Fertilizer carrying method for rice seedling raising

Abstract

The invention discloses a rice seedling raising fertilizer carrying method in the technical field of agricultural production. The rice seedling raising fertilizer carrying method comprises the following steps: S1, preparing a seedling raising tray; s2, laying a first layer of substrate; s3, laying a sustained and controlled release fertilizer; s4, covering a second layer of substrate; s5, sowing and seedling raising; s6, seedling transplantation; the fertilizer disclosed by the invention is wrapped by a root system in a seedling raising stage and can still continuously release nutrients after transplanting; fertilizer loss and volatilization are reduced, and the absorption and utilization rate of nutrients such as nitrogen, phosphorus and potassium is improved; base fertilizer and topdressing frequency in the tillering stage are reduced; a layered controlled-release fertilizer technology is adopted, and a polymer coating or a biodegradable film is combined to control the release rate, so that the nutrient continuous release period covers the rice from the early growth stage to the tillering stage; the first layer of matrix ensures uniform laying and porosity, and provides physical support for initial penetration of the root system; after light compaction, the porosity of the second-layer substrate is greater than or equal to 20%, the water-retaining property is enhanced, the microbial activity is promoted, meanwhile, nitrogen-fixing bacteria, phosphate solubilizing bacteria and other biological agents are doped, the fertilizer self-supply capacity of the substrate is improved, and external fertilizer dependence is reduced.

Description

Technical Field

[0001] The present invention relates to the field of agricultural production technology, more specifically to rice seedling raising and fertilizing technology, and particularly to a rice seedling raising and fertilizing method. Background Art

[0002] Rice is an important food crop, and its yield and quality are directly related to food security. Fertilization is a key measure to increase rice yield during rice production. However, traditional rice fertilization methods require application during the transplanting (seedling transplanting) or tillering phase, when rice plants are small and their nutrient absorption capacity is limited. As a result, most nutrients cannot be absorbed by the rice plants and are lost to the environment, resulting in low nutrient utilization and serious environmental pollution. Frequent fertilization also increases production input costs.

[0003] In recent years, slow-release and controlled-release fertilizers have gained some application in rice production due to their nutrient release patterns closely matching crop fertilizer requirements. However, existing technologies often broadcast or apply them in holes in the field, preventing them from fully integrating with the seedling roots during the seedling raising phase. This requires additional labor and production costs, and can be difficult to precisely match with the rice plant's root system, resulting in delayed fertilizer effectiveness or partial nutrient loss.

[0004] Therefore, there is an urgent need for a technology that can accurately load slow-release fertilizers during the rice seedling raising stage and ensure that the fertilizers can continue to supply nutrients after the seedlings are transplanted, so as to improve fertilizer utilization efficiency, reduce the number of fertilizations, reduce environmental risks and ensure yields. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention provides a new technical solution for a rice seedling fertilizer loading method, which is used to solve the problems of how to scientifically combine slow-release fertilizers with seedling substrates during the rice seedling raising stage so that the fertilizers can be wrapped by the seedling roots and form a stable fertilizer supply environment; how to ensure the continuous release of fertilizers in the early stage of rice growth and reduce nutrient loss, thereby reducing the amount of fertilizer applied in the early stage and throughout the entire growth period of rice; and how to increase rice yield while improving fertilizer utilization efficiency and reducing environmental pollution risks.

[0006] The object of the present invention is achieved in this way: a rice seedling raising and fertilizer loading method comprises the following steps: S1. Prepare the seedling tray: Use a standardized seedling tray with a honeycomb drainage hole structure; S2. Laying the first layer of substrate: Evenly lay the first layer of substrate on the bottom of the seedling tray with a thickness of 0.5–1.0 cm. S3. Laying of slow-release fertilizer: evenly spread slow-release fertilizer on the surface of the first layer of substrate, and the fertilizer particle size should be 1-3mm; S4. Second layer of substrate covering: Lay the second layer of substrate on top of the slow-release fertilizer with a thickness of 1.0–1.5 cm and gently compact the second layer of substrate; S5. Sowing and raising rice seedlings: Sow rice seeds evenly on the surface of the second layer of substrate according to the target yield and carry out routine rice seedling raising management; S6. Seedling cultivation and transplanting: After the rice seedlings are grown, they are transplanted to the field together with their roots and substrate using a rice transplanter.

[0007] Furthermore, the seedling tray in S1 is made of environmentally friendly polypropylene or high-strength fiber composite material, and a honeycomb drainage hole is provided at the bottom of the seedling tray. The pore size of the honeycomb drainage hole is 0.5-2.0 mm, and the hole spacing is 3-5 cm. A filter layer is provided on the honeycomb drainage hole, and the pore size of the filter layer is 0.1-0.3 mm; the surface of the seedling tray is provided with a detachable covering film, and the light transmittance of the covering film is 30-50%.

[0008] Furthermore, the first layer of substrate in S2 contains 50–70% coconut coir, 15–25% vermiculite, 5–10% perlite, and 5–10% organic matter. The total moisture content of the first layer of substrate is 15–20%. After laying, the first layer of substrate is vibrated at a frequency of 50–100 Hz to ensure uniform particle distribution. The first layer of substrate is sterilized by steam sterilization or ultraviolet irradiation before laying. The steam sterilization temperature is controlled at 120°C and the duration is 15-20 minutes. The ultraviolet irradiation light intensity is ≥100 μW / cm² and the duration is ≥2 hours. The first layer of matrix is ​​adjusted to a suitable range by adding lime or acidic substances; The particle diameter of the first layer matrix is ​​1-5 mm, forming a loose structure with a porosity of 30-40%.

[0009] Furthermore, the slow-release fertilizer in S3 is a composite formula, which contains nitrogen, phosphorus, potassium and trace elements, and the trace elements include Zn, B and Mn; The slow-release fertilizer is applied in layers, with the upper layer being a high-nitrogen slow-release fertilizer with a nitrogen release rate of >20%, and the bottom layer being a low-nitrogen, high-phosphorus slow-release fertilizer with a phosphorus release rate of <20%; The slow-release fertilizer has a particle size of 1-3 mm and adopts polymer coating or biodegradable film coating technology with a coating thickness of 0.1-0.3 mm, so that the nutrient release period covers at least the early growth stage to the tillering stage of rice.

[0010] Furthermore, the second layer of matrix in S4 covers the surface of the slow-release fertilizer, and the composition of the second layer of matrix is ​​the same as that of the first layer of matrix, and the particle diameter of the second layer of matrix is ​​0.5-2.0 mm.

[0011] Furthermore, biological agents are added to the second layer of substrate, wherein the biological agents include nitrogen-fixing bacteria and phosphate-solubilizing bacteria; The second layer of matrix is ​​compacted by a light compacting device during covering, and the degree of compaction is controlled by a pressure sensor. The porosity of the second layer of matrix is ​​≥20%.

[0012] Furthermore, the sowing in S5 calculates the amount of rice seeds required based on the target yield, and uses a high-precision seeder to sow evenly; After the rice seeds are evenly sown, a second layer of substrate with a thickness of 0.3–0.5 cm is covered on the surface of the rice seeds.

[0013] Furthermore, the seedling management in S5 includes temperature and humidity control, light regulation, pest and disease prevention and control, and nutrient solution supplementation. The temperature and humidity control adopts an intelligent temperature control system to maintain the temperature range of 20–32°C and the humidity range of 60–85%; The light adjustment is performed by an LED fill light, the spectral range of the LED fill light is 400–700 nm, and the light intensity is 500–1000 μmol / m² / s; The pest control is performed by adding biological pesticides to the second layer of matrix, or by irradiating the rice seeds covered with the second layer of matrix with ultraviolet light for ≥3 hours per day; The nutrient solution supplement is used for drip irrigation of nutrient solution as needed 5-7 days after sowing.

[0014] Furthermore, the formula of the drip irrigation nutrient solution is as follows: comprising basic ingredients, trace elements, organic ingredients, growth regulators and auxiliary ingredients; The essential components include nitrogen, phosphorus and potassium; The trace elements include iron, ferrous metal, zinc, copper, boron and molybdenum; The organic components include amino acids, fulvic acid and alginic acid; The growth regulator includes gibberellins and cytokinins; The auxiliary ingredients include chelating agents, pH regulators and bactericides; The steps of preparing the nutrient solution are as follows: Dissolve the basic ingredients, trace elements, organic ingredients, growth regulators and auxiliary ingredients in deionized water or purified water in proportion, stir evenly and filter to remove impurities; Use a pH meter to monitor and adjust the pH value to 5.5–6.5 in real time; After preparation, it is packaged into small packages of 500-1000 mL to facilitate precise control of the drip irrigation system; The drip irrigation system drips 200–500 mL / tray every 2–3 days. The pressure is controlled at 0.1–0.3 MPa to ensure uniform nutrient solution penetration. Each drip irrigation lasts 10–30 minutes to avoid excessive irrigation that may burn the seedlings. Before each drip irrigation, a portable conductivity meter is used to test the conductivity of the nutrient solution, and the concentration is adjusted according to the moisture content of the substrate and the growth status of the seedlings; combined with the real-time feedback data from the soil nutrient detector, the nutrient solution ratio is dynamically adjusted through the intelligent control system.

[0015] Furthermore, the seedling transplanting in S6 is performed using a dedicated rice transplanter, which is equipped with a substrate cutting device and a root protection device; The transplanting depth of the dedicated rice transplanter is 5-8 cm, and after transplanting, the nutrient solution is supplemented through a drip irrigation system. The supplementary nutrient solution contains trace elements of calcium, magnesium and iron, and the concentration of the nutrient solution is 0.1-0.5 μmol / L. The specific steps of the seedling raising and transplanting are as follows: Root wrapping: The rice seedlings, along with their roots and substrate, are cut and wrapped using a dedicated rice transplanter to form root balls with a diameter of 2–4 cm. Transplanting depth control: Insert the root ball into the field soil at a depth of 5–8 cm, using a depth sensor to ensure consistency; Soil mixing: When transplanting, mix the substrate with the field soil in proportion, with the substrate accounting for 10–20%; Mechanical assistance: The special rice transplanter is equipped with an automatic leveling function to ensure that the spacing error between seedlings is ≤2cm after transplanting.

[0016] Compared with the existing technology, the beneficial effects of the present invention are as follows: the fertilizer of the present invention is wrapped by the root system during the seedling raising stage and can continue to release nutrients after transplanting, which is highly consistent with the early fertilizer requirement of rice; it reduces fertilizer loss and volatilization, and improves the absorption and utilization rate of nutrients such as nitrogen, phosphorus, and potassium; it reduces the frequency of base fertilizer and topdressing during the tillering period, saving labor and mechanical operation costs; it reduces fertilizer leaching, runoff and gaseous loss, and reduces the risk of eutrophication of water bodies; the continuous and stable nutrient supply promotes early tillering and optimizes the population structure, thereby stabilizing or increasing yield; The present invention uses layered slow-release fertilizer technology, combined with polymer coating or biodegradable film to control the release rate, so that the nutrient release period covers the early growth stage to the tillering stage of rice, avoiding excessive or insufficient nutrient loss, and significantly improving the development of the seedling root system and the overall growth rate. The honeycomb-shaped drainage holes at the bottom of the seedling tray are combined with the filter layer to form a multi-level drainage network, ensuring smooth drainage of the substrate and preventing impurity blockage. At the same time, the substrate is sterilized through ultraviolet irradiation or steam sterilization. Combined with drip irrigation nutrient solution supplementation and biocides such as berberine, the incidence of root diseases is significantly reduced. The first layer of the matrix of the present invention ensures uniform laying and porosity, providing physical support for the initial penetration of the root system; the porosity of the second layer of the matrix after light compaction is ≥20%, which enhances water retention and promotes microbial activity. At the same time, biological agents such as nitrogen-fixing bacteria and phosphate-solubilizing bacteria are incorporated to improve the self-fertilization capacity of the matrix and reduce dependence on external fertilizers. In addition, the setting of the first layer of the matrix and the second layer of the matrix can maintain the stability of rice seedling cultivation, and through the setting of different diameters, it is convenient for the rice seedlings to take root and fix. In addition, the diameter of the second matrix is ​​relatively small, which facilitates the growth and development of the rice seedlings.

[0017] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0019] Figure 1 It is a schematic diagram of the steps of the present invention.

[0020] Figure 2 Schematic diagram of the steps for preparing the nutrient solution of the present invention.

[0021] Figure 3 It is a schematic diagram of the specific steps of seedling raising and transplanting of the present invention.

[0022] Figure 4 It is a hierarchical schematic diagram of the seedling raising matrix of the present invention.

[0023] Figure 5 This is a schematic diagram of the seedling raising entity of the present invention. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] like Figure 1-Figure 5 As shown, a method for raising rice seedlings and loading fertilizer comprises the following steps: S1. Prepare the seedling tray: Use a standardized seedling tray with a honeycomb drainage hole structure; S2. Laying the first layer of substrate: Evenly lay the first layer of substrate on the bottom of the seedling tray with a thickness of 0.5–1.0 cm. S3. Laying of slow-release fertilizer: evenly spread slow-release fertilizer on the surface of the first layer of substrate, and the fertilizer particle size should be 1-3mm; S4. Second layer of substrate covering: Lay the second layer of substrate on top of the slow-release fertilizer with a thickness of 1.0–1.5 cm and gently compact the second layer of substrate; S5. Sowing and raising rice seedlings: Sow rice seeds evenly on the surface of the second layer of substrate according to the target yield and carry out routine rice seedling raising management; S6. Seedling cultivation and transplanting: After the rice seedlings are grown, they are transplanted to the field together with their roots and substrate using a rice transplanter.

[0026] In this embodiment, preferably, the seedling tray in S1 is made of environmentally friendly polypropylene or high-strength fiber composite material, and a honeycomb drainage hole is provided at the bottom of the seedling tray. The pore size of the honeycomb drainage hole is 0.5-2.0 mm, and the hole spacing is 3-5 cm. A filter layer is provided on the honeycomb drainage hole, and the pore size of the filter layer is 0.1-0.3 mm. The surface of the seedling tray is provided with a detachable covering film, and the light transmittance of the covering film is 30-50%; It should be noted that the seedling trays are made of environmentally friendly polypropylene or high-strength fiber composite materials, so that the seedling trays can be reused. The honeycomb drainage holes at the bottom of the seedling tray work together with the filter layer to quickly drain excess water and prevent root rot, and effectively intercept impurities and extend the service life of the substrate. The removable covering film on the surface optimizes the photosynthesis efficiency of the seedlings by adjusting the light intensity and ambient humidity, while avoiding the excessive growth of seedlings caused by excessive light, ensuring the healthy growth of the seedlings.

[0027] In this embodiment, preferably, the first layer of substrate in S2 contains 50-70% coconut coir, 15-25% vermiculite, 5-10% perlite, and 5-10% organic matter. The total moisture content of the first layer of substrate is 15-20%. After laying, the first layer of substrate is vibrated by a vibration device with a frequency of 50-100 Hz to uniformly distribute the particles. The first layer of substrate is sterilized by steam sterilization or ultraviolet irradiation before laying. The steam sterilization temperature is controlled at 120℃ and the duration is 15-20 minutes. The ultraviolet irradiation light intensity is ≥100μW / cm² and the duration is ≥2 hours. The first layer of substrate is adjusted to a suitable range by adding lime or acidic substances; The particles of the first layer of matrix have a diameter of 1–5 mm, forming a loose structure with a porosity of 30–40%; It should be noted that the coconut coir facilitates the rooting of rice seedlings during the cultivation process, and the vermiculite and perlite are used to improve the air permeability and water permeability of the substrate, forming a loose structure with a porosity of 30-40%. This not only ensures good air permeability and drainage, but also enhances the water holding capacity of the substrate, providing suitable physical support and water supply for root development. Steam sterilization or ultraviolet irradiation treatment effectively kills pathogenic microorganisms in the substrate and reduces the risk of disease. By adding lime or acidic substances to adjust the pH of the substrate to an appropriate range, the solubility and utilization rate of nutrients are improved. After laying, a vibration device with a frequency of 50-100Hz is used to achieve uniform distribution of particles to avoid local accumulation or excessive gaps.

[0028] In this embodiment, preferably, the slow-release fertilizer in S3 is a composite formula, which contains nitrogen, phosphorus, potassium and trace elements, and the trace elements include Zn, B and Mn; Slow-release fertilizers are applied in layers, with the upper layer being high-nitrogen slow-release fertilizer with a nitrogen release rate of >20%, and the bottom layer being low-nitrogen, high-phosphorus slow-release fertilizer with a phosphorus release rate of <20%. Slow-release fertilizers have a particle size of 1–3 mm and are coated with polymer or biodegradable films with a thickness of 0.1–0.3 mm, ensuring that the nutrient release period covers at least the early rice growth stage to the tillering stage. It should be noted that the synergistic configuration of nitrogen, phosphorus, potassium and trace elements such as Zn, B and Mn in the slow-release fertilizer can meet the differentiated needs of rice for nutrients from the early growth stage to the tillering stage. The slow-release fertilizer is applied in layers, which makes the fertilizer release highly matched with the growth rhythm of rice, facilitates the release of the upper layer first to promote rice seedling, and the release of the bottom layer to absorb nutrients in the tillering stage. The slow-release fertilizer with a particle size of 1-3 mm is coated with a polymer or a biodegradable film with a thickness of 0.1-0.3 mm, which not only prolongs the nutrient release period, but also controls the degradation characteristics to achieve environmental friendliness. The layered structure ensures the close contact between the fertilizer and the substrate, and improves the nutrient diffusion efficiency.

[0029] In this embodiment, if necessary, the second layer of substrate in S4 covers the surface of the slow-release fertilizer, and the composition of the second layer of substrate is the same as that of the first layer of substrate, and the particle diameter of the second layer of substrate is 0.5-2.0 mm; The second layer of substrate is mixed with biological agents, wherein the biological agents include nitrogen-fixing bacteria and phosphorus-dissolving bacteria; The second layer of substrate is compacted by a light compaction device during covering, and the compaction degree is controlled by a pressure sensor. The porosity of the second layer of substrate is ≥20%; It should be noted that by covering the second layer of substrate on the surface of the slow-release fertilizer and incorporating biological agents, the nutrient supply efficiency and root development quality for rice seedling are realized, and the setting of biological agents promotes the synergistic decomposition of microorganisms on the slow-release fertilizer, accelerating the release of nutrients such as nitrogen and phosphorus. The fine particles of the second layer of substrate ensure the uniform distribution of water and air, providing a stable microenvironment for root growth, and ensuring the smoothness of root penetration and nutrient diffusion.

[0030] In this embodiment, preferably, the seeding in S5 calculates the amount of rice seeds according to the target yield, and uses a high-precision seeder to uniformly sow the seeds; After the rice seeds are uniformly sown, the surface of the rice seeds is again covered with a second layer of substrate with a thickness of 0.3-0.5 cm; It should be noted that by calculating the amount of rice seeds according to the target yield, seed waste is reduced, and by covering the surface with a second layer of substrate with a thickness of 0.3-0.5 cm after sowing, the water and nutrients are effectively locked, the stability of the seed germination environment is maintained, and the loose structure of the substrate promotes root penetration and early nutrient absorption of seedlings, avoiding nutrient loss due to water evaporation or fertilizer leaching.

[0031] In this embodiment, preferably, the seedling management in S5 includes temperature and humidity control, light regulation, pest control and nutrient solution supplementation, The temperature and humidity control uses an intelligent temperature control system to maintain the temperature range at 20-32℃ and the humidity at 60-85%; Light regulation is performed by LED light supplement, the spectral range of the LED light supplement is 400-700 nm, and the light intensity is 500-1000 μmol / m² / s; Disease and pest control is performed by adding biological pesticides in the second layer of substrate, or by irradiating the rice seeds covered by the second layer of substrate with ultraviolet light, and the irradiation time is ≥3 hours / day; Nutrient solution supplement is performed by drip irrigation of the nutrient solution as needed 5-7 days after sowing; It should be noted that the growth efficiency and quality stability of the rice seedlings are improved by intelligent temperature and humidity control, LED light supplement, biological disease and pest control, and precise nutrient solution supplement; the green control of diseases and pests is realized by adding biological pesticides in the second layer of substrate or by irradiating the seeds covered by the second layer of substrate with ultraviolet light, the use amount of chemical pesticides is reduced, and the environmental pollution is reduced; the nutrient supply is precisely controlled by drip irrigation of the nutrient solution as needed, the phased needs of the release period of the slow-release fertilizer are made up, and the root development and tillering stage nutrient balance of the seedlings are promoted.

[0032] In this embodiment, preferably, the formula of the drip irrigation nutrient solution is as follows: basic ingredients, trace elements, organic ingredients, growth regulators and auxiliary ingredients are included; The basic ingredients include nitrogen, phosphorus and potassium; The trace elements include iron, iron, zinc, copper, boron and molybdenum; The organic ingredients include amino acids, fulvic acid and alginic acid; The growth regulators include gibberellins and cytokinins; The auxiliary ingredients include chelating agents, pH regulators and bactericides; The nitrogen is provided in the form of ammonium nitrate or urea, and the concentration is 100-200 mg / L, so as to promote the stem and leaf growth of the seedlings; The phosphorus is provided in the form of potassium dihydrogen phosphate or potassium phosphate, and the concentration is 50-100 mg / L, so as to meet the root development needs; The potassium is provided in the form of potassium chloride or potassium sulfate, and the concentration is 80-150 mg / L, so as to enhance the cell osmotic pressure and stress resistance.

[0033] The iron is provided in the form of iron EDTA or iron citrate, and the concentration is 1-3 mg / L, so as to prevent iron deficiency; The iron is provided in the form of EDTA-Mn or manganese sulfate, and the concentration is 0.5-1.5 mg / L, so as to promote enzyme activity; The zinc is provided in the form of EDTA-Zn or zinc sulfate, and the concentration is 0.5-1.0 mg / L, so as to enhance photosynthesis; The copper is provided in the form of EDTA-Cu or copper sulfate, and the concentration is 0.1-0.5 mg / L, so as to regulate the metabolic process; The boron is provided in the form of boric acid or borax, and the concentration is 0.1-0.3 mg / L, so as to promote cell division; Molybdenum is provided in the form of sodium molybdate, with a concentration of 0.01-0.05 mg / L, enhancing nitrogen utilization efficiency.

[0034] Wherein the amino acid is glycine or glutamic acid, with a concentration of 10-50 mg / L, promoting protein synthesis and root growth; The concentration of fulvic acid is 10-30 mg / L, enhancing the water retention of the substrate and microbial activity; The concentration of alginic acid is 5-15 mg / L, serving as a natural plant growth regulator, promoting root development.

[0035] Wherein the concentration of gibberellin is 0.01-0.1 mg / L, promoting cell elongation and stem and leaf growth; The concentration of cytokinin is 0.05-0.2 mg / L, delaying aging and enhancing stress resistance.

[0036] Wherein the chelating agent is EDTA-Na or sodium citrate, with a concentration of 1-5 mg / L, preventing metal ion precipitation; The pH regulator is citric acid or sodium bicarbonate, adjusting the pH value of the nutrient solution to 5.5-6.5, which is the optimal absorption range for rice; The bactericide is berberine or Bacillus subtilis liquid, with a concentration of 0.1-0.5 mg / L, inhibiting the growth of pathogens; The preparation steps of the nutrient solution are as follows: Dissolve the basic ingredients, trace elements, organic ingredients, growth regulators, and auxiliary ingredients in deionized water or purified water according to the proportion, stir uniformly, and filter to remove impurities; Use a pH meter to monitor and adjust the pH value in real time to 5.5-6.5; After preparation, divide into 500-1000 mL small packages for easy precise control of the drip irrigation system; The drip irrigation system is dripped once every 2-3 days, with a drip irrigation amount of 200-500 mL per tray; control the pressure at 0.1-0.3 MPa to ensure uniform penetration; each time lasts for 10-30 minutes to avoid excessive burning of seedlings; Before each drip irrigation, use a portable conductivity meter to detect the conductivity of the nutrient solution, adjust the concentration according to the water content of the substrate and the growth state of the seedlings; combine with the real-time feedback data of the soil nutrient detector to dynamically adjust the nutrient solution ratio through the intelligent control system; It should be noted that by scientifically designing the formula of the drip irrigation nutrient solution and intelligently preparing and managing the drip irrigation, the nutrient supply efficiency and growth quality of rice seedling cultivation are improved, and the deep integration of resource conservation, environmental friendliness, and precision agriculture is realized; through multi-dimensional nutrient regulation and intelligent management, the use amount of chemical fertilizers and pesticides is reduced, and environmental pollution is reduced.

[0037] In this embodiment, preferably, the seedling transplanting in S6 is performed using a dedicated rice transplanter, which is equipped with a substrate cutting device and a root protection device; The transplanting depth of the dedicated rice transplanter is 5–8 cm, and after transplanting, the nutrient solution is supplemented through a drip irrigation system. The supplementary nutrient solution contains trace elements such as calcium, magnesium, and iron, and the concentration of the nutrient solution is 0.1–0.5 μmol / L. It should be noted that the transplanting depth is set at 5-8cm to ensure that the rice roots are fully in contact with the substrate and soil, promote rooting growth and tillering ability, and reduce root damage. The nutrient solution rich in calcium, magnesium, iron and other trace elements is supplemented through the drip irrigation system. It can not only quickly replenish the nutrients that may be lost during the transplanting process, but also enhance the plant cell wall strength, photosynthesis efficiency and nitrogen utilization ability through the synergistic effect of trace elements, thereby improving the stress resistance and growth rate of the seedlings.

[0038] In this embodiment, preferably, the specific steps of raising seedlings and transplanting are as follows: Root wrapping: The rice seedlings, along with their roots and substrate, are cut and wrapped using a dedicated rice transplanter to form root balls with a diameter of 2–4 cm. Transplanting depth control: Insert the root ball into the field soil at a depth of 5–8 cm, using a depth sensor to ensure consistency; Soil mixing: When transplanting, mix the substrate with the field soil in proportion, with the substrate accounting for 10–20%; Mechanical assistance: The dedicated rice transplanter is equipped with an automatic leveling function to ensure that the spacing error between seedlings is ≤2cm after transplanting; It should be noted that the root wrapping technology cuts and wraps the seedlings together with the roots and substrate as a whole to form a root sphere with a diameter of 2-4 cm, which protects the integrity of the root system and reduces damage during transplanting. At the same time, it promotes rapid contact between the roots and the field soil, and increases the rooting speed of the seedlings. The fertilization step is to add 1-2% urea solution through a slow-release fertilizer adding device on the third day after transplanting, accurately replenishing the nitrogen that may be lost during the transplanting process and accelerating the recovery of seedling growth. In the soil mixing operation, the entire substrate is mixed with the field soil in proportion, which not only retains the water retention and nutrient slow-release properties of the substrate, but also promotes root expansion by improving the physical structure of the field soil, thereby improving soil fertility and permeability.

[0039] Specific embodiments are as follows: Example 1: Materials: Use 50-hole plastic seedling trays. The substrate is a mixture of paddy field topsoil and the first or second substrate in a ratio of 7:3. Use a coated nitrogen, phosphorus, and potassium compound fertilizer for controlled-release fertilizer (the nitrogen-phosphorus ratio during the seedling stage (from sowing to the early tillering stage) is recommended to be 1:1.5–2; during the tillering stage (peak tillering period), the nitrogen-phosphorus ratio is recommended to be 2:1–1.5; from the jointing to the heading stage, the nitrogen-phosphorus ratio is recommended to be 1.5–2:1; during the grain filling stage, the nitrogen-phosphorus ratio is recommended to be 1:1). Particle size: 2mm. step: Spread the first layer of substrate mixed with paddy field topsoil evenly on the bottom of the seedling tray with a thickness of about 0.8 cm; Evenly spread slow-release fertilizer on the surface of the first layer of substrate in the mixed paddy field topsoil, with a fertilizer dosage of 8–10 g per tray; Cover with a second layer of mixed paddy topsoil about 1.2 cm thick and lightly compact; Sow the germinated rice seeds, sow the rice seeds in the amount calculated based on the target yield, and then cover the rice seeds with a second layer of mixed paddy topsoil with a thickness of 0.5 cm; With regular watering, temperature and humidity control, pest and disease control, and nutrient solution supplementation, seedlings will emerge in about 7 days and strong seedlings will form in 20-25 days; When transplanting, the fertilizer enters the field along with the root system, ensuring slow-release fertilizer supply until the end of tillering.

[0040] Example 2: Based on the operation of Example 1, a certain proportion of trace element fertilizers (such as zinc fertilizer and silicon fertilizer) is mixed into the fertilizer layer to further improve the stress resistance and quality of rice.

[0041] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for raising rice seedlings and loading fertilizer, characterized by: The following steps are involved: S1. Prepare the seedling tray: Use a standardized seedling tray with a honeycomb drainage hole structure; S2. Laying the first layer of substrate: Evenly lay the first layer of substrate on the bottom of the seedling tray with a thickness of 0.5–1.0 cm. S3. Laying of slow-release fertilizer: evenly spread slow-release fertilizer on the surface of the first layer of substrate, and the fertilizer particle size should be 1-3mm; S4. Second layer of substrate covering: Lay the second layer of substrate on top of the slow-release fertilizer with a thickness of 1.0–1.5 cm and gently compact the second layer of substrate; S5. Sowing and raising rice seedlings: Sow rice seeds evenly on the surface of the second layer of substrate according to the target yield and carry out routine rice seedling raising management; S6. Seedling cultivation and transplanting: After the rice seedlings are grown, they are transplanted to the field together with their roots and substrate using a rice transplanter.

2. A rice seedling raising and fertilizer loading method according to claim 1, characterized in that: The seedling tray in S1 is made of environmentally friendly polypropylene or high-strength fiber composite material. A honeycomb drainage hole is provided at the bottom of the seedling tray. The pore size of the honeycomb drainage hole is 0.5-2.0 mm, and the hole spacing is 3-5 cm. A filter layer is provided on the honeycomb drainage hole, and the pore size of the filter layer is 0.1-0.3 mm; the surface of the seedling tray is provided with a detachable covering film, and the light transmittance of the covering film is 30-50%.

3. A rice seedling raising and fertilizer loading method according to claim 1, characterized in that: The first layer of substrate in S2 contains 50-70% coconut coir, 15-25% vermiculite, 5-10% perlite, and 5-10% organic matter. The total moisture content of the first layer of substrate is 15-20%. After laying, the first layer of substrate is vibrated at a frequency of 50-100 Hz to ensure uniform distribution of particles. The first layer of substrate is sterilized by steam sterilization or ultraviolet irradiation before laying. The steam sterilization temperature is controlled at 120°C and the duration is 15-20 minutes. The ultraviolet irradiation light intensity is ≥100 μW / cm² and the duration is ≥2 hours. The first layer of matrix is ​​adjusted to a suitable range by adding lime or acidic substances; The particle diameter of the first layer matrix is ​​1-5 mm, forming a loose structure with a porosity of 30-40%.

4. A rice seedling raising and fertilizer loading method according to claim 1, characterized in that: The slow-release fertilizer in S3 is a composite formula, which contains nitrogen, phosphorus, potassium and trace elements, and the trace elements include Zn, B and Mn; The slow-release fertilizer is applied in layers, with the upper layer being a high-nitrogen slow-release fertilizer with a nitrogen release rate of >20%, and the bottom layer being a low-nitrogen, high-phosphorus slow-release fertilizer with a phosphorus release rate of <20%; The slow-release fertilizer has a particle size of 1-3 mm and adopts polymer coating or biodegradable film coating technology with a coating thickness of 0.1-0.3 mm, so that the nutrient release period covers at least the early growth stage to the tillering stage of rice.

5. A rice seedling raising and fertilizer loading method according to claim 4, characterized in that: The second layer of matrix in S4 covers the surface of the slow-release fertilizer, and the composition of the second layer of matrix is ​​the same as that of the first layer of matrix. The particle diameter of the second layer of matrix is ​​0.5-2.0 mm.

6. A rice seedling raising and fertilizer loading method according to claim 5, characterized in that: Biological agents are added to the second layer of substrate, wherein the biological agents include nitrogen-fixing bacteria and phosphate-solubilizing bacteria; The second layer of matrix is ​​compacted by a light compacting device during covering, and the degree of compaction is controlled by a pressure sensor. The porosity of the second layer of matrix is ​​≥20%.

7. A rice seedling raising and fertilizer loading method according to claim 1, characterized in that: The sowing in S5 is to calculate the amount of rice seeds according to the target yield, and use a high-precision seeder to sow evenly; After the rice seeds are evenly sown, a second layer of substrate with a thickness of 0.3–0.5 cm is covered on the surface of the rice seeds.

8. The method for raising rice seedlings and loading fertilizer according to claim 1, characterized in that: The seedling management in S5 includes temperature and humidity control, light regulation, pest and disease prevention and control, and nutrient solution supplementation. The temperature and humidity control adopts an intelligent temperature control system to maintain the temperature range of 20–32°C and the humidity of 60–85%; The light adjustment is performed by an LED fill light, the spectral range of the LED fill light is 400–700 nm, and the light intensity is 500–1000 μmol / m² / s; The pest control is performed by adding biological pesticides to the second layer of matrix, or by irradiating the rice seeds covered with the second layer of matrix with ultraviolet light for ≥3 hours per day; The nutrient solution supplement is used for drip irrigation of nutrient solution as needed 5-7 days after sowing.

9. A rice seedling raising and fertilizer loading method according to claim 8, characterized in that: The formula of the drip irrigation nutrient solution is as follows: comprising basic ingredients, trace elements, organic ingredients, growth regulators and auxiliary ingredients; The essential components include nitrogen, phosphorus and potassium; The trace elements include iron, ferrous metal, zinc, copper, boron and molybdenum; The organic components include amino acids, fulvic acid and alginic acid; The growth regulator includes gibberellins and cytokinins; The auxiliary ingredients include chelating agents, pH regulators and bactericides; The steps of preparing the nutrient solution are as follows: Dissolve the basic ingredients, trace elements, organic ingredients, growth regulators and auxiliary ingredients in deionized water or purified water in proportion, stir evenly and filter to remove impurities; Use a pH meter to monitor and adjust the pH value to 5.5–6.5 in real time; After preparation, it is packaged into small packages of 500-1000 mL to facilitate precise control of the drip irrigation system; The drip irrigation system drips 200–500 mL / tray every 2–3 days. The pressure is controlled at 0.1–0.3 MPa to ensure uniform nutrient solution penetration. Each drip irrigation lasts 10–30 minutes to avoid excessive irrigation that may burn the seedlings. Before each drip irrigation, a portable conductivity meter is used to test the conductivity of the nutrient solution, and the concentration is adjusted according to the moisture content of the substrate and the growth status of the seedlings; combined with the real-time feedback data from the soil nutrient detector, the nutrient solution ratio is dynamically adjusted through the intelligent control system.

10. The method for raising rice seedlings and loading fertilizer according to claim 1, characterized in that: The seedling transplanting in S6 is performed using a special rice transplanter equipped with a substrate cutting device and a root protection device; The transplanting depth of the dedicated rice transplanter is 5-8 cm, and after transplanting, the nutrient solution is supplemented through a drip irrigation system. The supplementary nutrient solution contains trace elements of calcium, magnesium and iron, and the concentration of the nutrient solution is 0.1-0.5 μmol / L. The specific steps of the seedling raising and transplanting are as follows: Root wrapping: The rice seedlings, along with their roots and substrate, are cut and wrapped using a dedicated rice transplanter to form root balls with a diameter of 2–4 cm. Transplanting depth control: Insert the root ball into the field soil at a depth of 5–8 cm, using a depth sensor to ensure consistency; Soil mixing: When transplanting, mix the substrate with the field soil in proportion, with the substrate accounting for 10–20%; Mechanical assistance: The special rice transplanter is equipped with an automatic leveling function to ensure that the spacing error between seedlings is ≤2cm after transplanting.

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