Customizing mode of nutrient mud capable of retaining absorbable beneficial components and auxiliary materials in soil

Abstract

The invention discloses a customizing mode of nutrient mud capable of retaining absorbable beneficial components and auxiliary materials in soil. The method comprises the following steps: carrying out safety screening on the soil; directionally extracting edible nutritional ingredients by adopting a food-grade extracting agent, and purifying the edible nutritional ingredients; the extraction residues are used as a main substrate, and are compounded with organic matters, structural materials, functional microorganisms and the like to form a targeted modifier; the high-quality improved soil is prepared through curing. According to the method, the dual goals of safely obtaining high-value nutritional products from the soil and synchronously achieving self-regeneration of the soil are achieved, secondary pollution and waste generation are avoided, and remarkable economic and environmental benefits are achieved.

Description

Technical Field

[0001] This invention relates to the field of soil resource high-value technology, and more specifically to a method for customizing nutrient mud that retains absorbable beneficial components and additives in the soil. Background Technology

[0002] Soils, especially certain types of high-quality soils (such as deep forest black soil and peat soil) or soils that have undergone stabilization and remediation, contain potential nutrients such as minerals and organic acids.

[0003] Currently, the utilization methods of this type of soil (such as agricultural fertilizers and substrates) have failed to achieve the high-value conversion of its nutrients. At the same time, if its components are extracted, the residue is usually discarded due to structural damage and fertility loss, resulting in resource waste and secondary environmental problems.

[0004] Existing technologies lack a closed-loop process that can simultaneously achieve "safe nutrient extraction" and "targeted improvement of residues". Summary of the Invention

[0005] This invention aims to provide a customized method for producing nutrient-rich mud that retains absorbable beneficial components and additives from the soil, thereby addressing the problems of broken resource utilization chains, insufficient extraction safety, and lack of targeted improvement in existing technologies. This method achieves high-value extraction of soil nutrients and zero-waste, targeted improvement of residues while ensuring product safety.

[0006] To achieve the above objectives, embodiments of the present invention provide a method for customizing nutrient mud that retains absorbable beneficial components and additives in the soil, comprising the following steps:

[0007] S1. Soil pretreatment and safety assessment: The target soil is pretreated and pollutants are tested according to GB15618-2018 standard. It can only be used after it meets the standard.

[0008] S2. Targeted extraction of edible nutrients: Mix qualified soil with safe extractant at a solid-liquid ratio of 1:3-1:10 and extract at 20-60℃ for 1-8 hours;

[0009] S3. Solid-liquid separation and nutrient solution purification: The mixture from step S2 is separated into solid and liquid components to obtain a crude extract and a primary residue; the crude extract is purified by adsorption with macroporous resin and ultrafiltration membrane, and then concentrated or dried to obtain an edible nutritional product.

[0010] S4. Preparation of Residue Targeted Modifier: The primary residue is dried and pulverized into a residue matrix, which is then mixed with organic matter supplement, structural modifier, functional microbial agent and pH adjuster to obtain a modifier mixture;

[0011] S5. Soil improvement and maturation: Adjust the moisture content of the amendment mixture from step S4 to 40-55%, pile it up and mature for 15-45 days to obtain improved soil.

[0012] Preferably, step S2 employs ultrasonic-assisted extraction with an ultrasonic power of 200-300W, an extraction temperature of 40-50℃, and an extraction time of 4-8 hours.

[0013] Preferably, in step S4, the components are as follows by mass percentage: 60-75% residual matrix, 10-20% organic matter supplement, 5-10% structure modifier, 3-8% functional microbial agent, and 1-5% pH adjuster.

[0014] Preferably, the organic matter supplement is selected from well-rotted straw fertilizer, kitchen waste organic fertilizer, or humic acid; the structure modifier is selected from perlite, vermiculite, or coconut coir; and the functional microbial agent includes nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and arbuscular mycorrhizal fungi.

[0015] Preferably, before the composting and maturation in step S5, the mixture of improvers from step S4 is further pre-fermented at 25-30°C for 5-7 days.

[0016] Preferably, the molecular weight cutoff of the ultrafiltration membrane in step S3 is 500-1000 Da.

[0017] It also provides an edible nutrient concentrate or dry powder.

[0018] It also provides a method for improving soil.

[0019] An application for soil improvement, wherein the soil is applied to the soil to be improved at a mass ratio of 5-15% and tilled to a depth of 15-25 cm.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] This invention, through pre-assessment and food-grade extraction and purification processes, fundamentally ensures the safety of the final nutritional product for consumption, addressing the core risks of direct utilization of soil-derived nutrients. Secondly, the method significantly improves the extraction efficiency and product purity of target nutrients through efficient technologies such as ultrasound-assisted extraction and membrane separation, achieving high-value utilization of soil resources. More importantly, this invention innovatively constructs a complete resource recycling chain, transforming extraction residues, traditionally considered waste, into a core matrix. Through precisely formulated amendments, targeted remediation is achieved, resulting in a dual improvement in soil physicochemical properties and ecological functions. The final improved soil exhibits excellent performance in terms of structure, fertility, and microbial activity. The entire process achieves full material recycling and zero waste, completely overcoming the industry challenge of secondary pollution during resource utilization.

[0022] Finally, the products of this invention have a wide range of applications. Edible nutritional products can be used as food ingredients or supplements, while soil improvement can be directly used for ecological restoration, landscaping, or sustainable agriculture, creating significant comprehensive economic and environmental benefits. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below with reference to specific embodiments. The embodiments described in this invention are only a part of the implementation methods of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] The present invention discloses a method for customizing nutrient mud that retains absorbable beneficial components and additives in the soil, comprising the following steps:

[0025] S1. Soil pretreatment and safety assessment: The target soil is pretreated and pollutants are tested according to GB15618-2018 standard. It can only be used after it meets the standard.

[0026] S2. Targeted extraction of edible nutrients: Mix qualified soil with safe extractant at a solid-liquid ratio of 1:3-1:10 and extract at 20-60℃ for 1-8 hours;

[0027] S3. Solid-liquid separation and nutrient solution purification: The mixture from step S2 is separated into solid and liquid components to obtain a crude extract and a primary residue; the crude extract is purified by adsorption with macroporous resin and ultrafiltration membrane, and then concentrated or dried to obtain an edible nutritional product.

[0028] S4. Preparation of Residue Targeted Modifier: The primary residue is dried and pulverized into a residue matrix, which is then mixed with organic matter supplement, structural modifier, functional microbial agent and pH adjuster to obtain a modifier mixture;

[0029] S5. Soil improvement and maturation: Adjust the moisture content of the amendment mixture from step S4 to 40-55%, pile it up and mature for 15-45 days to obtain improved soil.

[0030] Further, the safe extractant in step S2 is a food-grade citric acid solution with a mass fraction of 0.3-1.0%, a food-grade ethanol aqueous solution with a volume fraction of 30-50% and the pH adjusted to 4.5-6.0 by adding food-grade citric acid, or a compound enzyme preparation solution.

[0031] Furthermore, step S2 employs ultrasonic-assisted extraction with an ultrasonic power of 200-300W, an extraction temperature of 40-50℃, and an extraction time of 4-8 hours.

[0032] Further, in step S4, the components by mass percentage are: 60-75% residual matrix, 10-20% organic matter supplement, 5-10% structure modifier, 3-8% functional microbial agent, and 1-5% pH adjuster.

[0033] Furthermore, the organic matter supplement is selected from well-rotted straw fertilizer, kitchen waste organic fertilizer, or humic acid; the structure modifier is selected from perlite, vermiculite, or coconut coir; and the functional microbial agent includes nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and arbuscular mycorrhizal fungi.

[0034] Furthermore, before the composting and maturation in step S5, the mixture of improvers from step S4 is pre-fermented at 25-30°C for 5-7 days.

[0035] Furthermore, the ultrafiltration membrane in step S3 has a molecular weight cutoff of 500-1000 Da.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0037] Example 1: Extracting minerals and preparing cultivation substrate from deep forest black soil

[0038] This embodiment aims to demonstrate the process of extracting mineral nutrients from organic-rich, safe soil and improving the residue into a high-quality cultivation substrate.

[0039] (1) Soil pretreatment and safety assessment:

[0040] 10 kg of black soil from deep forests in Northeast China was collected, air-dried, mechanically crushed, and passed through a 30-mesh standard sieve to remove plant roots and gravel. The sieved soil was sampled and tested according to the "Soil Environmental Quality Standard for Agricultural Land Soil Pollution Risk Control" (GB15618-2018). Key indicator test results were as follows: Cadmium (Cd) content 0.05 mg / kg, Lead (Pb) content 15 mg / kg, Arsenic (As) content 5.1 mg / kg, and Mercury (Hg) content 0.02 mg / kg, all significantly lower than the risk screening values ​​specified in the standard (e.g., 0.6 mg / kg for Cd and 170 mg / kg for Pb when pH>7.5). The soil organic matter content was 32.5 g / kg, and the pH value was 6.8. Based on the overall assessment, this soil was determined to be "compliant soil" and suitable for subsequent extraction.

[0041] (2) Targeted extraction of edible nutrients:

[0042] Weigh 1.0 kg (accurate to 0.01 kg) of the above-mentioned qualified soil and place it in a 5 L glass extraction vessel. Add 5.0 L of a 0.8% (w / w) food-grade citric acid solution (solid-liquid ratio 1:5, g / mL). Place the extraction vessel in a constant temperature ultrasonic extraction device, set the extraction temperature to 50℃, the ultrasonic power to 250 W, and the extraction time to 6 hours. During the extraction process, manually stir for 2 minutes every 2 hours to ensure complete extraction.

[0043] (3) Solid-liquid separation and nutrient solution purification:

[0044] After extraction, the solution was first coarsely filtered using a plate and frame filter press (100-mesh filter cloth) to remove most of the solids. The filtrate was then centrifuged at 4°C and 5000 rpm for 15 minutes to obtain a supernatant (crude extract) and wet residue. The crude extract was decolorized by passing it through a glass column packed with 300 mL LD101 macroporous adsorption resin at a flow rate of 2 BV / h. The clear liquid after decolorization was then filtered using a ceramic ultrafiltration membrane module with a molecular weight cutoff of 800 Da at an operating pressure of 0.2 MPa to remove large molecular weight proteins, pigments, and potential colloidal impurities. The permeate was then rotary evaporated at 55°C and a vacuum of 0.07 MPa to concentrate it to 1 / 5 of its original volume (approximately 200 mL), yielding a brownish-yellow, clear mineral nutrient concentrate (product A1). Product A1 was sampled and tested using inductively coupled plasma mass spectrometry (ICP-MS). The main mineral contents were: calcium (Ca) 185 mg / 100 mL, iron (Fe) 102 mg / 100 mL, zinc (Zn) 38 mg / 100 mL, and magnesium (Mg) 45 mg / 100 mL, all of which existed in the form of easily absorbed organic acid complexes.

[0045] (4) Preparation of residue-targeted modifier:

[0046] The wet residue obtained from centrifugation in step (3) was dried in an oven at 75°C until constant weight, then pulverized using a small pulverizer and passed through a 60-mesh sieve to obtain a dry residue matrix. The following components were accurately weighed and mixed according to the mass percentage: 70.0% residue matrix, 15.0% well-rotted sheep manure (organic matter content ≥45%), 6.0% perlite (particle size 2-4mm), 3.0% vermiculite (particle size 1-3mm), and commercial compound microbial agent (containing ≥2×10⁻⁶ effective live bacteria). 9 5.0% (CFU / g of nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and potassium-solubilizing bacteria) and 1.0% (food-grade calcium carbonate, used to adjust pH). Mix thoroughly in a mixer for 10 minutes to obtain a homogeneous mixture of modifiers.

[0047] (5) Soil improvement, maturation, and functional verification:

[0048] Spray deionized water into the above-mentioned soil conditioner mixture while stirring until the moisture content reaches a uniform 50% (it should clump together when squeezed in hand but crumble easily when dropped). Pile the material into trapezoidal windrows 1.2m wide at the base and 1.0m high, and place them in an indoor fermentation workshop (maintaining an ambient temperature of 25-30℃). The maturation period is 35 days, during which the pile should be thoroughly turned every 5 days using a turning machine to ensure aerobic fermentation and even heat dissipation. After maturation, the material should be dark brown, loose in texture, and odorless, thus obtaining the improved soil (product B1).

[0049] Product B1 was tested and found to have the following characteristics: Bulk density of 0.95 g / cm³, a 24% decrease compared to virgin forest black soil (1.25 g / cm³); total porosity of 58.2%, an increase of approximately 35%; organic matter content of 38.7 g / kg, an increase of 19%; pH value of 7.1; and effective viable bacteria count (bacteria + fungi) of 3.5 × 10⁻⁶. 8 CFU / g. When this improved soil was used as a cultivation substrate in potted lettuce experiments, compared with commercially available ordinary nutrient soil, lettuce biomass increased by 22% and leaf chlorophyll content significantly increased.

[0050] Example 2: Extracting organic nutrients and preparing ecological restoration soil from stabilized and remediated mining area soil.

[0051] This embodiment aims to demonstrate the extraction of small-molecule organic nutrients from remediated soil that is poor in organic matter but meets the standards for pollutants, and the modification of the residue into soil materials suitable for ecological restoration.

[0052] (1) Soil pretreatment and safety assessment:

[0053] Ten kilograms of stabilized soil from a lead-zinc tailings dam, after remediation using a plant-microorganism combined process, were collected. The soil was air-dried, crushed, and sieved through a 20-mesh sieve, following the method described in Example 1. Testing showed a Cd content of 0.12 mg / kg and a Pb content of 42 mg / kg, meeting the GB15618-2018 standards for the control of remediated agricultural land. The soil organic matter content was extremely low, only 5.8 g / kg, the pH was 5.2, and the soil surface was compacted.

[0054] (2) Targeted extraction of edible nutrients:

[0055] Weigh 1.0 kg of qualified soil and add 7.0 L of compound extractant. This extractant is prepared by adding 45% (w / v) food-grade ethanol aqueous solution and 0.4% (w / v) food-grade citric acid. Adjust the final pH to 5.5 using NaOH solution. Extract for 8 hours in a 55℃ constant temperature water bath with mechanical stirring at 200 rpm.

[0056] (3) Solid-liquid separation and nutrient solution purification:

[0057] The extracted mixture was separated by centrifugation (under the same conditions as in Example 1). The supernatant was first decolorized using an AB-8 macroporous resin column, and then purified by ultrafiltration membrane with a molecular weight cutoff of 1000 Da. The purified solution was transferred to a spray dryer with an inlet air temperature of 135°C, an outlet air temperature of 70°C, and an atomizer frequency of 50 Hz for drying, yielding a light yellow nutrient powder (product A2). High-performance liquid chromatography (HPLC) and an amino acid analyzer showed that product A2 contained 15.2% total peptides, 8.5% total free amino acids, and various small-molecule organic acids.

[0058] (4) Preparation and pre-fermentation of residue-targeted modifier:

[0059] The residue was treated in the same manner as in Example 1, yielding a residue matrix. It was then compounded according to the following mass ratio: 65.0% residue matrix, 15.0% decomposed corn stalk powder (length <1cm), 5.0% humic acid (fulvic acid content ≥50%), 10.0% desalinated coconut coir, 4.0% commercially available arbuscular mycorrhizal fungi (AMF) inoculum (spore count ≥80 / g), and 1.0% food-grade citric acid (used to further activate the matrix and maintain a slightly acidic environment). After mixing all components thoroughly, the moisture content was adjusted to 45%, and the mixture was transferred to a fermentation chamber with ventilation holes for pre-fermentation at a constant temperature of 28℃. The pre-fermentation period was 6 days, with the mixture being turned over once daily for aeration. After pre-fermentation, the material became noticeably looser, and white mycelia appeared.

[0060] (5) Verification of soil improvement and application effects:

[0061] The pre-fermented materials were re-piled and subjected to a 45-day temperature-controlled maturation process (method as in Example 1). The resulting improved soil (Product B2) was obtained. Testing showed that Product B2 had an increased organic matter content of 18.5 g / kg, more than three times that of the raw soil; the pH value remained stable at 6.0; and the content of stable aggregates (>0.25 mm) reached 45%. Product B2 was applied in a 10 cm thickness to the surface of a simulated exposed mine slope (infertile soil). After three months, the vegetation coverage (using stress-resistant grass species) reached 85%, while the control group using only the original remediation soil had a coverage of only 40%. Product B2 significantly promoted soil crust formation and plant establishment.

[0062] Example 3: Enzymatic extraction and deep improvement of organic-rich soil as raw material

[0063] This embodiment aims to demonstrate the use of a gentler enzymatic extraction process and a deep modification of the residue, including pre-fermentation, to obtain a higher quality product.

[0064] (1) Soil pretreatment and safety assessment:

[0065] A mixture of organic-rich peat soil and farmland topsoil (volume ratio 1:1) was selected. Post-treatment testing showed that all pollutants met standards, with the mixed soil containing 40.2 g / kg of organic matter and having a pH of 6.0.

[0066] (2) Targeted extraction of edible nutrients (enzymatic method):

[0067] Weigh 1.0 kg of soil and add 4.0 L of compound enzymatic extraction solution (solid-liquid ratio 1:4). This extraction solution is a citrate-sodium citrate buffer system with a pH of 5.0, containing 2.0% cellulase (enzyme activity 8000 U / g) and 1.5% neutral protease (enzyme activity 10000 U / g). Extraction is carried out in a constant temperature shaker at 45℃ with shaking at 120 r / min for 4 hours, aiming to gently release the cellular contents and small molecule nutrients encapsulated by soil organic matter.

[0068] (3) Solid-liquid separation and nutrient solution purification:

[0069] The enzymatic hydrolysate was immediately sterilized in an 85°C water bath for 10 minutes to terminate the enzymatic reaction, and then centrifuged to collect the supernatant. The purification process followed Example 1, using resin decolorization and filtration through a 500Da ultrafiltration membrane. Finally, a grayish-white nutrient powder (product A3) was obtained by freeze-drying. Tests showed that product A3 is rich in nucleotides, B vitamins, and small molecule peptides, with a total water-soluble vitamin content of 2.3 mg / g.

[0070] (4) Preparation of residue-targeted modifier and enhanced pre-fermentation:

[0071] After drying and pulverizing, the residue is mixed according to the following innovative formula: 60.0% residue matrix, 25.0% refined organic fertilizer from kitchen waste (meeting NY / T525 standard), 8.0% biochar (particle size <2mm), and 8.0% highly active compound microbial agent (containing photosynthetic bacteria, lactic acid bacteria, yeast, etc., with a total bacterial count ≥5×10⁻⁶). 9 The mixture contains 6.0% CFU / g and 1.0% trace element chelating agent. After mixing, the moisture content is adjusted to 50%, and the mixture is placed in an intelligent temperature-controlled fermentation tank. It undergoes 7 days of enhanced aerobic fermentation at 30°C, with sterile air continuously introduced into the tank and automatic stirring every day.

[0072] (5) Soil improvement, maturation, and quality evaluation:

[0073] After the pre-fermented material is removed from the tank, it undergoes a second static composting and maturation process for 30 days to obtain advanced improved soil (product B3). Product B3 exhibits superior performance across various indicators: organic matter content reaches 50.1 g / kg; cation exchange capacity (CEC) reaches 25.8 cmol(+) / kg, demonstrating extremely strong fertilizer retention capacity; it is rich in probiotics, with a functional microbial diversity index 80% higher than that of the raw soil. When used as a core substrate component (accounting for 70%) for the seedling cultivation of high-value-added Chinese medicinal herbs, the seedling survival rate increases by 30%, and root development is significantly superior to that of commercial substrates.

[0074] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for customizing nutrient-rich mud that retains absorbable beneficial components and additives in the soil, characterized in that, Includes the following steps: S1. Soil pretreatment and safety assessment: The target soil is pretreated and pollutants are tested according to GB15618-2018 standard. It can only be used after it meets the standard. S2. Targeted extraction of edible nutrients: Mix qualified soil with safe extractant at a solid-liquid ratio of 1:3-1:10 and extract at 20-60℃ for 1-8 hours; S3. Solid-liquid separation and nutrient solution purification: The mixture from step S2 is separated into solid and liquid components to obtain a crude extract and a primary residue; the crude extract is purified by adsorption with macroporous resin and ultrafiltration membrane, and then concentrated or dried to obtain an edible nutritional product. S4. Preparation of Residue Targeted Modifier: The primary residue is dried and pulverized into a residue matrix, which is then mixed with organic matter supplement, structural modifier, functional microbial agent and pH adjuster to obtain a modifier mixture; S5. Soil improvement and maturation: Adjust the moisture content of the amendment mixture from step S4 to 40-55%, pile it up and mature for 15-45 days to obtain improved soil.

2. The method for customizing nutrient mud that retains absorbable beneficial components and additives in the soil according to claim 1, characterized in that, The safe extractant in step S2 is a food-grade citric acid solution with a mass fraction of 0.3-1.0%, a food-grade ethanol aqueous solution with a volume fraction of 30-50% and the pH adjusted to 4.5-6.0 by adding food-grade citric acid, or a compound enzyme preparation solution.

3. The method for customizing nutrient mud that retains absorbable beneficial components and additives in the soil according to claim 1, characterized in that, Step S2 employs ultrasonic-assisted extraction with an ultrasonic power of 200-300W, an extraction temperature of 40-50℃, and an extraction time of 4-8 hours.

4. The method for customizing nutrient mud that retains absorbable beneficial components and additives in the soil according to claim 1, characterized in that, In step S4, the components by mass percentage are: 60-75% residual matrix, 10-20% organic matter supplement, 5-10% structure modifier, 3-8% functional microbial agent, and 1-5% pH adjuster.

5. The method for customizing nutrient mud that retains absorbable beneficial components and additives in the soil according to claim 1, characterized in that, The organic matter supplement is selected from well-rotted straw fertilizer, kitchen waste organic fertilizer, or humic acid; the structure modifier is selected from perlite, vermiculite, or coconut coir; the functional microbial agent includes nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and arbuscular mycorrhizal fungi.

6. The method for customizing nutrient mud that retains absorbable beneficial components and additives in the soil according to claim 1, characterized in that, Before the composting and maturation in step S5, the mixture of improvers from step S4 is pre-fermented at 25-30°C for 5-7 days.

7. The method for customizing nutrient mud that retains absorbable beneficial components and additives in the soil according to claim 1, characterized in that, The ultrafiltration membrane in step S3 has a molecular weight cutoff of 500-1000 Da.

8. An edible nutrient concentrate or powder prepared by the method according to any one of claims 1-7.

9. An improved soil prepared by the method according to any one of claims 1-7.

10. An application of soil improvement as described in claim 9, characterized in that, Apply it to the soil to be improved at a ratio of 5-15% by weight, and till it to a depth of 15-25cm.