Phosphorus-solubilizing fungus soil remediation agent as well as preparation method and application thereof

Abstract

The invention discloses a phosphorus-solubilizing fungus soil remediation agent as well as a preparation method and application thereof, and belongs to the technical field of soil remediation. The phosphorus-solubilizing fungus soil remediation agent comprises micro-nano bone black and a penicillium deserticola solid fungicide. The preparation method comprises the following steps: pyrolyzing pig bones, and grinding to obtain the micro-nano bone black; the method comprises the following steps: coating a solid culture medium with penicillium deserticola for culturing to obtain a solid plate, washing the solid plate after spores are mature to obtain a spore liquid, mixing a solid carrier with sterile water, then adding a solid fungicide protective agent, and finally adding the spore liquid to obtain the penicillium deserticola solid fungicide. The phosphorus-solubilizing fungus soil remediation agent provided by the invention not only can effectively promote dissolution of insoluble phosphate, but also can fix heavy metal cadmium (Cd) in soil, has a very good application value for farmland Cd pollution remediation and environmental protection, is green and environment-friendly, can comprehensively improve soil fertility, and creates a good nutritional condition for crop growth.

Description

Technical Field

[0001] This invention belongs to the field of soil remediation technology, specifically relating to a phosphate-solubilizing fungal soil remediation agent, its preparation method, and its application. Background Technology

[0002] Currently, farmland soil is facing two major bottlenecks: firstly, phosphorus resources are difficult to utilize effectively, and secondly, cadmium pollution is becoming increasingly serious. The combination of these two issues poses a severe challenge to the agricultural ecology. As an essential element for crop growth, phosphorus exists in soil in a very unique form—more than 95% of phosphorus is fixed in the form of insoluble compounds such as calcium phosphate. This directly results in the actual utilization rate of artificially applied chemical phosphate fertilizers being less than 30%. At the same time, cadmium in the soil is easily absorbed by crop roots and transferred along the food chain, posing a potential threat to human health and food safety. These two problems together have become major obstacles to the green and sustainable development of agriculture.

[0003] In past remediation practices, phosphorus deficiency and cadmium pollution were typically addressed separately: chemical phosphate fertilizers were applied alone to supplement phosphorus, while cadmium passivators were used to reduce the activity of heavy metals. This approach not only increased agricultural production costs but could also lead to secondary problems such as soil compaction and deterioration of physicochemical properties due to the accumulation of chemical agents. In contrast, bioremediation technology, with its outstanding advantages of being environmentally friendly and cost-effective, is gradually becoming the preferred path to solve these problems. Research has found that some fungal strains possess a "dual-function" characteristic—they can secrete acidic metabolites to convert insoluble phosphorus into an effective form that crops can absorb; and they can also reduce the bioavailability of cadmium in the soil through physical adsorption and biological chelation via their cell walls, thus achieving a synergistic effect of phosphorus solubilization and cadmium reduction.

[0004] Soil cultivation experiments, as a crucial link between laboratory research and field application, can simulate the real microenvironment of farmland to the greatest extent, effectively solving the problem of the disconnect between shake-flask experiment results and actual application scenarios. Notably, bone char, as a natural and environmentally friendly carrier material, plays a dual role in this process: firstly, its rich content of calcium phosphate and insoluble phosphorus provides a specific substrate for functional fungi; secondly, its carbon, nitrogen, and other nutrients support the stable colonization and reproduction of fungi in the soil. Based on this, developing highly efficient bacterial agents with both phosphorus-solubilizing and cadmium-reducing functions can not only enhance the conversion efficiency of bone char-bound insoluble phosphorus in the soil and improve soil phosphorus utilization, but also solve the soil ecological problem of phosphorus-cadmium synergistic hazards, providing a solid theoretical basis and experimental support for the safe utilization and improvement of polluted farmland. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a phosphate-solubilizing fungal soil remediation agent, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a phosphate-solubilizing fungal soil remediation agent, comprising micro / nano bone char and Penicillium desertii solid inoculum.

[0007] This invention also provides a method for preparing the phosphorus-solubilizing fungal soil remediation agent according to the above-described method, comprising the following steps: pyrolyzing pig bones and grinding them to obtain the micro-nano bone char; preparing the *Penicillium deserticola* solid inoculant under sterile conditions, coating *Penicillium deserticola* onto a solid culture medium for cultivation to obtain a solid plate, rinsing the solid plate after spore maturation to obtain a spore solution, mixing the solid carrier with sterile water, then adding a solid inoculant protectant, and finally adding the spore solution to obtain the *Penicillium deserticola* solid inoculant.

[0008] As a preferred technical solution of the present invention, pig bones are pyrolyzed under an inert atmosphere at a temperature of 400–500 °C for 100–140 min, and the particles are ground to a particle size of 30 nm–100 μm.

[0009] As a preferred embodiment of the present invention, the solid culture medium is NBRIP solid culture medium, and each liter of NBRIP solid culture medium contains: 10 g glucose, 5 g MgCl2·6H2O, 0.25 g MgSO4·7H2O, 0.01 g FeSO4·7H2O, 0.2 g KCl, 0.1 g (NH4)2SO4, 5.0 g Ca3(PO4)2, 10 g sorbitol protectant, 20 g agar, and pH 5.0.

[0010] As a preferred embodiment of the present invention, the culture temperature is 30 ℃, and the time is 3-4 days; the number of spores in the spore solution is ≥1×10⁻⁶. 8 cells / mL; As a preferred embodiment of the present invention, the solid carrier includes bacterial bran, the ratio of solid carrier to sterile water is 1 g: (2.5-3.5) mL, the solid bacterial agent protectant includes sorbitol, and the amount of solid bacterial agent protectant added is 0.8-1.2 wt% of the total amount of solid carrier and sterile water; the amount of spore liquid added is 8-10 wt% of the total amount of solid carrier and sterile water.

[0011] This invention also provides an application of the phosphorus-solubilizing fungal soil remediation agent described above in reducing cadmium content and increasing phosphorus content in soil.

[0012] As a preferred technical solution of the present invention, the application amount of the phosphorus-solubilizing fungal soil remediation agent is as follows: the content of micro-nano bone char in the soil is 0.4-0.6 wt%, and the content of solid Penicillium desertii in the soil is 2-4 wt%.

[0013] Existing remediation technologies often focus on a single mechanism. The phosphate-solubilizing fungal soil remediation agent provided by this invention contains both micro / nano bone char and *Penicillium deserticola*, representing a combined remediation approach. In this combined remediation technology, the micro / nano bone char, with its abundant pore structure and large specific surface area, can rapidly adsorb cadmium ions from the soil. Meanwhile, *Penicillium deserticola* secretes organic acids and other substances, lowering the soil pH and transforming cadmium ions from a poorly soluble form into a more readily adsorbable one. The synergistic effect of these two agents significantly improves the removal and fixation efficiency of cadmium. Furthermore, the metabolites produced by *Penicillium deserticola* during phosphate solubilization can form stable complexes or precipitates with cadmium ions, further reducing the bioavailability of cadmium. This is more effective than using physical or chemical adsorption methods alone in reducing cadmium bioavailability.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) High efficiency remediation: The combined remediation technology provided by this invention can effectively promote the dissolution of insoluble phosphates, increasing the available phosphorus content in the soil by 198.00%; it can also fix the soil heavy metal Cd, reducing the available Cd in the soil by 43.82%, and has a strong Cd fixation capacity. It has great application value for the remediation of Cd pollution in farmland and environmental protection.

[0015] (2) Green and environmentally friendly: Traditional chemical remediation methods use a large amount of chemical agents, which are prone to residues and secondary pollution. However, the combined remediation technology of this invention uses *Penicillium desertii* and micro / nano bone char, both of which are of natural origin or biodegradable materials. They will not introduce harmful chemicals into the soil and are more friendly to the soil and the surrounding ecological environment. In addition, *Penicillium desertii* can improve the soil microbial community structure and promote the growth and reproduction of beneficial microorganisms, while micro / nano bone char can provide a good habitat for soil microorganisms and jointly maintain the soil ecological balance, which is difficult to achieve with many traditional remediation technologies.

[0016] (3) Soil improvement: In the phosphorus-solubilizing fungal soil remediation agent provided by the present invention, *Penicillium deserticola* can convert insoluble phosphorus in the soil into available phosphorus, increasing soil phosphorus nutrition. Micro-nano bone char can improve the soil's cation exchange capacity and enhance the soil's water and fertilizer retention capacity. The combination of the two can comprehensively improve soil fertility and create good nutritional conditions for crop growth. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1A graph showing the dynamic changes in soil pH under the influence of *Penicillium desertis* and bone char at different sampling times; Figure 2 A graph showing the dynamic changes in soil cation exchange capacity under the interaction of *Penicillium desertis* and bone char at different sampling times; Figure 3 A graph showing the dynamic changes in available phosphorus content in soil under the influence of *Penicillium desertii* and bone carbon at different sampling times. Figure 4 This figure shows the dynamic changes in available cadmium in the soil under the influence of *Penicillium desertii* and bone carbon at different sampling times. Detailed Implementation

[0019] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0020] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0021] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0022] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0023] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0024] The following examples use *Penicillium desertii* ( Penicillium desertorumThe sample was deposited on January 9, 2025, at the China General Microbiological Culture Collection Center (CGMCC), with accession number CGMCC NO: 41748; all other raw materials are commercially available conventional materials and are not subject to special restrictions. Further descriptions will not be repeated below.

[0025] Example 1 The preparation steps of the phosphate-solubilizing fungal soil remediation agent are as follows: (1) Preparation of micro / nano bone char: Pig bones were pyrolyzed at 400 °C for 120 min in a nitrogen-filled tube furnace at a heating rate of 10 °C / min to produce bone biochar (BC). Then, the BC was further ground to a particle size of 30 nm to 100 μm using a planetary ball mill to obtain micro / nano bone char (hereinafter referred to as MNBC).

[0026] (2) Preparation of solid inoculum of *Penicillium desertii*: *Penicillium desertii* preserved in glycerol at -80 ℃ was spread on NBRIP solid medium (1 L formulation: 10 g glucose, 5 g MgCl2·6H2O, 0.25 g MgSO4·7H2O, 0.01 g FeSO4·7H2O, 0.2 g KCl, 0.1 g (NH4)2SO4, 5.0 g Ca3(PO4)2, 10 g sorbitol protectant, 20 g agar, pH 5.0) and cultured at 30 ℃ for 4 days. After the spores matured, fungal spore solution was prepared. The prepared solid plates were rinsed with sterile water, and the spores were gently scraped off with a spreading stick during the rinsing process. The spore solution was rinsed with 50 mL of sterile water per plate to ensure that the number of spores in the spore solution reached 1×10⁻⁶. 8 spores / mL (spore counting was performed using a hemocytometer). Fungal residue was selected as the solid carrier. After sterilization, a material-to-liquid ratio of fungal residue:sterile water = 1 g:3 mL was used. Under aseptic conditions, 1 wt% of sorbitol (based on the total amount of fungal residue and sterile water) was added as a solid inoculum protectant. Finally, 9 wt% of spore liquid (based on the total amount of fungal residue and sterile water) was added to prepare the *Penicillium desertii* solid inoculum (hereinafter referred to as...). PD ).

[0027] Example 2 The preparation steps of the phosphate-solubilizing fungal soil remediation agent are as follows: (1) Preparation of micro / nano bone char: Pig bones were pyrolyzed at 500 °C for 100 min in a nitrogen-filled tube furnace at a heating rate of 10 °C / min to produce bone biochar (BC). Then, the BC was further ground to a particle size of 30 nm to 100 μm using a planetary ball mill to obtain micro / nano bone char (MNBC-2).

[0028] (2) Preparation of solid inoculum of *Penicillium desertii*: *Penicillium desertii* preserved in glycerol at -80 ℃ was spread on NBRIP solid medium (1 L formulation: 10 g glucose, 5 g MgCl2·6H2O, 0.25 g MgSO4·7H2O, 0.01 g FeSO4·7H2O, 0.2 g KCl, 0.1 g (NH4)2SO4, 5.0 g Ca3(PO4)2, 10 g sorbitol protectant, 20 g agar, pH 5.0) and cultured at 30 ℃ for 4 days. After the spores matured, fungal spore solution was prepared. The prepared solid plates were rinsed with sterile water, and the spores were gently scraped off with a spreading stick during the rinsing process. The spore solution was rinsed with 50 mL of sterile water per plate to ensure that the number of spores in the spore solution reached 1×10⁻⁶. 8 Specimen count / mL (spore count was performed using a hemocytometer). Fungal residue was selected as the solid carrier and sterilized. After sterilization, a material-to-liquid ratio of fungal residue:sterile water = 1 g:2.5 mL was used. Under sterile conditions, 1.2 wt% of sorbitol (based on the total amount of fungal residue and sterile water) was added as a solid inoculum protectant. Finally, 10 wt% of spore liquid (based on the total amount of fungal residue and sterile water) was added to prepare the *Penicillium desertii* solid inoculum (abbreviated as...). PD-2 ).

[0029] Example 3 The preparation steps of the phosphate-solubilizing fungal soil remediation agent are as follows: (1) Preparation of micro / nano bone char: Pig bones were pyrolyzed at 400 °C for 140 min in a nitrogen-filled tube furnace at a heating rate of 10 °C / min to produce bone biochar (BC). Then, the BC was further ground to a particle size of 30 nm to 100 μm using a planetary ball mill to obtain micro / nano bone char (MNBC-3).

[0030] (2) Preparation of solid inoculum of *Penicillium desertii*: *Penicillium desertii* preserved in glycerol at -80 ℃ was spread on NBRIP solid medium (1 L formulation: 10 g glucose, 5 g MgCl2·6H2O, 0.25 g MgSO4·7H2O, 0.01 g FeSO4·7H2O, 0.2 g KCl, 0.1 g (NH4)2SO4, 5.0 g Ca3(PO4)2, 10 g sorbitol protectant, 20 g agar, pH 5.0) and cultured at 30 ℃ for 4 days. After the spores matured, fungal spore solution was prepared. The prepared solid plates were rinsed with sterile water, and the spores were gently scraped off with a spreading stick during the rinsing process. The spore solution was rinsed with 50 mL of sterile water per plate to ensure that the number of spores in the spore solution reached 1×10⁻⁶. 81 spore / mL (spore counting was performed using a hemocytometer). Fungal residue was selected as the solid carrier and sterilized. After sterilization, a material-to-liquid ratio of fungal residue:sterile water = 1 g:3.5 mL was used. Under sterile conditions, 0.8 wt% of sorbitol (based on the total amount of fungal residue and sterile water) was added as a solid inoculum protectant. Finally, 8 wt% of spore liquid (based on the total amount of fungal residue and sterile water) was added to prepare the *Penicillium desertii* solid inoculum (abbreviated as...). PD-3 ).

[0031] Effect verification 1. Soil collection The soil used in the experiment was collected from the top 0-20 cm layer of paddy fields in Huadu District, Guangzhou (23.415°N, 113.047°E). Before use, the soil was air-dried, ground, and passed through a 2 mm mesh sieve.

[0032] 2. Soil cultivation experiment Based on the presence or absence of phosphate-solubilizing fungi combined with micro / nano bone char, three treatment groups were set up: a 15 mg / Kg Cd control group, a 15 mg / Kg Cd + 0.5% 450 ℃ MNBC (i.e., the MNBC prepared in step (1) of Example 1), and a 15 mg / Kg Cd + 0.5% 450 ℃ MNBC + 3% MNBC. PD (i.e., the product prepared in step (2) of Example 1) PD Each treatment was performed in quadruplicate, with a total weight of 300 g, and cultured in brown wide-mouth bottles. The bottles were placed in a constant temperature environment at 25 ℃, and water was added daily to maintain a constant moisture content. Soil samples were collected on days 0, 10, and 30, cooled, ground, and sieved through a 100-mesh sieve for subsequent testing. Cd treatment was performed by artificially adding an analytical grade CdCl2·2.5H2O aqueous solution to the soil.

[0033] 3. Measurement Indicators Soil pH determination: According to the "Determination of Soil pH Value by Potential Method" (HJ 962-2018), in short: vortex ratio 1:2.5 ( g / mL The soil water ratio of the sample was 2 min, and after standing for 30 min, the electrode was inserted to read the pH value of the soil in all treatments.

[0034] Determination of soil cation exchange capacity: soil to water 1:2 ( g / mL Soil cation exchange capacity (CEC) was measured using a cobalt trichloride solution spectrophotometric method.

[0035] Determination of available phosphorus content in soil: Following the standard "Determination of Available Phosphorus in Soil - Sodium Bicarbonate Extraction-Molybdenum Antimony Spectrophotometric Method" (HJ 704-2014), the soil was mixed with 0.5 mol / L sodium bicarbonate extract at a ratio of 1:20. g / mLThe sample was shaken for 30 min at a constant temperature reciprocating shaker at 25 ℃ and 200 r / min. The supernatant was then filtered and tested.

[0036] Determination of available Cd in soil: According to the "Determination of 8 available elements in soil by diethylenetriaminepentaacetic acid extraction-inductively coupled plasma atomic emission spectrometry" (HJ 804-2016), 5.00 g of freeze-dried and sieved soil sample was weighed and placed in a 50 mL centrifuge tube. 20 mL of diethylenetriaminepentaacetic acid (DTPA)-calcium chloride (CaCl2)-triethanolamine (TEA) extraction reagent (pH 7.3) was added. The sample was extracted at 160 r / min for 2 h at room temperature. After centrifugation, the supernatant was filtered through a 0.22 μm filter membrane and then analyzed.

[0037] 4. Statistical Analysis Statistical analysis was performed using IBM SPSS 26.0 software. One-way ANOVA and Duncan's test were used to analyze the data. All samples were replicated four times. Data are expressed as mean ± standard error. p < 0.05 is considered significant. GraphPad Prism version 8 software was used for graphing.

[0038] Test Results Figures 1-4 In the middle, Cd, Cd MNBC and Cd MNBC PD These represent the control group (15 mg / Kg Cd), the MNBC at 450 ℃ (15 mg / Kg Cd +0.5%), and the MNBC at 450 ℃ (15 mg / Kg Cd +0.5%) with a concentration of 3%, respectively. PD Groups, which will not be described further below.

[0039] 1. Dynamic changes in soil pH under the influence of *Penicillium desertii* and bone carbon at different sampling times, as shown in the figure. Figure 1 As shown, Figure 2 This illustrates the dynamic changes in soil cation exchange capacity under the interaction of *Penicillium desertii* and bone carbon at different sampling times. Figure 1 and Figure 2 It was found that co-culturing fungi and MNBC significantly increased soil pH and CEC, enhancing soil nutrient retention capacity. On day 10, compared to the cadmium control treatment, PD In synergy with fungi and MNBC, soil pH and CEC increased by 10.99% and 117.62%, respectively. Similarly, on day 30, compared with the cadmium control treatment, PD In synergy with fungi and MNBC, soil pH and CEC increased by 8.77% and 97.21%, respectively.

[0040] 2. Figure 3The graph shows the dynamic changes in available phosphorus content in soil under the influence of *Penicillium desertii* and bone biochar at different sampling times. As can be seen from the graph, the application of bone biochar significantly increased the available phosphorus content in the soil. Compared with the Cd control group, the combined effect of bone biochar and bone biochar significantly improved the soil's available phosphorus content. PD On day 10 of fungal treatment, the available phosphorus content in the soil increased by 134.15%, compared to 66.77% under MNBC treatment alone. This indicates that under cadmium pollution, the combined application of bone char and... DP Fungi can further increase the available phosphorus content in the soil. After 30 days of combined application of bone char and... PD The available phosphorus content in soil treated with fungi increased by 198.00%.

[0041] 3. Figure 4 The graph shows the dynamic changes in available cadmium in the soil under the influence of *Penicillium desertii* and bone biochar at different sampling times. As can be seen from the graph, the application of bone biochar significantly reduced the available cadmium content in the soil. Compared with the Cd control group, the MNBC treatment alone and the combined bone biochar treatment on day 10... PD The available cadmium content in the soil decreased by 15.06% and 31.22% in the fungal treatment group, respectively. After 30 days of combined application of bone char and... PD In soil treated with fungi, the available Cd decreased by 43.82%.

[0042] The effects of the phosphate-solubilizing fungal soil remediation agents prepared in Examples 2 and 3 were verified using the same verification method described above, and the results were basically equivalent to those of the phosphate-solubilizing fungal soil remediation agent in Example 1.

[0043] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A phosphate-solubilizing fungal soil remediation agent, characterized in that, Including micro / nano bone char and solid Penicillium desertii inoculum.

2. A method for preparing a phosphate-solubilizing fungal soil remediation agent according to claim 1, characterized in that, Includes the following steps: Pig bones were pyrolyzed and ground to obtain the micro-nano bone char; *Penicillium desertii* was coated onto a solid culture medium to obtain a solid plate; after the spores matured, the solid plate was washed to obtain a spore solution; the solid carrier was mixed with sterile water, then a solid inoculum protectant was added, and finally the spore solution was added to obtain the *Penicillium desertii* solid inoculum.

3. The preparation method of the phosphate-solubilizing fungal soil remediation agent according to claim 2, characterized in that, The pig bones were pyrolyzed under an inert atmosphere at a temperature of 400–500 °C for 100–140 min, and then ground to a particle size of 30 nm–100 μm.

4. The preparation method of the phosphate-solubilizing fungal soil remediation agent according to claim 2, characterized in that, The solid culture medium is NBRIP solid culture medium, and each liter of NBRIP solid culture medium contains: 10 g glucose, 5 g MgCl2·6H2O, 0.25 g MgSO4·7H2O, 0.01 g FeSO4·7H2O, 0.2 g KCl, 0.1 g (NH4)2SO4, 5.0 g Ca3(PO4)2, 10 g sorbitol protectant, 20 g agar, pH 5.

0.

5. The method for preparing the phosphate-solubilizing fungal soil remediation agent according to claim 2, characterized in that, The culture temperature was 30 ℃, and the time was 3–4 days; the number of spores in the spore solution was ≥1×10⁻⁶. 8 per mL.

6. The method for preparing the phosphate-solubilizing fungal soil remediation agent according to claim 2, characterized in that, The solid carrier includes bacterial bran, and the ratio of solid carrier to sterile water is 1 g: (2.5-3.5) mL. The solid bacterial agent protectant includes sorbitol, and the amount of solid bacterial agent protectant added is 0.8-1.2 wt% of the total amount of solid carrier and sterile water. The amount of spore liquid added is 8-10 wt% of the total amount of solid carrier and sterile water.

7. The application of the phosphorus-solubilizing fungal soil remediation agent according to claim 1 in reducing cadmium content and increasing phosphorus content in soil.

8. The application according to claim 7, characterized in that, The application rates of the phosphate-solubilizing fungal soil remediation agent are as follows: the content of micro-nano bone char in the soil is 0.4-0.6 wt%, and the content of solid Penicillium desertii in the soil is 2-4 wt%.

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