its extremely high total phosphorus content (19.75 g / kg P2O5).

[0047] (2) The total phosphorus leaching during the entire growth period of the sheep manure organic fertilizer treatment was only 148.08 mg P, which was not significantly different from the chemical fertilizer treatment. Moreover, the leaching amount was the lowest (64.75 mg P) during the peak phosphorus loss period (flowering and fruit setting period), which was significantly lower than other organic fertilizer treatments. Its phosphorus release curve was flat, which matched the phosphorus absorption pattern of peppers in the middle and late stages. It is suitable as an ideal compatibility material for the high-performance carbon-based materials (fir sawdust charcoal, rice husk charcoal) in Example 1.

[0048] (3) Although the leaching of the herbal medicine residue organic fertilizer was low in the early stage, a significant leaching peak (69.90 mgP) appeared during the fruiting period, which was significantly higher than other treatments. It is speculated that this is because this type of material contains more recalcitrant lignocellulose and secondary metabolites, which are limited in mineralization in the early stage and gradually decompose with the succession of the microbial community in the later stage of growth, resulting in "delayed release". If this type of organic fertilizer is used for crops with a long growth cycle, there may be potential pollution risks in the later stage. It needs to be used in conjunction with long-lasting fixation materials to avoid ecological risks.

[0049] Table 3 Total phosphorus leaching amount under different treatments

[0050] 3. Screening Criteria for "Low Phosphorus Emission - High Synergistic Effect" Organic Fertilizers This embodiment demonstrates through leaching kinetics experiments that the total phosphorus content (16-18 g / kg P2O5) and leaching characteristics (cumulative leaching loss over the entire growth period ≤150 mg P / bucket) of the organic fertilizer carrier are key indicators affecting its environmental risk. Sheep manure organic fertilizer, due to its moderate phosphorus content and slow-release characteristics, can form a good complement to carbon-based materials, and is therefore preferred as the organic carrier in subsequent embodiments.

[0051] Example 3: Synergistic effect of carbon-based organic fertilizer on phosphorus loss in vegetable fields and verification of its agronomic performance. After screening high-performance carbon-based materials and low-leaching organic fertilizer carriers in Examples 1 and 2 respectively, this example aims to verify the environmental benefits of the basic carbon-based organic fertilizer formed by the combination of the two in controlling phosphorus loss through field trials, while revealing its limitations in promoting crop phosphorus absorption, and providing experimental basis for the subsequent introduction of microbial agents.

[0052] 1. Preparation of carbon-based organic fertilizer Based on the carbon-based material screened in Example 1 and the sheep manure organic fertilizer screened in Example 2, two types of carbon-based organic fertilizers were prepared. In the construction of organic fertilizers, a carbon ratio that is too low results in insufficient retention, while a carbon ratio that is too high affects the physicochemical properties of the fertilizer. Preliminary experiments showed that when the mass ratio of the high-performance phosphorus-adsorbing carbon-based material to the low-phosphorus leaching organic fertilizer carrier is between 1:4 and 1:8, both phosphorus loss control and crop growth can be balanced. Therefore, in this example, the ratio of the two materials is 1:6 to synergistically combine environmental and agronomic benefits.

[0053] Fir wood charcoal-based organic fertilizer: Fir wood chip biochar (specific surface area 23.17 m²) 2 / g, microporous surface area 8.90 m² 2 / g) and sheep manure organic fertilizer are mixed at a mass ratio of 1:6; Rice husk biochar-based organic fertilizer: Rice husk biochar (specific surface area 19.42 m²) 2 / g, microporous surface area 13.67 m²2 Mix / g) with sheep manure organic fertilizer at a mass ratio of 1:6.

[0054] 2. Field trial design The experiment was conducted in a typical open-field vegetable growing area in Nanjing. The basic physicochemical properties of the tested soil (0-20 cm topsoil) were: pH 6.95, organic matter 17.0 g / kg, available phosphorus 65.1 mg / kg, which is a typical phosphorus-rich soil.

[0055] The experiment consisted of three treatments: a conventional control (CK): chemical fertilizer + sheep manure organic fertilizer; charcoal-based organic fertilizer treatment 1: chemical fertilizer + fir charcoal-based organic fertilizer; and charcoal-based organic fertilizer treatment 2: chemical fertilizer + rice husk charcoal-based organic fertilizer. Each treatment was replicated three times in a randomized block design. The total nitrogen (N), phosphorus (P2O5), and potassium (K2O) inputs were kept identical across all treatments. Phosphate fertilizer, organic fertilizer, and charcoal-based organic fertilizer were all applied as basal fertilizer in a single application. The tested crop was cabbage.

[0056] 3. Monitoring Methods and Data Analysis (1) Construction of runoff collection system The isolation units are constructed using PVC partitions (20 cm underground and 30 cm above ground) to separate each 6 m section. 2 The community is completely isolated to prevent lateral seepage and crossflow. The diversion and storage unit consists of diversion holes installed at the lowest point of the community's terrain, through which all surface runoff is diverted into 200 L HDPE collection tanks via PVC drainage pipes (slope 3°~5°). Figure 4 (As shown in B). Figure 4 In the middle, A, C represent, in order, the experimental plot, the runoff collection device, and the collection bucket.

[0057] (2) Sample collection and measurement Two effective runoff events were captured throughout the cabbage growing season. After each event, the runoff volume was precisely measured, and water samples were collected. The water samples were filtered through a 0.45 μm filter membrane, and the soluble phosphorus concentration was determined using a continuous flow analyzer (Skalar SAN++) to calculate the phosphorus loss load for each event.

[0058] (3) Determination of agronomic traits and phosphorus utilization After the cabbage matured, the yield and commercial characteristics (single head weight, transverse and longitudinal diameter, and compactness) of each plot were measured, and plant samples were collected. The phosphorus content of the plants was determined by the molybdenum-antimony colorimetric method, and the phosphorus uptake was calculated.

[0059] 4. Results and Analysis (1) Agronomic yield and phosphorus utilization Table 4 shows that the yield and key commercial traits of cabbage treated with the two carbon-based organic fertilizers were not significantly different from those of the conventional control. Among them, the rice husk carbon-based organic fertilizer treatment even slightly increased the yield and single head weight, indicating that carbon-based organic fertilizer can maintain normal crop growth under the same nutrient conditions. In Table 4, phosphorus uptake = aboveground biomass of cabbage (by dry weight) × aboveground phosphorus content of cabbage (see the literature "Xie Zhihui, Xiao Yaqin, Zhou Xun, Li Ting, Wu Qinxiang, Cao Jiwu, Sun Minhong. Effects of different phosphorus levels on root morphology and phosphorus uptake of Dalbergia odorifera seedlings [J]. Journal of Ecology, 2025, 44(6):1909-1916.").

[0060] It is noteworthy that, as shown in Table 4, the phosphorus uptake by plants treated with both carbon-based organic fertilizers showed a trend lower than that of the control. Combined with the fact that their yields were unaffected and even slightly increased, this phenomenon indicates that the carbon-based material effectively fixed readily leached active phosphorus in the soil, temporarily reducing its bioavailability, thereby reducing ineffective phosphorus cycling while ensuring crop growth. This finding also reveals the shortcomings of basic carbon-based organic fertilizers in activating fixed phosphorus, providing a clear direction for improvement through the subsequent introduction of phosphorus-solubilizing microorganisms.

[0061] Table 4. Effects of different treatments on cabbage yield, marketability, and phosphorus content in plants.

[0062] (2) Phosphorus loss control effect Table 5 shows that, compared with the conventional control, cedar charcoal-based organic fertilizer and rice husk charcoal-based organic fertilizer significantly reduced the total phosphorus loss in runoff by 32.9% and 36.7%, respectively. This significant environmental benefit confirms the good synergistic effect of high-performance charcoal-based materials and low-leaching organic fertilizer carriers in controlling phosphorus loss. Meanwhile, the slight decreasing trend in plant phosphorus uptake shown in Table 4 reveals the inadequacy of basic charcoal-based organic fertilizer in activating fixed phosphorus, providing clear experimental evidence and directions for improvement in the subsequent introduction of phosphorus-solubilizing microorganisms.

[0063] Table 5. Effects of different treatments on phosphorus loss load from vegetable field runoff.

[0064] Example 4: Construction of Carbon-Based Bio-Organic Fertilizer and Verification of Synergistic Effects of Microorganisms To screen for the most phosphorus-solubilizing microbial types in the "carbon-fertilizer" system and best address the "phosphorus fixation and activation" problem, this embodiment conducted a functional comparison experiment. By comparing different microbial combinations dominated by potent phosphorus-solubilizing fungi, multifunctional phosphorus-solubilizing bacteria, and growth-promoting bacteria, and using the increase in available phosphorus in the soil and the amount of phosphorus absorbed by crops as the core evaluation indicators, the phosphorus-solubilizing capacity of different types of microbial agents was assessed.

[0065] 1. Design Strategies for Functional Carbon-Based Bio-Organic Fertilizers Addressing the technical bottleneck in Example 3 where "carbon-based organic fertilizer fixes phosphorus but crop phosphorus absorption is not significantly improved," this example aims to construct a complete "carbon-fertilizer-microbe" ternary synergistic system by introducing compound functional microbial agents, and to verify its synergistic effect mechanism in simultaneously achieving phosphorus loss control and efficient utilization of crop phosphorus.

[0066] 2. Construction of Carbon-Based Bio-Organic Fertilizer (1) Targeted screening and preparation of highly efficient phosphate-solubilizing bacteria To achieve targeted activation of fixed phosphorus, two types of functionally complementary microbial agents were constructed: Fungal phosphate-solubilizing agents: Highly efficient phosphate-solubilizing strains—*Trichoderma viride* Tv41 (CGMCC NO. 9293) and *Trichoderma longicornis* TB2 (CGMCC NO. 17663). These fungi possess a well-developed hyphal network that can penetrate deep into carbon-based micropores; they also secrete organic acids such as citric acid and oxalic acid, effectively dissolving insoluble inorganic and organic phosphorus such as Fe-P, Al-P, and Ca-P. Using wheat bran:straw = 3:1 (w / w) as the solid-state fermentation substrate, and culturing at 28°C under aeration for 7 days, a highly active formulation was obtained (the viable cell concentration of both strains was not less than 1×10⁻⁶). 7 CFU / g).

[0067] Bacterial compound inoculant (purchased from Jiangsu Lvke Biotechnology Co., Ltd.): Contains Bacillus megaterium with phosphate-solubilizing function (… Bacillus megaterium ) and gelatinous spore-forming bacteria with potassium-solubilizing function ( Paenibacillus mucilaginosus ), and Bacillus licheniformis ( B. licheniformis ), Bacillus amyloliquefaciens ( B. amyloliquefaciens ), Bacillus laterosporus ( B. laterosporus It possesses the abilities to solubilize phosphorus, promote growth, suppress disease, and colonize the rhizosphere (in the compound microbial agent, the viable concentration of each strain is not less than 1×10⁻⁶). 7 CFU / g).

[0068] The above-mentioned specific combination is a compound scheme that was screened from various Bacillus strains through preliminary pot experiments and showed the best performance in terms of phosphorus solubilization, growth promotion and compatibility with carbon-based materials.

[0069] (2) Functional design of carbon-based bio-organic fertilizer By mass ratio, 1 part of the high-performance phosphorus adsorption carbon-based material (fir sawdust carbon) verified as effective in Example 3 and 6 parts of the low-phosphorus leaching organic fertilizer carrier (sheep manure organic fertilizer) were mixed evenly to form a base carrier. Then, fulvic acid was added at 1 / 9 of the total mass of this base carrier. The calculated amount of fulvic acid added was approximately 0.78 parts. Subsequently, a compound functional microbial agent was further inoculated to construct three types of carbon-based bio-organic fertilizers with clearly defined functions. The final viable concentration of each type of microorganism in the inoculated compound functional microbial agent in the carbon-based bio-organic fertilizer was ≥1×10⁻⁶. 7 (CFU / g).

[0070] Table 6. Carbon-based bio-organic fertilizer formulation design

[0071] All products are dried at low temperature (≤40°C) and packaged in a light-proof environment to ensure stable microbial activity. Basic physicochemical properties are shown in Table 7.

[0072] Table 7 Physicochemical Properties of Carbon-Based Bio-Organic Fertilizer Types of organic fertilizers pH Electrical conductivity (mS / cm) Organic matter (g / kg) Total nitrogen (g / kg) Total phosphorus (g / kg) Total potassium (g / kg) Conventional sheep manure organic fertilizer 8.83 10.6 524 27.0 16.4 30.1 Carbon-based bio-organic fertilizer 1 7.94 20.0 281 12.9 8.41 37.6 Carbon-based bio-organic fertilizer 2 8.10 21.6 269 12.4 8.88 37.4 Carbon-based bio-organic fertilizer 3 7.80 22.5 272 12.3 8.92 38.5 3. Field trial setup (1) Experimental conditions and treatment settings The experiment was conducted continuously in the same area of ​​Nanjing, with consistent soil conditions (pH 6.95, available phosphorus 65.1 mg / kg). The tested crop was cabbage, and four treatments were set up, each with three replicates, in a randomized block design: CK: chemical fertilizer + commercially available sheep manure organic fertilizer (Shijiazhuang Wofuwo Fertilizer Co., Ltd.); BOF1: chemical fertilizer + carbon-based bio-organic fertilizer 1 (fungus-dominated); BOF2: chemical fertilizer + carbon-based bio-organic fertilizer 2 (phosphorus-potassium synergistic); BOF3: chemical fertilizer + carbon-based bio-organic fertilizer 3.

[0073] All treatments maintained equal amounts of nitrogen, phosphorus, and potassium inputs. The fertilizer was applied as a base fertilizer, a single application three days before cabbage transplanting, at a rate of 187.5 kg / ha for chemical fertilizer and 6750 kg / h for organic fertilizer. In this implementation, the chemical fertilizer was purchased from Qingshang Chemical (Foshan) Co., Ltd. (N-P2O5-K2O=23-6-13). Other conventional fertilizers may also be used in specific implementations.

[0074] (2) Observation indicators and analysis methods During the crop's growth period, the rosette spread and plant height were recorded regularly, and growth was statistically analyzed by taking photos. After harvest, commercial traits such as single head weight, head diameter, head height, compactness, and central column length and width were measured to calculate yield per unit area and marketable rate. Plant samples were collected to determine total phosphorus content, and the total phosphorus uptake of the plants was calculated. At the same time, soil samples were collected from the 0-20 cm topsoil layer after harvest to determine available phosphorus content and assess the impact of each treatment on the available phosphorus pool in the soil.

[0075] 4. Analysis of Synergistic Effect (1) Agronomic performance The observation results from the seedling stage to the rosette stage of cabbage showed that ( Figure 5 , Figure 6 The application of carbon-based bio-organic fertilizer significantly improved plant growth. The BOF1 treatment (fungus-dominated type) showed the best performance, with a rosette spread of 42.9 cm and a plant height of 19.2 cm, both significantly higher than the control, and the lowest seedling failure rate. The BOF2 and BOF3 treatments were also better than the control, but the increases were smaller. This indicates that carbon-based bio-organic fertilizer, especially BOF1, can effectively promote seedling survival and vegetative growth, improve plant uniformity, and lay the foundation for later yield formation.

[0076] Harvest data (Table 8) shows that the BOF1 treatment yield reached 78.2 t / ha, an increase of 33.6% compared to the control, with a single pellet weight of 0.96 kg, a compactness increase of 17.8%, the highest marketable rate (63.3%), and the best overall marketability.

[0077] Table 8 Effects of different treatments on the marketability of cabbage deal with Weight of a single ball (kg) Leaf head diameter (cm) Head height (cm) Firmness Central column length (cm) Center column width (cm) CK 0.78±0.11 a 13.4±0.4 a 17.9±0.4 a 0.45±0.03 a 5.11±0.24 a 2.83±0.04 a BOF1 0.96±0.08 a 13.9±0.3 a 18.1±0.5 a 0.53±0.04 a 5.24±0.24 a 2.84±0.06 a BOF2 0.89±0.08 a 14.0±0.3 a 18.1±0.5 a 0.48±0.03 a 5.14±0.41 a 2.83±0.12 a BOF3 0.78±0.02 a 13.4±0.2 a 17.2±0.6 a 0.49±0.04 a 4.91±0.22 a 2.71±0.09 a The phosphorus uptake of the BOF1 treatment increased by 17.2% compared with the control, and the available phosphorus in the soil increased to 52.0 mg / kg, which was significantly higher than other treatments. This indicates that Tv41 / TB2 successfully activated the phosphorus pool held by the carbon-based material and realized the transformation of "locked phosphorus" into "usable phosphorus".

[0078] Table 9. Effects of different treatments on cabbage yield, marketability, phosphorus uptake, and available phosphorus content in soil. deal with Production (t / ha) Product rate (%) Phosphorus uptake (kg P / ha) Available phosphorus in soil (mg / kg) CK 58.5±5.7 c 58.8±0.5 b 18.92±1.30 b 39.4±7.1 b BOF1 78.2±3.7 a 63.3±0.9 a 22.18±1.05 a 52.0±1.4 a BOF2 69.8±0.4 ab 62.7±0.6 a 21.45±1.60 ab 47.7±3.1 b BOF3 63.0±3.0 bc 61.1±0.9 ab 20.87±0.95 ab 38.1±1.4 b (2) Functional Differentiation Response Although all three types of carbon-based bio-organic fertilizers were superior to the control, their functional focuses differed significantly, directly reflecting the functional specificity of different microbial inoculant combinations. Among them, BOF1 (fungus-dominant type) showed the most significant effect in phosphorus activation and yield enhancement, as shown in Tables 8 and 9. It had the highest soil available phosphorus content and crop phosphorus uptake, indicating that Trichoderma viride Tv41 and Trichoderma longifolia TB2 played a key role in activating the phosphorus held by the carbon-based materials, successfully realizing the conversion of "locked phosphorus" into "usable phosphorus".

[0079] It should be noted that the embodiments described above are only some embodiments of the present invention, and not all embodiments. Those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and all such improvements and modifications fall within the protection scope of the present invention.

Claims

1. A carbon-based bio-organic fertilizer that combines phosphorus retention and bioactivation, characterized in that, This organic fertilizer is composed of the following components in parts by weight: 1 part of high-performance phosphorus adsorption carbon-based material, 6 parts of low-phosphorus leaching organic fertilizer carrier, 0.6~1.3 parts of fulvic acid, and compound functional microbial agents; The high-performance phosphorus adsorption carbon-based material is at least one of fir sawdust charcoal or rice husk charcoal; its specific surface area is ≥19 m². 2 / g, the proportion of micropore volume to total pore volume is ≥60%; The low-phosphorus leaching organic fertilizer carrier is sheep manure organic fertilizer, and its total phosphorus content, calculated as P2O5, is 16~18 g / kg. The compound functional microbial agent is a fungal phosphate-solubilizing agent or a bacterial compound agent; the fungal phosphate-solubilizing agent contains at least one of Trichoderma viride or Trichoderma longibranchii; the bacterial compound agent contains at least three of Bacillus megaterium, Bacillus colloidis, Bacillus licheniformis, Bacillus amyloliquefaciens, or Bacillus laterosporus. In the aforementioned carbon-based bio-organic fertilizer, the viable bacterial concentration of each microorganism is not less than 1×10⁻⁶. 7 CFU / g.

2. The carbon-based bio-organic fertilizer with both phosphorus retention and bioactivation as described in claim 1, characterized in that, The fungal phosphate-solubilizing agent was obtained by compounding *Trichoderma viride* (accession number CGMCC NO.9293) and *Trichoderma longicornis* (accession number CGMCC NO.17663).

3. The carbon-based bio-organic fertilizer with both phosphorus retention and bioactivation as described in claim 1, characterized in that, The bacterial compound agent is obtained by combining Bacillus megaterium and Bacillus lentigines; or by combining Bacillus licheniformis, Bacillus amyloliquefaciens and Bacillus laterosporus.

4. The carbon-based bio-organic fertilizer with both phosphorus retention and bioactivation as described in claim 1, characterized in that, The high-performance phosphorus adsorption carbon-based material is prepared by the following method: Pyrolysis products were obtained by pyrolyzing fir sawdust at 600±10 °C for 6 hours or rice husks at 800±10 °C for 8 hours. The pyrolysis products were ball-milled and passed through a 40-mesh sieve. After soaking in 0.1 mol / L hydrochloric acid solution for 6 hours, the supernatant was removed by centrifugation. The centrifuged pyrolysis products were then washed with deionized water until the pH reached 6.5–7.5, and subsequently vacuum-dried at 60±2 °C to constant weight. Products with a specific surface area ≥19 m² were selected. 2 Carbon materials with a micropore volume ratio of ≥60% of the total pore volume are considered high-performance phosphorus adsorption carbon-based materials.

5. The application of the carbon-based bio-organic fertilizer with both phosphorus retention and bioactivation as described in any one of claims 1-4 in the retention of soil phosphorus.

6. The application of the carbon-based bio-organic fertilizer with both phosphorus retention and bio-activation as described in any one of claims 1-4 in increasing the phosphorus content of vegetable crops and improving the phosphorus utilization efficiency of vegetable crops.

7. The application as described in claim 6, characterized in that, The vegetables mentioned include cabbage and chili peppers.

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