A precise silicon fertilizer application method for birch

Abstract

The present application provides a kind of precise silicon fertilizer method of minghuo, belongs to the technical field of forest cultivation.The silicon fertilizer method of the present application includes seedling stage fertilization and adult stage fertilization;The seedling stage fertilization includes straw organic fertilizer, silicon ash and superphosphate as base fertilizer before sowing, after true leaf unfolding, sodium silicate and zinc sulfate are irrigated, and sea algae concentrate and silicon sol are sprayed when seedling height is 10-15cm;The adult stage fertilization includes root application of nitrogen, phosphorus and potassium compound fertilizer and calcium silicate before spring budding, and calcium-magnesium fertilizer and nano silicon dioxide are sprayed in summer fast-growing period.The fertilization method of the present application can promote the growth of minghuo, improve the stress resistance of seedling in nursery, and also can improve the wood performance of adult.

Description

Technical Field

[0001] This invention belongs to the field of forest tree cultivation technology, and in particular relates to a method for precise application of silicon fertilizer to *Betula spp.* Background Technology

[0002] Fujian birch (Betula fujianensis) is a deciduous broad-leaved tree species belonging to the genus Betula in the family Betulaceae. It is a rare plant endemic to Fujian Province, China. It is mainly distributed in Luobuyan Provincial Nature Reserve in Sanming City, Fujian Province, and mostly grows in subtropical evergreen and deciduous broad-leaved mixed forests at altitudes above 500m.

[0003] Fujian birch has high economic and ecological value. Economically, Fujian birch wood has medium density and moderate hardness, with an air-dry density of 0.683 g / cm³. 3 Approximately 0.634 g / cm³ when dry. 3 With a low differential shrinkage value, it possesses excellent machinability and can be widely used in furniture manufacturing, interior decoration, building materials, and handicrafts. Ecologically, the Fujian birch, as an important component of the forest ecosystem, plays a vital role in maintaining regional ecological balance. It conserves water resources, maintains soil and water, provides habitats for numerous organisms, and plays a crucial role in regulating climate and purifying the air.

[0004] CN110999701A discloses a method for sowing and raising seedlings of *Betula fusiforme*, but it only involves the sowing of *Betula fusiforme* and does not cover the subsequent management process. However, *Betula fusiforme* currently faces many challenges in its growth and reproduction, with fertilization being a particularly prominent issue. Inappropriate fertilization methods result in poor wood properties. Currently, fertilization of *Betula fusiforme* largely lacks scientific planning; the type, amount, and timing of fertilizer application are often determined based on experience, without fully considering the differences in nutritional needs at different growth stages.

[0005] Therefore, it is urgent to develop a scientific and reasonable fertilization method to promote the growth of birch seedlings, improve the stress resistance of birch seedlings and the timber performance of mature trees. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a method for precise application of silicon fertilizer to *Betula spp.*, which promotes the growth of *Betula spp.*, enhances the stress resistance of *Betula spp.* seedlings after they leave the nursery, and also improves the mechanical properties of mature *Betula spp.* wood.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] A method for precise silicon fertilizer application to *Betula spp.* includes fertilization during the seedling stage and fertilization during the mature plant stage. The seedling stage fertilization includes applying straw organic fertilizer, silica fume, and superphosphate as base fertilizer before sowing, applying sodium silicate and zinc sulfate after the true leaves unfold, and spraying seaweed extract and silica sol when the seedlings are 10-15cm tall. The mature plant stage fertilization includes applying nitrogen, phosphorus, and potassium compound fertilizer and calcium silicate to the roots before spring budding, and spraying calcium magnesium fertilizer and nano-silica during the rapid growth period in summer.

[0009] Preferably, the seedling stage is from sowing to 2-year-old seedlings being transplanted, and the mature plant stage is from transplanting to maturity.

[0010] Preferably, before sowing, 1.5-2.5 kg / m³ of straw organic fertilizer is applied. 2 Silica fume 30-50g / m 2 With superphosphate 30-50g / m 2 Mix and apply into the seedbed soil.

[0011] Preferably, after the true leaves have unfolded, a mixture of 0.03%-0.05% sodium silicate and 0.04-0.06% zinc sulfate is applied.

[0012] More preferably, the amount of the mixture applied is 100-150 mL / plant, applied once every 1-2 weeks, for a total of 2-3 applications.

[0013] Preferably, the seedlings are 10-15cm tall and are sprayed with a mixture of 0.1-0.2% seaweed extract and 0.1-0.3% silica sol until water droplets appear on the leaves but do not drip.

[0014] Preferably, before spring budding, the roots are treated with 50-80g of N:P2O5:K2O=10-20-10 compound fertilizer × transplanting years / plant and 10-15g of calcium silicate × transplanting years / plant.

[0015] More preferably, before spring budding, apply 5-7g of silica-dissolving bacteria agent × transplanting year / plant, with an effective viable count of ≥2×10⁻⁶ bacteria. 8 CFU / g.

[0016] Preferably, during the rapid growth period in summer, spray with 5-10g of calcium-magnesium fertilizer × transplanting years / plant and 1-2g of nano-silica × transplanting years / plant.

[0017] Preferably, the fertilization during the mature plant stage also includes applying basal fertilizer to the roots before autumn dormancy; the basal fertilizer includes 0.2-0.4 kg of well-rotted organic fertilizer × transplanting year / plant and 20-30 g of silicon-calcium-magnesium fertilizer × transplanting year / plant.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The method for precise silicon fertilizer application to *Betula spp.* provided by this invention forms a systematic nutrient management program by scientifically planning the types, amounts, and application times of fertilizers at different growth stages. This program has significant advantages in promoting the growth of *Betula spp.* and improving its wood properties, as detailed below:

[0020] Applying straw organic fertilizer, silica fume and superphosphate as base fertilizer before sowing can improve soil structure, promote seed germination and increase seedling emergence rate. After the true leaves unfold, apply sodium silicate and zinc sulfate. When the seedlings are 10-15cm tall, spray seaweed extract and silica sol to promote seedling growth, optimize seedling characteristics, especially increase phytolith content, and enhance the seedlings' resistance to lodging and pests.

[0021] To address the nutritional needs during the budding and rapid growth stages, this invention supplements micronutrients, ensuring a high degree of alignment between nutrient supply and the physiological requirements of *Betula fusiforme*. Experiments show that this fertilization method promotes *Betula fusiforme* growth, increasing plant height and diameter at breast height. Furthermore, this invention promotes silicon deposition in the xylem of *Betula fusiforme*, thereby enhancing the mechanical properties of the wood. Detailed Implementation

[0022] This invention provides a method for precise silicon fertilizer application to *Betula spp.* (Fujian birch). By optimizing the type and ratio of fertilizer, it promotes seedling emergence and growth, enhances stress resistance, and improves the mechanical properties of mature *Betula spp.* wood. The silicon fertilizer application method of this invention includes the following steps:

[0023] In this invention, the seedling stage is from sowing to two years old before being transplanted, and the mature plant stage is from transplanting to maturity. During the mature plant stage, the amount of fertilizer is gradually increased as the number of years after transplanting increases.

[0024] I. Fertilization during the seedling stage:

[0025] (1) Before sowing:

[0026] Apply straw organic fertilizer, silica fume, and superphosphate as base fertilizer; preferably, use 1.5-2.5 kg / m³ of straw organic fertilizer. 2 Silica fume 30-50g / m 2 With superphosphate 30-50g / m 2 Mix and apply into the seedbed soil; further optimize the application of straw organic fertilizer at 2 kg / m³. 2 Silica fume 40g / m 2 With superphosphate 40g / m 2 Straw organic fertilizer and silica fume can improve soil structure, increase soil organic matter content, and provide a good soil environment for seed germination and seedling growth; superphosphate can provide the phosphorus element needed for seedling growth and promote root development. This invention does not specifically limit the sources of straw organic fertilizer, silica fume, and superphosphate. As one possible implementation method, the straw organic fertilizer is obtained through the fermentation and decomposition of crop straw, the silica fume is an industrial by-product, and the superphosphate is purchased directly from the market.

[0027] This invention does not have any special limitations on the sowing method of *Birchia stenoptera*. As one possible implementation method, the sowing and seedling raising method of CN110999701A is adopted. The seedbed soil is slightly acidic loam. Spread a layer of 0.8cm thick humus soil, then spread a layer of 2cm thick red soil, and then scrape it level with a board. Mix the base fertilizer into the red soil.

[0028] (2) After the true leaves unfold:

[0029] Apply sodium silicate and zinc sulfate by irrigation; preferably, use a mixture of 0.03%-0.05% sodium silicate and 0.04%-0.06% zinc sulfate; more preferably, use a mixture of 0.04% sodium silicate and 0.05% zinc sulfate. The preferred application rate is 100-150 mL / plant, more preferably 125 mL / plant; preferably, apply once every 1-2 weeks, for 2-3 applications, more preferably once every 10 days, for 2 consecutive applications. Sodium silicate provides silicon to seedlings, which enhances their stress resistance; zinc sulfate provides zinc, which participates in the synthesis of various enzymes in plants and plays an important role in seedling growth and development.

[0030] (3) Seedling height 10-15cm:

[0031] Spray with seaweed extract and silica sol; preferably, spray a mixture of 0.1-0.2% seaweed extract and 0.1-0.3% silica sol until water droplets form on the leaves but do not drip; even more preferably, spray a mixture of 0.15% seaweed extract and 0.2% silica sol. Seaweed extract contains various plant hormones, amino acids, and trace elements, which can promote the growth and development of seedlings; silica sol can form a protective film on the leaf surface, enhancing the mechanical strength and stress resistance of the leaves.

[0032] II. Fertilization of *Birchia zebrina* seedlings after 2 years of cultivation, transplanting them to the mature stage:

[0033] (1) Before spring budding:

[0034] Apply NPK compound fertilizer and calcium silicate to the roots; preferably, apply 50-80g of N:P2O5:K2O=10-20-10 compound fertilizer per plant for the roots, multiplied by the transplanting year, and 10-15g of calcium silicate per plant for the transplanting year; further preferably, apply 65g of N:P2O5:K2O=10-20-10 compound fertilizer per plant for the roots, multiplied by the transplanting year, and 12.5g of calcium silicate per plant for the transplanting year.

[0035] As one possible implementation method, in the first year after transplanting, apply 65g / plant of N:P2O5:K2O=10-20-10 compound fertilizer and 12.5g / plant of calcium silicate to the roots; in the second year, apply 130g / plant of N:P2O5:K2O=10-20-10 compound fertilizer and 25g / plant of calcium silicate to the roots; ... in the fifth year, apply 325g / plant of N:P2O5:K2O=10-20-10 compound fertilizer and 62.5g / plant of calcium silicate to the roots; ... in the tenth year, apply 650g / plant of N:P2O5:K2O=10-20-10 compound fertilizer and 125g / plant of calcium silicate to the roots.

[0036] Before spring budding, the roots of the birch tree begin to become active, and the division of dormant bud cells accelerates, preparing for the leaf expansion stage. At this time, the demand for nitrogen (to promote leaf formation), phosphorus (to activate root enzyme activity), and potassium (to regulate osmotic pressure) surges. Compound fertilizers with a high phosphorus ratio can stimulate the division of the root tip meristem of the birch tree, enhancing the young roots' ability to absorb silicon and potassium; supplemental application of silicon fertilizer can strengthen the cuticle of new leaves and reduce cell membrane damage caused by low temperatures in early spring.

[0037] In this invention, it is preferable to mix 5-7g of silica-dissolving bacterial agent with the above-mentioned fertilizer application, multiplying the transplanting year by the number of plants, with an effective viable count of ≥2×10⁻⁶. 8 CFU / g; further optimization involves applying 6g of silica-degrading bacteria per transplanting year. The silica-degrading bacteria can decompose fixed silicon in the soil into soluble form (H4SiO4), thus improving the bioavailability of silicon.

[0038] (2) Summer rapid growth period:

[0039] Spray calcium and magnesium fertilizer and nano-silica; preferably spray 5-10g of calcium and magnesium fertilizer × transplanting years / plant and 1-2g of nano-silica × transplanting years / plant; further preferably spray 7.5g of calcium and magnesium fertilizer × transplanting years / plant and 1.5g of nano-silica × transplanting years / plant.

[0040] During the rapid growth period in summer, the xylem of the Fujian birch stem thickens rapidly, and the photosynthetic rate of the leaves reaches its peak. High temperatures increase transpiration, leading to easy loss of calcium and magnesium. Topdressing with calcium and magnesium fertilizer can help remove calcium ions (Ca). 2+ Magnesium (Mg) can stabilize cell wall pectin and prevent cell collapse at high temperatures. 2+ As a core element of chlorophyll, it ensures the efficiency of light reaction; nano-silica directly enters mesophyll cells through stomata, enhancing the mechanical strength of mesophyll cells.

[0041] In this invention, the preferred method for applying basal fertilizer to the roots before autumn dormancy during the mature plant stage is further preferably to include 0.2-0.4 kg of well-rotted organic fertilizer × transplanting year / plant and 20-30 g of silicon-calcium-magnesium fertilizer × transplanting year / plant. More preferably, the application of 0.3 kg of well-rotted organic fertilizer × transplanting year / plant and 25 g of silicon-calcium-magnesium fertilizer × transplanting year / plant is also recommended. Before autumn dormancy, the leaves of the *Birchia zebrina* begin to fall off, and the root system enters its second growth peak, with nutrients flowing back to the roots for storage. The well-rotted organic fertilizer slowly releases humic acid, stimulating the root system to produce new absorbing roots; the supplemental application of silicon-calcium-magnesium fertilizer promotes root development and tree growth.

[0042] In this invention, when applying fertilizer to the roots, a circular trench is dug along the outer edge of the tree canopy projection, with a depth of 20-30cm. The fertilizer is mixed with the topsoil and then covered with soil and watered. When applying fertilizer by spraying, it is preferred to spray on a cloudy day or in the evening until the leaves are evenly moistened but not dripping.

[0043] In this invention, it is preferable to further include applying quicklime or sulfur powder to the transplanting site after the seedlings have left the nursery to adjust the soil pH to 5.5-6.5, and more preferably to adjust the soil pH to 6.0. *Birchia zebrina* is a species that prefers slightly acidic soil (pH 5.5-6.5), and adjusting the soil pH to this range is beneficial to its growth.

[0044] The present invention does not have any special restrictions on the source of the fertilizers or microbial agents used above, and they can all be purchased through market channels.

[0045] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0046] Example 1

[0047] A method for precise application of silicon fertilizer to *Betula spp.* includes the following steps:

[0048] Fertilization during the seedling stage:

[0049] (1) Before sowing

[0050] Straw organic fertilizer 2kg / m 2 Silica fume 40g / m 2 With superphosphate 40g / m 2 Mix and apply into the seedbed soil.

[0051] (2) After the true leaves unfold

[0052] Apply a mixture of 0.04% sodium silicate and 0.05% zinc sulfate by irrigation. The application rate of the mixture is 125 mL per plant. Apply once every 10 days for two consecutive applications.

[0053] (3) When the seedlings are 10-15cm tall

[0054] Spray a mixture of 0.15% seaweed extract and 0.2% silica sol until water droplets appear on the leaves but do not drip.

[0055] Fertilization during the mature plant stage:

[0056] The initial pH of the soil at the transplanting site was 5.4, and quicklime was applied to adjust the pH to 6.0.

[0057] (1) Before spring budding

[0058] Apply 65g of N-P2O5-K2O=10-20-10 compound fertilizer per plant (based on transplanting years) and 12.5g of calcium silicate per plant (based on transplanting years). Mix in 6g of silica-dissolving bacteria per plant (based on transplanting years) (effective viable bacteria count ≥2×10⁻⁶). 8 (CFU / g); dig a circular trench (25cm deep) along the outer edge of the tree canopy projection, mix the fertilizer with the topsoil, cover with soil and water.

[0059] (2) Summer growth period

[0060] On a cloudy afternoon at 4 PM, spray 7.5g of calcium magnesium fertilizer × transplanting year / plant (CaO:MgO = 2:1) and 1.5g of nano silica × transplanting year / plant (nano SiO2 content 30%) until the leaves are evenly moistened but not dripping.

[0061] (3) Before autumn dormancy

[0062] Apply 0.3 kg of well-rotted organic fertilizer (prepared by fermentation of cow manure and straw in a 7:3 ratio) and 25 g of silicon-calcium-magnesium fertilizer (prepared by fermentation of cow manure and straw in a 7:3 ratio) to the roots of the tree. Dig a circular trench (25 cm deep) along the outer edge of the tree canopy projection, mix the fertilizer with the topsoil, cover with soil and water.

[0063] Example 2

[0064] A method for precise application of silicon fertilizer to *Betula spp.* includes the following steps:

[0065] Fertilization during the seedling stage:

[0066] (1) Before sowing

[0067] Straw organic fertilizer 1.5kg / m³ 2 Silica fume 30g / m 2 With superphosphate 30g / m 2 Mix and apply into the seedbed soil.

[0068] (2) After the true leaves unfold

[0069] Apply a mixture of 0.03% sodium silicate and 0.04% zinc sulfate by irrigation, at a rate of 100 mL per plant, once a week for three weeks.

[0070] (3) When the seedlings are 10-15cm tall

[0071] Spray a mixture of 0.1% seaweed extract and 0.1% silica sol until water droplets appear on the leaves but do not drip.

[0072] Fertilization during the mature plant stage:

[0073] The initial pH of the soil at the transplanting site was 5.4, and quicklime was applied to adjust the pH to 6.0.

[0074] (1) Before spring budding

[0075] Apply 50g of N-P2O5-K2O=10-20-10 compound fertilizer per plant (based on transplanting years) and 10g of calcium silicate per plant (based on transplanting years), mixed with 5g of silica-dissolving bacteria per plant (based on transplanting years) (effective viable bacteria count ≥2×10⁻⁶). 8 (CFU / g); dig a circular trench (20cm deep) along the outer edge of the tree canopy projection, mix the fertilizer with the topsoil, cover with soil and water.

[0076] (2) Summer growth period

[0077] On a cloudy afternoon at 4 pm, spray 5g of calcium magnesium fertilizer × transplanting years / plant (CaO:MgO = 2:1) and 1g of nano silica × transplanting years / plant (nano SiO2 content 30%) until the leaves are evenly moistened but not dripping.

[0078] (3) Before autumn dormancy

[0079] Apply 0.2 kg of well-rotted organic fertilizer (prepared by fermentation of cow manure and straw in a 7:3 ratio) and 20 g of silicon-calcium-magnesium fertilizer (prepared by fermentation of cow manure and straw in a 7:3 ratio) to the roots of the tree. Dig a circular trench (20 cm deep) along the outer edge of the tree canopy projection, mix the fertilizer with the topsoil, cover with soil and water.

[0080] Example 3

[0081] A method for precise application of silicon fertilizer to *Betula spp.* includes the following steps:

[0082] Fertilization during the seedling stage:

[0083] (1) Before sowing

[0084] Straw organic fertilizer 2.5kg / m³ 2 Silica fume 50g / m 2 With superphosphate 50g / m 2 Mix and apply into the seedbed soil.

[0085] (2) After the true leaves unfold

[0086] Apply a mixture of 0.05% sodium silicate and 0.06% zinc sulfate by irrigation. The amount of the mixture is 150 mL per plant. Apply once every 2 weeks for 2 consecutive applications.

[0087] (3) When the seedlings are 10-15cm tall

[0088] Spray a mixture of 0.2% seaweed extract and 0.3% silica sol until water droplets appear on the leaves but do not drip.

[0089] Fertilization during the mature plant stage:

[0090] The initial pH of the soil at the transplanting site was 6.7, and sulfur powder was applied to adjust the pH to 6.3.

[0091] (1) Before spring budding

[0092] Apply 80g of N-P2O5-K2O=10-20-10 compound fertilizer per plant (per transplanting year) and 15g of calcium silicate per plant (per transplanting year), mixed with 7g of silica-dissolving bacteria per plant (effective viable count ≥2×10⁻⁶). 8 (CFU / g); dig a circular trench (30cm deep) along the outer edge of the tree canopy projection, mix the fertilizer with the topsoil, cover with soil and water.

[0093] (2) Summer growth period

[0094] On a cloudy afternoon at 4 pm, spray 10g of calcium magnesium fertilizer × transplanting years / plant (CaO:MgO = 2:1) and 2g of nano silica × transplanting years / plant (nano SiO2 content 30%) until the leaves are evenly moistened but not dripping.

[0095] (3) Before autumn dormancy

[0096] Apply 0.4 kg of well-rotted organic fertilizer (prepared by fermentation of cow manure and straw in a 7:3 ratio) and 30 g of silicon-calcium-magnesium fertilizer (prepared by fermentation of cow manure and straw in a 7:3 ratio) to the roots of the tree. Dig a circular trench (30 cm deep) along the outer edge of the tree canopy projection, mix the fertilizer with the topsoil, cover with soil and water.

[0097] Experimental Example 1

[0098] The effect of fertilization methods during the seedling stage on the growth (plant height, stem diameter, crown width) of *Betula buergeriana* seedlings

[0099] 1. Experimental Design

[0100] Materials: Yellow birch seeds (from Fujian Academy of Forestry Sciences, 1000-seed weight ≥0.15g, germination rate ≥60%).

[0101] Grouping (3 replicates per group, 50 seedlings per replicate):

[0102] CK group (blank control): only basic seedbed (slightly acidic loam, with a 0.8cm thick layer of humus soil, followed by a 2cm thick layer of red soil, and then leveled with a board), no fertilizer applied.

[0103] CF group (conventional fertilization): Follow the local nursery's conventional methods (apply compound fertilizer 50g / m² before sowing). 2Spray with 0.1% urea after the true leaves unfold.

[0104] Group T1 (Complete Fertilizer of this Invention): Fertilization during the seedling stage as described in Example 1 (Base fertilizer: straw organic fertilizer, silica fume 4kg / m³) 2 +40g / m³ of superphosphate 2 During the true leaf stage, irrigate with a mixture of 0.04% sodium silicate and 0.05% zinc sulfate at 125 mL / plant; when seedlings reach 12 cm in height, spray with a mixture of 0.15% seaweed extract and 0.2% silica sol.

[0105] Group T2 (Silicon-free version of this invention): Based on T1, all silicon-related fertilizers are removed (only straw organic fertilizer and superphosphate are applied as base fertilizer; only zinc sulfate is applied during the true leaf stage; only seaweed extract is applied during the seedling height stage).

[0106] Management: Greenhouse cultivation (25±2℃), unified irrigation (maintain soil moisture 60%), 12h / d light.

[0107] 2. Measurement Indicators and Methods

[0108] Emergence rate (%): Statistical data was collected on the 20th day after sowing.

[0109] Growth indicators (measured every 30 days):

[0110] Plant height (cm): Vertical height from the base of the stem to the terminal bud.

[0111] Stem diameter (mm): Diameter 1 cm above the cotyledon (vernier caliper).

[0112] Leaf count: A leaf with a true leaf unfolding ≥ 1cm is considered a valid leaf.

[0113] Biomass (at the time of transplanting):

[0114] Dry weight of aerial parts (g): dried at 105℃ to constant weight.

[0115] Root activity (μg / g·h): Dehydrogenase activity was determined by TTC method.

[0116] Phytolith content (mg / g dry weight) at the time of nursery: 10 seedlings were randomly selected from each group, and the middle part of the stem was taken as a sample. After being washed with deionized water, the sample was dried at 105℃ to constant weight, ground into powder, and chemical digestion was used to remove organic matter such as cellulose, lignin, and protein, as well as soluble minerals such as calcium and magnesium from the powder, while retaining pure phytoliths, and their content was determined.

[0117] 3. Test Results

[0118] As shown in Table 1, the emergence rate of group T1 was significantly higher than that of groups CF and CK, indicating that straw organic fertilizer and silica fume + superphosphate basal fertilizer effectively improved the soil structure of the seedbed and promoted seed germination. At 60 days, the plant height of group T1 was 43.7% higher than that of group CF, proving that the combination of sodium silicate + zinc sulfate significantly accelerated early vegetative growth. All indicators of group T2 were significantly lower than those of group T1, indicating that silica sol and seaweed extract synergistically promoted biomass accumulation by enhancing leaf mechanical strength and photosynthetic efficiency. The root activity of group T1 was 2.1 times that of group CK, indicating that sodium silicate significantly activated root metabolism, laying the foundation for rapid growth in the mature stage. The phytolith density and content of group T1 were significantly higher than those of other groups, indicating that the application of silicon fertilizer during the seedling stage can significantly promote the synthesis and deposition of phytoliths in the stems of *Betula spp.*, and can simultaneously enhance lodging resistance and pest resistance.

[0119] Table 1. Effects of different fertilization methods on growth indicators and post-nursery traits of *Betula buergeriana* seedlings.

[0120]

[0121] Experimental Example 2

[0122] The effect of fertilization methods after seedling transplanting on the stress resistance (drought resistance, cold resistance, and disease resistance) of *Betula buergeriana* seedlings

[0123] 1. Experimental Design

[0124] At the time of transplanting of the *Birchia zebrina* seedlings in Experiment 1 (seedling age 2 years), three stress tests were conducted (30 seedlings in each group, 3 replicates):

[0125] (1) Drought stress: Stop watering for 7 days, measure the wilting index (0-5, 0 = no wilting) and the survival rate 24 hours after rehydration.

[0126] (2) Low temperature stress: Seedlings were placed in an artificial climate chamber at 5℃ for 48 hours, and the electrolyte permeability (relative conductivity method) and the malondialdehyde (MDA) content in the leaves (thiobarbituric acid method) were measured.

[0127] (3) Pathogen inoculation: Leaves were inoculated with a suspension of spores of *Betula buergeriana* anthracnose (10... 5 Spores / mL), and the area of ​​lesions on the whole plant (mm²) was measured after 72 hours. 2 ).

[0128] 2. Test Results

[0129] As shown in Table 2, the wilting index of group T1 was only 1.3, and the rehydration survival rate reached 92.4%, significantly better than groups CK and CF. This is because straw organic fertilizer, silica fume, and sodium silicate improved the water retention capacity of the soil around the roots, the protective film formed by silica sol on the leaf surface reduced transpiration water loss, and zinc sulfate and seaweed extract synergistically enhanced the cell osmotic pressure regulation capacity. The survival rate of group T2 decreased by 17.4% compared with T1, confirming the core role of silicon in the drought resistance mechanism. The electrolyte permeability and MDA content of group T1 were significantly lower than those of group CK, indicating that the cell membrane damage caused by low temperature was significantly reduced. Calcium silicate and silica-dissolving bacteria promoted the deposition of silicon in the cell wall, forming a "silicification barrier," which can reduce the rate of cell membrane fluid loss at low temperature; the Ca in calcium magnesium fertilizer 2+ It can stabilize cell membrane protein structure and reduce electrolyte leakage. Due to the lack of silicon fertilizer, the MDA content in group T2 was 37.4% higher than that in group T1, indicating that the synergistic effect of silicon, calcium, and magnesium is key to cold resistance. The lesion area in group T1 was reduced by 54.7% compared to the control group, which is directly related to the mechanical barrier formed by silica sol in mesophyll cells—silica deposition can hinder the penetration of pathogen hyphae, while plant hormones in seaweed extract can induce the expression of disease-related proteins. The lesion area in group T2 was increased by 44.1% compared to T1, further demonstrating the indispensability of silicon in enhancing the disease resistance of *Betula spp.*

[0130] Table 2. Effects of different fertilization methods on the stress resistance of *Betula buergeriana* seedlings at the time of nursery transplanting.

[0131]

[0132] Experimental Example 3

[0133] The effects of fertilization methods during the mature stage on the growth indicators (tree height, diameter at breast height) and mechanical properties (density, bending strength) of *Betula buergeriana*.

[0134] 1. Experimental Design

[0135] Thirty similarly growing *Betula fusiforme* seedlings were selected and transplanted to red soil forest (pH 6.0±0.2, organic matter content 2.1%). They were randomly divided into three groups of 10 seedlings each. Irrigation, weeding, and pest and disease control were consistent across the three groups, and fertilization was applied continuously for eight years.

[0136] CK group (conventional fertilization group): 500g / plant of N:P2O5:K2O=15-15-15 compound fertilizer was applied to the roots in spring, summer and autumn respectively.

[0137] Group T1 (Complete Fertilizer of the Invention): Fertilized according to the fertilization method of the mature plant stage in Example 1.

[0138] Group T2 (Silicon removal of this invention): The difference between this and the T1 fertilization method is that no silicon fertilizer, silicon-removing bacteria, and nano-silica were applied.

[0139] 2. Indicator Measurement

[0140] Growth indicators: The height and diameter at breast height (DBH) of *Betula buxiflora* were measured in November of the 1st, 3rd, and 8th years after transplanting. Eight years after fertilization, timber characteristics were measured: 5mm diameter core samples were collected from the base of the main trunk, and basic density (GB / T 1933-2009 Method for Determination of Timber Density) and bending strength (three-point bending test, ASTM D143-2014) were tested. Average values ​​were calculated.

[0141] 3. Test Results

[0142] As shown in Table 3, the plant height growth of group T1 (fully fertilized) in the first year was significantly higher than that of groups CK and T2, demonstrating the promoting effect of silicon fertilizer on early growth. In the fourth year, the diameter at breast height (DBH) reached 8.2 cm, consistent with the characteristics of rapid growth in *Betula buergeriana* (average annual diameter increase ≥2 cm). Group T2 (de-siliconized) showed better growth indicators than CK but significantly lower than T1, proving that silicon is a key factor in synergistically enhancing growth efficiency with nitrogen, phosphorus, and potassium. The basic density of group T1 was 7.5% higher than that of group CK, because silicon promotes silicification of xylem cell walls, increasing microfibril density. The bending strength of group T1 was 21.5% higher than that of group CK, because nano-silica and calcium-magnesium fertilizer synergistically enhance the cellulose-lignin crosslinking strength.

[0143] Table 3. Effects of different fertilization methods on growth indicators and mechanical properties of *Betula buergeriana* wood.

[0144]

[0145]

[0146] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for precise application of silicon fertilizer to *Betula spp.*, characterized in that, This includes fertilization during the seedling stage and fertilization during the mature plant stage; Fertilization during the seedling stage includes: Before sowing, apply 1.5-2.5 kg / m² of straw organic fertilizer. 2 Silica fume 30-50g / m 2 With superphosphate 30-50g / m 2 Mix and apply into the seedbed soil; After the true leaves unfold, apply a mixture of 0.03%-0.05% sodium silicate and 0.04%-0.06% zinc sulfate; the amount of the mixture applied is 100-150 mL / plant, applied once every 1-2 weeks, for 2-3 applications. When the seedlings are 10-15cm tall, spray them with a mixture of 0.1-0.2% seaweed extract and 0.1-0.3% silica sol until water droplets appear on the leaves but do not drip. Fertilization during the mature plant stage includes: Before spring budding, apply 50-80g of N:P2O5:K2O=10-20-10 compound fertilizer per plant (50-80g x transplanting years) and 10-15g of calcium silicate per plant (10-15g x transplanting years); mix in 5-7g of silica-dissolving bacteria per plant (50-7g x transplanting years), ensuring the bacteria have ≥2×10⁻⁶ viable bacteria. 8 CFU / g; During the rapid growth period in summer, spray with 5-10g of calcium-magnesium fertilizer per transplanting year and 1-2g of nano-silica per transplanting year. Before autumn dormancy, apply 0.2-0.4 kg of well-rotted organic fertilizer per plant, multiplied by the transplanting year, and 20-30 g of silicon-calcium-magnesium fertilizer per plant, multiplied by the transplanting year.

2. The method according to claim 1, characterized in that, The seedling stage refers to the period from sowing of *Birchia zebrina* to its second year of growth before being transplanted, while the mature stage refers to the period from transplanting *Birchia zebrina* to its maturity.

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