Rhododendron lapponicum seedling culture medium and preparation method thereof

Abstract

The invention discloses a rhododendron lapponicum seedling culture medium and a preparation method thereof, and relates to the technical field of ornamental plant culture. The rhododendron lapponicum seedling culture medium is prepared from the following raw material components in parts by mass: 30 to 40 parts of masson pine needle compost, 25 to 35 parts of camellia oleifera shell ferment, 10 to 15 parts of perlite, 8 to 12 parts of vermiculite, 5 to 10 parts of peat soil, 0.3 to 0.8 part of folium cortex eucommiae extract, 0.2 to 0.6 part of honeysuckle vine extract, 0.5 to 1.0 part of humic acid and 0.3 to 0.7 part of calcium superphosphate. According to the method, agricultural and forestry waste source organic materials and inorganic conditioning materials are reasonably proportioned, plant extracts with biological activity are introduced, a seedling raising system which is synergistically optimized in the aspects of a physical structure, a chemical environment and biological functions is constructed, the growth vigor of seedlings is remarkably improved, and the yield of the seedlings is increased. A new technical scheme is provided for green, efficient and sustainable industrial seedling culture of the alpine rhododendron.

Description

Technical Field

[0001] This invention relates to the field of ornamental plant cultivation technology, and in particular to a cultivation substrate for alpine rhododendron seedlings and its preparation method. Background Technology

[0002] Alpine rhododendrons are evergreen shrubs or small trees belonging to the genus Rhododendron in the family Ericaceae. They are highly valued for their bright colors and diverse flower shapes and are widely used in landscaping and potted plants.

[0003] Alpine rhododendrons naturally inhabit high-altitude, cold, and humid regions, and have stringent requirements for their growth environment, particularly preferring acidic, well-drained soil with good water and fertilizer retention capabilities. During the seedling stage, alpine rhododendrons have delicate and fragile root systems with weak absorption capacity, making them extremely sensitive to the physical and chemical properties of the cultivation substrate. The quality of the substrate directly determines the survival rate, growth rate, and subsequent flowering quality of the seedlings.

[0004] Currently, the cultivation of alpine rhododendron seedlings generally uses a traditional substrate based on peat moss or leaf mold, supplemented with materials such as perlite and vermiculite to adjust the structure. However, this type of substrate has the following prominent problems: (1) Peat soil is a non-renewable resource. Large-scale mining can easily lead to the degradation of wetland ecosystems. At the same time, its acid stability is poor. During long-term cultivation, the pH value is easy to rise, causing root yellowing, nutrient absorption obstacles, and even growth stagnation in alpine rhododendrons. (2) Traditional substrates are difficult to effectively balance water retention and air permeability: excessive water retention can easily cause root hypoxia and induce root rot, while excessive emphasis on air permeability can lead to rapid loss of water and nutrients, which is not conducive to the continuous healthy growth of seedlings. (3) Existing substrates mostly rely on chemical fertilizers to supplement nutrients, which not only easily causes substrate compaction and salinization, but also lacks natural active substances that can promote root development and enhance stress resistance, resulting in weak seedling growth, poor disease resistance, and low transplant survival rate.

[0005] In summary, there is an urgent need to develop a new type of cultivation substrate that is eco-friendly, has stable physicochemical properties, is rich in natural growth-promoting factors, and does not rely on chemical fertilizers or exogenous microbial agents, in order to systematically solve the key technical bottlenecks in the cultivation of alpine rhododendron seedlings. Summary of the Invention

[0006] The purpose of this invention is to provide a cultivation substrate for alpine rhododendron seedlings and its preparation method, so as to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention provides a cultivation substrate for alpine rhododendron seedlings. By weight, the raw material components include: 30-40 parts of pine needle compost, 25-35 parts of fermented camellia oleifera shells, 10-15 parts of perlite, 8-12 parts of vermiculite, 5-10 parts of peat moss, 0.3-0.8 parts of Eucommia ulmoides leaf extract, 0.2-0.6 parts of Lonicera japonica vine extract, 0.5-1.0 parts of humic acid, and 0.3-0.7 parts of superphosphate.

[0008] Furthermore, the method for preparing the pine needle compost includes the following steps: After crushing the pine needles, add peanut shells, urea and brown sugar, and compost them at 55-65℃. After fermentation, dry them to obtain the pine needle compost.

[0009] Furthermore, the peanut shells, urea, and brown sugar constitute 8-9%, 5-7%, and 2-3% of the mass of the pine needles, respectively; the composting fermentation time is 18-22 days.

[0010] Furthermore, the preparation method of the fermented camellia shell product includes the following steps: Furthermore, after crushing the camellia shells, rice bran and corn flour are added, and fermentation is carried out at 55-65℃ and an aeration rate of 0.3-0.5 m³ / (m³•h). After fermentation, the product is dried to obtain the fermented camellia shell product.

[0011] Furthermore, the amount of rice bran and corn flour added is 10-15% and 5-8% of the mass of the camellia oleifera shell, respectively; the fermentation time is 18-20 days.

[0012] Camellia oleifera shells have a high degree of lignification and a dense structure. Therefore, during fermentation, the aeration rate should be controlled at 0.3-0.5 m³ / (m³•h) to ensure that aerobic microorganisms receive sufficient oxygen, promote lignin decomposition, and form a loose and porous fibrous structure. If the aeration rate is not controlled (natural aeration), it will lead to oxygen deficiency inside the fermented material and a dense structure, which will affect the water retention and air permeability.

[0013] Furthermore, the preparation method of the Eucommia ulmoides leaf extract includes the following steps: Eucommia ulmoides leaves were added to ethanol and refluxed for extraction. The resulting extract was then dried to obtain the Eucommia ulmoides leaf extract.

[0014] Furthermore, the preparation method of the honeysuckle vine extract includes the following steps: The honeysuckle vine was added to ethanol and extracted by ultrasonication at 55°C, followed by drying to obtain the honeysuckle vine extract.

[0015] Furthermore, the humic acid is brown humic acid.

[0016] This invention also provides a method for preparing the above-mentioned cultivation substrate for alpine rhododendron seedlings, comprising the following steps: Mix the raw material components according to the mass ratio, adjust the moisture content to 20-25%, and the pH value to 5.0-5.5 to obtain the alpine rhododendron seedling cultivation substrate.

[0017] Furthermore, the pH value is adjusted using organic acids, including citric acid.

[0018] This invention provides a cultivation substrate for alpine rhododendron seedlings. The core organic raw materials are camellia husks and pine needles. After fermentation and composting using a specific process, the substrate is combined with perlite and vermiculite to form a composite substrate. This not only realizes the resource utilization of agricultural and forestry waste and reduces the consumption of non-renewable peat soil, but also forms a loose and porous physical structure through the structural complementarity between the components. This ensures sufficient aeration for root respiration and achieves excellent water and fertilizer retention, laying a solid foundation for seedling growth.

[0019] Regarding pH regulation, the cultivation substrate of this invention constructs a stable composite acidic buffer system to match the acidic growth requirements of alpine rhododendron seedlings: the natural organic acids contained in the pine needle compost and the acetic acid produced by the fermentation of camellia shells can initially reduce the pH value of the substrate; the added humic acid, through its carboxyl and phenolic hydroxyl groups, can bind to the Ca in the substrate. 2+ Mg 2+ The addition of alkaline ions prevents their accumulation and subsequent pH increase; further supplemented by extracts of Eucommia ulmoides leaves and Lonicera japonica vines ensures that the substrate pH remains stable within the suitable range of 4.5-5.5, thus completely resolving problems such as root yellowing and nutrient absorption disorders caused by the instability of traditional acidic substrates.

[0020] The superior performance of the cultivation substrate of this invention also benefits from the synergistic effect of bioactive components, significantly improving seedling growth quality and stress resistance. Eucommia ulmoides leaf extract and honeysuckle vine extract work synergistically to exert their bioactivity, combined with the chelating effect of humic acid on nutrients, greatly enhancing root vitality and nutrient absorption efficiency, effectively improving the slow growth of seedlings under traditional substrate cultivation. Simultaneously, the entire substrate system relies on the characteristics of natural organic materials and the bioactivity of the extracts, eliminating the need for chemical fertilizers or exogenous microbial agents. This not only ensures stable physicochemical properties but also reduces usage costs and operational difficulty. The resulting seedling survival rate can reach over 95%, with plant height and diameter growth rates increasing by 30-40% compared to traditional substrates, root fresh weight increasing by 50-60%, and significantly improved leaf chlorophyll content and stress-resistant enzyme activity, resulting in stronger transplant adaptability.

[0021] The aforementioned effects are achieved through a synergistic effect formed by the matrix in three aspects: optimization of physical structure, regulation of chemical environment, and regulation of biological activity. At the physical structure level, the loose, porous fiber structure of camellia shell fermentation and the interwoven fibers of pine needle compost form a continuous pore network. Combined with the large particle gaps of perlite and the layered water-absorbing structure of vermiculite, a reasonable distribution of aeration and water-holding pores is achieved, balancing drainage and flood prevention with water retention and moisture retention. At the chemical environment level, the synergistic effect of natural organic acids, humic acid, and plant extracts precisely regulates acidity and ensures long-term stability, creating favorable conditions for the absorption of trace elements. At the bioactivity level, the complementary nutrient chelation effect of the two plant extracts and humic acid comprehensively enhances the growth performance and stress resistance of seedlings. Together, these three elements construct a complete system for the healthy growth of seedlings, providing a strong guarantee for industrial cultivation.

[0022] The present invention discloses the following technical effects: The alpine rhododendron seedling cultivation substrate provided by this invention constructs a seedling cultivation system that is synergistically optimized in terms of physical structure, chemical environment, and biological function by rationally combining organic materials from agricultural and forestry waste sources with inorganic conditioning materials and introducing bioactive plant extracts.

[0023] The cultivation substrate of this invention uses pine needle compost and camellia shell fermentation as core organic components, which not only realizes resource utilization and significantly reduces dependence on non-renewable peat soil, but also forms an ideal structure that is loose and porous, and combines aeration and water retention, effectively solving the problem of balancing drainage and water retention in traditional substrates.

[0024] This invention utilizes a composite buffer system constructed from natural organic acids, humic acid, and plant extracts to maintain a stable, slightly acidic environment suitable for alpine rhododendron growth over the long term, preventing nutrient absorption and root physiological disorders caused by pH fluctuations. Simultaneously, the synergistic effect of Eucommia ulmoides leaf extract and Lonicera japonica vine extract endows the substrate with bioactive functions that promote root development and enhance plant stress resistance. Combined with the chelating and slow-release effects of humic acid on nutrients, this significantly improves the growth vigor and physiological health of seedlings.

[0025] The cultivation substrate of this invention does not require the addition of additional chemical fertilizers or exogenous microbial agents, which can support the robust growth of alpine rhododendron seedlings, greatly improve the survival rate and transplant adaptability, and provide a new technical solution for the green, efficient and sustainable industrialized seedling cultivation of alpine rhododendrons. Detailed Implementation

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0028] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0029] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0030] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0031] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0032] This invention provides a cultivation substrate for alpine rhododendron seedlings, comprising, by weight, the following raw material components: 30-40 parts of pine needle compost, 25-35 parts of fermented camellia oleifera shells, 10-15 parts of perlite, 8-12 parts of vermiculite, 5-10 parts of peat moss, 0.3-0.8 parts of Eucommia ulmoides leaf extract, 0.2-0.6 parts of Lonicera japonica vine extract, 0.5-1.0 parts of humic acid, and 0.3-0.7 parts of superphosphate.

[0033] Furthermore, the preparation of the pine needle compost preferably adopts the following steps: fresh pine needles are crushed to 1-3 cm, 8-9% of their mass of peanut shells, 5-7% of urea and 2-3% of brown sugar are added, the moisture content is adjusted to 60-65%, and the pile is stacked into windrows 1.2-1.5 m high. The compost is fermented for 18-22 days under natural ventilation conditions at 55-65℃, and the pile is turned over every 3 days during the period. After the fermentation is completed, the compost is dried until the moisture content is ≤20%, and then passed through a 10-mesh sieve to obtain the final product.

[0034] Furthermore, the preferred method for preparing fermented camellia oleifera shells is as follows: crush the camellia oleifera shells to a particle size of 2-5 mm, add 10-15% of their mass of rice bran and 5-8% of their mass of corn flour, adjust the moisture content to 55-65%, and aerobic ferment for 18-20 days at a temperature of 55-65℃ and an aeration rate of 0.3-0.5 m³ / (m³•h), turning the pile over every 5 days during the fermentation period. After fermentation, dry the product to a moisture content of 15-20%.

[0035] Furthermore, the preferred method for preparing Eucommia ulmoides leaf extract is as follows: Take dried Eucommia ulmoides leaves, pulverize them to 20-40 mesh, add 8-12 times their weight of 70-80% ethanol solution, reflux extract at 60-70℃ 2-3 times, each time for 0.5-1 hour, combine the extracts, concentrate under reduced pressure to an extract with a relative density of 1.10-1.20 (60℃), vacuum dry, and pulverize to 80-100 mesh to obtain the extract.

[0036] Furthermore, the preparation of honeysuckle vine extract preferably adopts the following steps: take dried honeysuckle vine (dried in the shade after harvest), pulverize to 30-50 mesh, add 10-15 times its weight of 60-70 vol% ethanol solution, ultrasonically extract for 10-15 min at ultrasonic power of 250 W and temperature of 55℃, filter, concentrate the filtrate under reduced pressure until there is no alcohol odor, vacuum dry to water content ≤5%, and pulverize to 80-100 mesh.

[0037] Furthermore, the humic acid is brown humic acid.

[0038] The second aspect of this invention provides a method for preparing the above-mentioned cultivation substrate for alpine rhododendron seedlings, comprising the following steps: Mix the raw material components according to the mass ratio, adjust the moisture content to 20-25%, and the pH value to 5.0-5.5 to obtain the alpine rhododendron seedling cultivation substrate.

[0039] Furthermore, the pH value is adjusted using organic acids, including citric acid.

[0040] Example 1 This embodiment provides a cultivation substrate for alpine rhododendron seedlings. The raw material components, by weight, are as follows: The mixture consists of 30 parts of pine needle compost, 25 parts of fermented camellia shells, 13 parts of perlite, 8 parts of vermiculite, 5 parts of peat moss, 0.8 parts of Eucommia ulmoides leaf extract, 0.3 parts of honeysuckle vine extract, 0.5 parts of humic acid, and 0.3 parts of superphosphate.

[0041] The preparation steps are as follows: (1) Preparation of pine needle compost: Fresh pine needles are crushed to 2cm, and 8% of peanut shells, 7% of urea and 3% of brown sugar are added. The moisture content is adjusted to 60%, and the pile is stacked into a 1.2m high winds. The compost is fermented for 18 days under natural ventilation at 60℃. During the period, the pile is turned over once every 3 days. After the fermentation is completed, the compost is dried until the moisture content is ≤20%, and then passed through a 10-mesh sieve.

[0042] (2) Preparation of fermented camellia shell: Pulverize camellia shells to a particle size of 2-5 mm, add 10% of rice bran and 8% of corn flour by weight, adjust the moisture content to 60%, and aerobic ferment for 18 days at a temperature of 65℃ and an aeration rate of 0.5 m³ / (m³•h). Turn the pile over once every 5 days during the fermentation period. After the fermentation is completed, dry it to a moisture content of 15% to obtain the product.

[0043] (3) Preparation of Eucommia ulmoides leaf extract: Take dried Eucommia ulmoides leaves, pulverize them to 40 mesh, add 10 times their weight of 80 vol% ethanol solution, reflux extract twice at 65℃ for 0.5 hours each time, combine the extracts, concentrate under reduced pressure to a paste with a relative density of 1.10 (60℃), vacuum dry and pulverize to 100 mesh to obtain the extract.

[0044] (4) Preparation of honeysuckle vine extract: Take dried honeysuckle vine (dried in the shade after harvest), pulverize to 50 mesh, add 10 times its weight of 60 vol% ethanol solution, and extract by ultrasonic extraction at ultrasonic power of 250 W and temperature of 55℃ for 15 min. Filter, concentrate the filtrate under reduced pressure until there is no alcohol taste, vacuum dry to water content ≤5%, and pulverize to 100 mesh.

[0045] (5) Preparation of cultivation substrate: a. Weigh out the following ingredients according to weight: pine needle compost, camellia shell fermentation product, perlite, vermiculite, and peat moss. Put them into a mixer and mix at 150 r / min for 10 minutes to obtain a uniform base substrate. b. Add the Eucommia ulmoides leaf extract, honeysuckle vine extract, humic acid and superphosphate to the base matrix and continue stirring for 15 minutes to ensure that the components are evenly dispersed. c. Spray deionized water into the mixture obtained in step b to adjust the substrate moisture content to 25%, and at the same time use citric acid solution to adjust the substrate pH to 5.5, thus obtaining the alpine rhododendron seedling cultivation substrate.

[0046] Example 2 This embodiment provides a cultivation substrate for alpine rhododendron seedlings. The raw material components, by weight, are as follows: The mixture consists of 30 parts of pine needle compost, 28 parts of fermented camellia shells, 14 parts of perlite, 11 parts of vermiculite, 9 parts of peat moss, 0.6 parts of Eucommia ulmoides leaf extract, 0.5 parts of honeysuckle vine extract, 0.8 parts of humic acid, and 0.5 parts of superphosphate.

[0047] The preparation steps are as follows: (1) Preparation of pine needle compost: Fresh pine needles are crushed to 2cm, and 8% of peanut shells, 7% of urea and 3% of brown sugar are added. The moisture content is adjusted to 60%, and the pile is stacked into a 1.2m high winds. The compost is fermented for 18 days under natural ventilation at 60℃. During the period, the pile is turned over once every 3 days. After the fermentation is completed, the compost is dried until the moisture content is ≤20%, and then passed through a 10-mesh sieve.

[0048] (2) Preparation of fermented camellia shell: Pulverize camellia shells to a particle size of 2-5 mm, add 10% of rice bran and 8% of corn flour by weight, adjust the moisture content to 60%, and aerobic ferment for 18 days at a temperature of 65℃ and an aeration rate of 0.5 m³ / (m³•h). Turn the pile over once every 5 days during the fermentation period. After the fermentation is completed, dry it to a moisture content of 15% to obtain the product.

[0049] (3) Preparation of Eucommia ulmoides leaf extract: Take dried Eucommia ulmoides leaves, pulverize them to 40 mesh, add 10 times their weight of 80 vol% ethanol solution, reflux extract twice at 60-70℃ for 0.5 hours each time, combine the extracts, concentrate under reduced pressure to a paste with a relative density of 1.15 (60℃), vacuum dry and pulverize to 100 mesh to obtain the extract.

[0050] (4) Preparation of honeysuckle vine extract: Take dried honeysuckle vine (dried in the shade after harvest), pulverize to 50 mesh, add 10 times its weight of 65 vol% ethanol solution, extract by ultrasonication at 250 W and 55℃ for 15 min, filter, concentrate the filtrate under reduced pressure until there is no alcohol taste, vacuum dry to water content ≤5%, and pulverize to 100 mesh.

[0051] (5) Preparation of cultivation substrate: a. Weigh out the following ingredients according to weight: pine needle compost, camellia shell fermentation product, perlite, vermiculite, and peat moss. Put them into a mixer and mix at 150 r / min for 10 minutes to obtain a uniform base substrate. b. Add the Eucommia ulmoides leaf extract, honeysuckle vine extract, humic acid and superphosphate to the base matrix and continue stirring for 15 minutes to ensure that the components are evenly dispersed. c. Spray deionized water into the mixture obtained in step b to adjust the substrate moisture content to 25%, and at the same time use citric acid solution to adjust the substrate pH to 5.5, thus obtaining the alpine rhododendron seedling cultivation substrate.

[0052] Example 3 This embodiment provides a cultivation substrate for alpine rhododendron seedlings. The raw material components, by weight, are as follows: The mixture consists of 40 parts of pine needle compost, 35 parts of fermented camellia shells, 10 parts of perlite, 12 parts of vermiculite, 10 parts of peat moss, 0.3 parts of Eucommia ulmoides leaf extract, 0.5 parts of honeysuckle vine extract, 0.8 parts of humic acid, and 0.4 parts of superphosphate.

[0053] The preparation steps are as follows: (1) Preparation of pine needle compost: Fresh pine needles are crushed to 2cm, and 8% of peanut shells, 7% of urea and 3% of brown sugar are added. The moisture content is adjusted to 60%, and the pile is stacked into a 1.2m high winds. The compost is fermented for 18 days under natural ventilation at 60℃. During the period, the pile is turned over once every 3 days. After the fermentation is completed, the compost is dried until the moisture content is ≤20%, and then passed through a 10-mesh sieve.

[0054] (2) Preparation of fermented camellia shell: Pulverize camellia shells to a particle size of 2-5 mm, add 10% of rice bran and 8% of corn flour by weight, adjust the moisture content to 60%, and aerobic ferment for 18 days at a temperature of 65℃ and an aeration rate of 0.5 m³ / (m³•h). Turn the pile over once every 5 days during the fermentation period. After the fermentation is completed, dry it to a moisture content of 15% to obtain the product.

[0055] (3) Preparation of Eucommia ulmoides leaf extract: Take dried Eucommia ulmoides leaves, pulverize them to 40 mesh, add 70 vol% ethanol solution with 12 times their weight, reflux extract twice at 65℃ for 0.5 hours each time, combine the extracts, concentrate under reduced pressure to an extract with a relative density of 1.20 (60℃), vacuum dry and pulverize to 100 mesh to obtain the extract.

[0056] (4) Preparation of honeysuckle vine extract: Take dried honeysuckle vine (dried in the shade after harvest), pulverize to 50 mesh, add 70 vol% ethanol solution with 15 times its weight, extract by ultrasonic extraction at ultrasonic power of 250 W and temperature of 55℃ for 15 min, filter, concentrate the filtrate under reduced pressure until there is no alcohol taste, vacuum dry to water content ≤5%, and pulverize to 100 mesh.

[0057] (5) Preparation of cultivation substrate: a. Weigh out the following ingredients according to weight: pine needle compost, camellia shell fermentation product, perlite, vermiculite, and peat moss. Put them into a mixer and mix at 150 r / min for 10 minutes to obtain a uniform base substrate. b. Add the Eucommia ulmoides leaf extract, honeysuckle vine extract, humic acid and superphosphate to the base matrix and continue stirring for 15 minutes to ensure that the components are evenly dispersed. c. Spray deionized water into the mixture obtained in step b to adjust the substrate moisture content to 25%, and at the same time use citric acid solution to adjust the substrate pH to 5.5, thus obtaining the alpine rhododendron seedling cultivation substrate.

[0058] Comparative Example 1 The only difference from Example 1 is that Eucommia ulmoides leaf extract is not added.

[0059] Comparative Example 2 The only difference from Example 1 is that honeysuckle vine extract is not added.

[0060] Comparative Example 3 This comparative example provides a cultivation substrate for alpine rhododendron seedlings. The raw material components, by weight, are as follows: 60 parts peat moss, 20 parts perlite, 15 parts vermiculite, and 0.5 parts superphosphate.

[0061] The preparation method is as follows: mix all components evenly, adjust the water content to 25-30%, and adjust the pH value to 5.0 to obtain the final product.

[0062] Example of effect verification: 1. Experimental materials: Select one-year-old seedlings of alpine rhododendron (Rhododendron simsii) with uniform growth, plant height 3-5cm, ground diameter 0.2-0.3cm, free from pests and diseases, and growing vigorously.

[0063] 2. Experimental Design: A randomized block design was used, with six treatment groups: Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3. Each group was replicated three times, with 50 seedlings per replicate. The cultivation containers were 10cm × 12cm nutrient pots. The cultivation environment was a greenhouse, with a controlled temperature of 15-25℃, relative humidity of 70-80%, and light intensity of 15000-20000 lux. Standard water management was maintained, and no additional fertilizer was applied. The cultivation period was six months.

[0064] 3. Test metrics and methods: (1) Determination of the physicochemical properties of the matrix pH value: The soil-to-water ratio was 1:2.5 (mass-to-volume ratio), and the pH value of the substrate was measured using a pH meter at the beginning of cultivation and after 6 months of cultivation. Bulk density, total porosity, aeration porosity, and water-holding porosity were determined using the ring sampler method. Water retention rate: After watering to saturation, leave for 48 hours and measure the substrate moisture content to calculate the water retention rate; Organic matter content: determined by potassium dichromate oxidation-external heating method; Total nitrogen, total phosphorus, and total potassium content were determined by the Kjeldahl method, the molybdenum-antimony colorimetric method, and the flame photometry method, respectively.

[0065] (2) Measurement of seedling growth indicators 1. Survival rate: After 6 months of cultivation, count the number of surviving seedlings and calculate the survival rate (survival rate = number of surviving seedlings / total number of seedlings × 100%). 2. Plant height growth rate: Measure the plant height at the beginning and end of the cultivation period, and calculate the growth rate (plant height growth rate = (plant height at the end of the cultivation period - plant height at the beginning of the cultivation period) / plant height at the beginning of the cultivation period × 100%). 3. Diameter growth rate: Measure the diameter at the beginning and end of the cultivation period and calculate the growth rate (diameter growth rate = (diameter at the end of the cultivation period - diameter at the beginning of the cultivation period) / diameter at the beginning of the cultivation period × 100%). 4. Fresh weight of roots: Six months after cultivation, take the complete root system of the seedlings, wash it, and measure the fresh weight using an electronic balance; 5. Chlorophyll content: The SPAD value of functional leaves was measured using a SPAD-502 chlorophyll meter. Three leaves were measured for each plant, and the average value was taken.

[0066] (3) Determination of seedling stress resistance index 1. Superoxide dismutase (SOD) activity: determined by the nitroblue tetrazolium (NBT) photoreduction method; 2. Peroxidase (POD) activity: determined using the guaiacol method; 3. Malondialdehyde (MDA) content: determined by the thiobarbituric acid (TBA) colorimetric method.

[0067] (4) Measurement of transplant survival rate After 6 months of cultivation, the seedlings of each treatment group were transplanted to the field experimental site. After 3 months of routine management, the transplant survival rate was calculated (transplant survival rate = number of surviving plants after transplanting / total number of transplanted plants × 100%).

[0068] The test results are shown in Table 1-5.

[0069] Table 1 The substrates of Examples 1-3 maintained a stable pH value within the suitable range of 4.5-5.5 over a long period, with lower bulk density, more reasonable total porosity and aeration / water retention porosity ratio, and a water retention rate of 66-70%. Comparative Example 3 (traditional substrate) showed a significant increase in pH value, excessively high bulk density, unbalanced pore structure, and a significant difference in water retention and aeration performance. Comparative Examples 1-2, lacking a single plant extract, had lower physicochemical stability than the Examples, but were superior to the traditional substrate of Comparative Example 3.

[0070] Table 2 The organic matter, total nitrogen, total phosphorus, and total potassium content of the substrates in Examples 1-3 were significantly higher than those in the comparative examples, with Example 2 having the highest nutrient content; Comparative Example 3 had the lowest nutrient content due to the lack of organic fermentation components; and Comparative Examples 1-2 had lower nutrient content than the examples.

[0071] Table 3 The seedling survival rate, growth rate, and root development quality of Examples 1-3 were significantly better than those of the comparative examples, with a plant height / diameter growth rate increase of more than 30%, a root fresh weight increase of more than 50%, and a significant increase in chlorophyll content. The growth-promoting effect of Comparative Examples 1-2 was lower than that of Examples 1-3, which was due to the lack of synergistic growth-promoting effect of the two extracts. Comparative Example 3 (traditional substrate) had the worst growth indicators.

[0072] Table 4 The SOD and POD stress-resistance enzyme activities of the seedlings in Examples 1-3 were significantly higher than those in the control examples, while the MDA content was significantly lower, demonstrating the role of the substrate in enhancing the stress resistance of the seedlings. The stress-resistance enzyme activities of Control Examples 1-2 decreased and the MDA content increased. Control Example 3 had the worst stress resistance index.

[0073] Table 5 The seedling survival rate after transplanting in Examples 1-3 reached over 92%, significantly higher than that in Comparative Examples 1-2 and Comparative Example 3. The seedlings cultivated in the substrate of this invention have well-developed root systems and strong resistance to adverse conditions, enabling them to quickly adapt to new environments after transplanting, thus providing a guarantee for field planting of seedlings in industrial-scale cultivation.

[0074] In summary, the cultivation substrate technology for alpine rhododendron seedlings provided by this invention has significant effects. Its physicochemical properties are stable, and its pH value can be maintained within a suitable range of 4.5-5.5 for a long period. Its bulk density, pore structure, and water and fertilizer retention capacity are highly compatible with the growth requirements of alpine rhododendron seedlings, laying a solid foundation for seedling growth. Under these conditions, the substrate can significantly improve the seedling survival rate and effectively accelerate seedling growth, resulting in increased plant height and diameter growth rates compared to traditional substrates, and significantly improving root development quality. Simultaneously, the substrate can effectively increase the chlorophyll content and stress-resistant enzyme activity in seedling leaves, reduce membrane lipid peroxidation damage, and greatly enhance the seedling's stress resistance. Furthermore, it can significantly improve the transplant survival rate of seedlings, providing a strong guarantee for the industrial cultivation of alpine rhododendron seedlings.

[0075] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A cultivation substrate for alpine rhododendron seedlings, characterized in that, By weight, the raw material components include: 30-40 parts of pine needle compost, 25-35 parts of fermented camellia shells, 10-15 parts of perlite, 8-12 parts of vermiculite, 5-10 parts of peat moss, 0.3-0.8 parts of Eucommia ulmoides leaf extract, 0.2-0.6 parts of honeysuckle vine extract, 0.5-1.0 parts of humic acid, and 0.3-0.7 parts of superphosphate.

2. The cultivation substrate for alpine rhododendron seedlings according to claim 1, characterized in that, The method for preparing the pine needle compost includes the following steps: After crushing the pine needles, add peanut shells, urea and brown sugar, and compost them at 55-65℃. After fermentation, dry them to obtain the pine needle compost.

3. The cultivation substrate for alpine rhododendron seedlings according to claim 2, characterized in that, The peanut shells, urea, and brown sugar constitute 8-9%, 5-7%, and 2-3% of the mass of the pine needles, respectively; the composting fermentation time is 18-22 days.

4. The cultivation substrate for alpine rhododendron seedlings according to claim 1, characterized in that, The preparation method of the camellia oleifera shell ferment includes the following steps: After crushing the camellia oleifera shells, rice bran and corn flour are added, and fermentation is carried out at 55-65℃ and an aeration rate of 0.3-0.5 m³ / (m³•h). After fermentation, the product is dried to obtain the fermented camellia oleifera shells.

5. The cultivation substrate for alpine rhododendron seedlings according to claim 4, characterized in that, The amount of rice bran and corn flour added is 10-15% and 5-8% of the weight of the camellia oleifera shells, respectively; the fermentation time is 18-20 days.

6. The cultivation substrate for alpine rhododendron seedlings according to claim 1, characterized in that, The preparation method of the Eucommia ulmoides leaf extract includes the following steps: Eucommia ulmoides leaves were added to ethanol and refluxed for extraction. The resulting extract was then dried to obtain the Eucommia ulmoides leaf extract.

7. The cultivation substrate for alpine rhododendron seedlings according to claim 1, characterized in that, The preparation method of the honeysuckle vine extract includes the following steps: The honeysuckle vine was added to ethanol and extracted by ultrasonication at 55°C, followed by drying to obtain the honeysuckle vine extract.

8. The cultivation substrate for alpine rhododendron seedlings according to claim 1, characterized in that, The humic acid is brown humic acid.

9. The method for preparing the cultivation substrate for alpine rhododendron seedlings as described in any one of claims 1-8, characterized in that, Includes the following steps: Mix the raw material components according to the mass ratio, adjust the moisture content to 20-25%, and the pH value to 5.0-5.5 to obtain the alpine rhododendron seedling cultivation substrate.

10. The preparation method according to claim 9, characterized in that, The pH value is adjusted using organic acids, including citric acid.

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