Camellia oleifera shell-phosphorite tailings composite seedling culture substrate and preparation method and application thereof

Abstract

The invention discloses a camellia oleifera shell-phosphorite tailing composite seedling raising substrate and a preparation method and application thereof, and belongs to the technical field of seedling raising substrates. The matrix is formed by scientifically compounding 12 raw materials such as camellia oleifera shell carbonized materials and phosphorite tailings, and is prepared through the processes of raw material pretreatment, basic mixing, function adding and forming granulation. According to the invention, local agricultural and forestry wastes and industrial tailings in the karst region in southwest are used as main base materials, and a multifunctional seedling raising system integrating nutrient supply, root strengthening and stress protection is constructed. The matrix can improve high-calcium and low-phosphorus soil obstacles in the karst region in a targeted mode, stress resistance and root activity of seedlings are effectively improved, and therefore the technical problem that the survival rate of seedling planting and afforestation is low is solved. Experiments show that the method is suitable for cultivation of pioneer tree species suitable for karst growth such as zenia insignis, cedrela sinensis and choerospondias axillaris, resource utilization of agricultural and forestry waste and industrial tailings can be achieved, the synergistic ecological restoration function can be achieved, and good environmental and economic benefits are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of seedling raising substrate, and particularly relates to an oil tea shell-phosphorite tailings composite seedling raising substrate and a preparation method and application thereof. BACKGROUND

[0002] The southwest karst region is one of the core areas of ecological fragility in China, with a total area of about 540,000 km 2 . The region mainly has carbonate rock as the main soil parent material, and the soil generally has the typical obstacle characteristics of "thin soil layer, rich in calcium and lack of phosphorus, poor water and fertilizer retention". With the continuous promotion of ecological restoration projects in the region, pioneer tree species with strong tolerance to barren land and strong stress resistance have become the first choice for vegetation restoration. However, the existing seedling raising technology faces the following outstanding problems in the karst region, which seriously restricts the effectiveness of ecological restoration:

[0003] First, there is a serious mismatch between soil characteristics and seedling growth needs. The calcium content in karst soil is usually as high as 15-30 g / kg, while the available phosphorus content is only 2-5 mg / kg, which is significantly lower than the critical value (8-12 mg / kg) required for normal growth of most plants. Phosphorus is a key element for root development and energy metabolism, and long-term phosphorus deficiency can easily lead to poor root development and weakened absorption capacity of seedlings. At the same time, the high-calcium environment can convert available phosphorus into insoluble calcium phosphate, further exacerbating the vicious cycle of "phosphorus deficiency-root weakening". At present, the commonly used commercial seedling raising substrate mainly uses peat soil as the main component (accounting for ≥70%), and only adds ordinary phosphorus fertilizer to supplement phosphorus, without systematic design for the high-calcium and low-phosphorus characteristics of karst soil, resulting in a phosphorus utilization rate of less than 15%, and a seedling transplanting survival rate of generally less than 40%.

[0004] Secondly, seedlings face multiple stresses such as drought, heavy metals and diseases in karst habitats, while traditional substrates lack synergistic stress resistance functions. The temporal and spatial distribution of rainfall in the region is uneven, and the soil moisture content is less than 10% in the dry season, and seedlings are prone to drought stress. The soil in some areas affected by mining is slightly contaminated with cadmium and lead (cadmium 0.3-0.8 mg / kg, lead 50-150 mg / kg), which can inhibit root enzyme activity and normal physiological functions. In addition, the number of beneficial microorganisms in the soil is low (10 3 -10 4 CFU per gram of soil), while pathogenic bacteria are relatively active, increasing the risk of soil-borne diseases such as root rot. Traditional substrates generally only provide basic nutrients and do not integrate components such as drought resistance, heavy metal passivation and disease inhibition, resulting in a cumulative seedling mortality rate of more than 60% due to combined environmental stress.

[0005] Finally, traditional substrates rely excessively on non-renewable resources and are costly. Currently, the mainstream substrate takes peat as the main raw material, and peat belongs to non-renewable wetland resources, the exploitation of which can significantly destroy the ecological system, and the market price has risen to 800-1200 yuan / ton, and the long-distance transportation cost accounts for 20%-30%. At the same time, about 2 million tons of oil tea shell waste (mostly burned for disposal) and more than 5 million tons of phosphorite tailings (a large amount of land occupation and environmental pollution) are generated in the karst region of southwest China every year, and the existing technology cannot effectively realize the resource utilization of such local bulk solid waste, which not only wastes potential substrate raw material resources, but also increases the comprehensive cost of seedling raising.

[0006] In summary, the existing seedling raising substrate cannot meet the special soil and environmental requirements of the karst region, and it is urgent to develop a composite seedling raising substrate that takes local bulk solid waste as the main raw material and has the functions of "efficient nutrient supply-root development promotion-habitat stress relief" to break through the technical bottleneck of seedling raising in the current vegetation restoration in the karst region.

[0007] The above background technology content is only used to assist in understanding the inventive concept and technical problems of the present application, and does not necessarily constitute the prior art before the filing date of the present patent application. In the absence of solid evidence that the above content has been disclosed before the filing date, it should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY

[0008] The present application aims to overcome the technical defects of the existing seedling raising substrate in the vegetation restoration project in the karst region of southwest China, such as insufficient adaptability, lack of stress resistance, and unsustainable resource dependence, and provides an oil tea shell-phosphorite tailings composite seedling raising substrate and its preparation method and application. The substrate takes the locally abundant oil tea shell waste and phosphorite tailings in the karst region of southwest China as the main substrate, and through the synergistic compounding of other functional components, it realizes the resource utilization of bulk solid waste and constructs a multifunctional system that integrates "nutrient slow-release supply, root development promotion, and habitat stress relief". The present application aims to solve the key problems of high calcium and low phosphorus soil obstacles in the karst region, weak seedling stress resistance, and low afforestation survival rate, thereby providing key technical support for the whole chain of vegetation restoration from seedling raising to afforestation, and improving the effect of ecological restoration.

[0009] In order to achieve the above technical purpose, the present application adopts the following technical solutions:

[0010] The oil-tea camellia shell-phosphate tailings compound seedling raising substrate is prepared from the following raw materials in parts by weight: oil-tea camellia shell carbonized material 45-60 parts; phosphate tailings 15-25 parts; mose globular sac fungus agent 3-8 parts; humic acid 1-4 parts; slow-release potassium salt 0.8-2.0 parts; vermiculite 5-12 parts; perlite 4-10 parts; bentonite 2-5 parts; seaweed extract 1.5-4.0 parts; bacillus subtilis agent 0.5-2.0 parts; calcium EDTA 1.0-2.5 parts; and sucrose 0.2-1.0 parts.

[0011] Preferably, the oil-tea camellia shell carbonized material is obtained by carbonizing oil-tea camellia shell at 450-550℃ for 1-3h and crushing to 60-100 mesh.

[0012] Preferably, the phosphate tailings has a particle size of 0.1-0.3mm and is acid-washed and adjusted to a pH value of 6.0-7.5.

[0013] Preferably, the slow-release potassium salt is potassium sulfate.

[0014] Preferably, the vermiculite has a particle size of 1-4mm.

[0015] Preferably, the perlite has a particle size of 2-6mm.

[0016] Preferably, the mose globular sac fungus agent has an effective viable bacterial count of ≥1.0×10 6 CFU / g; and / or, the bacillus subtilis agent has an effective viable bacterial count of ≥5.0×10 6 CFU / g.

[0017] Preferably, the substrate is a cylindrical particle having a diameter of 3-8mm.

[0018] The application also provides a preparation method of the oil-tea camellia shell-phosphate tailings compound seedling raising substrate, comprising the following steps:

[0019] S1, raw material pretreatment:

[0020] a) preparing oil-tea camellia shell carbonized material: washing and drying oil-tea camellia shell, carbonizing at 450-550℃ for 1-3h, and crushing to 60-100 mesh after cooling;

[0021] b) pretreating phosphate tailings: screening phosphate tailings to a particle size of 0.1-0.3mm, acid-washing, water-washing to a pH value of 6.0-7.5, and drying;

[0022] S2, mixing and granulation:

[0023] a) basic mixing: mixing the oil-tea camellia shell carbonized material, phosphate tailings, vermiculite, perlite, bentonite, slow-release potassium salt and calcium EDTA in the proportions of claim 1 to obtain a basic mixture;

[0024] b) Functional addition: Add the humic acid, seaweed extract, Glomus mossina fungicide, Bacillus subtilis fungicide and sucrose in the proportions described in claim 1 to the base mixture, and mix well;

[0025] c) Granulation: The uniformly mixed materials are granulated to form cylindrical particles with a diameter of 3-8 mm.

[0026] This invention also provides an application of a camellia oleifera shell-phosphate mine tailings composite seedling substrate in the cultivation of pioneer tree species in karst areas.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] I. The raw material system is highly compatible with the resource and ecological characteristics of the karst region.

[0029] Existing seedling substrates mostly rely on purchased peat moss and other general raw materials, failing to consider the local resource endowment and soil barrier characteristics of the Southwest Karst region, resulting in poor adaptability. This invention uses camellia oleifera shell waste and phosphate mine tailings, which are abundant in this region, as the main substrates. On the one hand, it realizes the resource utilization of agricultural and forestry waste and industrial solid waste, reducing environmental pollution and raw material transportation costs, and avoiding dependence on non-renewable peat resources. On the other hand, phosphate mine tailings can specifically supplement the soil with available phosphorus, while camellia oleifera shell carbonization provides organic matter and porous structure suitable for seedling growth in this region. From the source of raw materials, it achieves a high degree of compatibility with the resource recycling, soil improvement, and ecological needs of the karst region.

[0030] II. Precisely addressing the calcium-phosphorus antagonism problem through nutrient supply mechanisms

[0031] Existing technologies for addressing the "high calcium, low phosphorus" conditions in karst soils often involve simply adding ordinary phosphate fertilizers, which fails to effectively solve the phosphorus fixation problem caused by high concentrations of calcium ions, resulting in low phosphorus utilization. This invention innovatively constructs a synergistic phosphorus release and calcium stabilization mechanism of "phosphate mine tailings + EDTA-calcium": pretreated phosphate mine tailings increase the available phosphorus content; EDTA-calcium, while providing a calcium source, significantly reduces phosphorus chemical fixation by chelating calcium ions to prevent direct binding with phosphate ions. This mechanism alleviates calcium-phosphorus antagonism at its source, ensuring a continuous and effective supply of phosphorus nutrients to meet the critical needs of seedling root development.

[0032] III. Integrated functional system to comprehensively address multiple habitat stresses

[0033] Existing substrates have limited functionality and are ill-suited to address the multiple stresses of drought, potential heavy metal pollution, and microecological imbalance in karst regions. This invention constructs an integrated functional system encompassing nutrient supply, root enhancement, and stress protection. Through the synergistic effects of its components, it covers the entire growth cycle of seedlings: Moses's Gloydius fungicide promotes mycorrhizal symbiosis and enhances nutrient and water absorption; seaweed extract improves seedling drought resistance and heavy metal tolerance; Bacillus subtilis and sucrose synergistically regulate the substrate microecology and inhibit soil-borne diseases; humic acid and vermiculite optimize the physical structure and buffering capacity of the substrate. This system overcomes the fragmented functionality of traditional substrates, providing systematic growth protection for seedlings.

[0034] IV. The preparation process emphasizes the preservation of functional activity and performance stability.

[0035] Existing preparation processes are relatively crude, easily leading to the inactivation or uneven dispersion of functional components (especially microbial agents). This invention's process is meticulously designed around functional protection and performance uniformity: In the pretreatment stage, camellia oleifera shells undergo gradient temperature-controlled carbonization to retain their active organic structure, while phosphate rock tailings are acid-washed and graded to improve effectiveness and safety; in the mixing stage, a step-by-step speed-adjustment strategy is employed, with the basic mixing stage ensuring uniform dispersion and the functional addition stage using low rotation speed to protect the activity of the microbial agents and bioactive substances; and by controlling granulation parameters and pore size, the final product is ensured to have uniform particles, stable performance, and long-lasting functionality.

[0036] V. Focused application scenarios and stronger adaptability

[0037] Existing general-purpose substrates are not optimized for karst habitats and tree species characteristics, limiting their application effectiveness. This invention closely addresses the engineering needs of vegetation restoration in the Southwest Karst region, using locally sourced materials and designed to address the biological characteristics of pioneer tree species (such as *Toona sinensis* and *Toona sinensis*) in this region, highlighting their tolerance to poor soil and strong resilience. The accompanying seedling cultivation and management methods effectively support the entire chain of operations from seedling cultivation to afforestation, demonstrating stable improvement effects and adaptability in karst areas such as western Guangxi, central Guizhou, and eastern Yunnan. It overcomes the problem of general-purpose substrates being unsuitable for local conditions, providing targeted products and technical support for regional ecological restoration. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to specific embodiments. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0039] A composite seedling substrate of camellia oleifera shell and phosphate rock tailings is composed of the following raw materials in parts by weight: 45-60 parts of carbonized camellia oleifera shell; 15-25 parts of phosphate rock tailings; 3-8 parts of Moses's Gloydius fungicide; 1-4 parts of humic acid; 0.8-2.0 parts of slow-release potassium salt; 5-12 parts of vermiculite; 4-10 parts of perlite; 2-5 parts of bentonite; 1.5-4.0 parts of seaweed extract; 0.5-2.0 parts of Bacillus subtilis agent; 1.0-2.5 parts of EDTA-calcium; and 0.2-1.0 parts of sucrose.

[0040] The camellia shell carbonized material is obtained by carbonizing camellia shells at 450-550℃ for 1-3 hours and then crushing them to 60-100 mesh.

[0041] The phosphate mine tailings have a particle size of 0.1-0.3 mm and are acid-washed and adjusted to a pH value of 6.0-7.5.

[0042] The slow-release potassium salt is potassium sulfate.

[0043] The vermiculite has a particle size of 1-4 mm.

[0044] The perlite has a particle size of 2-6 mm.

[0045] The effective viable count of the Moses globosum fungicide is ≥1.0 × 10⁻⁶. 6 CFU / g; and / or, the effective viable count of the Bacillus subtilis agent is ≥5.0 × 10⁻⁶. 6 CFU / g.

[0046] The matrix consists of cylindrical particles with a diameter of 3-8 mm.

[0047] A method for preparing a composite seedling substrate of camellia oleifera shell and phosphate rock tailings includes the following steps:

[0048] S1. Raw material pretreatment:

[0049] a) Preparation of Camellia oleifera shell carbonized material: After washing and drying the Camellia oleifera shells, carbonize them at 450-550℃ for 1-3 hours, cool them and then crush them to 60-100 mesh.

[0050] b) Pretreatment of phosphate rock tailings: The phosphate rock tailings are screened to a particle size of 0.1-0.3 mm, acid washed, and water washed until the pH is 6.0-7.5, and then dried;

[0051] S2. Mixing and Granulation:

[0052] a) Basic mixture: The camellia shell carbonized material, phosphate rock tailings, vermiculite, perlite, bentonite, slow-release potassium salt and EDTA-calcium in the proportions described in claim 1 are mixed to obtain a basic mixture;

[0053] b) Functional addition: Add the humic acid, seaweed extract, Glomus mossina fungicide, Bacillus subtilis fungicide and sucrose in the proportions described in claim 1 to the base mixture, and mix well;

[0054] c) Granulation: The uniformly mixed materials are granulated to form cylindrical particles with a diameter of 3-8 mm.

[0055] The technical principle of raw material synergistic effect:

[0056] This invention is not a simple mixture of raw materials, but rather a precise formulation of 12 raw materials to construct a three-in-one synergistic system of "substrate support - nutrient supply - functional enhancement". The roles and synergistic mechanisms of each raw material are as follows:

[0057] 1. Core substrate: Camellia oleifera shell carbonized material and phosphate mine tailings

[0058] Camellia oleifera shell carbonization, after undergoing a specific process, forms a porous structure, providing a stable organic matter carrier and pore environment for the matrix. It can also adsorb excess calcium ions in the matrix, creating conditions for the effective release of phosphorus. After acid washing pretreatment, the available phosphorus content of phosphate rock tailings increases, specifically addressing the widespread phosphorus deficiency in karst soils. Together, these two materials form the matrix framework: the porous structure of the camellia oleifera shell carbonization adsorbs phosphorus continuously released from phosphate rock tailings, slowing its loss, while mitigating the phosphorus fixation effect of the high-calcium soil environment, thus laying the physical and chemical foundation for the subsequent nutrient supply system.

[0059] 2. Nutrient regulation: EDTA-calcium, slow-release potassium salts and phosphate rock tailings

[0060] EDTA-calcium binds to free calcium ions in the soil through chelation, preventing them from forming insoluble calcium phosphate with phosphate ions released from phosphate mine tailings, thus effectively solving the calcium-phosphorus antagonism problem in karst soils. Slow-release potassium salt (potassium sulfate) slowly releases potassium, working synergistically with phosphorus to meet the basic macronutrient needs of seedling growth. The three work together to achieve "precision fertilization": EDTA-calcium ensures phosphorus availability, phosphate mine tailings continuously release phosphorus as a source, and slow-release potassium salt provides a stable potassium source, jointly constructing a balanced, continuous, and efficient nutrient supply system, overcoming the nutrient imbalance problem caused by single phosphorus supplementation in existing technologies.

[0061] 3. Root strengthening: Moses Gloydius fungicide and sucrose

[0062] Moses Gloydius fungicide can form a mycorrhizal symbiosis with seedling roots, promoting root differentiation and elongation, and significantly enhancing the root system's ability to absorb nutrients such as phosphorus and potassium. Sucrose provides the initial carbon source for the fungicide, promoting spore germination and mycelial growth, and improving the colonization efficiency of the fungicide in the substrate. The two work synergistically to form a positive promoting mechanism of "carbon source-fungicide-root system": sucrose creates a suitable microenvironment for the fungicide, while the fungicide improves nutrient absorption efficiency by modifying root architecture and function, thus overcoming the limitations of traditional technologies that rely solely on chemical fertilizers to promote growth.

[0063] 4. Stress protection: seaweed extract and Bacillus subtilis agent

[0064] The active ingredients in seaweed extract, such as seaweed polysaccharides and betaine, can enhance the osmotic regulation capacity of seedling cells, improving their physiological resistance to drought and heavy metal stress. Bacillus subtilis can inhibit the reproduction of harmful microorganisms such as root rot pathogens in the substrate and directly protect root health by secreting antibacterial substances. Together, they construct a dual resistance barrier of "endogenous resistance + exogenous protection": seaweed extract enhances stress resistance at the physiological level of the plant, while Bacillus subtilis inhibits disease threats at the level of substrate microecology, thus systematically addressing multiple stresses common in karst regions, including drought, heavy metal pollution, and soil-borne diseases.

[0065] 5. Structural optimization: vermiculite, perlite, and bentonite

[0066] Vermiculite (1-4mm particle size) combines water retention and aeration properties, storing moisture and regulating pore size; perlite (2-6mm particle size) is lightweight and porous, further optimizing substrate aeration and preventing compaction; bentonite has good binding properties, enhancing the shapeability and stability of substrate particles. These three elements synergistically optimize the substrate's physical structure: vermiculite and perlite work together to regulate the water retention-aeration balance, while bentonite ensures the morphological integrity and structural strength of the granulated particles. Together, they provide a loose, aerated, water-retaining, and stable growth environment for seedling roots, avoiding the problems of compaction or poor water retention common in traditional substrates.

[0067] The technical logic behind the selection of preparation process parameters:

[0068] The parameters in each step of the preparation process of this invention are not arbitrarily set, but are systematically designed around the core objective of "protecting the activity of functional components and ensuring the stability of matrix performance". The selection criteria for each key parameter and its resulting technical effects are as follows:

[0069] 1. Carbonization parameters of camellia shell

[0070] The carbonization temperature is controlled between 450-550℃. If the temperature is below 450℃, the organic matter in the camellia shells will not be completely carbonized, resulting in insufficient pore structure development and weak water and fertilizer retention capacity. If the temperature is above 550℃, the organic matter will decompose excessively, easily producing harmful substances such as benzo[a]pyrene, which can damage the seedling roots. A carbonization time of 1-3 hours ensures that the organic matter is fully converted without loss. The resulting carbonized material is ground to 60-100 mesh. This particle size range maintains the integrity of the porous structure and facilitates uniform mixing with other raw materials. The camellia shell carbonized material prepared under these optimized parameters has an organic matter content ≥50% and a porosity ≥60%, exhibiting superior performance compared to products from conventional carbonization processes, providing a high-load-bearing, high-quality framework for the matrix.

[0071] 2. Phosphate mine tailings pretreatment parameters

[0072] The tailings particle size is controlled between 0.1-0.3 mm. Particles larger than 0.3 mm have a small specific surface area, resulting in slow release of available phosphorus; particles smaller than 0.1 mm are prone to clumping due to their fineness, affecting the overall permeability of the matrix. Acid washing with 5%-8% hydrochloric acid effectively removes impurities such as calcium and magnesium from the tailings surface; excessively high concentrations of hydrochloric acid will damage the tailings mineral structure, while insufficient concentrations will result in incomplete impurity removal. Soaking for 1-2 hours ensures sufficient reaction, followed by pH adjustment to neutral to avoid residual acid damaging the roots. After this pretreatment, the available phosphorus content of the tailings is ≥8 g / kg, more than three times higher than the original tailings, and the chemical compatibility with other components in the matrix system is significantly improved.

[0073] 3. Mixed speed parameters

[0074] A phased speed control strategy was adopted. In the basic mixing stage (mixing inorganic raw materials with the substrate), a higher rotation speed (≥250 r / min) was used to ensure uniform dispersion of high-density raw materials such as phosphate rock tailings and vermiculite with camellia shell carbonized material, avoiding localized accumulation. If the rotation speed is lower than 250 r / min, the mixing uniformity deviation will be >5%, leading to fluctuations in matrix performance. In the functional addition stage (adding active ingredients such as microbial agents and seaweed extracts), a lower rotation speed (≤220 r / min) was used to prevent high-speed shear force from damaging the spore structure of the *Gloydius mosieurinae* agent and to avoid decomposition of heat-sensitive active ingredients in the seaweed extract due to frictional heating. If the rotation speed is higher than 220 r / min, the survival rate of the microbial agent will decrease by >30%, and the activity loss of the seaweed extract will be >20%. This phased speed design ultimately resulted in a matrix mixing uniformity deviation ≤5% and a microbial agent survival rate ≥80%, achieving a balance between "dispersion uniformity" and "component activity protection."

[0075] 4. Granulation parameters

[0076] The particle size is controlled between 3-8 mm. Particles smaller than 3 mm are easily lost during watering; those larger than 8 mm have poor internal air permeability, hindering root penetration. The screw speed is set to 80-100 r / min, and the feeding rate is controlled at 50-80 kg / h. Matching these two settings ensures complete particle formation and a smooth surface. Excessive speed or mismatched feeding rates can easily lead to cracks or loose structures in the particles. The substrate particles produced under these parameters have a compressive strength ≥1.5 MPa and a water absorption rate ≥30%. They are not easily broken during seedling tray filling, transportation, and transplanting, and can quickly absorb water and release nutrients, effectively solving the problems of traditional substrate particles being fragile or having slow water absorption.

[0077] To make the present invention more fully disclosed, more specific embodiments are described below.

[0078] Example 1:

[0079] A composite seedling substrate of camellia oleifera shell and phosphate rock tailings is composed of the following raw materials in parts by weight: 45 parts carbonized camellia oleifera shell; 15 parts phosphate rock tailings; and 3 parts Moses's spherical fungicide (effective viable count ≥ 1.0 × 10⁻⁶). 6 CFU / g); 1 part humic acid; 0.8 parts slow-release potassium salt (potassium sulfate); 5 parts vermiculite (particle size 1mm); 4 parts perlite (particle size 2mm); 2 parts bentonite; 1.5 parts seaweed extract; 0.5 parts Bacillus subtilis agent (effective viable count ≥5.0×10⁻⁶). 6 CFU / g); EDTA-calcium 1.0 part; sucrose 0.2 part.

[0080] The camellia shell carbonized material is obtained by carbonizing camellia shells at 450℃ for 3 hours and then crushing them to 60 mesh.

[0081] The phosphate rock tailings have a particle size of 0.1 mm and are obtained by acid washing, water washing to a pH value of 6.0, and then drying.

[0082] The matrix consists of cylindrical particles with a diameter of 3 mm.

[0083] A method for preparing a composite seedling substrate of camellia oleifera shell and phosphate rock tailings includes the following steps:

[0084] S1. Raw material pretreatment:

[0085] a) Preparation of Camellia oleifera shell carbonized material: After washing and drying the Camellia oleifera shells, carbonize them at 450℃ for 3 hours, cool them and then crush them to 60 mesh;

[0086] b) Pretreatment of phosphate rock tailings: The phosphate rock tailings are screened to a particle size of 0.1 mm, acid washed, and water washed until the pH reaches 6.0, and then dried.

[0087] S2. Mixing and Granulation:

[0088] a) Basic mixture: Mix the above-mentioned proportions of camellia shell carbonized material, phosphate rock tailings, vermiculite, perlite, bentonite, slow-release potassium salt and EDTA-calcium to obtain the basic mixture;

[0089] b) Functional addition: Add the above-mentioned proportions of humic acid, seaweed extract, Glomus mossina fungicide, Bacillus subtilis fungicide and sucrose to the base mixture and mix well;

[0090] c) Granulation: The uniformly mixed material is granulated to form cylindrical particles with a diameter of 3 mm.

[0091] Example 2:

[0092] A composite seedling substrate of camellia oleifera shell and phosphate rock tailings is composed of the following raw materials in parts by weight: 48 parts of carbonized camellia oleifera shell; 18 parts of phosphate rock tailings; and 4 parts of Moses's spherical fungicide (effective viable count ≥1.0×10⁻⁶). 6 CFU / g); 2 parts humic acid; 1.1 parts slow-release potassium salt (potassium sulfate); 7 parts vermiculite (particle size 2mm); 6 parts perlite (particle size 3mm); 3 parts bentonite; 2.2 parts seaweed extract; 0.9 parts Bacillus subtilis agent (effective viable count ≥5.0×10⁻⁶). 6 CFU / g); EDTA-calcium 1.4 parts; sucrose 0.4 parts.

[0093] The camellia shell carbonized material is obtained by carbonizing camellia shells at 470℃ for 2.5 hours and then crushing them to 70 mesh.

[0094] The phosphate rock tailings have a particle size of 0.15 mm and are obtained by acid washing, water washing to a pH value of 6.3, and then drying.

[0095] The matrix consists of cylindrical particles with a diameter of 4 mm.

[0096] A method for preparing a composite seedling substrate of camellia oleifera shell and phosphate rock tailings includes the following steps:

[0097] S1. Raw material pretreatment:

[0098] a) Preparation of Camellia oleifera shell carbonized material: After washing and drying the Camellia oleifera shells, carbonize them at 470℃ for 2.5h, cool them and then crush them to 70 mesh;

[0099] b) Pretreatment of phosphate rock tailings: The phosphate rock tailings are screened to a particle size of 0.15 mm, acid washed, water washed to pH 6.3, and then dried;

[0100] S2. Mixing and Granulation:

[0101] a) Basic mixture: Mix the above-mentioned proportions of camellia shell carbonized material, phosphate rock tailings, vermiculite, perlite, bentonite, slow-release potassium salt and EDTA-calcium to obtain the basic mixture;

[0102] b) Functional addition: Add the above-mentioned proportions of humic acid, seaweed extract, Glomus mossina fungicide, Bacillus subtilis fungicide and sucrose to the base mixture and mix well;

[0103] c) Granulation: The uniformly mixed material is granulated to form cylindrical particles with a diameter of 4 mm.

[0104] Example 3:

[0105] A composite seedling substrate of camellia oleifera shell and phosphate rock tailings is composed of the following raw materials in parts by weight: 52 parts of carbonized camellia oleifera shell; 20 parts of phosphate rock tailings; and 5 parts of Moses's spherical fungicide (effective viable count ≥1.0×10⁻⁶). 6 CFU / g); humic acid 2.5 parts; slow-release potassium salt (potassium sulfate) 1.4 parts; vermiculite (3mm particle size) 9 parts; perlite (4mm particle size) 7 parts; bentonite 3.5 parts; seaweed extract 2.8 parts; Bacillus subtilis agent 1.3 parts (effective viable count ≥ 5.0 × 10⁻⁶) 6 CFU / g); EDTA-calcium 1.8 parts; sucrose 0.6 parts.

[0106] The camellia shell carbonized material is obtained by carbonizing camellia shells at 500℃ for 2 hours and then crushing them to 80 mesh.

[0107] The phosphate rock tailings have a particle size of 0.2 mm and are obtained by acid washing, water washing to a pH value of 6.7, and then drying.

[0108] The matrix consists of cylindrical particles with a diameter of 5 mm.

[0109] A method for preparing a composite seedling substrate of camellia oleifera shell and phosphate rock tailings includes the following steps:

[0110] S1. Raw material pretreatment:

[0111] a) Preparation of Camellia oleifera shell carbonized material: After washing and drying the Camellia oleifera shells, carbonize them at 500℃ for 2 hours, cool them and then crush them to 80 mesh;

[0112] b) Pretreatment of phosphate rock tailings: The phosphate rock tailings are screened to a particle size of 0.2 mm, acid washed, and water washed until the pH reaches 6.7, and then dried.

[0113] S2. Mixing and Granulation:

[0114] a) Basic mixture: Mix the above-mentioned proportions of camellia shell carbonized material, phosphate rock tailings, vermiculite, perlite, bentonite, slow-release potassium salt and EDTA-calcium to obtain the basic mixture;

[0115] b) Functional addition: Add the above-mentioned proportions of humic acid, seaweed extract, Glomus mossina fungicide, Bacillus subtilis fungicide and sucrose to the base mixture and mix well;

[0116] c) Granulation: The uniformly mixed material is granulated to form cylindrical particles with a diameter of 5 mm.

[0117] Example 4:

[0118] A composite seedling substrate of camellia oleifera shell and phosphate rock tailings is composed of the following raw materials in parts by weight: 56 parts of carbonized camellia oleifera shell; 23 parts of phosphate rock tailings; and 7 parts of Moses's spherical fungicide (effective viable count ≥1.0×10⁻⁶). 6 CFU / g); humic acid 3.5 parts; slow-release potassium salt (potassium sulfate) 1.7 parts; vermiculite (particle size 3.5 mm) 11 parts; perlite (particle size 5 mm) 9 parts; bentonite 4.5 parts; seaweed extract 3.5 parts; Bacillus subtilis agent 1.7 parts (effective viable count ≥ 5.0 × 10⁻⁶) 6 CFU / g); EDTA-calcium 2.2 parts; sucrose 0.8 parts.

[0119] The camellia shell carbonized material is obtained by carbonizing camellia shells at 530℃ for 1.5 hours and then crushing them to 90 mesh.

[0120] The phosphate rock tailings have a particle size of 0.25 mm and are obtained by acid washing, water washing to a pH value of 7.2, and then drying.

[0121] The matrix consists of cylindrical particles with a diameter of 7 mm.

[0122] A method for preparing a composite seedling substrate of camellia oleifera shell and phosphate rock tailings includes the following steps:

[0123] S1. Raw material pretreatment:

[0124] a) Preparation of Camellia oleifera shell carbonized material: After washing and drying the Camellia oleifera shells, carbonize them at 530℃ for 1.5h, cool them and then crush them to 90 mesh;

[0125] b) Pretreatment of phosphate rock tailings: The phosphate rock tailings are screened to a particle size of 0.25 mm, acid washed, water washed to pH 7.2, and then dried;

[0126] S2. Mixing and Granulation:

[0127] a) Basic mixture: Mix the above-mentioned proportions of camellia shell carbonized material, phosphate rock tailings, vermiculite, perlite, bentonite, slow-release potassium salt and EDTA-calcium to obtain the basic mixture;

[0128] b) Functional addition: Add the above-mentioned proportions of humic acid, seaweed extract, Glomus mossina fungicide, Bacillus subtilis fungicide and sucrose to the base mixture and mix well;

[0129] c) Granulation: The uniformly mixed material is granulated to form cylindrical particles with a diameter of 7 mm.

[0130] Example 5:

[0131] A composite seedling substrate of camellia oleifera shell and phosphate rock tailings is composed of the following raw materials in parts by weight: 60 parts of carbonized camellia oleifera shell; 25 parts of phosphate rock tailings; and 8 parts of Moses's spherical fungicide (effective viable count ≥1.0×10⁻⁶). 6 CFU / g); 4 parts humic acid; 2.0 parts slow-release potassium salt (potassium sulfate); 12 parts vermiculite (4mm particle size); 10 parts perlite (6mm particle size); 5 parts bentonite; 4.0 parts seaweed extract; 2.0 parts Bacillus subtilis agent (effective viable count ≥ 5.0 × 10⁻⁶). 6 CFU / g); EDTA-calcium 2.5 parts; sucrose 1.0 part.

[0132] The camellia shell carbonized material is obtained by carbonizing camellia shells at 550℃ for 1 hour and then crushing them to 100 mesh.

[0133] The phosphate rock tailings have a particle size of 0.3 mm and are obtained by acid washing, water washing to a pH value of 7.5, and then drying.

[0134] The matrix consists of cylindrical particles with a diameter of 8 mm.

[0135] A method for preparing a composite seedling substrate of camellia oleifera shell and phosphate rock tailings includes the following steps:

[0136] S1. Raw material pretreatment:

[0137] a) Preparation of Camellia oleifera shell carbonized material: After washing and drying the Camellia oleifera shells, carbonize them at 550℃ for 1 hour, cool them and then crush them to 100 mesh.

[0138] b) Pretreatment of phosphate rock tailings: The phosphate rock tailings are screened to a particle size of 0.3 mm, acid washed, and water washed until the pH reaches 7.5, and then dried.

[0139] S2. Mixing and Granulation:

[0140] a) Basic mixture: Mix the above-mentioned proportions of camellia shell carbonized material, phosphate rock tailings, vermiculite, perlite, bentonite, slow-release potassium salt and EDTA-calcium to obtain the basic mixture;

[0141] b) Functional addition: Add the above-mentioned proportions of humic acid, seaweed extract, Glomus mossina fungicide, Bacillus subtilis fungicide and sucrose to the base mixture and mix well;

[0142] c) Granulation: The uniformly mixed material is granulated to form cylindrical particles with a diameter of 8 mm.

[0143] Example 6:

[0144] A composite seedling substrate of camellia oleifera shell and phosphate rock tailings is composed of the following raw materials in parts by weight: 50 parts of carbonized camellia oleifera shell; 22 parts of phosphate rock tailings; and 6 parts of Moses's spherical fungicide (effective viable count ≥1.0×10⁻⁶). 6 CFU / g); 3 parts humic acid; 1.5 parts slow-release potassium salt (potassium sulfate); 10 parts vermiculite (particle size 2.5mm); 8 parts perlite (particle size 4.5mm); 4 parts bentonite; 3.2 parts seaweed extract; 1.5 parts Bacillus subtilis agent (effective viable count ≥ 5.0 × 10⁻⁶). 6 CFU / g); EDTA-calcium 2.0 parts; sucrose 0.7 parts.

[0145] The camellia shell carbonized material is obtained by carbonizing camellia shells at 490℃ for 1.8 hours and then crushing them to 85 mesh.

[0146] The phosphate rock tailings have a particle size of 0.22 mm and are obtained by acid washing, water washing to a pH value of 6.9, and then drying.

[0147] The matrix consists of cylindrical particles with a diameter of 6 mm.

[0148] A method for preparing a composite seedling substrate of camellia oleifera shell and phosphate rock tailings includes the following steps:

[0149] S1. Raw material pretreatment:

[0150] a) Preparation of Camellia oleifera shell carbonized material: After washing and drying the Camellia oleifera shells, carbonize them at 490℃ for 1.8h, cool them and then crush them to 85 mesh;

[0151] b) Pretreatment of phosphate rock tailings: The phosphate rock tailings are screened to a particle size of 0.22 mm, acid washed, water washed to pH 6.9, and then dried;

[0152] S2. Mixing and Granulation:

[0153] a) Basic mixture: Mix the above-mentioned proportions of camellia shell carbonized material, phosphate rock tailings, vermiculite, perlite, bentonite, slow-release potassium salt and EDTA-calcium to obtain the basic mixture;

[0154] b) Functional addition: Add the above-mentioned proportions of humic acid, seaweed extract, Glomus mossina fungicide, Bacillus subtilis fungicide and sucrose to the base mixture and mix well;

[0155] c) Granulation: The uniformly mixed material is granulated to form cylindrical particles with a diameter of 6 mm.

[0156] Comparative Example 1 (matrix lacking "EDTA-calcium"):

[0157] Raw material composition (parts by weight): 50 parts of carbonized camellia oleifera shells; 22 parts of phosphate rock tailings; 6 parts of Moses spheroidophylline fungicide (effective viable count ≥1.0×10⁻⁶). 6 CFU / g); 3 parts humic acid; 1.5 parts slow-release potassium salt (potassium sulfate); 10 parts vermiculite (particle size 2.5mm); 8 parts perlite (particle size 4.5mm); 4 parts bentonite; 3.2 parts seaweed extract; 1.5 parts Bacillus subtilis agent (effective viable count ≥ 5.0 × 10⁻⁶). 6 CFU / g); sucrose 0.7 parts (2.0 parts EDTA-calcium missing).

[0158] Key process parameters: completely consistent with those in Example 6.

[0159] Comparative Example 2 (substrate lacking "Moses's Globulus Fungal Agent"):

[0160] Raw material composition (parts by weight): 50 parts of carbonized camellia shell; 22 parts of phosphate rock tailings; 3 parts of humic acid; 1.5 parts of slow-release potassium salt (potassium sulfate); 10 parts of vermiculite (particle size 2.5 mm); 8 parts of perlite (particle size 4.5 mm); 4 parts of bentonite; 3.2 parts of seaweed extract; 1.5 parts of Bacillus subtilis agent (effective viable count ≥ 5.0 × 10⁻⁶). 6 CFU / g); EDTA-calcium 2.0 parts; sucrose 0.7 parts (omitting 6 parts of Moses Globulus fungicide).

[0161] Key process parameters: Same as in Example 6, except that Moses Globulus fungicide was not added during the function addition stage.

[0162] Comparative Example 3 (Matrix lacking "seaweed extract"):

[0163] Raw material composition (parts by weight): 50 parts of carbonized camellia oleifera shells; 22 parts of phosphate rock tailings; 6 parts of Moses spheroidophylline fungicide (effective viable count ≥1.0×10⁻⁶). 6 CFU / g); 3 parts humic acid; 1.5 parts slow-release potassium salt (potassium sulfate); 10 parts vermiculite (particle size 2.5mm); 8 parts perlite (particle size 4.5mm); 4 parts bentonite; 1.5 parts Bacillus subtilis agent (effective viable count ≥ 5.0 × 10⁻⁶). 6 CFU / g); EDTA-calcium 2.0 parts; sucrose 0.7 parts (seaweed extract missing).

[0164] Key process parameters: Same as in Example 6, except that seaweed extract was not added during the functional addition stage.

[0165] Single-factor experiment:

[0166] Based on Example 6 (best example), only one process parameter was changed while the other parameters remained unchanged. The test indicators were "seedling taproot length (cm), phosphorus uptake (mg / plant), and transplant survival rate (%)". The experimental results are as follows:

[0167] (I) Single-factor experiment on carbonization temperature of camellia shell

[0168] The process is basically the same as that of the optimal embodiment 6, except that the carbonization temperature of the camellia shell is set at five levels: 350℃, 420℃, 490℃, 560℃ and 630℃. The results are shown in Table 1.

[0169]

[0170] Conclusion Analysis:

[0171] When the temperature is below 490℃, the organic matter in the camellia shell is not fully carbonized, the pore structure is poorly developed, and it cannot effectively adsorb the phosphorus released by the tailings of the phosphate mine. In addition, the water and fertilizer retention capacity is weak, resulting in insufficient nutrient acquisition by the seedling roots, short taproots, low phosphorus absorption, and poor survival rate.

[0172] When the temperature exceeds 490℃, the organic matter in the camellia oleifera shell decomposes excessively, producing a small amount of acidic substances that stimulate seedling root growth. Simultaneously, the porous structure collapses due to high temperatures, accelerating nutrient loss and leading to a decline in performance indicators. In this single-factor experiment, the optimal temperature parameter for the carbonization of camellia oleifera shells was 490℃.

[0173] (II) Single-factor experiment on carbonization time of camellia shells

[0174] The process is basically the same as that of the optimal embodiment 6, except that the carbonization time of the camellia shell is set to five levels: 0.6h, 1.2h, 1.8h, 2.4h and 3.0h. The results are shown in Table 2.

[0175]

[0176] Conclusion Analysis:

[0177] When the time is less than 1.8 hours, the camellia shell is not completely carbonized, and the remaining uncarbonized organic matter is easily decomposed to produce ammonia, which inhibits root growth and has a low effective phosphorus adsorption, resulting in poor performance.

[0178] When the carbonization time exceeds 1.8 hours, the carbonized material excessively consumes organic matter, failing to provide sufficient carbon source for the seedlings. Simultaneously, phosphorus in the phosphate rock tailings is fixed due to prolonged high temperatures, leading to a decrease in performance indicators. In this single-factor experiment, the optimal time parameter for camellia shell carbonization was 1.8 hours.

[0179] (III) Single-factor experiment on the particle size of phosphate mine tailings

[0180] The process is basically the same as that of the optimal embodiment 6, except that the particle size of the phosphate rock tailings is set at five levels: 0.07 mm, 0.12 mm, 0.17 mm, 0.22 mm and 0.27 mm. The results are shown in Table 3.

[0181]

[0182] Conclusion Analysis:

[0183] When the particle size is less than 0.22mm, the tailings are prone to agglomeration and clumping, resulting in poor substrate permeability, root hypoxia and inability to grow normally, and excessively rapid phosphorus release, leading to insufficient nutrients in the later stages.

[0184] When the particle size is greater than 0.22 mm, the tailings have a small specific surface area, resulting in slow release of available phosphorus and insufficient phosphorus supply during the seedling growth period, leading to poor root development and low survival rate. In this single-factor experiment, the optimal particle size parameter for phosphate rock tailings was 0.22 mm.

[0185] (iv) Single-factor experiment on mixed rotation speed during the function addition stage

[0186] The process is basically the same as that of the optimal embodiment 6, except that the mixing speed in the function addition stage is set to five levels: 100 r / min, 150 r / min, 200 r / min, 250 r / min and 300 r / min. The results are shown in Table 4.

[0187]

[0188] Conclusion Analysis:

[0189] When the rotation speed is below 200 r / min, the functional components (Moses Gloydius fungicide and seaweed extract) are unevenly dispersed in the basic mixture, resulting in low local concentrations of fungicide, which cannot effectively promote root growth. Furthermore, the uneven distribution of seaweed extract leads to significant differences in stress resistance.

[0190] When the rotation speed exceeds 200 r / min, the high rotation speed damages the spore structure of *Gastrodia elata*, and the decomposition rate of effective components of seaweed extract (such as seaweed polysaccharides) is >30%, weakening the stress resistance and leading to a decrease in indicators. In this single-factor experiment, the optimal mixing rotation speed parameter for the functional addition stage is 200 r / min.

[0191] (V) Single-factor experiment on granulation diameter

[0192] The process is basically the same as that in Example 6, except that the matrix granulation diameter is set to five levels: 2 mm, 4 mm, 6 mm, 8 mm and 10 mm. The results are shown in Table 5.

[0193]

[0194] Conclusion Analysis:

[0195] When the diameter is less than 6mm, the particles are easily broken, the substrate loss rate after watering is >20%, nutrients are lost with water, and the small gaps between particles restrict root growth.

[0196] When the diameter is greater than 6mm, water conduction within the granules is slow, causing the internal substrate to dry out after watering, preventing the roots from obtaining sufficient water. Furthermore, excessively large granules result in uneven filling of the seedling tray holes, leading to significant differences in seedling growth space. In this single-factor experiment, the optimal diameter parameter for substrate granulation was 6mm.

[0197] Performance index testing:

[0198] (a) Experimental Design

[0199] Example group: The substrates prepared in Examples 1-6 were used to cultivate soybean seedlings;

[0200] Comparative example group (lacking only one key component; all other raw materials and processes are the same as in Example 6):

[0201] Comparative Example 1: Matrix lacking "EDTA-calcium" (no EDTA-calcium, other components are the same as in Example 6).

[0202] Comparative Example 2: Matrix lacking "Moses' Globulus Antifungal Agent" (without Moses' Globulus Antifungal Agent, the other components are the same as in Example 6);

[0203] Comparative Example 3: Matrix lacking "seaweed extract" (no seaweed extract, other components are the same as in Example 6);

[0204] Test indicators: Main root length (cm), phosphorus uptake (mg / plant), transplant survival rate (%), drought stress wilting rate (%), heavy metal cadmium uptake rate (%), root rot incidence (%).

[0205] Testing conditions: Seedlings were raised for 3 months and then transplanted to the karst region of Guangxi (soil calcium content 22g / kg, available phosphorus 3.5mg / kg, cadmium content 0.5mg / kg). They were observed for 6 months after transplanting.

[0206] (II) Test Results

[0207]

[0208] (III) Data Comparison and Theoretical Analysis

[0209] 1. Comparative Analysis of Key Data in Example Groups

[0210] Example 6 showed a 15.2% rate of "wilt rate under drought stress," slightly higher than Example 4's 12.5%. However, among the five core indicators—main root length (15.3 cm), phosphorus uptake (6.7 mg / plant), transplant survival rate (82.1%), cadmium uptake rate (4.1%), and root rot incidence (6.8%)—Example 6 still performed best, demonstrating the most outstanding overall performance.

[0211] The reason why Example 4 showed better performance in terms of wilting rate under drought stress is that the vermiculite particle size used was 3.5 mm, slightly larger than the 2.5 mm in Example 6, resulting in larger interparticle gaps and an air permeability of 68.2% (higher than 65.3% in Example 6). Under drought conditions, a better ventilation structure helps to slow down moisture evaporation, thereby reducing the wilting rate. This difference reflects the local advantages that different parameter combinations may have in specific functional indicators.

[0212] 2. The impact and mechanism of the absence of key components on performance

[0213] Comparative Example 1 (EDTA-calcium deficiency): The main root length decreased by 24.2% compared to Example 6 (from 15.3 cm to 11.6 cm), phosphorus uptake decreased by 26.9% (from 6.7 mg / plant to 4.9 mg / plant), and cadmium uptake increased by 236.6% (from 4.1% to 13.8%).

[0214] Mechanism analysis: EDTA-calcium deficiency leads to the binding of free calcium ions with phosphate ions in the soil to form insoluble calcium phosphate, resulting in insufficient available phosphorus supply. Simultaneously, cadmium ions are excessively absorbed by roots due to the loss of competitive chelation sites. The results indicate that EDTA-calcium is a crucial and irreplaceable component for breaking calcium-phosphorus antagonism and simultaneously reducing the absorption of the heavy metal cadmium.

[0215] Comparative Example 2 (without Moses's Gloydius fungicide): taproot length decreased by 29.4% (from 15.3 cm to 10.8 cm), and transplant survival rate decreased by 16.6% (from 82.1% to 68.5%).

[0216] Mechanism analysis: Without symbiotic microbial agents, the root system cannot form an effective mycorrhizal structure, significantly reducing the absorption area, making it difficult to efficiently utilize even sufficient available phosphorus in the soil. This demonstrates that the microbial agent is the core functional component for promoting root development, improving nutrient utilization, and enhancing transplant survival.

[0217] Comparative Example 3 (lacking seaweed extract): The wilting rate under drought stress increased by 188.2% (from 15.2% to 43.8%), and the transplant survival rate decreased by 8.4% (from 82.1% to 75.2%).

[0218] Mechanism analysis: The polysaccharides, betaine and other active substances contained in seaweed extract can enhance cell osmotic regulation and water retention capacity; their deficiency leads to a sharp decline in seedling drought resistance, confirming that this component is the key to improving stress resistance, and other components cannot be equivalently replaced.

[0219] 3. Comprehensive performance comparison and synergistic effect analysis

[0220] Even though Example 6 was slightly inferior to Example 4 in terms of drought stress wilting rate, it was still significantly better than all comparative examples: for example, the wilting rate was 0.8% lower than that of comparative example 1, 2.1% lower than that of comparative example 2, and 28.6% lower than that of comparative example 3; while in terms of indicators such as main root length and phosphorus uptake, Example 6 was generally higher than the comparative examples, showing obvious advantages.

[0221] The above data differences demonstrate that this invention achieves an overall functional improvement of "1+1+1 > 3" through the synergistic formulation of all components: EDTA-calcium ensures phosphorus availability and reduces cadmium absorption; Moses Gloydius fungicide strengthens root structure and absorption efficiency; and seaweed extract system enhances stress resistance. The organic combination of these three components makes the matrix superior to solutions lacking any single key component in multiple indicators, thus effectively overcoming the technical limitations of existing technologies that are functionally singular and unable to comprehensively address the complex habitat constraints of karst regions.

[0222] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the inventive concept, and all such substitutions or modifications should be considered within the scope of protection of the present invention.

[0223] Although the invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the invention. Furthermore, the scope of the invention is not limited to the specific embodiments of the processes, methods, and steps described in the specification. From the disclosure of this invention, those skilled in the art will readily utilize existing or future processes, methods, steps that substantially perform the same function or achieve the same results as the corresponding embodiments described herein. Therefore, the appended claims are intended to cover such processes, methods, steps.

Claims

1. A composite seedling substrate of camellia oleifera shell and phosphate rock tailings, characterized in that, It is composed of the following raw materials in parts by weight: 45-60 parts of camellia shell carbonized material; 15-25 parts of phosphate rock tailings; 3-8 parts of Moses Globulus fungicide; 1-4 parts of humic acid; 0.8-2.0 parts of slow-release potassium salt; 5-12 parts of vermiculite; 4-10 parts of perlite; 2-5 parts of bentonite; 1.5-4.0 parts of seaweed extract; 0.5-2.0 parts of Bacillus subtilis agent; 1.0-2.5 parts of EDTA-calcium; and 0.2-1.0 parts of sucrose.

2. The camellia oleifera shell-phosphate rock tailings composite seedling substrate according to claim 1, characterized in that, The camellia shell carbonized material is obtained by carbonizing camellia shells at 450-550℃ for 1-3 hours and then crushing them to 60-100 mesh.

3. The camellia oleifera shell-phosphate rock tailings composite seedling substrate according to claim 1, characterized in that, The phosphate mine tailings have a particle size of 0.1-0.3 mm and are acid-washed and adjusted to a pH value of 6.0-7.

5.

4. The camellia oleifera shell-phosphate rock tailings composite seedling substrate according to claim 1, characterized in that, The slow-release potassium salt is potassium sulfate.

5. The camellia oleifera shell-phosphate rock tailings composite seedling substrate according to claim 1, characterized in that, The vermiculite has a particle size of 1-4 mm.

6. The camellia oleifera shell-phosphate rock tailings composite seedling substrate according to claim 1, characterized in that, The perlite has a particle size of 2-6 mm.

7. The camellia oleifera shell-phosphate rock tailings composite seedling substrate according to claim 1, characterized in that, The effective viable count of the Moses globosum fungicide is ≥1.0 × 10⁻⁶. 6 CFU / g; and / or, the effective viable count of the Bacillus subtilis agent is ≥5.0 × 10⁻⁶. 6 CFU / g.

8. The camellia oleifera shell-phosphate rock tailings composite seedling substrate according to any one of claims 1 to 7, characterized in that, The matrix consists of cylindrical particles with a diameter of 3-8 mm.

9. A method for preparing a composite seedling substrate of camellia oleifera shell and phosphate rock tailings according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Raw material pretreatment: a) Preparation of Camellia oleifera shell carbonized material: After washing and drying the Camellia oleifera shells, carbonize them at 450-550℃ for 1-3 hours, cool them and then crush them to 60-100 mesh. b) Pretreatment of phosphate rock tailings: The phosphate rock tailings are screened to a particle size of 0.1-0.3 mm, acid washed, and water washed until the pH is 6.0-7.5, and then dried; S2. Mixing and Granulation: a) Basic mixture: The camellia shell carbonized material, phosphate rock tailings, vermiculite, perlite, bentonite, slow-release potassium salt and EDTA-calcium in the proportions described in claim 1 are mixed to obtain a basic mixture; b) Functional addition: Add the humic acid, seaweed extract, Glomus mossina fungicide, Bacillus subtilis fungicide and sucrose in the proportions described in claim 1 to the base mixture, and mix well; c) Granulation: The uniformly mixed materials are granulated to form cylindrical particles with a diameter of 3-8 mm.

10. The application of a Camellia oleifera shell-phosphate rock tailings composite seedling substrate prepared according to the method of claim 9 in the cultivation of pioneer tree species in karst areas.

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