A volcanic rock-based vegetable cultivation substrate and a method of preparing the same

Abstract

The application discloses a vegetable cultivation substrate based on volcanic rock and a preparation method thereof. The cultivation substrate comprises a carrier and a functional improvement component, wherein the carrier accounts for 60-80% and the functional improvement component accounts for 20-40% in terms of mass percentage; the carrier is composed of peat moss and humus soil; and the functional improvement component is composed of activated modified volcanic rock, lignin sulfonate modified chitosan and calcium-magnesium amino acid complex. The cultivation substrate can significantly reduce the chromium content of edible parts of vegetables under heavy metal chromium pollution conditions, stably provide essential nutrient elements such as calcium and magnesium, effectively improve the yield and quality of vegetables, and is particularly suitable for safe cultivation of vegetables such as facility tomatoes and cucumbers.

Description

Technical Field

[0001] This invention belongs to the field of agricultural cultivation substrate technology, specifically relating to a vegetable cultivation substrate based on volcanic rock and its preparation method. Background Technology

[0002] In soilless cultivation and greenhouse vegetable production, traditional substrates such as peat, coconut coir, and rock wool perform reasonably well in terms of water and fertilizer retention, air and water permeability, but they generally have two prominent problems: First, they have almost no ability to actively adsorb and reduce heavy metals, making it difficult to meet the safe production requirements under polluted or contaminated irrigation water conditions; second, the substrates themselves are highly inert and have insufficient mineral nutrient content, requiring frequent application of chemical fertilizers, and long-term use can easily lead to root zone compaction, salinization, and groundwater pollution.

[0003] Organic modifiers such as chitosan and biochar are widely used in heavy metal control research. Chitosan has amino and hydroxyl functional groups, which can chelate heavy metal ions. However, its structure is dense, it is easily degraded, and its water retention is poor. Adding large amounts of it alone to the matrix can easily cause root suffocation and root rot. Although biochar is porous, its ash content fluctuates greatly with the raw materials. Its reductive adsorption efficiency for chromium is limited, and its adsorption sites are easily deactivated after long-term interaction with acidic media.

[0004] Volcanic rock is a porous basaltic or trachyte rock formed after volcanic eruptions and cooling. It has a natural honeycomb-like porous structure with a porosity of over 40%, a large specific surface area, high mechanical strength, and stable chemical properties. Volcanic rock is rich in Si, Al, Fe, Mg, Ca, K, and various essential micronutrients for plants (such as Zn, Mn, B, and Mo). It also possesses good water retention, air permeability, and acid and alkali resistance, and has seen preliminary applications in ecological filtration and horticultural substrates. However, currently, volcanic rock in cultivation substrates is mostly used as a simple physical filler or drainage layer, without being effectively activated and utilized. Its slow-release function of mineral elements, heavy metal adsorption potential, and synergistic effect with organic amendments have not been fully explored. Furthermore, the inner walls of the pores in unactivated volcanic rock are often sealed by volcanic glass, resulting in few active adsorption sites and insufficient reduction capacity for strongly oxidized heavy metals such as Cr(VI). Summary of the Invention

[0005] The purpose of this invention is to provide a vegetable cultivation substrate that uses volcanic rock as the skeleton material and integrates three functions—"heavy metal adsorption and reduction," "slow release of mineral nutrients," and "breathability and water retention"—through directional activation and functional modification, thereby achieving safe and high-quality vegetable production.

[0006] To achieve the above-mentioned objectives, in a first aspect, the present invention provides a vegetable cultivation substrate based on volcanic rock, comprising a carrier and a functional improvement component; by mass percentage, the carrier accounts for 60% to 80%, and the functional improvement component accounts for 20% to 40%.

[0007] The carrier comprises peat moss and humus; by mass percentage, peat moss accounts for 20% to 40% of the carrier, and humus accounts for 60% to 80% of the carrier.

[0008] The functional improvement components include activated modified volcanic rock, lignin sulfonate modified chitosan, and amino acid calcium magnesium complex; by mass percentage, activated modified volcanic rock accounts for 65% to 85% of the functional improvement components, lignin sulfonate modified chitosan accounts for 8% to 20%, and amino acid calcium magnesium complex accounts for 5% to 15%.

[0009] Furthermore, after multiple sets of experiments, the optimal ratio of the functional improvement components is: 75% activated modified volcanic rock, 15% lignin sulfonate modified chitosan, and 10% amino acid calcium magnesium complex; the optimal mass ratio of the carrier to the functional improvement components is 70:30; and the optimal mass ratio of peat moss to humus in the carrier is 30:70.

[0010] Furthermore, the activated modified volcanic rock, lignin sulfonate modified chitosan, and amino acid calcium-magnesium complex together constitute a ternary synergistic composite gel system: Fe²⁺ enriched in the inner wall of the activated modified volcanic rock pores + The active site can reduce Cr(VI) to Cr(III), and then the amino / hydroxyl groups of chitosan and the hydroxyl and carboxyl groups on the surface of volcanic rock can chelate and fix Cr(III) through hydrogen bonding and coordination. The amino acid calcium magnesium complex in this system serves as both a calcium and magnesium source that can be directly absorbed by plants and an ion shuttle carrier, which can directionally transport nutrients such as calcium, magnesium, and iron adsorbed on volcanic rock and chitosan to the plant roots.

[0011] Furthermore, the preparation method of the activated modified volcanic rock includes the following steps: S11. Raw material pretreatment: Take volcanic rock particles with a particle size of 2-5mm, place them in deionized water and ultrasonically clean for 20-30 minutes to remove surface dust and free powder, and dry them in an oven at 105℃ until constant weight. S12, Acid Activation: Immerse the dried volcanic rock in a 5%~10% dilute hydrochloric acid solution with a solid-liquid ratio of 1:5~1:10 (g / mL), and mechanically stir at 60~80℃ for 2~4 hours to dissolve the volcanic glassy material in the pores and expose the internal active sites. Then wash repeatedly with deionized water until the pH of the filtrate is 6.5~7.0. S13. Alkali activation and introduction of oxygen-containing functional groups: Immerse the acid-activated volcanic rock in a 1 mol / L NaOH solution with a solid-liquid ratio of 1:5 (g / mL) and stir at 60℃ for 6-8 hours to introduce abundant silanol groups (Si-OH) and aluminum hydroxyl groups (Al-OH) onto the surface. Wash until neutral. S14, Ferrous Loading: Alkali-activated volcanic rock is immersed in a 0.1~0.3 mol / L solution of ferrous sulfate heptahydrate (FeSO4·7H2O) and stirred at 60°C for 4 hours under nitrogen protection to allow Fe²⁺ to be loaded. + By anchoring to hydroxyl groups within the pores through ion exchange, uniformly distributed reducing active sites are formed; S15, Silane Coupling Agent Surface Modification: The volcanic rock treated with S14 was transferred to a 2% (w / w) γ-aminopropyltriethoxysilane (KH550) ethanol solution with a solid-liquid ratio of 1:8 (g / mL). The solution was refluxed and stirred at 50°C for 2 hours to graft active amino groups onto the surface of the volcanic rock, which facilitates the formation of hydrogen bonds and coordination bonds with chitosan and amino acid complexes. After filtration, the solution was washed three times with anhydrous ethanol and then vacuum dried at 80°C for 6 hours to obtain activated modified volcanic rock.

[0012] Furthermore, the preparation method of the lignin sulfonate modified chitosan includes the following steps: S21. Weigh distilled water, add glacial acetic acid, then add chitosan, and stir continuously for 12-24 hours until the solution is clear, transparent, and viscous. S22. Weigh out lignin sulfonate and dissolve it in distilled water, stirring until completely dissolved; S23. Under vigorous stirring conditions, the lignin sulfonate solution is slowly added dropwise to the chitosan solution, and stirring is continued for 2-4 hours to induce an electrostatic complexation reaction, thereby obtaining lignin sulfonate modified chitosan.

[0013] Furthermore, in the preparation method of the lignin sulfonate modified chitosan, the mass ratio of water: glacial acetic acid: chitosan is 100:1:2, the mass ratio of water: lignin sulfonate is 50:1, and the lignin sulfonate is preferably sodium lignin sulfonate.

[0014] Furthermore, the preparation method of the amino acid calcium-magnesium complex includes the following steps: S31. Add the amino acids to water, heat to 90~95℃ and stir until completely dissolved; S32. While maintaining high temperature and stirring, slowly add calcium carbonate in batches until the solution becomes clear, forming an amino acid calcium complex. S33. Cool to 70℃, add magnesium carbonate in batches, and continue stirring for 30 minutes until completely dissolved; S34. Measure the pH value of the solution and control it between 6.0 and 7.0. If the pH is too low, add calcium and magnesium source; if it is too high, add amino acids. Keep warm and stir for 1 hour to obtain the amino acid calcium and magnesium complex.

[0015] Furthermore, in the method for preparing the amino acid calcium-magnesium complex, the mass ratio of water: amino acid: calcium carbonate: magnesium carbonate is 25:5:1:2, and the amino acid is preferably aspartic acid or glutamic acid.

[0016] Secondly, the present invention also provides a method for preparing a vegetable cultivation substrate based on volcanic rock, comprising the following steps: S101, Preparation of activated modified volcanic rock; Preparation of S102, lignin sulfonate modified chitosan; Preparation of S103 and amino acid calcium-magnesium complex; S104. Activated modified volcanic rock, lignin sulfonate modified chitosan, and amino acid calcium magnesium complex are mixed at a set mass ratio and stirred at 80°C in a constant temperature water bath for 1-2 hours to ensure that the liquid phase components are uniformly loaded into the pores of the activated modified volcanic rock and form a ternary synergistic composite gel system. After cooling, it is air-dried at 40°C until the matrix moisture content drops to 30%-40%. S105. The above-mentioned functional improvement components are thoroughly mixed with the carrier composed of peat moss and humus at a set mass ratio to obtain the vegetable cultivation substrate based on volcanic rock.

[0017] Compared with the prior art, the beneficial effects of this invention are: The cultivation substrate described in this invention has good air permeability and strong water and fertilizer retention capacity, which can significantly reduce the accumulation of chromium in the edible parts of vegetables, increase fruit setting rate and yield per plant, and is particularly suitable for soil improvement of chromium contamination and safe cultivation and production of vegetables such as tomatoes, cucumbers, peppers and lettuce in greenhouses. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0019] Unless otherwise specified, all raw materials used in the following examples are commercially available industrial products or analytical grade reagents; the volcanic rock raw material is basaltic porous volcanic rock particles with a particle size of 2-5 mm (origin: Wudalianchi, Heilongjiang Province), and its chemical composition mainly includes: SiO2 48.5%, Al2O3 15.2%, Fe2O3 10.6%, CaO 8.7%, MgO 6.9%, K2O 2.1%, Na2O 3.2%, and loss on ignition of about 2.6%.

[0020] In Examples 1-3 and Comparative Examples 1-4, the cultivation substrates were prepared according to the same formula ratio, and 10 "Golden Powder No. 1" tomatoes were planted in the same greenhouse environment. Potassium dichromate was artificially added to the soil background to make the Cr(VI) content reach 80 mg / kg to simulate chromium pollution conditions. The remaining water and fertilizer management was completely consistent with the cultivation management. After the fruit matured, the results were statistically analyzed and the chromium content in the tomato pulp was measured.

[0021] Example 1 This embodiment provides a vegetable cultivation substrate based on volcanic rock, which is composed of a carrier and a functional improvement component mixed at a mass ratio of 70:30; the mass ratio of peat moss to humus in the carrier is 30:70; in the functional improvement component, the mass percentages of activated modified volcanic rock, lignin sulfonate modified chitosan, and amino acid calcium magnesium complex are 65%, 20%, and 15%, respectively.

[0022] The specific preparation steps are as follows: (1) Preparation of activated modified volcanic rock: Take 1000g of volcanic rock particles with a particle size of 2-5mm, ultrasonically clean them with deionized water for 30 minutes, and dry them at 105℃ to constant weight. Immerse the dried volcanic rock in 5L of 8% hydrochloric acid solution and mechanically stir at 70℃ for 3 hours. After discarding the acid solution, wash repeatedly with deionized water until the pH value is 6.8. Then immerse it in 5L of 1mol / L NaOH solution and stir at 60℃ for 6 hours, washing until neutral. After that, immerse it in 5L of 0.2mol / L FeSO4·7H2O solution, purge with nitrogen for protection, and stir at 60℃ for 4 hours. After filtration, add the volcanic rock to 8L of 2% KH550 ethanol solution, reflux and stir at 50℃ for 2 hours, wash three times with anhydrous ethanol, and vacuum dry at 80℃ for 6 hours to obtain activated modified volcanic rock.

[0023] (2) Preparation of chitosan modified with lignin sulfonate: Take 100 mL of distilled water, add 1 mL of glacial acetic acid, weigh 2 g of chitosan powder and slowly add it to the dilute acid water, stirring continuously for 18 hours until the solution becomes clear, transparent and viscous; weigh 1 g of sodium lignosulfonate and dissolve it in 50 mL of distilled water, stirring until completely dissolved; under vigorous stirring, slowly add the sodium lignosulfonate solution dropwise to the chitosan solution, and continue stirring for 3 hours to allow the complexation reaction to proceed fully, thus obtaining a lignosulfonate-modified chitosan solution.

[0024] (3) Preparation of amino acid calcium-magnesium complex: Add 50g of aspartic acid to 250mL of water, heat to 90℃ and stir until completely dissolved; while maintaining high temperature and stirring, slowly add 10g of calcium carbonate in batches, react for about 30 minutes until the solution becomes clear; cool to 70℃, add 20g of magnesium carbonate in batches, and continue stirring for 30 minutes until completely dissolved; check the pH value of the solution and adjust it to between 6.0 and 7.0, keep warm and stir for 1 hour to obtain the amino acid calcium magnesium complex.

[0025] (4) Formation of the ternary synergistic composite gel system and matrix preparation: According to the above-mentioned mass percentages, the activated modified volcanic rock, lignin sulfonate modified chitosan, and amino acid calcium magnesium complex were mixed and placed in an 80°C constant temperature water bath for 1.5 hours to keep them warm and stirred, so that the chitosan solution and amino acid complex solution were uniformly loaded on the inner wall of the pores of the activated modified volcanic rock and formed a ternary synergistic composite gel system. After cooling to room temperature, the mixture was air-dried at 40°C until the moisture content was about 35%. Then, according to the mass ratio of carrier to functional improvement component of 70:30, a carrier prepared by peat moss and humus in a ratio of 30:70 was added, and the mixture was thoroughly mixed and passed through an 8-mesh sieve to obtain the cultivation substrate described in this embodiment.

[0026] Example 2 The preparation process of this embodiment is exactly the same as that of Example 1, except that the mass percentage of each component in the functional improvement component is as follows: 85% activated modified volcanic rock, 10% lignin sulfonate modified chitosan, and 5% amino acid calcium magnesium complex; the mass ratio of carrier to functional improvement component is 70:30.

[0027] Example 3 The preparation process of this embodiment is exactly the same as that of Example 1. The only difference is that the mass percentage of each component in the functional improvement component is as follows: 75% activated modified volcanic rock, 15% lignin sulfonate modified chitosan, and 10% amino acid calcium magnesium complex; the mass ratio of the carrier to the functional improvement component is 70:30; this ratio is the optimal ratio obtained through multiple sets of orthogonal experiments.

[0028] Comparative Example 1 Compared with Example 3, in Comparative Example 1, untreated volcanic rock ore (only washed and dried) was used instead of activated modified volcanic rock, while the other raw materials, proportions and preparation processes were exactly the same as in Example 3.

[0029] Comparative Example 2 Compared with Example 3, in Comparative Example 2, ordinary horticultural perlite of equal mass was used to replace activated modified volcanic rock, while the other raw materials, proportions and preparation processes were exactly the same as in Example 3.

[0030] Comparative Example 3 Compared with Example 3, Comparative Example 3 did not add lignin sulfonate-modified chitosan, but used an equal mass of deionized water instead. The other raw materials, proportions and preparation processes were exactly the same as in Example 3.

[0031] Comparative Example 4 Compared with Example 3, Comparative Example 4 did not add the amino acid calcium magnesium complex, but used an equal mass of deionized water instead. The other raw materials, proportions and preparation processes were exactly the same as in Example 3.

[0032] Experimental process Seven groups of cultivation substrates (Examples 1-3 and Comparative Examples 1-4) were placed in identical cultivation troughs and placed under the same greenhouse environment. Ten plants of each "Jinfen No. 1" tomato variety were cultivated using uniform water, fertilizer, and management methods. The background Cr(VI) content of the soil was artificially adjusted to 80 mg / kg. The period from transplanting to fruit maturity was 90 days. During this period, plant growth was recorded, and after fruit maturity, samples were taken to determine the chromium content in the tomato pulp.

[0033] The fruit set of each group of tomato plants is shown in Table 1: Table 1. Statistical table of tomato plant results in each group. Table 1 shows that the tomato plants in Examples 1-3 grew well and set fruit normally. Example 3 had the highest number of fruits (51), with the best fruit size and quality. In Comparative Example 1, the volcanic rock was not activated, resulting in insufficient active sites and uneven fruit load in the pores. Although the plants could bear fruit normally, the yield per plant was significantly reduced, and some plants showed mild chromium poisoning symptoms. In Comparative Example 2, perlite was used instead of volcanic rock. Since perlite itself has almost no ability to supply mineral nutrients and has a very weak adsorption effect on heavy metals, two tomato plants died from chromium poisoning at the roots. The yield and fruit quality of the surviving plants were significantly reduced. Comparative Example 3 lacked lignin sulfonate-modified chitosan, which weakened the adsorption and reduction effect on chromium. At the same time, some fruits showed blossom-end rot, indicating that the effective supply of calcium and magnesium was affected. Comparative Example 4 lacked amino acid calcium-magnesium complex, and the plants showed typical nutrient deficiency symptoms such as yellowing leaves and reduced yield.

[0034] Methods for determining the chromium content in tomato fruits: Four fruits of similar size and color were randomly selected from each group. Edible tomato pulp was taken, washed, dried, chopped, and ground into a uniform pulp in a high-speed grinder. 0.2g of the sample was weighed and placed in a special digestion vessel. 5mL of nitric acid was added, and the vessel was sealed and placed in a microwave digester for digestion according to the programmed temperature rise. After digestion, the acid was removed, and the digestion solution was finally brought to a final volume of 25mL with dilute nitric acid. The chromium content was determined by inductively coupled plasma mass spectrometry (ICP-MS).

[0035] The results of the determination of chromium content in tomato pulp in each group are shown in Table 2: Table 2. Results of Chromium Content in Tomato Pulp for Each Group (mg / kg) According to GB 2762—2022 "National Food Safety Standard - Limits of Contaminants in Food", the limit for chromium in fresh vegetables is 0.5 mg / kg. As shown in Table 2, the chromium content in the tomato pulp of Examples 1-3 and Comparative Example 4 was significantly lower than the limit (with Example 3 having the lowest at only 0.076 mg / kg); while the chromium content in Comparative Example 1 (unactivated volcanic rock), Comparative Example 2 (perlite substitute), and Comparative Example 3 (unmodified chitosan) was significantly higher than that of the Example groups, with Comparative Example 2 even exceeding the national limit by nearly double.

[0036] The above results indicate that volcanic rock must undergo a four-step systematic modification process—"acid activation—alkali activation—ferrous loading—silane grafting"—to fully exert its functions of adsorbing and reducing Cr(VI) (Comparative Example 1); ordinary skeleton materials such as perlite cannot replace volcanic rock in providing the dual functions of mineral nutrition and heavy metal inhibition (Comparative Example 2); there is a significant synergistic effect between lignin sulfonate-modified chitosan and activated modified volcanic rock, and the chromium inhibition effect is far superior to either single component when the two are used together (Comparative Example 3); although the amino acid calcium-magnesium complex has limited adsorption effect on chromium itself in the system, it is crucial for the normal absorption of calcium and magnesium by plants and for improving yield and quality (Comparative Example 4).

[0037] Based on the data in Tables 1 and 2, when the mass percentages of activated modified volcanic rock, lignin sulfonate modified chitosan, and amino acid calcium magnesium complex in the functional improvement components are 75%, 15%, and 10% respectively (i.e., Example 3), the vegetable cultivation substrate based on volcanic rock described in this invention simultaneously achieves the lowest chromium accumulation, the highest fruit setting rate, and the highest yield per plant, thus achieving the best overall performance.

[0038] In addition, the physical properties of the cultivation substrate prepared in Example 3 were measured. The results showed that its total porosity was 62.4%, its aeration porosity was 28.1%, its water-holding porosity was 34.3%, its bulk density was 0.41 g / cm³, its pH value was 6.8, and its electrical conductivity was 1.25 mS / cm. These properties meet the physicochemical performance requirements for vegetable cultivation substrates in GB / T 33891-2017 "Organic Substrates for Greening". Moreover, all the indicators are better than the comparative sample corresponding to Example 3.

[0039] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vegetable cultivation substrate based on volcanic rock, characterized in that, It includes a carrier and a functional improvement component; by mass percentage, the carrier accounts for 60% to 80%, and the functional improvement component accounts for 20% to 40%. The carrier comprises peat moss and humus; by mass percentage, peat moss accounts for 20% to 40% of the carrier, and humus accounts for 60% to 80% of the carrier. The functional improvement components include activated modified volcanic rock, lignin sulfonate modified chitosan, and amino acid calcium magnesium complex; by mass percentage, activated modified volcanic rock accounts for 65% to 85% of the functional improvement components, lignin sulfonate modified chitosan accounts for 8% to 20%, and amino acid calcium magnesium complex accounts for 5% to 15%.

2. The cultivation substrate according to claim 1, characterized in that, The activated modified volcanic rock, lignin sulfonate modified chitosan, and amino acid calcium magnesium complex together constitute a ternary synergistic composite gel system.

3. The cultivation substrate according to claim 1, characterized in that, The preparation method of the activated modified volcanic rock includes the following steps: S11. The volcanic rock particles with a particle size of 2~5mm are ultrasonically cleaned in deionized water and dried at 105℃ to constant weight. S12. Immerse the dried volcanic rock in a 5%~10% dilute hydrochloric acid solution, stir at 60~80℃ for 2~4 hours, wash until neutral, and complete acid activation; S13. Immerse the acid-activated volcanic rock in a 1 mol / L NaOH solution, stir at 60°C for 6-8 hours, wash until neutral, and complete the alkali activation and introduce silanol and aluminumol groups on the surface. S14. Immerse the alkali-activated volcanic rock in a 0.1~0.3 mol / L solution of ferrous sulfate heptahydrate, and stir at 60°C for 4 hours under nitrogen protection to allow Fe²⁺ to form a precipitate. + Anchored to the inner wall of the pores, forming reducing active sites; S15. The volcanic rock treated in S14 is immersed in a 2% (w / w) γ-aminopropyltriethoxysilane ethanol solution, refluxed and stirred at 50°C for 2 hours, washed with anhydrous ethanol, and then vacuum dried at 80°C for 6 hours to obtain activated modified volcanic rock.

4. The cultivation substrate according to claim 3, characterized in that, In step S12, the solid-liquid ratio of volcanic rock to dilute hydrochloric acid is 1:5 to 1:10 (g / mL); in step S13, the solid-liquid ratio of volcanic rock to NaOH solution is 1:5 (g / mL); in step S15, the solid-liquid ratio of volcanic rock to silane coupling agent ethanol solution is 1:8 (g / mL).

5. The cultivation substrate according to claim 1, characterized in that, The preparation method of the lignin sulfonate modified chitosan includes the following steps: S21. Measure distilled water, add glacial acetic acid, then add chitosan, and stir continuously for 12-24 hours until the solution is clear, transparent and viscous. S22. Weigh out lignin sulfonate, dissolve it in distilled water, and stir until completely dissolved; S23. Under vigorous stirring, the lignin sulfonate solution is slowly added dropwise to the chitosan solution, and stirring is continued for 2-4 hours to induce a complexation reaction, thereby obtaining lignin sulfonate modified chitosan.

6. The cultivation substrate according to claim 5, characterized in that, In step S21, the mass ratio of water: glacial acetic acid: chitosan is 100:1:2; in step S22, the mass ratio of water: lignin sulfonate is 50:1; the lignin sulfonate is sodium lignin sulfonate.

7. The cultivation substrate according to claim 1, characterized in that, The preparation method of the amino acid calcium-magnesium complex includes the following steps: S31. Add the amino acids to water, heat to 90~95℃ and stir until completely dissolved; S32. While maintaining high temperature and stirring, slowly add calcium carbonate in batches until the solution becomes clear, forming an amino acid calcium complex. S33. Cool to 70℃, add magnesium carbonate in batches, and continue stirring for 30 minutes until completely dissolved; S34. Detect the pH value of the solution and control it between 6.0 and 7.

0. Keep it warm and stir for 1 hour to obtain the amino acid calcium magnesium complex.

8. The cultivation substrate according to claim 7, characterized in that, In the method for preparing the amino acid calcium-magnesium complex, the mass ratio of water: amino acid: calcium carbonate: magnesium carbonate is 25:5:1:2; the amino acid is aspartic acid or glutamic acid.

9. The cultivation substrate according to claim 1, characterized in that, The functional improvement components contain activated modified volcanic rock, lignin sulfonate modified chitosan, and amino acid calcium magnesium complex in a mass percentage of 75%, 15%, and 10%, respectively; the mass ratio of the carrier to the functional improvement components is 70:30; and the mass ratio of peat moss to humus in the carrier is 30:

70.

10. A method for preparing a vegetable cultivation substrate based on volcanic rock, applied to the preparation of the cultivation substrate as described in any one of claims 1 to 9, characterized in that, The method includes the following steps: S101, Preparation of activated modified volcanic rock; Preparation of S102, lignin sulfonate modified chitosan; Preparation of S103 and amino acid calcium-magnesium complex; S104. Activated modified volcanic rock, lignin sulfonate modified chitosan and amino acid calcium magnesium complex are mixed at a set mass ratio and stirred in a constant temperature water bath at 80℃ for 1-2 hours to load the liquid phase component into the pores of the activated modified volcanic rock and form a ternary synergistic composite gel system. After cooling, it is air-dried at 40℃ until the water content is 30%-40%. S105. The functional improvement component obtained in step S104 is thoroughly mixed with the carrier composed of peat moss and humus at a set mass ratio to obtain the vegetable cultivation substrate based on volcanic rock.

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