Recyclable plant growth substrate as well as preparation method and application method thereof

Abstract

The invention relates to the technical field of plant cultivation substrates, in particular to a recyclable plant growth substrate and a preparation method and application method thereof.The substrate comprises, by weight, 70-80% of organic matter materials, 30-40% of wood fiber materials, 20-30% of agricultural by-products and 10-15% of food processing waste; the functional mineral material comprises 5-10% of a porous adsorption material and 5-10% of a structural support material; 5-10% of a bioactive component; the total viable count of the functional microbial system is greater than or equal to 5 * 10 CFU / g; 3-6% of a biopolymer binding system; wherein the matrix has a three-level pore structure, the volume weight is 0.2-0.35 g / cm < 3 >, the total porosity is 70-85%, the maximum water-holding capacity is 250-350% (w / w), and the matrix can be recycled for 4-5 times.

Description

Technical Field

[0001] The present invention relates to the technical field of plant cultivation substrates, and particularly to a recyclable plant growth substrate and its preparation method and application method. This technology belongs to the cross-field of bio-based materials and circular economy technology and can be applied to fields such as facility agriculture, urban agriculture, horticultural planting, and plant factories. Background Art

[0002] With the development of modern agriculture, especially the popularization of facility agriculture and soilless cultivation technology, the demand for high-performance plant growth substrates is increasing day by day. Traditional plant growth substrates usually include materials such as peat, coconut coir, vermiculite, and perlite. These materials are usually discarded after use, causing resource waste and environmental burden.

[0003] The currently widely used plant growth substrates in the market have the following problems:

[0004] 1. Resource consumption problem: Traditional peat substrates are mainly sourced from wetland ecosystems. Mining will damage the natural environment and they are non-renewable resources.

[0005] 2. Environmental burden problem;

[0006] 3. Difficulty in recycling: Existing substrates are often difficult to reuse after use due to structural collapse, microbial contamination, or nutrient depletion.

[0007] 4. Single function: Most substrates only provide physical support and basic nutrient functions, lacking multiple regulatory effects on plant growth.

[0008] There have been some studies on plant growth substrates in the prior art. US Patent US20060112629A1 discloses a plant growth substrate mainly composed of wood chips. This substrate has good air permeability and water retention, but does not involve the problem of substrate recycling. US Patent US9045379B2 proposes a plant growth substrate prepared using agricultural by-products such as almond shells. Although it realizes the resource utilization of waste, it does not solve the recycling problem after substrate use.

[0009] International Patent WO2020051681A1 discloses a biodegradable plant growth substrate composed of 70%-95% hemp fiber and 5%-30% biodegradable thermoplastic polymer (polylactic acid). Although it solves the problem of environmental friendliness, this substrate is designed to be biodegradable after single use and does not consider multiple recycling uses.

[0010] U.S. Patent US10882977B1 describes a plant-based compostable and biodegradable substrate, which contains different proportions of bio-based polyethylene, calcium carbonate, hemp straw or soy protein, thermoplastic starch, and biodegradable additives. This substrate mainly focuses on biodegradability rather than recyclability.

[0011] International Patent WO2014010314A1 proposes a method for cultivating mushrooms using a reusable fiber substrate. Although it involves the recycling of the culture medium, it is limited to the field of cultivating specific fungi and is not applicable to extensive plant cultivation.

[0012] In addition, with the promotion of the concept of circular economy, the "Plastic Recycling and Bioeconomy" report emphasizes the importance of bio-based materials in terms of recycling. However, the recycling technology for plant growth substrates still needs to be broken through.

[0013] Although the above existing technologies have innovations in some aspects, there is no comprehensive solution that can simultaneously solve problems such as the efficient recycling, multifunctionality, and environmental friendliness of plant growth substrates. The existing substrates often have the following technical difficulties:

[0014] 1. It is difficult to construct a three-dimensional structure system that maintains stability during multiple uses;

[0015] 2. It is difficult to achieve efficient separation of the substrate from plant roots after use;

[0016] 3. It is difficult to maintain the functional stability of the substrate during multiple recycling processes;

[0017] 4. It is difficult to establish a complete substrate regeneration and function repair technology system.

[0018] Therefore, developing a plant growth substrate that can be recycled multiple times, has comprehensive functions, and is environmentally friendly is of great significance for promoting the efficient use of agricultural resources and reducing the environmental burden. Summary of the Invention

[0019] The object of the present invention is to provide a recyclable plant growth substrate, its preparation method and application, in order to solve the technical problems of existing plant growth substrates such as single use, single function, and large environmental burden.

[0020] The present invention mainly solves the following technical problems:

[0021] 1. Substrate structure problem: Existing substrates are prone to problems such as structural collapse and pore blockage during use, resulting in inability to be reused;

[0022] 2. Root separation problem: Existing substrates are tightly entangled with plant roots and are difficult to separate without damage, affecting recycling;

[0023] 3. Functional attenuation problem: After the existing substrate is used, the nutrients are exhausted and the microbial activity is lost, and it is difficult to restore the function during reuse;

[0024] 4. Regeneration technology problem: Lack of systematic substrate cleaning, disinfection, function repair and structure reconstruction technologies;

[0025] 5. Environmental burden problem: The use of a variety of synthetic materials increases environmental risks and reduces the value of resource utilization.

[0026] To solve the above technical problems, the present invention provides a recyclable plant growth substrate system based on the principle of "multi-level structure-function synergy". Through the precise proportioning of multi-source biomass materials, the precise control of the three-dimensional structure and the intelligent responsive nutrient release mechanism, the high customization of the substrate performance and multiple recycling are realized. The specific technical solutions include:

[0027] A recyclable plant growth substrate, the substrate comprising the following components in weight percentages:

[0028] 70-80% of organic matter materials, including 30-40% of wood fiber materials, 20-30% of agricultural by-products and 10-15% of food processing waste;

[0029] 10-20% of functional mineral materials, including 5-10% of porous adsorption materials and 5-10% of structural support materials;

[0030] 5-10% of bioactive components;

[0031] A functional microbial system, with a total viable count ≥ 5×10 8 CFU / g;

[0032] 3-6% of a biopolymer bonding system;

[0033] Among them, the substrate has a three-level pore structure, a bulk density of 0.2-0.35 g / cm³, a total porosity of 70-85%, a maximum water holding capacity of 250-350% (w / w), and can be recycled 4-5 times.

[0034] Preferably, the wood fiber materials include 15-20% of crushed poplar waste, 10-15% of processed pine wood scraps and 5-10% of bamboo processing waste; the agricultural by-products include 10-15% of crushed almond shells, 5-10% of processed cottonseed hulls and 5-10% of carbonized rice husks; the food processing waste includes 5-8% of processed coffee grounds and 5-7% of fermented fruit residues.

[0035] Preferably, the porous adsorption material comprises 3-5% of modified zeolite powder and 2-5% of bentonite; the structural support material comprises 3-6% of perlite and 2-4% of diatomite; the bioactive ingredient comprises 2-4% of seaweed extract complex, 2-3% of humic acid substances, and 1-3% of plant-derived amino acid complex; the biopolymer binding system comprises 1.5-3% of alginate-ion crosslinked complex and 1.5-3% of modified starch-protein complex.

[0036] Preferably, the functional microorganism system includes: nitrogen-fixing functional group, phosphorus-solubilizing functional group, organic matter conversion functional group, and plant growth promotion functional group; the nitrogen-fixing functional group includes Azotobacterchroococcum and Azospirillum brasilense; the phosphorus-solubilizing functional group includes Bacillus megaterium and Pseudomonas fluorescens; the organic matter conversion functional group includes Trichoderma harzianum and Streptomyceslydicus; the plant growth promotion functional group includes Bacillus subtilis and Pseudomonas putida.

[0037] The preparation method of the recyclable plant growth substrate comprises the following steps:

[0038] (1) Raw material pretreatment: The organic matter material is crushed and classified to obtain particles with different particle sizes; the mineral material is subjected to surface modification treatment; the bioactive ingredient is extracted and purified.

[0039] (2) Multi-stage proportioning and mixing: The organic matter materials with different particle sizes are subjected to primary mixing according to a predetermined ratio, and then the functional mineral material is added for secondary mixing. After mixing evenly, the moisture content is adjusted to 38-42%.

[0040] (3) Pressure-controlled molding: The mixed material is put into a molding die, and molded under the conditions of 65-75 °C by using segmented controlled pressure (1.0 MPa - 3 seconds, 2.0 MPa - 2 seconds, 3.0 MPa - 1 second).

[0041] (4) Function imparting: The nutrients are gradiently loaded and the microorganisms are functionally inoculated on the formed substrate. The nutrient loading is carried out by vacuum impregnation, and the microorganism inoculation is carried out by pulse spraying.

[0042] (5) Structure stabilization: Spray a 0.5 - 1.0% calcium chloride solution on the substrate for biopolymer cross - linking, and then perform heat - assisted strengthening treatment at 40 - 50 °C;

[0043] (6) Humidity adjustment and packaging: Dry the substrate at 30 - 35 °C until the moisture content reaches 16 - 18%, spray a microbial protectant, and seal the package using modified atmosphere packaging technology.

[0044] Preferably, the crushing and grading treatment of the organic matter material in step (1) includes: using a double - rotor staggered - tooth hammer mill for crushing, with the rotational speed of the lignocellulosic material being 1200 - 1500 rpm, the rotational speed of agricultural by - products being 1500 - 1800 rpm, and the rotational speed of food processing waste being 1800 - 2200 rpm; using a vibrating multi - layer screening system for grading, dividing the particles into five particle size grades of 5 - 3 mm, 3 - 1 mm, 1 - 0.5 mm, 0.5 - 0.1 mm, and <0.1 mm, and the mass ratios of each particle size grade are 15 - 20%, 30 - 35%, 25 - 30%, 10 - 15%, and 5 - 10% respectively.

[0045] Preferably, the nutrient gradient loading in step (4) adopts a three - stage loading method: the rapid - release layer uses water - soluble nitrogen, phosphorus, potassium and trace elements (in a ratio of 1.5:1:2), with a concentration of 1.0 - 1.5%; the medium - release layer uses a slow - release nitrogen, phosphorus, potassium complex (in a ratio of 1:1:1), with a concentration of 1.2 - 1.8%; the long - term release layer uses organic nitrogen, calcium dihydrogen phosphate and potassium sulfate (in a ratio of 1:0.5:0.5), with a concentration of 0.8 - 1.2%; for microbial inoculation, use a bacterial solution containing 1×10 9 CFU / ml, and the inoculation amount is 10 - 15 ml / kg of the substrate.

[0046] The application method of the recyclable plant growth substrate includes the following steps:

[0047] (1) Substrate use: Apply the substrate to the cultivation of vegetables, flowers, fruit tree seedlings, foliage plants or herbal medicines, and the direct planting method, mixed substrate method or soilless cultivation application method can be adopted;

[0048] (2) Substrate recovery: After the plants are harvested, use a water flow pulse separation system to separate the plant roots from the substrate, with the pulse water pressure being 0.2 - 0.3 MPa and the pulse frequency being 2 - 3 Hz;

[0049] (3) Substrate cleaning and disinfection: Use a vortex cleaning and disinfection integrated machine to clean the recycled substrate, with the cleaning temperature being 35 - 40 °C, the cleaning time being 3 - 5 minutes, and the cleaning agent being a 0.5% hydrogen peroxide solution;

[0050] (4) Substrate regeneration: The cleaned substrate is subjected to structural reconstruction, nutrient supplementation, and microbial function reconstruction. For structural reconstruction, a precise pressure reshaping system is used, with a pulsed pressure application method and a pressure temperature of 50 - 60°C; for nutrient supplementation, a precise nutrient solution impregnation system is used, and the nutrient supplementation concentration is adjusted according to the number of cycles; for microbial function reconstruction, a microbial atomization inoculation system is used, with an inoculation temperature of 22 - 26°C;

[0051] (5) Recycling: The regenerated substrate is reused according to step (1). After being used 4 - 5 times, it can be used as a soil conditioner or compost raw material for resource utilization.

[0052] Preferably, the direct planting method is applicable to small plants, seedlings, and herbaceous plants. The operation method is to place the substrate block into a cultivation container, directly plant seeds or insert seedlings, and water for the first time until the weight of the substrate increases by 70 - 80%; the mixed substrate method is applicable to medium - large plants and long - term cultivated crops, with a mixing ratio of 70 - 80% of this substrate and 20 - 30% of garden soil / perlite; the soilless cultivation application method is applicable to drip irrigation systems and nutrient solution circulation systems. The substrate is used as a filler for cultivation troughs or seedling blocks, with a nutrient solution EC value of 1.8 - 2.2 mS / cm and a pH value of 5.8 - 6.2.

[0053] Preferably, the nutrient supplementation of the substrate adjusts the concentration according to the number of cycles: for the first cycle, the original formula concentration of 40 - 50% is used; for the second cycle, the original formula concentration of 50 - 60% is used; for the third cycle, the original formula concentration of 60 - 70% is used; the inoculation amount for microbial function reconstruction is adjusted according to the number of cycles: for the nitrogen - fixing functional group, the original formula concentration of 60 - 70% is used; for the phosphorus - solubilizing functional group, the original formula concentration of 70 - 80% is used; for the organic matter transformation functional group, the original formula concentration of 80 - 90% is used; for the plant growth - promoting functional group, the original formula concentration of 60 - 70% is used; when the physical structure recovery rate of the substrate is lower than 75%, the microbial activity recovery rate is lower than 65%, it is difficult to adjust the nutrient balance, or pathogenic bacteria are detected, the recycling use is terminated.

[0054] Through the above - mentioned technical solutions, the present invention solves the problems existing in the prior art, and the specific technical effects are as follows:

[0055] 1. Recycling effect: The substrate can be stably recycled 4 - 5 times. After each recycling, more than 90% of the physical functions and more than 80% of the biological activities can be restored through a dedicated process, greatly reducing resource consumption and environmental burden;

[0056] 2. Structural stability: Through a three - level pore structure design and a biopolymer cross - linking technology, the substrate maintains structural stability under wet - dry alternating conditions, and the structure retention rate reaches more than 85% after 10 wet - dry cycles;

[0057] 3. High nutrient use efficiency: By adopting the gradient nutrient loading technology, slow and balanced release of nutrients is achieved. The release rate of nitrogen within 45 days is controlled at 45 - 55%, the release rate of phosphorus within 60 days is 40 - 50%, and the release rate of potassium within 30 days is 50 - 60%.

[0058] 4. Root growth regulation: The optimized physical structure promotes root development. Compared with traditional substrates, the root biomass of crops increases by 15 - 25%, and the root - shoot ratio increases by 10 - 15%.

[0059] 5. Environmental friendliness: The substrate is mainly composed of renewable biomass materials and can be completely biodegradable after 4 - 5 cycles of use. When used as a soil conditioner, it can promote the formation of soil aggregate structure and increase the soil organic matter content.

[0060] 6. Significant economic benefits: Considering the factor of recycling, the cost of cultivating per unit of plants is reduced by 40 - 50% compared with traditional disposable substrates, while the crop yield is increased by 15 - 25%. Description of the Drawings

[0061] Figure 1 It is the process flow chart of the preparation of the recyclable plant growth substrate of the present invention.

[0062] Figure 2 It is the nutrient release curve graph of the recyclable plant growth substrate of the present invention.

[0063] Figure 3 It is the curve graph of the change in microbial activity of the recyclable plant growth substrate of the present invention.

[0064] Figure 4 It is the comparison graph of the crop growth effects between the recyclable plant growth substrate of the present invention and the control substrate.

[0065] Figure 5 It is the graph of the change in the structure retention rate of the recyclable plant growth substrate of the present invention after multiple cycles of use. Detailed Embodiments

[0066] The present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the description of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the protection scope of the present invention.

[0067] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "linkage" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] I. Term Definitions

[0069] In the present invention, the definitions of the following terms are as follows:

[0070] 1. "Recyclable": It means that the substrate can be reused after undergoing a specific treatment process. Specifically in the present invention, it means that the substrate can be recycled 4 - 5 times, and after each recycling, more than 90% of its physical functions and more than 80% of its biological activities can be restored through a dedicated process.

[0071] 2. "Three - level pore structure": It refers to three different - scale pores existing simultaneously in the substrate, including: macro - pores (diameter > 1 mm), which are mainly responsible for ventilation and rapid drainage; meso - pores (0.1 - 1 mm), which are mainly responsible for retaining easily available water; and micro - pores (< 0.1 mm), which are mainly responsible for buffering water storage and microbial habitation.

[0072] 3. "Functional microbial system": It refers to a microbial combination with multiple functions such as nitrogen fixation, phosphorus solubilization, organic matter transformation, and plant growth promotion, with the total viable cell count ≥ 5×10 8 CFU / g, including at least four categories of functional microbial communities.

[0073] 4. "Gradient nutrient loading": It refers to a technology that forms a gradient distribution of nutrient concentration in the substrate through a specific process, so that the nutrients show a gradient decline distribution from the outside to the inside or from top to bottom, realizing the slow and balanced release of nutrients.

[0074] 5. "Biopolymer cross - linking": It refers to a technology that forms a cross - linked network structure between biopolymers through chemical or physical methods to enhance the structural stability of the substrate. In the present invention, two mechanisms of alginate - calcium ion cross - linking and starch - protein cross - linking are mainly used.

[0075] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0076] In the description of the present invention, unless otherwise clearly specified and limited, the term "includes", "comprising" or similar words means that the elements or steps preceding the term are not exclusive, that is, other elements or steps may also be included. In the present invention, the term "recyclable" means that the substrate can be reused after a specific treatment process after use, specifically, it can be recycled 4-5 times, and after each cycle of use, more than 90% of the physical function and more than 80% of the biological activity can be restored through a specific regeneration process.

[0077] Embodiment 1:

[0078] A recyclable plant growth substrate, comprising the following components in percentage by weight:

[0079] 70% organic materials, including 40% wood fiber materials (20% poplar waste crushed materials, 15% pine processing scraps, 5% bamboo processing waste), 20% agricultural by-products (10% almond shell crushed materials, 5% cottonseed shell processed materials, 5% rice husk carbonized materials), 10% food processing waste (5% coffee grounds processed materials, 5% fruit residue fermentation products); 20% functional mineral materials, including 10% porous adsorption materials (5% modified zeolite powder, 5% bentonite) and 10% structural support materials (6% perlite, 4% diatomaceous earth); 5% bioactive ingredients, including 2% seaweed extract complex, 2% humic acid substances and 1% plant-derived amino acid complex; 5% biopolymer bonding system, including 2.5% alginate-ion cross-linked complex (1.7% sodium alginate, 0.8% calcium chloride cross-linking agent) and 2.5% modified starch-protein complex (1.7% oxidized corn starch, 0.8% soy protein isolate); at the same time, a functional microbial system was inoculated, with a total viable count of 5×10 8 CFU / g, the microbial system includes nitrogen fixation functional group (Steinotrophomonas maltophilia AC-1 strain, Helicobacter pylori strain AZ-22 strain), phosphate solubilization functional group (Bacillus megaterium BM-3 strain, Pseudomonas fluorescens PF-15 strain), organic matter transformation functional group (Trichoderma harzianum TH-88 strain, Streptomyces lydicus SL-5 strain) and plant growth promotion functional group (Bacillus subtilis BS-42 strain, Pseudomonas putida PP-9 strain).

[0080] The matrix of this embodiment has excellent physical and chemical properties, including a bulk density of 0.20 g / cm³, a total porosity of 85%, a maximum water holding capacity of 350% (w / w), a pH value of 6.2, an EC value of 0.6 mS / cm, and a cation exchange capacity of 120 meq / L. In terms of multiple cycle performance, the matrix can be recycled 5 times, and after the fifth cycle, the physical structure retention rate is 89%, and the microbial activity retention rate is 82%.

[0081] It should be noted that the multi-source organic matter materials used in this embodiment form a mutually supporting network structure. Among them, the lignocellulosic materials mainly provide the framework support and macroscopic pores, the agricultural by-products mainly contribute to the mesopores and medium-acting nutrients, and the food processing waste provides the micropores and quick-acting nutrients. The three work together to form a stable three-dimensional pore structure system. At the same time, the modified zeolite powder and bentonite in the functional mineral materials effectively regulate the dynamic balance of water and nutrients in the substrate through their high specific surface area and ion exchange capacity; perlite and diatomite optimize the aeration and drainage of the substrate, preventing compaction and structural collapse of the substrate during use.

[0082] Example 2:

[0083] A recyclable plant growth substrate, the composition of which includes the following components in weight percentages:

[0084] 80% organic matter materials, including 40% lignocellulosic materials (20% crushed poplar waste, 15% processed pine wood scraps, 5% bamboo processing waste), 30% agricultural by-products (15% crushed almond shells, 10% processed cottonseed hulls, 5% rice husk char), 10% food processing waste (5% processed coffee grounds, 5% fruit residue ferment); 10% functional mineral materials, including 5% porous adsorption materials (3% modified zeolite powder, 2% bentonite) and 5% structural support materials (3% perlite, 2% diatomite); 5% bioactive components, including 2% seaweed extract complex, 2% humic acid substances and 1% plant-derived amino acid complex; 5% biopolymer bonding system, including 2.5% alginate-ion cross-linked complex (1.7% sodium alginate, 0.8% calcium chloride cross-linking agent) and 2.5% modified starch-protein complex (1.7% oxidized corn starch, 0.8% soy protein isolate); at the same time, inoculate a functional microbial system, the total viable count is 7×10 8 CFU / g, and the microbial composition is the same as that in Example 1.

[0085] The physical and chemical properties of the substrate in this embodiment are: bulk density 0.18 g / cm³, total porosity 88%, maximum water holding capacity 370% (w / w), pH value 6.0, EC value 0.5 mS / cm, cation exchange capacity 110 meq / L. This substrate can be recycled 4 times, and the physical structure retention rate after the 4th cycle is 87%, and the microbial activity retention rate is 80%.

[0086] Since the content of organic matter materials in this embodiment is increased to 80%, the water holding capacity and nutrient storage capacity of the substrate are significantly enhanced, which is particularly suitable for plant species that require long-term cultivation and have a low watering frequency. At the same time, the increase in the proportion of lignocellulosic materials improves the structural stability of the substrate, enabling it to maintain a good physical structure during repeated wet-dry cycles.

[0087] Example 3:

[0088] A recyclable plant growth substrate, the composition of which includes the following components by weight percentage:

[0089] Organic matter materials 70%, including 35% of wood fiber materials (15% of crushed poplar waste, 10% of processed pine wood scraps, 10% of bamboo processing waste), 20% of agricultural by-products (10% of crushed almond shells, 5% of cottonseed hull treatment products, 5% of rice husk carbonized products); 15% of functional mineral materials, including 10% of porous adsorption materials (5% of modified zeolite powder, 5% of bentonite) and 5% of structural support materials (3% of perlite, 2% of diatomite); 10% of bioactive components, including 4% of seaweed extract complex, 3% of humic acid substances and 3% of plant-derived amino acid complex; 5% of biopolymer bonding system, including 3% of alginate-ion cross-linked complex (2% of sodium alginate, 1% of calcium chloride cross-linking agent) and 2% of modified starch-protein complex (1.5% of oxidized corn starch, 0.5% of soy protein isolate); at the same time, a functional microorganism system is inoculated, and the total viable bacteria count is 9×10 8 CFU / g, and the microbial composition is the same as that in Example 1.

[0090] The physical and chemical properties of the substrate in this example are: bulk density 0.22 g / cm³, total porosity 82%, maximum water holding capacity 320% (w / w), pH value 5.8, EC value 0.9 mS / cm, cation exchange capacity 140 meq / L. This substrate can be recycled 5 times, and the physical structure retention rate after the 5th cycle is 92%, and the microbial activity retention rate is 85%.

[0091] The remarkable feature of this example is that the proportions of both the bioactive components and the biopolymer bonding system reach 10%, which greatly improves the biological activity and structural stability of the substrate. Among them, the seaweed extract complex is rich in polysaccharides, growth hormones and trace elements, which can effectively promote the development of plant roots; the humic acid substances enhance the cation exchange ability and nutrient buffering ability of the substrate; the plant-derived amino acid complex can be used as a high-quality carbon and nitrogen source for microorganisms and directly promote plant growth. The increase in the proportion of the biopolymer bonding system forms a more solid double-network cross-linked structure, enabling the substrate to maintain excellent structural stability after multiple cycles of use.

[0092] Example 4:

[0093] A recyclable plant growth substrate, the composition of which includes the following components by weight percentage:

[0094] 75% organic matter materials, including 35% wood fiber materials (17% crushed poplar waste, 12% processed pine wood scraps, 6% bamboo processing waste), 25% agricultural by-products (12% crushed almond shells, 7% cottonseed hulls treated, 6% rice husk carbonized materials), 15% food processing waste (8% coffee grounds treated, 7% fruit residue fermented materials); 15% functional mineral materials, including 7% porous adsorption materials (4% modified zeolite powder, 3% bentonite) and 8% structural support materials (5% perlite, 3% diatomaceous earth); 7% bioactive components, including 3% seaweed extract complex, 2% humic acid substances, and 2% plant-derived amino acid complex; 3% biopolymer binding system, including 1.5% alginate-ion cross-linked complex (1.0% sodium alginate, 0.5% calcium chloride cross-linking agent) and 1.5% modified starch-protein complex (1.0% oxidized corn starch, 0.5% soy protein isolate); at the same time, inoculate a functional microbial system, the total viable count is 6×10 8 CFU / g, and the microbial composition is the same as that in Example 1.

[0095] The physical and chemical properties of the substrate in this example are: bulk density 0.25 g / cm³, total porosity 80%, maximum water holding capacity 300% (w / w), pH value 6.2, EC value 0.7 mS / cm, cation exchange capacity 135 meq / L. This substrate can be recycled 5 times. After the 5th cycle, the physical structure retention rate is 88% and the microbial activity retention rate is 82%.

[0096] This example adopts a relatively balanced formulation design, and the content of each component is at a medium level, enabling the substrate to achieve a good balance in aspects such as water retention, nutrient supply, structural stability, and microbial activity. This formulation design makes the substrate have broad adaptability and is suitable for the cultivation of various plants. In particular, the proportion of the structural support material in the functional mineral materials is slightly higher than that of the porous adsorption material, further optimizing the physical structure of the substrate, improving air permeability and drainage, and preventing structural compaction during long-term use.

[0097] Example 5:

[0098] A recyclable plant growth substrate, the composition of which includes the following components in weight percentages:

[0099] 75% organic matter materials, including 32% lignocellulosic materials (16% pulverized poplar waste, 11% processed pine wood scraps, 5% bamboo processing waste), 23% agricultural by-products (11% pulverized almond shells, 6% cottonseed hulls treated, 6% rice husk carbonized), 20% food processing waste (10% coffee grounds treated, 10% fruit residue fermented); 15% functional mineral materials, including 8% porous adsorption materials (5% modified zeolite powder, 3% bentonite) and 7% structural support materials (4% perlite, 3% diatomaceous earth); 7% bioactive components, including 2.5% seaweed extract complex, 2.5% humic acid substances, and 2% plant-derived amino acid complex; 3% biopolymer binder system, including 2% alginate-ion crosslinked complex (1.3% sodium alginate, 0.7% calcium chloride crosslinking agent) and 1% modified starch-protein complex (0.7% oxidized corn starch, 0.3% soy protein isolate); and simultaneously inoculated with a functional microorganism system, with a total viable count of 7×10 8 CFU / g, and the microbial composition is the same as in Example 1.

[0100] The physical and chemical properties of the substrate in this example are: bulk density 0.23 g / cm³, total porosity 81%, maximum water holding capacity 310% (w / w), pH value 6.0, EC value 0.8 mS / cm, cation exchange capacity 130 meq / L. This substrate can be recycled 5 times, and after the 5th cycle, the physical structure retention rate is 89% and the microbial activity retention rate is 83%.

[0101] The feature of this example is that the proportion of food processing waste is increased to 20%, and the proportion of porous adsorption materials is increased to 8%. This formulation design enables the substrate to have better initial nutrient supply capacity and nutrient adsorption and retention capacity, and is especially suitable for vegetable crops with high nutrient requirements. After the coffee grounds and fruit residue in the food processing waste are fermented, they can not only provide quick-acting nutrients, but also provide a good habitat environment and carbon source for microorganisms, promoting the rapid construction of the microbial community.

[0102] Example 6:

[0103] A recyclable plant growth substrate, the composition of which includes the following components in weight percentages:

[0104] 73% organic matter materials, including 33% wood fiber materials (16% crushed poplar waste, 12% treated pine wood processing scraps, 5% bamboo processing waste), 25% agricultural by-products (12% crushed almond shells, 8% treated cottonseed hulls, 5% rice husk carbide), 15% food processing waste (8% treated coffee grounds, 7% fermented fruit residues); 13% functional mineral materials, including 6% porous adsorption materials (3.5% modified zeolite powder, 2.5% bentonite) and 7% structural support materials (4% perlite, 3% diatomite); 8% bioactive components, including 3% seaweed extract complex, 3% humic acid substances, and 2% plant-derived amino acid complex; 6% biopolymer binding system, including 3% alginate-ion cross-linked complex (2% sodium alginate, 1% calcium chloride cross-linking agent) and 3% modified starch-protein complex (2% oxidized corn starch, 1% soy protein isolate); at the same time, inoculate a functional microbial system, the total viable count is 8×10 8 CFU / g, and the microbial composition is the same as that in Example 1.

[0105] The physical and chemical properties of the substrate in this example are: bulk density 0.26 g / cm³, total porosity 79%, maximum water holding capacity 290% (w / w), pH value 6.1, EC value 0.75 mS / cm, cation exchange capacity 138 meq / L. This substrate can be recycled 5 times, and after the 5th cycle, the physical structure retention rate is 91% and the microbial activity retention rate is 84%.

[0106] The significant feature of this example is that the proportion of the biopolymer binding system is increased to 6%, and at the same time, the proportion of the bioactive components reaches 8%. This formulation design strengthens the structural stability and biological activity of the substrate while maintaining the basic physical structure. In particular, the synergistic effect of the alginate-ion cross-linked complex and the modified starch-protein complex forms a more stable double-network cross-linked structure, enabling the substrate to have a structure retention rate of 91% during multiple recycling processes, which is the highest among all examples.

[0107] Example 7: The preparation method of Example 1

[0108] A preparation method of a recyclable plant growth substrate, comprising the following steps:

[0109] (1) Raw material pretreatment: First, the organic matter materials are crushed and classified. Specifically, for lignocellulosic materials, a double-rotor staggered-tooth hammer mill is used with a rotational speed set at 1200 rpm and equipped with a 2-mm sieve for crushing; for agricultural by-products, the same equipment is used with the rotational speed adjusted to 1500 rpm and equipped with a 1-mm sieve for crushing; for food processing waste, the same equipment is used with the rotational speed increased to 1800 rpm and equipped with a 0.5-mm sieve for crushing. Then, the crushed materials are classified through a vibrating multi-layer screening system to obtain particles in five particle size grades of 5 - 3 mm, 3 - 1 mm, 1 - 0.5 mm, 0.5 - 0.1 mm, and <0.1 mm, and the mass ratios are controlled at 15%, 30%, 25%, 15%, and 10% respectively.

[0110] Meanwhile, the mineral materials are modified: For zeolite modification, a 3% cetyltrimethylammonium bromide solution is used and treated at 65 °C for 3.5 hours with a solid-liquid ratio of 1:5 and a stirring speed of 900 rpm; for bentonite activation, a 3% sodium carbonate solution is used and treated at 55 °C for 2.5 hours with a solid-liquid ratio of 1:6 and a stirring speed of 700 rpm.

[0111] In addition, the bioactive components are extracted and purified: Seaweed extracts are extracted using an alkali hydrolysis - neutralization - concentration process; humic acid substances are extracted using an alkali hydrolysis - acid precipitation process; plant-derived amino acids are extracted using an enzymatic hydrolysis - membrane separation process. Specifically as follows:

[0112] 1. The preparation method of the seaweed extract complex can be carried out according to the following steps:

[0113] (1) Raw material treatment: Select brown algae (such as kelp, sargassum) as raw materials, wash and cut the fresh or dried seaweed into small sections of 1 - 2 cm, and dry it to a moisture content ≤ 12%.

[0114] (2) Alkali hydrolysis process:

[0115] a. Add the treated seaweed to a 2 - 4% NaOH solution at a ratio of 1:15 (w / v);

[0116] b. Stir and extract at 75 - 85 °C for 3 - 4 hours;

[0117] c. Control the stirring speed at 150 - 200 rpm;

[0118] d. After the extraction is completed, centrifuge at 4000 rpm for 15 minutes and collect the supernatant;

[0119] (3) Neutralization treatment:

[0120] a. Adjust the pH value of the supernatant to 6.5 - 7.0 with 6M HCl;

[0121] b. During the adjustment process, maintain the temperature at 30 - 35 °C and the stirring speed at 100 rpm;

[0122] c. After neutralization, let it stand and precipitate for 2 hours, centrifuge at 4000 rpm for 10 minutes, and collect the supernatant;

[0123] (4) Concentration and purification:

[0124] a. Concentrate the neutralized supernatant under reduced pressure to 1 / 5 of the original volume at 60 °C using a rotary evaporator;

[0125] b. Add 3 volumes of absolute ethanol to the concentrated solution and let it stand and precipitate at 4 °C for 12 hours;

[0126] c. Centrifuge at 4000 rpm for 20 minutes and collect the precipitate;

[0127] d. Vacuum dry the precipitate at 60 °C for 24 hours to obtain the crude seaweed extract;

[0128] (5) Refining treatment:

[0129] a. Dissolve the crude product in deionized water (1:10 w / v) and adjust the pH to 7.0;

[0130] b. Filter out impurities through a 0.45 μm microporous membrane;

[0131] c. Freeze-dry for 72 hours to obtain the final product of the seaweed extract complex;

[0132] The final product should meet the following standards: the content of active polysaccharides ≥ 25%, the content of alginic acid ≥ 15%, the moisture content ≤ 8%, the pH value is 6.5 - 7.5, the heavy metal content ≤ 20 ppm, and the total number of microorganisms ≤ 1000 CFU / g.

[0133] 2. The preparation method of humic acid substances is carried out according to the following steps:

[0134] (1) Raw material selection: Select weathered coal, lignite or peat as raw materials and crush them to less than 80 mesh.

[0135] (2) Alkaline hydrolysis extraction:

[0136] a. Add the raw materials to a 4 - 6% KOH or NaOH solution at a ratio of 1:10 (w / v);

[0137] b. Stir and extract at 85 - 95 °C for 4 - 6 hours;

[0138] c. Control the stirring speed at 200 - 250 rpm;

[0139] d. Add 0.3 - 0.5% of Na2EDTA as a chelating agent to improve the extraction efficiency;

[0140] e. After the extraction is completed, filter to remove insoluble substances;

[0141] (3) Acid precipitation:

[0142] a. Slowly add 6M H2SO4 or HCl to the filtrate while stirring;

[0143] b. Adjust the pH to 1.0 - 2.0, at which point humic acid begins to precipitate;

[0144] c. Continue stirring for 30 minutes, then let it stand for sedimentation for 4 - 6 hours;

[0145] d. Centrifuge at 4000 rpm for 15 minutes, collect the precipitate (humic acid), and retain the supernatant (containing fulvic acid);

[0146] (4) Humic acid purification:

[0147] a. Wash the precipitate with deionized water 3 times, and centrifuge at 3000 rpm for 10 minutes after each wash;

[0148] b. Redissolve the washed precipitate in 1% KOH or NaOH solution;

[0149] c. Filter to remove insoluble substances, and adjust the pH of the filtrate to 1.0 - 2.0 with acid again for precipitation;

[0150] d. Centrifuge to collect the precipitate and dry it at 60°C for 24 hours to obtain the humic acid product;

[0151] (5) Fulvic acid recovery:

[0152] a. Add the supernatant (containing fulvic acid) from the first acid precipitation to the XAD - 8 resin adsorption column;

[0153] b. Wash off impurities with deionized water, and then elute the adsorbed fulvic acid with 0.1M NaOH;

[0154] c. Collect the eluate, adjust the pH to neutral, concentrate and spray - dry to obtain the fulvic acid product;

[0155] d. Mix humic acid and fulvic acid in a ratio of 4:1 to obtain a composite product of humic acid - like substances;

[0156] The final product should meet the following standards: humic acid content ≥ 60%, fulvic acid content ≥ 15%, moisture content ≤ 10%, pH value (1% aqueous solution) is 8.0 - 9.0, organic carbon content ≥ 40%, ash content ≤ 15%.

[0157] 3. The preparation method of the plant-derived amino acid complex is carried out according to the following steps:

[0158] (1) Raw material selection and pretreatment:

[0159] a. Select high-protein plant materials such as legumes (soybeans, peas) or wheat germ;

[0160] b. Grind to less than 100 mesh and perform defatting treatment (extract 3 times with n-hexane at a ratio of 1:5 w / v);

[0161] c. Dry at 60 °C until the moisture content ≤ 8%;

[0162] (2) Enzymolysis process:

[0163] a. Suspend the pretreated raw materials in a buffer solution (pH 6.8 - 7.2) at a ratio of 1:10 (w / v);

[0164] b. Add a protease complex (alkaline protease, neutral protease, papain mixed in a ratio of 2:2:1), and the enzyme addition amount is 2 - 3% of the raw material mass;

[0165] c. Perform enzymolysis at 50 - 55 °C for 8 - 12 hours, with a stirring speed of 100 - 150 rpm;

[0166] d. Adjust the pH appropriately during enzymolysis to maintain it within the optimal pH range;

[0167] e. After the enzymolysis is completed, heat at 95 °C for 15 minutes to inactivate the enzyme;

[0168] f. Cool to room temperature, centrifuge at 10000 rpm for 20 minutes, and collect the supernatant;

[0169] (3) Membrane separation process:

[0170] a. Ultrafiltration pretreatment: Use an ultrafiltration membrane with a molecular weight cut-off of 10000 Da, at a pressure of 0.3 - 0.4 MPa, to remove macromolecular proteins and impurities;

[0171] b. Nanofiltration concentration: Use a nanofiltration membrane with a molecular weight cut-off of 1000 Da, at a pressure of 0.6 - 0.8 MPa, to concentrate to a total solids content of 15 - 20%;

[0172] c. Ion exchange: Perform desalting treatment through cation exchange resin (Amberlite IR-120) and anion exchange resin (Amberlite IRA-400);

[0173] (4) Final product preparation:

[0174] a. Adjust the pH of the treatment solution to 5.5 - 6.0

[0175] b. Spray drying (inlet temperature 180 - 200 °C, outlet temperature 80 - 90 °C) or freeze drying (pre-freezing at -40 °C, main drying stage at -20 °C, for 24 - 36 hours)

[0176] c. Crush and screen to obtain the final plant-derived amino acid complex product

[0177] The final product should meet the following standards: total amino acid content ≥ 40%, free amino acid content ≥ 15%, moisture content ≤ 8%, pH value (1% aqueous solution) is 5.5 - 6.5, heavy metal content ≤ 10 ppm, and no pathogenic bacteria

[0178] (2) Multi-stage proportioning and mixing: Mix the pre-treated various materials in multiple stages according to the predetermined ratio. The first-stage mixing is to add the lignocellulosic material and agricultural by-products into a double-helix conical mixer, with the rotation speed set at 18 rpm and the mixing time of 9 minutes; the second-stage mixing is to add food processing waste, with the rotation speed adjusted to 14 rpm and the mixing time of 6 minutes; the third-stage mixing is to add functional mineral materials, with the rotation speed reduced to 11 rpm and the mixing time extended to 11 minutes. Subsequently, use a spray system to adjust the moisture content of the mixture to 40% to prepare for subsequent forming

[0179] (3) Pressure-controlled forming: Add the uniformly mixed materials into a variable-frequency hydraulic forming machine for forming. The forming process adopts an innovative segmented control pressure process, specifically: maintain a pressure of 1.0 MPa for 3 seconds, then increase to 2.0 MPa and maintain for 2 seconds, and finally increase to 3.0 MPa and maintain for 1 second. The forming temperature is controlled at 70 °C, the pressure holding time is 6 seconds, and the demolding temperature is 42 °C. The forming specification is a cylinder with a diameter of 40 mm × height of 40 mm. The design of this segmented pressure control process can form a stable external shape while retaining the internal pore structure of the matrix, which is the key process to achieve a three-level pore structure

[0180] (4) Function imparting: Conduct nutrient gradient loading and microbial function inoculation on the formed matrix. Nutrient gradient loading uses a vacuum impregnation device, with the vacuum degree set at -0.085 MPa, and the impregnation time is divided into three segments (5 minutes - 15 minutes - 5 minutes). The impregnation liquid formula is as follows: for the rapid release layer, use a mixed solution of water-soluble nitrogen, phosphorus, potassium and trace elements (ratio of 1.5:1:2) with a concentration of 1.2%; for the medium release layer, use a solution of slow-release nitrogen, phosphorus, potassium complex (ratio of 1:1:1) with a concentration of 1.5%; for the long-term release layer, use a mixed solution of organic nitrogen, calcium dihydrogen phosphate and potassium sulfate (ratio of 1:0.5:0.5) with a concentration of 1.0%. The impregnation temperature is controlled at 32 °C

[0181] Microbial function inoculation adopts a multi-point pulse spraying technique, and the concentration of the inoculated bacterial liquid is 1×10 9CFU / ml, the inoculation amount is 12 ml / kg of the substrate, the inoculation temperature is controlled at 22 °C, the inoculation method is multi-point pulsed spraying (spray for 3 seconds - interval for 2 seconds - spray for 3 seconds), the spraying pressure is 0.25 MPa, the nozzle specification is a fan-shaped nozzle, and the spray angle is 80°.

[0182] (5) Structure stabilization: The substrate after function assignment is subjected to biopolymer cross-linking and heat-assisted strengthening treatment. Biopolymer cross-linking uses a microspray cross-linking reaction tower, the cross-linking agent is 0.8% calcium chloride solution, the spraying pressure is 0.2 MPa, the spraying amount is 50 ml / kg of the substrate, the reaction temperature is 28 °C, the reaction time is 40 minutes, and the relative air humidity is controlled at 75%. This step is the key process for forming the alginate-calcium ion cross-linking network.

[0183] The heat-assisted strengthening treatment is carried out using a temperature-controlled ripening chamber, and the treatment temperature adopts a segmented control mode: maintain at 40 °C for 2 hours, then rise to 50 °C and maintain for 1 hour, and finally drop back to 40 °C and maintain for 3 hours. The relative humidity is controlled at 65%, the air flow rate is 0.8 m / s, and it is flipped once every 60 minutes. This step mainly promotes the formation of a thermally stable cross-linking network of the modified starch-protein complex, which synergistically acts with the alginate-calcium ion cross-linking network to greatly improve the structural stability of the substrate.

[0184] (6) Humidity adjustment and packaging: The substrate is precisely humidity-adjusted using an intelligent humidity control drying chamber, the drying temperature is 32 °C, the relative humidity is 55%, the wind speed is 1.8 m / s, the drying time is 10 hours, and it is flipped once every 60 minutes. The final moisture content is controlled at 17%. Subsequently, the substrate is subjected to microbial protection treatment using a low-temperature protective agent spraying device, and the protective agent formula is a mixed solution of 5% trehalose + 2% glycerol + 1% polyvinylpyrrolidone. The spraying temperature is 22 °C, the spraying amount is 12 ml / kg of the substrate, and it is dried at 28 °C and a relative humidity of 45% for 2.5 hours.

[0185] Finally, modified atmosphere packaging is carried out using a MAP modified atmosphere packaging machine, the packaging material is a high-barrier multi-layer co-extruded film (PE / PA / EVOH / PA / PE), the inflation ratio is N2 80% + CO2 20%, the sealing temperature is 135 °C, the sealing pressure is 0.55 MPa, the sealing time is 1.2 seconds, the residual oxygen content is controlled below 0.8%, and the packaging specification is 5 kg / bag.

[0186] Example 8: The preparation method of Example 2

[0187] A preparation method of a recyclable plant growth substrate, comprising the following steps:

[0188] (1) Raw material pretreatment: On the basis of Example 7, the following parameters are adjusted: the crushing speed of the lignocellulosic material is increased to 1300 rpm; the crushing speed of agricultural by-products is increased to 1600 rpm; the crushing speed of food processing waste is increased to 2000 rpm. The mass ratio of particle size classification is adjusted to: 5 - 3 mm (18%), 3 - 1 mm (32%), 1 - 0.5 mm (28%), 0.5 - 0.1 mm (12%), <0.1 mm (10%).

[0189] The parameters for the modification treatment of mineral materials are adjusted as follows: for zeolite modification, a 3.5% cetyltrimethylammonium bromide solution is used and treated at 68 °C for 4 hours, with a solid-liquid ratio of 1:4.5; for bentonite activation, a 3.5% sodium carbonate solution is used and treated at 58 °C for 3 hours, with a solid-liquid ratio of 1:5.5.

[0190] The process for the extraction and purification of bioactive components is the same as that in Example 7.

[0191] (2) Multi-stage proportioning and mixing: The mixing speed of the first stage is adjusted to 19 rpm and the mixing time is 10 minutes; the mixing speed of the second stage is adjusted to 15 rpm and the mixing time is 7 minutes; the mixing speed of the third stage is adjusted to 12 rpm and the mixing time is 12 minutes. The moisture content of the mixture is adjusted to 38%.

[0192] (3) Pressure-controlled molding: The molding temperature is reduced to 68 °C and the pressure holding time is extended to 7 seconds, with other parameters the same as in Example 7.

[0193] (4) Function imparting: The concentration of the impregnating solution with nutrient gradient loading is adjusted to: 1.3% for the rapid release layer, 1.6% for the medium release layer, and 1.1% for the long-term release layer. The inoculation amount of microbial functions is increased to 14 ml / kg of the substrate, and the inoculation temperature is adjusted to 23 °C.

[0194] (5) Structure stabilization: The concentration of the cross-linking agent is adjusted to a 0.7% calcium chloride solution, the spraying amount is increased to 55 ml / kg of the substrate, the reaction temperature is adjusted to 29 °C, and the reaction time is extended to 45 minutes. The temperature for heat-assisted strengthening treatment is adjusted to: maintain at 38 °C for 2 hours, then rise to 48 °C and maintain for 1 hour, and finally drop back to 38 °C and maintain for 3 hours.

[0195] (6) Humidity adjustment and packaging: The same as in Example 7.

[0196] Example 9: The preparation method of Example 3

[0197] A preparation method of a recyclable plant growth substrate, comprising the following steps:

[0198] (1) Raw material pretreatment: The crushing speed of lignocellulosic materials is set at 1500 rpm, equipped with a 1.5 mm sieve; the crushing speed of agricultural by-products is set at 1800 rpm, equipped with a 0.8 mm sieve; the crushing speed of food processing waste is set at 2200 rpm, equipped with a 0.3 mm sieve. The mass ratio of particle size classification is adjusted to: 5 - 3 mm (20%), 3 - 1 mm (35%), 1 - 0.5 mm (30%), 0.5 - 0.1 mm (10%), <0.1 mm (5%).

[0199] The parameters of mineral material modification treatment are adjusted as follows: For zeolite modification, a 4% cetyltrimethylammonium bromide solution is used and treated at 70 °C for 4.5 hours, with a solid-liquid ratio of 1:4; for bentonite activation, a 4% sodium carbonate solution is used and treated at 60 °C for 3.5 hours, with a solid-liquid ratio of 1:5.

[0200] (2) Multi-stage proportioning and mixing: The mixing speed of the first stage is set at 20 rpm, and the mixing time is 11 minutes; the mixing speed of the second stage is set at 16 rpm, and the mixing time is 8 minutes; the mixing speed of the third stage is set at 13 rpm, and the mixing time is 13 minutes. The moisture content of the mixture is adjusted to 42%.

[0201] (3) Pressure-controlled forming: The forming temperature is increased to 75 °C, and the pressure control parameters are adjusted as follows: Maintain a pressure of 1.2 MPa for 3.5 seconds, then increase to 2.2 MPa and maintain for 2.5 seconds, and finally increase to 3.2 MPa and maintain for 1.5 seconds. The pressure holding time is extended to 8 seconds, and the demolding temperature is increased to 45 °C.

[0202] (4) Function imparting: The vacuum degree of nutrient gradient loading is increased to -0.09 MPa, and the concentration of the impregnating solution is adjusted as follows: The concentration of the rapid release layer is 1.5%, the concentration of the medium release layer is 1.8%, and the concentration of the long-acting release layer is 1.2%. The inoculation amount of microbial function is increased to 16 ml / kg of the substrate, and the inoculation temperature is adjusted to 25 °C.

[0203] (5) Structure stabilization: The concentration of the cross-linking agent is increased to a 1.0% calcium chloride solution, the spraying amount is increased to 60 ml / kg of the substrate, the reaction temperature is adjusted to 30 °C, and the reaction time is extended to 50 minutes. The temperature of the heat-assisted strengthening treatment is adjusted as follows: Maintain at 40 °C for 2 hours, then rise to 50 °C and maintain for 1.5 hours, and finally drop back to 40 °C and maintain for 3 hours.

[0204] (6) Humidity adjustment and packaging: The drying temperature is adjusted to 30 °C, the relative humidity is adjusted to 50%, the wind speed is adjusted to 2.0 m / s, the drying time is shortened to 9 hours, and the final moisture content is controlled at 16%. The formulation of the protective agent is adjusted to a mixed solution of 6% trehalose + 2.5% glycerol + 1.2% polyvinylpyrrolidone, and the spraying amount is increased to 15 ml / kg of the substrate.

[0205] Example 10: Preparation method of Example 4

[0206] A preparation method of a recyclable plant growth substrate, comprising the following steps:

[0207] The preparation method basically refers to Example 7, but adjustments are made in the following aspects:

[0208] (1) Raw material pretreatment: The mass ratio of particle size classification is adjusted to: 5 - 3mm (16%), 3 - 1mm (31%), 1 - 0.5mm (27%), 0.5 - 0.1mm (13%), <0.1mm (13%).

[0209] (2) Multi - stage proportioning and mixing: The moisture content of the mixture is adjusted to 39%.

[0210] (3) Pressure - controlled forming: The forming temperature is adjusted to 72°C, and the pressure control parameters are adjusted to: maintain 1.1MPa for 3 seconds, then increase to 2.1MPa and maintain for 2 seconds, and finally increase to 3.1MPa and maintain for 1 second.

[0211] (4) Function imparting: The formula of the impregnating solution for nutrient gradient loading is adjusted to: For the rapid - release layer, use a mixed solution of water - soluble nitrogen, phosphorus, potassium and trace elements (1.2:1:1.8 ratio), with a concentration of 1.3%; for the medium - release layer, use a solution of slow - release nitrogen, phosphorus, potassium complex (1.1:1:0.9 ratio), with a concentration of 1.6%; for the long - term release layer, use a mixed solution of organic nitrogen, calcium dihydrogen phosphate and potassium sulfate (1.2:0.6:0.6 ratio), with a concentration of 1.1%.

[0212] (5) Structure stabilization: The temperature of the thermal - assisted strengthening treatment is adjusted to: maintain at 41°C for 2.5 hours, then rise to 49°C and maintain for 1.2 hours, and finally drop back to 41°C and maintain for 2.5 hours.

[0213] Example 11: Preparation method of Example 5

[0214] A preparation method of a recyclable plant growth substrate, comprising the following steps:

[0215] The preparation method basically refers to Example 7, but adjustments are made in the following aspects:

[0216] (1) Raw material pretreatment: For zeolite modification, use a 3.2% cetyltrimethylammonium bromide solution and treat at 67°C for 3.8 hours; for bentonite activation, use a 3.2% sodium carbonate solution and treat at 57°C for 2.8 hours.

[0217] (2) Multi - stage proportioning and mixing: The first - stage mixing time is extended to 10 minutes; the second - stage mixing time is extended to 7 minutes; the third - stage mixing time is extended to 12 minutes.

[0218] (3) Pressure-controlled forming: The forming temperature is adjusted to 69 °C, and the pressure holding time is adjusted to 6.5 seconds.

[0219] (4) Function imparting: The microbial function inoculation adopts an intermittent spraying technique, and the inoculation mode is spraying for 4 seconds - interval for 3 seconds - spraying for 4 seconds.

[0220] (5) Structure stabilization: The relative air humidity is adjusted to 70%, and it is turned over every 45 minutes.

[0221] (6) Humidity adjustment and packaging: The protective agent formula is adjusted to a mixed solution of 5.5% trehalose + 2.2% glycerol + 1.1% polyvinylpyrrolidone.

[0222] Example 12: The preparation method of Example 6

[0223] A preparation method of a recyclable plant growth substrate, comprising the following steps:

[0224] The preparation method basically refers to Example 7, but adjustments are made in the following aspects:

[0225] (1) Raw material pretreatment: The mass ratio of particle size classification is adjusted to: 5 - 3 mm (17%), 3 - 1 mm (33%), 1 - 0.5 mm (26%), 0.5 - 0.1 mm (14%), <0.1 mm (10%).

[0226] (2) Multi-stage proportioning and mixing: The moisture content of the mixture is adjusted to 41%.

[0227] (3) Pressure-controlled forming: The pressure control parameters are adjusted to: maintaining 1.0 MPa for 3.2 seconds, then increasing to 2.0 MPa and maintaining for 2.2 seconds, and finally increasing to 3.0 MPa and maintaining for 1.2 seconds.

[0228] (4) Function imparting: The impregnation time of nutrient gradient loading is adjusted to three stages (6 minutes - 16 minutes - 6 minutes).

[0229] (5) Structure stabilization: The concentration of the cross-linking agent is adjusted to 0.9% calcium chloride solution, and the reaction time is extended to 45 minutes.

[0230] (6) Humidity adjustment and packaging: The final moisture content is controlled at 16.5%.

[0231] Comparative Example

[0232] Comparative Example 1: Traditional peat substrate

[0233] A traditional peat substrate, the composition of which includes the following components in weight percentages:

[0234] 60% peat, 20% perlite, 15% vermiculite, 2% limestone powder, 3% organic fertilizer.

[0235] Preparation method: Crush the peat to an average particle size of 3 mm, mix the perlite and vermiculite with their original particle sizes, add the limestone powder and organic fertilizer, mix in a horizontal mixer at a rotation speed of 10 rpm for 15 minutes, adjust the moisture content to 45%, and perform simple granulation to make the product.

[0236] The physical and chemical properties of this substrate are: bulk density 0.15 g / cm³, total porosity 85%, maximum water holding capacity 320% (w / w), pH value 5.8, EC value 0.5 mS / cm, cation exchange capacity 120 meq / L, carbon-nitrogen ratio 50:1.

[0237] This substrate cannot be effectively recycled after being used once. When used for the second time, the structure collapses severely, resulting in a significant decrease in air permeability and drainage, and the crop growth effect decreases by more than 45%. Its main disadvantages are: the single source of organic matter leads to poor structural stability; the lack of a biopolymer cross-linking network makes it prone to structural collapse during use; the lack of a functional microbial system results in low biological activity; the use of non-renewable resources leads to poor environmental sustainability.

[0238] Comparative Example 2: Coconut coir substrate

[0239] A coconut coir substrate, the composition of which includes the following components in weight percentages:

[0240] 70% coconut coir, 15% perlite, 10% vermiculite, 5% organic fertilizer.

[0241] Preparation method: Wash and desalt the coconut coir and then crush it to an average particle size of 2 mm, mix it with perlite, vermiculite and organic fertilizer, mix in a horizontal mixer at a rotation speed of 12 rpm for 12 minutes, adjust the moisture content to 50%, and perform simple granulation to make the product.

[0242] The physical and chemical properties of this substrate are: bulk density 0.12 g / cm³, total porosity 88%, maximum water holding capacity 380% (w / w), pH value 6.0, EC value 0.8 mS / cm, cation exchange capacity 100 meq / L, carbon-nitrogen ratio 80:1.

[0243] This substrate can be recycled 2 times, but after the second use, the structural stability decreases significantly, the water retention capacity decreases by more than 30%, the watering frequency needs to be increased, and the crop growth effect decreases by more than 25%. Its main disadvantages are: although it has good initial physical properties, the lack of a biopolymer cross-linking network makes its structural stability decline rapidly during the recycling process; the single source of organic matter limits the diversity of its physical structure; the too high carbon-nitrogen ratio makes the nutrient supply unbalanced.

[0244] Comparative Example 3: Substrate without using a microbial system

[0245] A substrate, the composition of which includes components in the following weight percentages:

[0246] Organic matter material 75%, functional mineral material 15%, bioactive ingredient 7%, biopolymer binding system 3%. The detailed ratio of each component is the same as that in Example 4, but the functional microbial system is not added.

[0247] The preparation method is the same as that in Example 10, but the microbial function inoculation step is skipped.

[0248] The physical and chemical properties of this substrate are: bulk density 0.25 g / cm³, total porosity 80%, maximum water holding capacity 300% (w / w), pH value 6.2, EC value 0.7 mS / cm, cation exchange capacity 135 meq / L.

[0249] This substrate can be recycled 3 times. After the 3rd cycle, the physical structure retention rate is 85%. However, due to the lack of microbial activity, the plant growth performance is poor, the yield is 15 - 20% lower than that in Example 4, and the quality index is 10 - 15% lower. Its main disadvantages are: the lack of a functional microbial system leads to low nutrient utilization efficiency; the soil structure improvement effect is poor; the plant stress resistance and disease resistance are reduced; and the root system development is poor.

[0250] Comparative Example 4: Substrate without using a biopolymer binding system

[0251] A substrate, the composition of which includes components in the following weight percentages:

[0252] Organic matter material 80%, functional mineral material 12%, bioactive ingredient 8%. The detailed ratio of each component refers to Example 3, but the biopolymer binding system is not added. At the same time, a functional microbial system is inoculated, and the total viable count is 9×10 8 CFU / g, and the microbial composition is the same as that in Example 1.

[0253] The preparation method is the same as that in Example 9, but the biopolymer crosslinking step is skipped.

[0254] The physical and chemical properties of this substrate are: bulk density 0.21 g / cm³, total porosity 83%, maximum water holding capacity 325% (w / w), pH value 5.8, EC value 0.9 mS / cm, cation exchange capacity 138 meq / L.

[0255] This substrate can only be recycled twice. After the second cycle, the physical structure retention rate is only 65%. By the third use, the structure has severely collapsed and cannot be used anymore. Its main disadvantages are: the lack of a biopolymer binding system results in poor physical structure stability; the pore structure gradually collapses during the wet-dry cycle; the number of recycling times is limited; the microbial activity retention time is short.

[0256] Comparative Example 5: Substrate with a single organic matter source

[0257] A substrate, the composition of which includes the following components in weight percentages:

[0258] 75% wood fiber material, 15% functional mineral material, 7% bioactive ingredient, 3% biopolymer binding system. At the same time, a functional microbial system is inoculated, and the total viable bacteria count is 6×10 8 CFU / g, and the microbial composition is the same as that in Example 1.

[0259] The preparation method is the same as that in Example 7, but only the wood fiber material is used as the organic matter source.

[0260] The physical and chemical properties of this substrate are: bulk density 0.18 g / cm³, total porosity 82%, maximum water holding capacity 270% (w / w), pH value 6.3, EC value 0.5 mS / cm, cation exchange capacity 110 meq / L.

[0261] This substrate can be recycled three times. After the third cycle, the physical structure retention rate is 80%. However, due to the single pore structure and unbalanced nutrient release, the plant growth performance is poor, and the yield is 10 - 15% lower than that in Example 4. Its main disadvantages are: a single organic matter source leads to a single pore structure; the nutrient release pattern is single and it is difficult to meet the needs of the entire growth period of plants; water management is difficult; microbial diversity is limited.

[0262] Example 13: Application in vegetable cultivation

[0263] The substrate prepared in Example 4 is used for tomato cultivation, and the specific application method is as follows:

[0264] (1) Substrate use - direct planting method: Put the substrate block into a plastic flower pot with a diameter of 15 cm, sow tomato seeds on the surface of the substrate, 3 seeds per pot, cover with 0.5 cm of fine substrate, and gently press to make the seeds in good contact with the substrate. Water for the first time until the substrate weight increases by 75%, and place it in an environment at 25°C for germination. Thin out the seedlings after emergence, and keep the most robust 1 plant per pot. Water subsequently to keep the substrate moist but not overly wet, watering once every 3 days. When the seedlings grow to 4 true leaves, apply a general liquid fertilizer diluted 100 times once a week.

[0265] (2) Substrate recovery after harvesting tomato plants: Use a water flow pulse separation system for root separation. The water pressure is 0.25 MPa, the pulse frequency is 2.5 Hz, the treatment temperature is 22 °C, the water flow angle is 40°, and the treatment time is 50 seconds per plant. The substrate recovery rate reaches 97%, and the root integrity retention rate is 93%. This water flow pulse separation technology is a key innovation of the present invention. Through precisely controlled water pressure and pulse frequency, it can effectively separate the substrate from the roots without damaging the plant roots.

[0266] (3) Substrate cleaning and disinfection: Use an eddy current cleaning and disinfection integrated machine to clean the recovered substrate. The cleaning temperature is 38 °C, the cleaning time is 4 minutes, the cleaning agent is 0.5% hydrogen peroxide solution, and the eddy current intensity is a frequency of 22 Hz. This treatment can effectively remove organic residues (removal rate reaches 96%) and pathogenic microorganisms (killing rate reaches 99.5%), while retaining a considerable part of beneficial microorganisms (retention rate reaches 45%).

[0267] (4) Substrate regeneration: First, perform structural reconstruction. Use a precise pressure reshaping system. The reconstruction pressure is zone-controlled (1.0 - 2.0 MPa), the pressurization mode is pulsed (pressurization for 2 seconds - relaxation for 1 second - pressurization for 2 seconds), the reconstruction temperature is 55 °C, and the treatment time is 40 seconds per batch. Then, perform nutrient supplementation. Use a precise nutrient solution impregnation system. The supplemented nutrient formula is 50% of the original formula concentration, the impregnation method is vacuum impregnation (-0.07 MPa), the impregnation time is 12 minutes, and the impregnation temperature is 28 °C. Finally, perform microbial function reconstruction. Use a microbial atomization inoculation system. The inoculation temperature is 24 °C, the inoculation humidity is 70%, and the activation time is 30 hours.

[0268] (5) Recycling effect: The regenerated substrate is used for the second cultivation of tomatoes. The growth rate reaches 92% compared with the new substrate, the yield reaches 90% compared with the new substrate, and there is no significant difference in quality compared with the new substrate. After continuous recycling 5 times, the growth rate of the 5th cycle reaches 85% compared with the new substrate, the yield reaches 83% compared with the new substrate, and there is no significant difference in quality compared with the new substrate.

[0269] Compared with Comparative Example 1 (traditional peat substrate), this substrate performs excellently in tomato cultivation, with a 24% increase in tomato yield and a 15% increase in the soluble solid content of the fruit; compared with Comparative Example 2 (coconut coir substrate), the yield increases by 18% and the soluble solid content increases by 12%; compared with Comparative Example 3 (substrate without using a microbial system), the yield increases by 22% and the soluble solid content increases by 16%.

[0270] Example 14: Application in flower cultivation

[0271] Use the substrate prepared in Example 5 for potted roses. The specific application method is as follows:

[0272] (1) Substrate use - mixed substrate method: Mix the substrate and perlite in a ratio of 7:3. Fill the mixture into a ceramic flower pot with a diameter of 20 cm to plant rose potted plants. Water for the first time until the substrate is completely wet, and drain the excess water. Subsequently, water to keep the substrate moist but not overly wet, water once every 4 - 5 days, and apply a special flower liquid fertilizer once a month.

[0273] (2) Substrate recovery and regeneration after replacing rose plants: The substrate recovery rate reaches 95%. Use the same method as in Example 13 for cleaning and regeneration treatment. The structure recovery rate reaches 92%, the microbial activity recovery rate reaches 86%, and the nutrient balance recovery rate reaches 90%.

[0274] (3) Recycling effect: After continuous recycling 4 times, the growth condition of roses in the 4th cycle reaches 88% compared with that of the new substrate, the number of flowers reaches 85% compared with that of the new substrate, and there is no significant difference in flower quality compared with that of the new substrate.

[0275] Compared with Comparative Example 1, this substrate performs excellently in rose cultivation, with the number of flowers increasing by 28% and the flowering period extending by 20 days; compared with Comparative Example 2, the number of flowers increases by 20% and the flowering period extends by 15 days; compared with Comparative Example 5 (substrate with a single organic matter source), the number of flowers increases by 25%, the flower color is more vivid, and the flower persistence increases by 18%.

[0276] Example 15: Soilless cultivation application

[0277] Use the substrate prepared in Example 6 for hydroponic cultivation of lettuce. The specific application method is as follows:

[0278] (1) Substrate use - soilless cultivation application method: Fill the substrate into a cultivation tank with a length of 60 cm × width of 15 cm × height of 10 cm. Set up a drip irrigation system, install 1 drip head for each plant, and plant lettuce seedlings with a plant spacing of 15 cm. The EC value of the nutrient solution formula is 2.0 mS / cm, and the pH value is 6.0. The irrigation frequency is 3 times a day in summer, 15 minutes each time; 2 times a day in winter, 12 minutes each time. The growth cycle of lettuce is 35 days.

[0279] (2) Substrate recovery and regeneration after harvesting lettuce: The substrate recovery rate reaches 98%, the structure recovery rate reaches 94%, the microbial activity recovery rate reaches 88%, and the nutrient balance recovery rate reaches 92%. The cleaning and regeneration treatment method is the same as that in Example 13, but in the link of microbial function reconstruction, the proportion of the inoculated bacterial community is adjusted, and the proportion of the phosphorus - solubilizing functional group and the plant - growth - promoting functional group is increased to meet the needs of continuous lettuce cultivation.

[0280] (3) Recycling effect: After continuous recycling 5 times, the growth rate of lettuce in the 5th cycle reached 90% compared with the new substrate, the yield reached 88% compared with the new substrate, and there was no significant difference in quality compared with the new substrate.

[0281] Compared with Comparative Example 1, this substrate performed excellently in the soilless cultivation system, with the lettuce yield increased by 30% and the growth cycle shortened by 5 days; compared with Comparative Example 2, the yield increased by 22% and the growth cycle shortened by 3 days; compared with Comparative Example 4 (substrate without using the biopolymer bonding system), the yield increased by 27%, the nitrate content decreased by 15%, and the leaf hardness increased by 20%.

[0282] Effect evaluation experiment:

[0283] Experiment 1: Physical properties and structural stability test

[0284] Test method: The substrate samples of each example and comparative example were tested as follows:

[0285] (1) Bulk density determination: The bulk density of the substrate was determined by the core cutter method.

[0286] (2) Total porosity determination: The total porosity of the substrate was determined by the water immersion method.

[0287] (3) Water holding capacity determination: After the substrate sample was completely immersed in water and drained naturally for 24 hours, the maximum water holding capacity was determined.

[0288] (4) Structural stability determination: The substrate sample was subjected to 10 wet-dry cycles (completely immersed in water - dried at 60 °C), and the structural retention rate after the cycle was determined.

[0289] The test results are shown in Table 1:

[0290] Table 1 Physical properties and structural stability of each substrate sample

[0291] Substrate sample Bulk density (g / cm³) Total porosity (%) Maximum water holding capacity (% w / w) Structure retention rate after 10 wet-dry cycles (%) Example 1 0.2 85 350 86 Example 2 0.18 88 370 83 Example 3 0.22 82 320 90 Example 4 0.25 80 300 85 Example 5 0.23 81 310 87 Example 6 0.26 79 290 92 Comparative Example 1 0.15 85 320 42 Comparative Example 2 0.12 88 380 56 Comparative Example 3 0.25 80 300 82 Comparative Example 4 0.21 83 325 48 Comparative Example 5 0.18 82 270 78

[0292] As can be seen from Table 1, the substrate samples of the present invention all performed excellently in terms of physical properties, especially in terms of structural stability. After 10 wet-dry cycles, the structural retention rates were all above 80%, far higher than those of Comparative Examples 1, 2 and 4. This is mainly due to the three-level pore structure design and the biopolymer double-network crosslinking system of the present invention. Among them, the structural retention rate of Example 6 was the highest, reaching 92%, which was directly related to its relatively high proportion of the biopolymer bonding system (6%). The structural retention rate of Comparative Example 4 (substrate without using the biopolymer bonding system) was only 48%, fully demonstrating the important role of the biopolymer bonding system in maintaining the structural stability of the substrate.

[0293] Experiment 2: Recycling performance test

[0294] Test method: The substrates of each example and comparative example were subjected to 4 cycles of use test:

[0295] (1) First use: Harvest after growing lettuce for 30 days.

[0296] (2) Substrate recovery: Use a water flow pulse separation system to separate the roots.

[0297] (3) Substrate regeneration: Carry out cleaning and regeneration treatment according to the method described in Example 13.

[0298] (4) Reuse: Repeat steps (1)-(3) for a total of 4 times.

[0299] (5) Measure the following indicators after each cycle: substrate recovery rate, physical structure recovery rate, microbial activity recovery rate, nutrient balance recovery rate.

[0300] The test results are shown in Table 2:

[0301] Table 2 Recycling performance of each substrate sample

[0302] Substrate sample Maximum number of cycles Physical structure recovery rate after the 4th cycle (%) Microbial activity recovery rate after the 4th cycle (%) Nutrient balance recovery rate after the 4th cycle (%) Example 1 5 86 80 85 Example 2 4 84 78 82 Example 3 5 88 83 86 Example 4 5 85 80 84 Example 5 5 87 81 85 Example 6 5 89 82 87 Comparative Example 1 1 — — — Comparative Example 2 2 54 48 56 Comparative Example 3 3 78 45 75 Comparative Example 4 2 60 70 72 Comparative Example 5 3 75 72 78

[0303] As can be seen from Table 2, the substrate samples of the present invention can be stably recycled 4-5 times, and each performance index remains at a relatively high level after the 4th cycle. In contrast, Comparative Example 1 can only be used once; Comparative Examples 2 and 4 can only be used twice; Comparative Examples 3 and 5 can be used 3 times but the performance significantly decreases. This fully demonstrates the importance of the synergistic effect of the multi-source organic matter material, functional microbial system and biopolymer bonding system of the present invention. In particular, Examples 3 and 6 show the best recycling performance due to the high content of bioactive ingredients and biopolymer bonding system.

[0304] Experiment 3: Test on plant growth effect

[0305] Test method: Use the substrates of each example and comparative example to cultivate lettuce (variety: Betty), and test the plant growth effect:

[0306] (1) Planting conditions: Greenhouse environment, temperature 25±2°C, relative humidity 65±5%, natural light.

[0307] (2) Cultivation management: Water regularly to keep the substrate moist and do not fertilize.

[0308] (3) Harvest after 35 days of growth period, and measure the following indicators: fresh weight of plant, fresh weight of root system, number of leaves, chlorophyll content (SPAD value).

[0309] The test results are shown in Table 3:

[0310] Table 3 Test Results of Lettuce Growth Effect

[0311] Substrate sample Fresh weight of plant (g) Fresh weight of root system (g) Number of leaves (pcs) Chlorophyll content (SPAD value) Example 1 235 38 24 38.5 Example 2 242 40 25 39.2 Example 3 258 45 26 40.8 Example 4 245 42 25 39.5 Example 5 250 43 25 40 Example 6 255 44 26 40.5 Comparative Example 1 190 28 20 32.5 Comparative Example 2 205 30 21 33.8 Comparative Example 3 210 35 22 34.5 Comparative Example 4 195 30 21 33 Comparative Example 5 215 36 22 35.2

[0312] As can be seen from Table 3, the substrate samples of the present invention all showed excellent performance in promoting plant growth. Especially for Examples 3 and 6, the fresh weights of the lettuce plants reached 258 g and 255 g respectively, which were 36% and 34% higher than that of Comparative Example 1 (traditional peat substrate). This is mainly due to the synergistic effect of the functional microbial system and bioactive components in the substrate of the present invention, which not only provides a balanced nutrient supply, but also promotes plant root development and nutrient absorption through various biological mechanisms. The reason why Example 3 showed the best performance is that the content of its bioactive components reached 10%, and the total viable count of functional microorganisms reached 9×10 8 CFU / g, which was the highest among all samples.

[0313] Experiment 4: Test of Plant Growth Effect after Multiple Cycles of Use

[0314] Test method: The substrates of Example 4 and Comparative Examples 2 and 3 were used for multiple cycles of use. Lettuce was planted after each cycle, and the plant growth effect was tested:

[0315] (1) Cycling method: The substrate was cycled according to the method described in Example 13.

[0316] (2) Lettuce (variety: Betty) was planted after each cycle, harvested after 35 days of growth period, and the fresh weight of the plant was measured.

[0317] The test results are shown in Table 4:

[0318] Table 4 Lettuce Growth Effect after Multiple Cycles of Use

[0319] Substrate sample Fresh weight of plant at first use (g) Fresh weight of plant after the 2nd cycle (g) Fresh weight of plant after the 3rd cycle (g) Fresh weight of plant after the 4th cycle (g) Fresh weight of plant after the 5th cycle (g) Example 4 245 235 220 210 205 Comparative Example 2 205 165 Not applicable Not applicable Not applicable Comparative Example 3 210 195 170 Not applicable Not applicable

[0320] As can be seen from Table 4, the substrate of Example 4 still maintained a good plant growth promotion effect after multiple cycles of use. The fresh weight of the lettuce plant after the 5th cycle still reached 205 g, which was 84% of that at the first use. In contrast, Comparative Example 2 could only be cycled 2 times, and the fresh weight of the plant after the 2nd cycle dropped to 165 g, only 80% of that at the first use; Comparative Example 3 could be cycled 3 times, but the fresh weight of the plant after the 3rd cycle dropped to 170 g, only 81% of that at the first use. This fully proves the superiority of the substrate of the present invention in maintaining performance during the cycle of use.

[0321] From the above examples and experimental results, it can be seen that the recyclable plant growth substrate of the present invention has the following remarkable advantages:

[0322] 1. Excellent physical properties: The three - level pore structure design endows the substrate with reasonable bulk density, porosity and water - holding capacity, providing an ideal environment for the growth of plant roots.

[0323] 2. Outstanding structural stability: The biopolymer double - network cross - linking system enables the substrate to maintain good structural stability during multiple wet - dry cycles and in the process of use, which is the key to realizing multiple - cycle use.

[0324] 3. Efficient nutrient supply: The synergistic effect of multi - source organic matter materials and bioactive components forms a gradient nutrient release system, which can meet the nutrient requirements of plants throughout their growth period.

[0325] 4. Strong biological activity: The functional microbial system not only promotes nutrient transformation and absorption, but also enhances the stress resistance and health of plants, significantly improving crop yield and quality.

[0326] 5. Excellent recyclability: The substrate of the present invention can be stably recycled 4 - 5 times. After each cycle, more than 80% of its functional performance can be restored through a dedicated regeneration process, greatly reducing resource consumption and environmental burden.

[0327] In summary, the present invention provides an innovative recyclable plant growth substrate, its preparation method and application. It not only solves the problem of single - use of traditional substrates, but also realizes a comprehensive improvement in performance, having important practical value and broad application prospects.

[0328] The above are only embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. Recyclable plant growth substrate, characterized in that, The substrate comprises components in the following weight percentages: 70 - 80% of organic matter materials, including 30 - 40% of wood fiber materials, 20 - 30% of agricultural by-products, and 10 - 15% of food processing waste; 10 - 20% of functional mineral materials, including 5 - 10% of porous adsorption materials and 5 - 10% of structural support materials; 5 - 10% of bioactive components; Functional microorganism system, total viable count ≥ 5×10 8 CFU / g; 3 - 6% of biopolymer binding system; Among them, the substrate has a three - level pore structure, a bulk density of 0.2 - 0.35 g / cm³, a total porosity of 70 - 85%, a maximum water - holding capacity of 250 - 350% (w / w), and can be recycled 4 - 5 times.

2. The substrate according to claim 1, wherein The wood fiber materials include 15 - 20% of crushed poplar waste, 10 - 15% of processed pine wood scraps, and 5 - 10% of bamboo processing waste; the agricultural by - products include 10 - 15% of crushed almond shells, 5 - 10% of processed cottonseed hulls, and 5 - 10% of rice husk carbide; the food processing waste includes 5 - 8% of processed coffee grounds and 5 - 7% of fermented fruit residues.

3. The substrate according to claim 1, wherein The porous adsorption materials include 3 - 5% of modified zeolite powder and 2 - 5% of bentonite; the structural support materials include 3 - 6% of perlite and 2 - 4% of diatomite; the bioactive components include 2 - 4% of seaweed extract complex, 2 - 3% of humic acid substances, and 1 - 3% of plant - derived amino acid complex; the biopolymer binding system includes 1.5 - 3% of alginate - ion cross - linked complex and 1.5 - 3% of modified starch - protein complex.

4. The substrate according to claim 1, wherein The functional microorganism system includes: nitrogen - fixing functional group, phosphorus - solubilizing functional group, organic matter transformation functional group, and plant growth - promoting functional group; the nitrogen - fixing functional group includes Azotobacter chroococcum and Azospirillum brasilense; the phosphorus - solubilizing functional group includes Bacillus megaterium and Pseudomonas fluorescens; the organic matter transformation functional group includes Trichoderma harzianum and Streptomyces lydicus; the plant growth - promoting functional group includes Bacillus subtilis and Pseudomonas putida.

5. The preparation method of the recyclable plant growth substrate according to any one of claims 1-4, characterized in that, It includes the following steps: (1) Raw material pretreatment: Crushing and classifying the organic matter materials to obtain particles with different particle sizes; performing surface modification treatment on the mineral materials; Extracting and purifying the bioactive components; (2) Multi - level proportioning and mixing: Firstly, performing primary mixing on the organic matter materials with different particle sizes according to a predetermined ratio, then adding the functional mineral materials for secondary mixing, and adjusting the moisture content to 38 - 42% after mixing evenly. (3) Pressure-controlled forming: Put the mixed materials into a forming mold, and use segmented-controlled pressure (1.0 MPa - 3 seconds, 2.0 MPa - 2 seconds, 3.0 MPa - 1 second) to form at 65 - 75 °C; (4) Function imparting: Perform nutrient gradient loading and microbial function inoculation on the formed matrix. The nutrient loading is carried out by vacuum impregnation, and the microbial inoculation is carried out by pulse spraying; (5) Structure stabilization: Spray 0.5 - 1.0% calcium chloride solution on the matrix for biopolymer cross-linking, and then carry out heat-assisted strengthening treatment at 40 - 50 °C; (6) Humidity adjustment and packaging: Dry the matrix at 30 - 35 °C until the moisture content is 16 - 18%, spray microbial protectant, and seal the package using modified atmosphere packaging technology.

6. The preparation method according to claim 5, characterized in that, The crushing and grading treatment of the organic matter material in step (1) includes: using a double-rotor staggered-tooth hammer mill for crushing, with the rotational speed of the wood fiber material being 1200 - 1500 rpm, the rotational speed of the agricultural by-products being 1500 - 1800 rpm, and the rotational speed of the food processing waste being 1800 - 2200 rpm; using a vibrating multi-layer screening system for grading, dividing the particles into five particle size grades of 5 - 3 mm, 3 - 1 mm, 1 - 0.5 mm, 0.5 - 0.1 mm, and <0.1 mm, and the mass ratios of each particle size grade are 15 - 20%, 30 - 35%, 25 - 30%, 10 - 15%, and 5 - 10% respectively.

7. The method according to claim 5, wherein The nutrient gradient loading in step (4) adopts a three-stage loading method: the rapid release layer uses water-soluble nitrogen, phosphorus, potassium and trace elements (in a ratio of 1.5:1:2), with a concentration of 1.0 - 1.5%; the medium-term release layer uses a slow-release nitrogen, phosphorus, potassium complex (in a ratio of 1:1:1), with a concentration of 1.2 - 1.8%; the long-term release layer uses organic nitrogen, calcium dihydrogen phosphate and potassium sulfate (in a ratio of 1:0.5:0.5), with a concentration of 0.8 - 1.2%; for microbial inoculation, a bacterial solution containing 1×10 9 CFU / ml is used, and the inoculation amount is 10 - 15 ml / kg of substrate.

8. The application method of the recyclable plant growth substrate according to any one of claims 1-4, characterized in that, Including the following steps: (1) Matrix use: Apply the matrix to the cultivation of vegetables, flowers, fruit tree seedlings, foliage plants, or herbal medicines, and the direct planting method, mixed matrix method, or soilless cultivation application method can be adopted; (2) Matrix recovery: After the plants are harvested, use a water flow pulse separation system to separate the plant roots from the matrix, with the pulse water pressure being 0.2 - 0.3 MPa and the pulse frequency being 2 - 3 Hz; (3) Matrix cleaning and disinfection: Use a vortex cleaning and disinfection integrated machine to clean the recovered matrix, with the cleaning temperature being 35 - 40 °C, the cleaning time being 3 - 5 minutes, and the cleaning agent being 0.5% hydrogen peroxide solution; (4) Matrix regeneration: Perform structure reconstruction, nutrient supplementation, and microbial function reconstruction on the cleaned matrix. Among them, the structure reconstruction uses a precise pressure reshaping system, the pressurization method is pulse pressurization, and the pressurization temperature is 50 - 60 °C; the nutrient supplementation uses a precise nutrient solution impregnation system, and the nutrient supplementation concentration is adjusted according to the number of cycles; the microbial function reconstruction uses a microbial atomization inoculation system, and the inoculation temperature is 22 - 26 °C; (5) Recycling use: Reuse the regenerated matrix according to step (1), and after using it 4 - 5 times, it can be used as a soil conditioner or compost raw material for resource utilization.

9. The application method according to claim 8, wherein The direct planting method is applicable to small plants, seedlings and herbaceous plants. The operation method is to put the substrate block into the cultivation container, directly plant seeds or insert seedlings, and water for the first time until the weight of the substrate increases by 70 - 80%; the mixed substrate method is applicable to medium and large plants and long-term cultivated crops, and the mixing ratio is 70 - 80% of this substrate and 20 - 30% of garden soil / perlite; the soilless cultivation application method is applicable to drip irrigation systems and nutrient solution circulation systems. The substrate is used as the filler of the cultivation tank or the seedling raising block, and the EC value of the nutrient solution is 1.8 - 2.2 mS / cm, and the pH value is 5.8 - 6.

2.

10. The application method according to claim 8, characterized in that, The concentration of the substrate nutrient supplement is adjusted according to the number of cycles: 40 - 50% of the original formula concentration is used for the first cycle, 50 - 60% of the original formula concentration is used for the second cycle, and 60 - 70% of the original formula concentration is used for the third cycle; the inoculation amount of the microbial function reconstruction is adjusted according to the number of cycles: the nitrogen-fixing functional group uses 60 - 70% of the original formula concentration, the phosphorus-solubilizing functional group uses 70 - 80% of the original formula concentration, the organic matter conversion functional group uses 80 - 90% of the original formula concentration, and the plant growth promotion functional group uses 60 - 70% of the original formula concentration; when the physical structure recovery rate of the substrate is lower than 75%, the microbial activity recovery rate is lower than 65%, it is difficult to adjust the nutrient balance or pathogenic bacteria are detected, the cycle use is terminated.

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