Foliar fertilizer for planting dendrobium nobile and preparation method thereof

Abstract

The invention discloses a leaf fertilizer for planting dendrobium nobile and a preparation method of the leaf fertilizer, and relates to the field of agricultural fertilizers. The foliar fertilizer comprises a plant source Chinese herbal medicine extract, a basic nutrition component, a growth regulation component and a solvent. The botanical Chinese herbal medicine extract is prepared from folium isatidis, dandelion, honeysuckle, radix isatidis, houttuynia cordata, bunge corydalis herb, radix sophorae flavescentis and artemisia apiacea according to a specific proportion; the basic nutrition component comprises urea, monopotassium phosphate, potassium sulfate, potassium fulvate and polyglutamic acid; the growth regulating component comprises vitamin B1, vitamin B6, inositol and folic acid. The invention also provides a preparation method of the foliar fertilizer. The preparation method comprises the following steps: preparing the Chinese herbal medicine extract, mixing and stirring, and packaging a finished product. The leaf fertilizer disclosed by the invention can effectively promote the growth of dendrobium nobile, increase the content of polysaccharide and alkaloid and enhance the disease and pest resistance, and is environment-friendly.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foliar fertilizers, in particular to a foliar fertilizer for planting Dendrobium nobile and a preparation method thereof. BACKGROUND

[0002] Dendrobium nobile is a traditional Chinese medicinal material in China, which has the effects of nourishing yin and clearing heat, benefiting the stomach and generating saliva, etc. Its main effective components are dendrobium polysaccharide and alkaloids. In recent years, with the expansion of the artificial planting scale of Dendrobium nobile, the fertilization technology has become a key factor affecting its yield and quality.

[0003] At present, the fertilizers commonly used in the planting of Dendrobium nobile mainly include chemical fertilizers and organic fertilizers. Although chemical fertilizers such as potassium dihydrogen phosphate and urea can provide available nutrients, they have the problem of low fertilizer utilization rate. Organic fertilizers such as decomposed cow dung have the disadvantages of slow nutrient release and possible carrying of pathogenic bacteria. In addition, conventional foliar fertilizers have the problems of low leaf absorption rate, easy dripping, and difficult nutrient transfer in the application of Dendrobium nobile, especially the thick cuticle layer of the leaves of Dendrobium nobile, which further reduces the absorption efficiency of the foliar fertilizer.

[0004] In recent years, some studies have attempted to apply Chinese herbal medicine components to the preparation of fertilizers. CN104529624A discloses a plant source Chinese herbal medicine biological foliar fertilizer, which is prepared by microorganism fermentation of various Chinese herbal medicines such as largeleaf figwort and dandelion, and has the functions of disinfection and repellence on crop diseases and insect pests. However, this foliar fertilizer is not specially designed for the growth and development characteristics of Dendrobium nobile, and the special nutritional requirements and medicinal component accumulation rules of Dendrobium nobile are not fully considered.

[0005] Therefore, it has become a technical problem to be solved in the field to develop a special foliar fertilizer that can effectively promote the growth of Dendrobium nobile, increase the content of medicinal components, enhance the stress resistance, and is environmentally friendly. SUMMARY

[0006] The purpose of the present application is to provide a foliar fertilizer for planting Dendrobium nobile and a preparation method thereof, which can effectively improve the problems of slow growth and weak disease and insect resistance of Dendrobium nobile.

[0007] To solve the above technical problems, the present application adopts the following technical scheme:

[0008] A preparation method of a plant source Chinese herbal medicine extract, comprising the following contents: after the raw materials are crushed, a composite microbial inoculum is added for pre-fermentation treatment; water is added for reflux extraction, the filtrate is filtered and combined, and the filtrate is concentrated into an extract, to obtain a plant source Chinese herbal medicine extract;

[0009] The raw materials, by weight, include the following components: 5-8 parts of Isatis tinctoria leaf, 3-4 parts of dandelion, 3-5 parts of honeysuckle, 3-4 parts of Isatis tinctoria root, 2-4 parts of Houttuynia cordata, 2-3 parts of Viola yedoensis, 1-2 parts of Sophora flavescens, and 3-6 parts of Artemisia annua.

[0010] This invention utilizes a specific compound microbial agent for pre-fermentation treatment to biotransform traditional Chinese medicine raw materials. This process not only effectively disrupts plant cell wall structures using microbial enzymes, but more importantly, it decomposes some of the large organic molecules in the raw materials into smaller, more readily absorbed and utilized active substances, generating entirely new beneficial metabolites, thus achieving a qualitative change from simple impregnation to deep activation.

[0011] This invention addresses the growth-promoting and disease-resistant needs of Dendrobium nobile by precisely selecting a synergistic combination of microbial strains (Bacillus subtilis, Trichoderma harzianum, and thermophilic cellulose-decomposing bacteria) and using pre-fermentation as a necessary pre-step in the water extraction process. This tandem process design of microbial pre-activation and hot water synergistic extraction innovatively combines the high efficiency of biotransformation with the broad-spectrum nature of water extraction, aiming to maximize the diversity and bioactivity of functional components in the extract. The product not only contains the inherent active ingredients of the raw material but is also rich in growth-promoting factors and natural antibacterial substances produced by microbial metabolism, enabling the final foliar fertilizer to possess both nutritional and plant protection functions. Furthermore, pre-fermentation softens the raw material and degrades cellulose, reducing mass transfer resistance in the subsequent water extraction process, thereby achieving a higher extraction rate of effective components under gentler conditions.

[0012] The extract formulation of this invention (eight ingredients including Isatis tinctoria leaf, dandelion, honeysuckle, etc.) is not a simple compound. The oligosaccharides, phenolic acids, microbial lipopeptides, matrine, and other components, under specific ratios, can not only inhibit pathogens but also activate the phenylpropane metabolic pathway of Dendrobium nobile. This pathway is the key to the synthesis of Dendrobium nobile polysaccharides and alkaloids.

[0013] Furthermore, the compound microbial agent includes Bacillus subtilis, Trichoderma harzianum, and thermophilic fiber-decomposing bacteria; in the compound microbial agent, the mass ratio of Bacillus subtilis to Trichoderma harzianum is 1:1, and the total mass of the two is 3-5 times the mass ratio of the thermophilic fiber-decomposing bacteria.

[0014] Furthermore, 1-2% of the total weight of the raw materials is added as a compound microbial agent for pre-fermentation treatment. The pre-fermentation conditions are a temperature of 35-40℃ and a time of 3-5 days.

[0015] Further, weigh the Chinese herbal medicine raw materials according to the specified proportions, pulverize them, and pass them through a 60-80 mesh sieve. Add 5-8 times the total weight of water to the raw materials, and reflux extract at 90-100℃ 2-3 times, 1-2 hours each time. Filter, combine the filtrates, and concentrate to a density of 1.10-1.15 g / cm³.3 The extract was obtained from the plant-derived herbal extract.

[0016] A plant-derived herbal extract prepared by the method described above.

[0017] A foliar fertilizer for Dendrobium nobile cultivation, comprising the following components by weight:

[0018] 15-30 parts of plant-derived herbal extracts, 40-60 parts of basic nutrients, 0.5-2 parts of growth regulators, and 100-150 parts of solvent;

[0019] The basic nutrient components, by weight, include the following: 13-17 parts urea, 8-12 parts potassium dihydrogen phosphate, 5-8 parts potassium sulfate, 6.5-10 parts potassium humate, and 7.5-13 parts polyglutamic acid; the growth regulator components include the following: 0.1-0.3 parts vitamin B1, 0.03-0.2 parts vitamin B6, 0.35-1.45 parts cyclohexanehexol, and 0.02-0.05 parts folic acid; the solvent is water, with the pH adjusted to 5.5-6.5.

[0020] The extract of this invention not only inhibits pathogens but also activates the phenylpropanoid metabolic pathway in *Dendrobium nobile*, a pathway crucial for the synthesis of polysaccharides and alkaloids. The use of potassium humate and polyglutamic acid to form a hydrophilic system revolutionizes the traditional foliar fertilizer penetration model. Potassium humate softens the leaf cuticle, while the network structure of polyglutamic acid carries nutrient molecules, forming a slow-release "pharmacy" on the leaf surface. This allows for the simultaneous and sustained absorption of active ingredients from traditional Chinese medicine and mineral nutrients, solving the industry pain points of foliar fertilizers drying out and dripping easily. The growth-regulating components abandon conventional plant hormones, selecting a combination of vitamins B1, B6, cyclohexanehexol, and folic acid, key cofactors for sugar metabolism and alkaloid synthesis in plants. They exhibit the highest activity in a weakly acidic (pH 5.5-6.5) solvent environment, directly acting on the primary and secondary metabolic hubs of *Dendrobium nobile*, efficiently converting absorbed nutrients into target medicinal components.

[0021] The formula of this invention achieves a systematic improvement from fertilizer supply to fertilizer delivery, growth promotion, and quality enhancement. Field trials have confirmed that after application, the fertilizer's retention time on the leaves is extended by approximately 40%, and the leaf absorption rate is increased by over 25%. This not only directly manifests as a significant improvement in growth indicators such as tiller number and stem diameter, but more importantly, it can efficiently convert the dry matter accumulated during vegetative growth into Dendrobium polysaccharides and total alkaloids, achieving a simultaneous increase in yield and quality. Simultaneously, the sustained action of the herbal components disrupts the pathogen infection cycle, effectively reducing the incidence of soil-borne diseases such as anthracnose, providing core technical support for the green and sustainable cultivation of Dendrobium nobile.

[0022] A method for preparing a foliar fertilizer suitable for planting Dendrobium nobile includes the following steps:

[0023] S100. After mixing the above extract with a portion of the solvent, heat and stir until homogeneous; add the basic nutrient components, keep warm and stir until homogeneous; add the growth regulating components and stir until completely dissolved.

[0024] S200. Adjust the pH value of the mixture obtained in step S100, filter it, and the filtrate is the foliar fertilizer.

[0025] The preparation method of this invention breaks away from the conventional "one-pot" mixing mode, adopting a three-step sequential addition method of "traditional Chinese medicine extract - basic nutrient components - growth regulator components", and incorporating a sub-step of "potassium humate and polyglutamic acid premixing". This preparation method, based on the differences in the physicochemical properties of each component, effectively prevents flocculation and encapsulation phenomena that may occur when polyglutamic acid comes into direct contact with high-concentration electrolytes by controlling the order of addition and premixing. This ensures the uniformity and stability of the system and solves the technical problem of easy inactivation of functional polymers in compound fertilizer solutions.

[0026] Further, in step S100, the plant-derived herbal extract is mixed with a solvent accounting for 30% to 50% of the total solvent mass, and stirred at 240 to 300 r / min for 10 to 15 minutes at a temperature of 55 to 60°C; basic nutrient components are added, and stirring is continued for 20 to 30 minutes while maintaining the temperature at 55 to 60°C; finally, growth regulator components are added and stirred until completely dissolved.

[0027] By precisely controlling the particle size, material-to-liquid ratio, extraction temperature, and number of extractions, the degradation and deactivation of heat-sensitive active ingredients are minimized while ensuring extraction efficiency.

[0028] Furthermore, in step S100, when adding the basic nutrient components, potassium humate and polyglutamic acid are first pre-mixed with a portion of the solvent at 40~50℃ to form a homogeneous solution, and then added together with the other basic nutrient components.

[0029] Further, in step S200, the pH value of the prepared foliar fertilizer is adjusted to 5.5~6.5.

[0030] The pH of the final product is precisely controlled within a slightly acidic range of 5.5 to 6.5. This environment is most conducive to the absorption of Dendrobium nobile leaf cells and ensures the chemical stability of all active ingredients during storage, preventing hydrolysis, precipitation and other deterioration phenomena.

[0031] Foliar fertilizer should be diluted with water at a volume ratio of 1:800~1000 to obtain a diluted solution, which can be applied by soaking or foliar spraying.

[0032] When transplanting tissue culture seedlings, soak them in diluted solution for 5-10 minutes before transplanting, or spray once every 8-12 days after transplanting, for 2-3 consecutive times; for plants in the growing season, spray once every 8-10 days, for 3-4 consecutive times; spray once before flower buds open.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. The plant-derived herbal ingredients and active substances produced through a pre-fermentation process of this invention jointly endow the foliar fertilizer with inherent antibacterial and insecticidal capabilities, helping to reduce the incidence of common diseases such as anthracnose and enhancing the plant's resistance to adverse conditions. The entire preparation process has clearly defined parameters and a stable flow, ensuring a high degree of consistency in the quality between batches of the final product.

[0035] 2. The foliar fertilizer of this invention, through its unique component design and refined preparation process, can significantly promote the growth of Dendrobium nobile plants, specifically by increasing the number of tillers, stem diameter, and leaf quantity, thereby improving the fresh and dry weight per unit yield. More importantly, it can effectively enhance the core medicinal quality of Dendrobium nobile, significantly increasing the content of Dendrobium polysaccharides and total alkaloids, directly enhancing its economic and application value as a traditional Chinese medicine. Detailed Implementation

[0036] The present invention will now be further described.

[0037] Example 1

[0038] A method for preparing a plant-derived herbal extract includes the following steps: pulverizing the raw material and passing it through a 70-mesh sieve; adding 1.5% (by weight of the total raw material) of a compound microbial agent for pre-fermentation at 37°C for 3-5 days; adding 6.5 times the total weight of water and refluxing at 95°C three times, each time for 1.5 hours; filtering; combining the filtrates; and concentrating to a density of 1.12 g / cm³. 3 The extract was obtained from the plant-derived herbal extract.

[0039] The raw materials include the following components: 65g of Isatis tinctoria leaf, 35g of dandelion, 40g of honeysuckle, 35g of Isatis tinctoria root, 30g of houttuynia cordata, 25g of Viola yedoensis, 15g of Sophora flavescens, and 45g of Artemisia annua.

[0040] The compound microbial agent includes Bacillus subtilis, Trichoderma harzianum, and thermophilic fiber-decomposing bacteria; in the compound microbial agent, the mass ratio of Bacillus subtilis to Trichoderma harzianum is 1:1, and the total mass ratio of the two to the mass ratio of the thermophilic fiber-decomposing bacteria is 4:1.

[0041] Example 2

[0042] A method for preparing a plant-derived herbal extract includes the following steps: pulverizing the raw material and passing it through a 60-mesh sieve; adding 1% (by weight of the total raw material) of a compound microbial agent for pre-fermentation at 35°C for 3 days; adding 5 times the total weight of water and refluxing twice at 90°C for 1 hour each time; filtering; combining the filtrates; and concentrating to a density of 1.10 g / cm³. 3 The extract was obtained from the plant-derived herbal extract.

[0043] The raw materials include the following components: 50g of Isatis tinctoria leaf, 30g of dandelion, 30g of honeysuckle, 30g of Isatis tinctoria root, 20g of Houttuynia cordata, 20g of Viola yedoensis, 10g of Sophora flavescens, and 30g of Artemisia annua.

[0044] The compound microbial agent includes Bacillus subtilis, Trichoderma harzianum, and thermophilic fiber-decomposing bacteria; in the compound microbial agent, the mass ratio of Bacillus subtilis to Trichoderma harzianum is 1:1, and the total mass ratio of the two to the mass ratio of thermophilic fiber-decomposing bacteria is 3:1.

[0045] Example 3

[0046] A method for preparing a plant-derived herbal extract includes the following steps: pulverizing the raw material and passing it through an 80-mesh sieve; adding 2% (by weight of the total raw material) of a compound microbial agent for pre-fermentation at 40°C for 5 days; adding 8 times the total weight of water and refluxing at 100°C for 2 hours each time, followed by filtration; combining the filtrates and concentrating to a density of 1.15 g / cm³. 3 The extract was obtained from the plant-derived herbal extract.

[0047] The raw materials include the following components: 80g of Isatis tinctoria leaf, 40g of dandelion, 50g of honeysuckle, 40g of Isatis tinctoria root, 40g of Houttuynia cordata, 30g of Viola yedoensis, 20g of Sophora flavescens, and 60g of Artemisia annua.

[0048] The compound microbial agent includes Bacillus subtilis, Trichoderma harzianum, and thermophilic fiber-decomposing bacteria; in the compound microbial agent, the mass ratio of Bacillus subtilis to Trichoderma harzianum is 1:1, and the total mass ratio of the two to the mass ratio of the thermophilic fiber-decomposing bacteria is 5:1.

[0049] Comparative Example 1

[0050] Pre-fermentation was carried out using only Bacillus subtilis, with the amount being equivalent to the total bacterial agent; other aspects were the same as in Example 1.

[0051] Comparative Example 2

[0052] No pre-fermentation is performed; the raw materials are directly extracted by reflux after being crushed; otherwise, it is the same as in Example 1.

[0053] Comparative Example 3

[0054] First, water extraction was performed, then the residue was pre-fermented, and the fermentation liquid was combined with the extract; otherwise, it was the same as in Example 1.

[0055] The performance parameters of the plant-derived herbal extracts prepared by the methods of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1.

[0056] Item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Cell wall breaking rate (%) 92.5 85.3 94.1 78.4 62.1 75.2 Small molecule peptide / amino acid content (mg / g) 25.6 20.9 27.2 19.8 12.1 14.5 Total flavonoid yield (mg / g) 43.8 37.5 45.2 38.1 34.9 37.3 Oligosaccharide content (mg / g) 15.3 11.5 16.1 9.8 8.4 5.2 Chlorogenic acid content (mg / g) 3.85 2.95 3.95 4.25 3.52 3.10 Microbial lipopeptide content (μg / g) 45.2 35.8 48.5 42.1 15.6 Not detected

[0057] As shown in Table 1, the cell wall breakage rate in Examples 1-3 can reach 94.1%, the content of small molecule peptides / amino acids can reach 27.2 mg / g, the total flavonoid yield is >37.5 mg / g, the oligosaccharide content is ≥11.5 mg / g, the chlorogenic acid content reaches 3.95 mg / g, and the microbial lipopeptide content is 48.5 μg / g.

[0058] In Comparative Example 1, fermentation using a single microbial strain resulted in all indicators being lower than those in Example 1, particularly the cell wall disruption rate and small molecule peptide content. This demonstrates the synergistic necessity of combining Bacillus subtilis, Trichoderma harzianum, and thermophilic cellulose-decomposing bacteria. Single microbial strains have limited functionality and cannot accomplish complex integrated tasks; only specific combinations can achieve optimal bioactivation effects.

[0059] In Comparative Example 2, no pre-fermentation was performed, and water extraction was carried out directly. The cell wall disruption rate was extremely low, only 62.1%, resulting in unsatisfactory yields and activities of all subsequent active ingredients. This demonstrates that the pre-fermentation step is crucial for improving overall efficiency. Furthermore, using only Bacillus subtilis lacked the strong cell wall disruption capabilities of Trichoderma harzianum and other cellulolytic bacteria, leading to low biotransformation efficiency throughout the system. This not only affected the yield of lipopeptides but also reduced the source of oligosaccharides due to insufficient cell wall disruption.

[0060] In Comparative Example 3, water extraction was performed first, followed by fermentation of the residue. All indicators were lower than in Example 1, demonstrating that the fermentation-extraction sequence is irreversible. Without the pre-fermentation step, the core link of biotransformation is lost. Simple hot water extraction can only dissolve some of the inherent water-soluble components (chlorogenic acid) in the raw material, failing to effectively disrupt the cell wall, resulting in extremely low oligosaccharide yield; and it cannot produce microbial-specific signaling molecules (lipopeptides).

[0061] Example 4

[0062] A foliar fertilizer for Dendrobium nobile cultivation, comprising the following components:

[0063] Example 1: 230g of plant-derived herbal extract, 500g of basic nutrient components, 13g of growth regulator components, and 1250g of solvent were prepared by the method.

[0064] The basic nutrient components include the following: 150g urea, 100g potassium dihydrogen phosphate, 70g potassium sulfate, 80g potassium humate, and 100g polyglutamic acid; the growth regulator components include the following: 2g vitamin B1, 1g vitamin B6, 9.6g cyclohexanehexol, and 0.4g folic acid; the solvent is water, and the pH of the water is adjusted to 6.0.

[0065] A method for preparing a foliar fertilizer suitable for planting Dendrobium nobile includes the following steps:

[0066] S100, Polymer Premix: Take 220g of solvent, preheat to 45℃, add potassium humate and polyglutamic acid while stirring, and prepare a homogeneous solution for later use.

[0067] Preparation of mother liquor from Chinese herbal medicine: Take 400g of solvent, heat to 58℃, mix with plant-derived Chinese herbal medicine extract, stir at 270r / min for 12 minutes to form a homogeneous mother liquor.

[0068] Pour the premixed polymer solution into the herbal extract. Rinse the container holding the polymer solution with 130g of solvent and pour the rinsing solution into the container as well. At 58℃, while continuously stirring, add urea, potassium dihydrogen phosphate, potassium sulfate, and other basic nutrients in sequence, maintaining stirring for 25 minutes. Add the growth regulators (vitamin B1, B6, cyclohexanehexol, and folic acid) to the above mixture and stir until completely dissolved.

[0069] S200, add the remaining solvent and mix well; at the same time, precisely adjust the pH value of the mixture to 6.0, filter the pH-adjusted foliar fertilizer solution through a 200-mesh filter, and the resulting clear filtrate is the foliar fertilizer.

[0070] Example 5

[0071] A foliar fertilizer for Dendrobium nobile cultivation, comprising the following components:

[0072] Example 1: 150g of plant-derived herbal extract, 400g of basic nutrient components, 5g of growth regulator components, and 1000g of solvent were prepared by the method.

[0073] The basic nutrient components include the following: 130g urea, 80g potassium dihydrogen phosphate, 50g potassium sulfate, 65g potassium humate, and 75g polyglutamic acid; the growth regulator components include the following: 1g vitamin B1, 0.3g vitamin B6, 3.5g cyclohexanehexol, and 0.2g folic acid; the solvent is water, and the pH of the water is adjusted to 5.5.

[0074] A method for preparing a foliar fertilizer suitable for planting Dendrobium nobile includes the following steps:

[0075] S100, Polymer Premix: Take 200g of solvent, preheat to 40℃, add potassium humate and polyglutamic acid while stirring, and prepare a homogeneous solution for later use.

[0076] Preparation of herbal mother liquor: Take 300g of solvent, heat to 55℃, mix with plant-derived herbal extract, stir at 240r / min for 10 minutes to form a homogeneous mother liquor.

[0077] Pour the premixed polymer solution into the herbal extract. Rinse the container holding the polymer solution with 100g of solvent and pour the rinsing solution into the container as well. At 55℃, while continuously stirring, add urea, potassium dihydrogen phosphate, potassium sulfate, and other basic nutrients in sequence, maintaining stirring for 20 minutes. Add the growth regulators (vitamin B1, B6, cyclohexanehexol, and folic acid) to the above mixture and stir until completely dissolved.

[0078] S200, add the remaining solvent and mix well; at the same time, precisely adjust the pH value of the mixture to 5.5, filter the pH-adjusted foliar fertilizer solution through a 200-mesh filter, and the resulting clear filtrate is the foliar fertilizer.

[0079] Example 6

[0080] A foliar fertilizer for Dendrobium nobile cultivation, comprising the following components:

[0081] Example 1: 300g of plant-derived herbal extract, 600g of basic nutrient components, 20g of growth regulator components, and 1500g of solvent were prepared by the method.

[0082] The basic nutrient components include the following: 170g urea, 120g potassium dihydrogen phosphate, 80g potassium sulfate, 100g potassium humate, and 130g polyglutamic acid; the growth regulator components include the following: 3g vitamin B1, 2g vitamin B6, 14.5g cyclohexanehexol, and 0.5g folic acid; the solvent is water, and the pH of the water is adjusted to 6.5.

[0083] A method for preparing a foliar fertilizer suitable for planting Dendrobium nobile includes the following steps:

[0084] S100, Polymer Premix: Take 250g of solvent, preheat to 50℃, add potassium humate and polyglutamic acid while stirring, and prepare a homogeneous solution for later use.

[0085] Preparation of herbal mother liquor: Take 500g of solvent, heat to 60℃, mix with plant-derived herbal extract, stir at 300r / min for 15 minutes to form a homogeneous mother liquor.

[0086] Pour the premixed polymer solution into the herbal extract. Rinse the container holding the polymer solution with 150g of solvent and pour the rinsing solution into the container as well. At 60℃, while continuously stirring, add urea, potassium dihydrogen phosphate, potassium sulfate, and other basic nutrients in sequence, maintaining stirring for 30 minutes. Add the growth regulators (vitamin B1, vitamin B6, cyclohexanehexol, and folic acid) to the above mixture and stir until completely dissolved.

[0087] S200, add the remaining solvent and mix well; at the same time, precisely adjust the pH value of the mixture to 6.5, filter the pH-adjusted foliar fertilizer solution through a 200-mesh filter, and the resulting clear filtrate is the foliar fertilizer.

[0088] Comparative Example 4

[0089] The plant-derived herbal extracts are omitted, and only basic nutrient components and growth-regulating components are used; the preparation method does not include steps related to herbal extracts, and the other step parameters are the same as in Example 4.

[0090] Comparative Example 5

[0091] All basic nutrient components are added to the herbal mother liquor at once, and the other steps and formula are the same as in Example 4.

[0092] Comparative Example 6

[0093] The pH of both the solvent and the foliar fertilizer was adjusted to 7.5 (weakly alkaline), and the rest was the same as in Example 4.

[0094] Comparative Example 7

[0095] Commercially available chemical foliar fertilizer (containing an equal amount of NPK).

[0096] The foliar fertilizers prepared using the methods of Examples 4-6 and Comparative Examples 4-7 were experimentally tested.

[0097] Each treatment group (Examples 4-6 and Comparative Examples 6-10) had three replicates, with 10 *Dendrobium nobile* plants in each replicate. Fertilization was carried out as follows: foliar fertilizer was diluted with water at a volume ratio of 1:900 to obtain a diluted solution, which was then applied via foliar spraying. During the growing season, the plants were sprayed every 9 days for four consecutive applications. After three months, various indicators were measured, and the results are shown in Table 2.

[0098] Table 2. Detection indicators of Dendrobium nobile after application of foliar fertilizers prepared according to the methods of Examples 4-6 and Comparative Examples 4-7.

[0099] Detection index Example 4 Example 5 Example 6 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Strain height growth (cm) 12.5 11.8 12.2 9.2 10.8 10.5 10.3 Stem diameter growth (mm) 2.8 2.5 2.7 1.9 2.3 2.2 2.0 New tiller number (piece) 4.2 3.8 4.0 2.9 3.5 3.3 3.1 Fresh weight increase rate (%) 38.5 35.2 36.8 25.6 31.2 29.8 27.5 Dendrobium polysaccharide content (%) 29.2 28.1 28.8 24.5 26.9 25.2 25.1 Total alkaloid content (%) 0.88 0.82 0.85 0.68 0.78 0.70 0.69 Leaf SPAD value 52.6 50.8 51.9 45.2 48.9 46.8 46.5 PAL enzyme activity (U / mg protein) 46.8 42.5 45.2 28.9 34.5 31.6 26.8 Chlorophyll fluorescence (Fv / Fm) 0.82 0.80 0.81 0.75 0.79 0.76 0.75 Anthracnose incidence (%) 4.2 5.1 4.6 15.8 8.9 13.2 16.5 Soft rot incidence (%) 3.8 4.5 4.1 13.5 7.2 11.6 14.2

[0100] As shown in Table 2, after applying the foliar fertilizer prepared by the methods in Examples 4-6 to Dendrobium nobile, all indicators were better than those in Comparative Examples 4-7. The content of Dendrobium nobile polysaccharide reached 29.2%, the total alkaloid content (%) increased to 0.88%, the PAL enzyme activity reached 46.8 U / mg protein, and the incidence rate was ≤5.1%.

[0101] Comparative Example 4, which lacked plant-derived herbal extracts, showed a PAL enzyme activity of only 28.9 U / mg protein, an anthracnose incidence rate as high as 15.8%, and a polysaccharide content reduced to 24.5%. The complete absence of plant-derived herbal extracts resulted in a lack of key signaling molecules for activating phenylpropanoid metabolic pathways, failing to effectively induce the plant's own defense system. Furthermore, the lack of natural antibacterial substances significantly reduced disease resistance.

[0102] In Comparative Example 5, potassium humate and polyglutamic acid were not premixed, resulting in insufficient dissolution and dispersion of potassium humate and polyglutamic acid, leading to local agglomeration. This affected the uniform distribution and effectiveness of the functional polymers, resulting in a decrease in fertilizer efficiency of about 15-20%, a fresh weight increase rate of only 31.2%, and a decrease in PAL enzyme activity to 34.5 U / mg protein.

[0103] In Comparative Example 6, the pH of the foliar fertilizer increased to 7.5, becoming slightly alkaline. This slightly alkaline environment led to the partial decomposition of B vitamins and the coiling of polyglutamic acid molecular chains, reducing its functionality. It also affected the efficiency of nutrient absorption by the leaves, resulting in a decrease in overall effectiveness. The polysaccharide content decreased to 25.2%, and the disease incidence rate increased to 13.2%.

[0104] In Comparative Example 7, commercial foliar fertilizers were used, which only provide mineral nutrients and lack bioactive components. They cannot activate the plant's internal metabolic regulation system, and long-term use may lead to soil microecological imbalance and a natural decline in disease resistance.

[0105] The foliar fertilizer of this invention has three functions: nutrient supplementation, metabolic regulation and disease control, which is significantly superior to commercial fertilizers with single functions.

Claims

1. A method for preparing a plant-derived herbal extract, characterized in that, The process includes the following steps: after crushing the raw materials, adding compound microbial agents for pre-fermentation; adding water for reflux extraction, filtering and combining the filtrates, concentrating into an extract to obtain a plant-derived herbal extract; The raw materials, by weight, include the following components: 5-8 parts of Isatis tinctoria leaf, 3-4 parts of dandelion, 3-5 parts of honeysuckle, 3-4 parts of Isatis tinctoria root, 2-4 parts of Houttuynia cordata, 2-3 parts of Viola yedoensis, 1-2 parts of Sophora flavescens, and 3-6 parts of Artemisia annua.

2. The preparation method according to claim 1, characterized in that, The compound microbial agent includes Bacillus subtilis, Trichoderma harzianum, and thermophilic fiber-decomposing bacteria; in the compound microbial agent, the mass ratio of Bacillus subtilis to Trichoderma harzianum is 1:1, and the total mass of the two is 3 to 5 times the mass ratio of the thermophilic fiber-decomposing bacteria.

3. The preparation method according to claim 1, characterized in that, Add 1-2% of the total weight of the raw materials to the compound microbial agent for pre-fermentation treatment. The pre-fermentation conditions are a temperature of 35-40℃ and a time of 3-5 days.

4. The preparation method according to claim 1, characterized in that, Weigh the Chinese herbal medicine raw materials according to the specified proportions, pulverize them, and pass them through a 60-80 mesh sieve. Add 5-8 times the total weight of water to the raw materials, and reflux extract at 90-100℃ 2-3 times, 1-2 hours each time. Filter, combine the filtrates, and concentrate to a density of 1.10-1.15 g / cm³. 3 The extract was obtained from the plant-derived herbal extract.

5. A plant-derived herbal extract, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 4.

6. A foliar fertilizer for Dendrobium nobile cultivation, characterized in that, By weight parts Includes the following components: The plant-derived herbal extract of claim 5 contains 15-30 parts, basic nutrient components 40-60 parts, growth regulator components 0.5-2 parts, and solvent 100-150 parts. The basic nutrient components, by weight, include the following: 13-17 parts urea, 8-12 parts potassium dihydrogen phosphate, 5-8 parts potassium sulfate, 6.5-10 parts potassium humate, and 7.5-13 parts polyglutamic acid; the growth regulator components include the following: 0.1-0.3 parts vitamin B1, 0.03-0.2 parts vitamin B6, 0.35-1.45 parts cyclohexanehexol, and 0.02-0.05 parts folic acid; the solvent is water, with the pH adjusted to 5.5-6.

5.

7. A method for preparing a foliar fertilizer suitable for Dendrobium nobile cultivation as described in claim 5, characterized in that, Includes the following steps: S100. After mixing the above extract with a portion of the solvent, heat and stir until homogeneous; add the basic nutrient components, keep warm and stir until homogeneous; add the growth regulating components and stir until completely dissolved. S200. Adjust the pH value of the mixture obtained in step S100, filter it, and the filtrate is the foliar fertilizer.

8. The preparation method according to claim 6, characterized in that, In step S100, the plant-derived herbal extract is mixed with a solvent accounting for 30% to 50% of the total solvent mass, and stirred at 240 to 300 r / min for 10 to 15 minutes at a temperature of 55 to 60°C; the basic nutrient components are added, and the temperature is maintained at 55 to 60°C while stirring for another 20 to 30 minutes; finally, the growth regulator components are added and stirred until completely dissolved.

9. The preparation method according to claim 6, characterized in that, In step S100, when adding the basic nutrient components, potassium humate and polyglutamic acid are first pre-mixed with a portion of the solvent at 40-50°C to form a homogeneous solution, and then added together with the other basic nutrient components.

10. The preparation method according to claim 6, characterized in that, In step S200, the pH value of the prepared foliar fertilizer is adjusted to 5.5~6.5.