Method for high yield cultivation of forage grass in infertile red soil

Abstract

The present application relates to the field of agricultural planting technology, and discloses a high-yield cultivation method for forage grass in infertile red soil, which comprises the following steps: preparing a paclobutrazol microemulsion by shearing phase inversion emulsification of paclobutrazol, cyclohexanone and a composite emulsifier; grafting copolymerization of corn starch and acrylamide monomers to obtain a prepolymer, mixing the prepolymer with n-butyl thiophosphoric triamide after cooling to prepare a composite coating liquid, and spraying the composite coating liquid on large granular urea by using a fluidized bed to obtain slow-release urea resistant to loss; storing hybrid pennisetum stems in a cellar with a ventilation pipe laid at the bottom after bacteriostatic spraying; cutting and disinfecting and inoculating sprouts, and culturing the sprouts in a rooting culture medium added with the paclobutrazol microemulsion to obtain tissue culture seedlings; and applying base fertilizer to the red soil, planting the tissue culture seedlings, and applying slow-release urea when the grass layer meets the standard. The method improves the initial root development of plants, reduces the risk of nitrogen loss by combining physical barriers and chemical inhibition mechanisms, and improves the survival rate of planting and the yield of forage grass.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, specifically a method for high-yield cultivation of forage grasses in barren red soil. Background Technology

[0002] Southern red soil regions generally suffer from problems such as high soil acidity, lack of organic matter, and enrichment of iron and aluminum oxides. The soil has a weak ability to retain water and fertilizer. Planting high-quality forage grasses such as hybrid Napier grass in these areas can provide the roughage needed for animal husbandry and help control local soil and water erosion.

[0003] However, complex and unfavorable habitats pose significant obstacles to the high-yield cultivation of forage grasses. When conventionally cultivated forage grass seedlings are transplanted to barren and arid red soil, their relatively thin root systems make it difficult for them to quickly penetrate the compacted soil layer to obtain deep water and nutrients. This results in a longer recovery period and a lower survival rate in the early stages of transplanting. Some studies have attempted to use plant growth regulators such as paclobutrazol to promote the lateral thickening of plant roots. However, conventional paclobutrazol technical has poor water solubility and will aggregate and precipitate in tissue culture substrates or aqueous solutions, causing uneven absorption by plant tissues and making it difficult to achieve a stable and expected root-promoting effect. At the same time, forage grass seedlings often rot during the dormant storage stage due to anaerobic respiration and acid production caused by sealed stacking, or due to infection by pathogenic fungi, reducing the quality of healthy seedlings supplied.

[0004] Nutrient management is another challenge for forage cultivation in red soil regions. Rainfall is concentrated in these areas, and conventionally applied urea is leached away by surface runoff. While commonly used physically coated slow-release fertilizers can slow nutrient release to some extent, the polymer shell alone is prone to premature breakage and failure under high humidity fluctuations. Some synthetic resin coatings degrade slowly in acidic soils, leading to microplastic residues with long-term use. Furthermore, if urea hydrolyzes too rapidly to produce ammonia under the action of soil urease, it not only deviates from the nitrogen release curve to the nutrient requirements of forage plants during their jointing stage but also increases the risk of eutrophication in surrounding water bodies. Existing single-item agricultural technologies often address localized problems without organically integrating seed preservation, root promotion and seedling cultivation, red soil substrate improvement, and environmentally responsive fertilization. Consequently, the overall yield and ecological benefits of forage in red soil regions are difficult to substantially improve. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-yield cultivation method for forage grasses in barren red soil. This method solves the problems of poor root development and low survival rate of forage grasses in the early stage of planting in barren red soil environments in southern China, anaerobic respiration and infection rot during seed storage, and low fertilizer utilization due to severe loss of conventional nitrogen fertilizers by rainfall.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for high-yield cultivation of forage grass in barren red soil, comprising the following steps: Paclobutrazol technical, cyclohexanone and composite emulsifier are mixed to form an oil phase, propylene glycol is dissolved in deionized water to form an aqueous phase, and phase transition occurs through shear emulsification to obtain paclobutrazol microemulsion; A prepolymer was obtained by graft copolymerization of corn starch, acrylamide monomer, N,N'-methylenebisacrylamide, potassium persulfate and deionized water. After cooling, n-butylthiophosphoric triamine was added and mixed evenly to prepare a composite coating liquid. The composite coating liquid was sprayed onto the surface of large urea particles in a fluidized bed and dried and cured to obtain anti-loss slow-release urea. Ventilation pipes were laid at the bottom of the storage cellar. Hybrid Napier grass seed stems were cut, treated with antibacterial solution and then placed into the cellar for storage. Tender shoots were cut, disinfected, and then inoculated sequentially into induction medium and rooting medium with added paclobutrazol microemulsion to obtain tissue culture seedlings. The tissue culture seedlings were planted in red soil that had been tilled and treated with basal fertilizer. The grass growth height was dynamically monitored. When the grass reached a preset height threshold, the anti-loss slow-release urea was applied to match the fertilizer requirements of forage and maximize the anti-loss performance of the coating fertilizer.

[0007] By adopting the above technical solution, the following technical effects are achieved: Aeration pipes are laid at the bottom of the cellar to create an aerobic microenvironment, reducing the probability of the seed stems rotting due to anaerobic respiration and acid production.

[0008] Paclobutrazol technical has low water solubility. It is prepared into a microemulsion and dispersed into nano-sized droplets to improve the uniformity of drug dispersion in the tissue culture matrix and the absorption and conversion rate of plant tissues. The introduction of microemulsified paclobutrazol during the rooting stage can block the gibberellin synthesis pathway in plants, guide the assimilation products to the roots, promote the development of short, thick and dense root networks in tissue culture seedlings, and enhance the plant's ability to take root and absorb fertilizer in barren red soil.

[0009] Anti-leaking slow-release urea controls nitrogen release through a dual mechanism of physical barrier and chemical inhibition. In hot water, corn starch absorbs water and swells, releasing active hydroxyl groups. After nitrogen purging and deoxygenation, added potassium persulfate decomposes upon heating to generate sulfate free radicals, which capture hydrogen atoms from hydroxyl groups to form macromolecular backbone free radicals. Acrylamide monomers are then grafted and copolymerized at the free radical sites. Combined with the chemical cross-linking effect of N,N'-methylenebisacrylamide, a three-dimensional network polymer matrix is ​​constructed. After cooling, n-butylthiophosphoric acid powder is mixed in and coated on the urea surface to form a polymer hydrogel film. After application to the soil, the film absorbs water and swells, regulating the rate of urea molecule diffusion. Simultaneously released n-butylthiophosphoric acid binds to the active center of soil urease, competitively inhibiting urea hydrolysis to produce ammonia. The synergistic effect of physical barrier control and chemical enzyme inhibition reduces the risk of nitrogen loss caused by rainfall in red soil areas.

[0010] Preferably, the paclobutrazol microemulsion is made from the following raw materials in weight percentages: The composition includes 10.0 to 15.0 wt% paclobutrazol technical grade; 15.0 to 20.0 wt% cyclohexanone; 10.0 to 15.0 wt% compound emulsifier, wherein the compound emulsifier is composed of polyoxyethylene castor oil ether EL-40 and calcium alkylbenzene sulfonate in a mass ratio of 2:1; 3.0 to 5.0 wt% propylene glycol; 45.0 to 62.0 wt% deionized water; and the sum of the weight percentages of the above raw materials is 100%.

[0011] By adopting the above technical solution, the nonionic surfactant polyoxyethylene castor oil ether EL-40 and the anionic surfactant calcium alkylbenzene sulfonate are compounded in a specific ratio in the composite emulsifier system to produce a synergistic effect. The nonionic component provides a steric hindrance effect, while the anionic component forms a double-layer repulsive force at the oil-water interface, which helps to regulate the hydrophilic-lipophilic balance of the system. The propylene glycol introduced in the formulation, as a co-surfactant, can insert into the interstices between surfactant molecules in the interfacial film, reduce interfacial tension and increase the flexibility of the interfacial film, and maintain the stability of the microemulsion under long-term storage conditions as much as possible, reducing demulsification and stratification.

[0012] Preferably, the step of obtaining the paclobutrazol microemulsion includes: Paclobutrazol technical was completely dissolved in cyclohexanone at 40 to 50°C to form a homogeneous oil phase. A composite emulsifier was added and the mixture was stirred at 500 to 800 rpm for 20 to 30 minutes while maintaining a constant temperature. Propylene glycol was dissolved in deionized water to form an aqueous phase. Under the action of a shear emulsifier at 2000 to 3000 rpm, the aqueous phase was slowly added dropwise to the oil phase at a rate of 10 to 15 mL / min. After a phase transition occurred and blue fluorescence was observed, shearing was continued for 10 to 15 minutes. The mixture was then cooled to room temperature to obtain a paclobutrazol microemulsion.

[0013] By adopting the above technical solution, during the preparation process using the phase inversion emulsification method, the initial mixture of the added aqueous phase presents an oil-in-water emulsion state. As the volume fraction of the aqueous phase increases, when the internal phase volume exceeds the critical point, the viscosity of the system changes and a phase inversion is triggered, resulting in an oil-in-water structure. Accompanied by the action of high-speed shear force, the internal phase droplets are broken and reorganized, and the particle size can be reduced to the micrometer or even nanometer level. The blue fluorescence that appears in the system corresponds to the Tyndall effect, indicating that a relatively stable transparent or semi-transparent microemulsion has been formed and has good permeability.

[0014] Preferably, the raw materials for preparing the composite coating solution comprise the following components in parts by weight: Corn starch 10.0 to 15.0 parts; acrylamide monomer 30.0 to 40.0 parts; N,N'-methylenebisacrylamide 0.05 to 0.1 parts; potassium persulfate 0.1 to 0.2 parts; n-butylthiophosphoric triamine 0.5 to 1.0 parts; deionized water 150.0 to 200.0 parts.

[0015] By adopting the above technical solution, the ratio of starch to acrylamide affects the film-forming toughness and water permeability of the coating layer. Excessive starch addition will cause the membrane pores to become larger and the water solubility to increase, affecting the slow-release effect; while excessive acrylamide will increase the difficulty of membrane degradation and bring the risk of soil microplastic residues. The limited ratio range ensures that the polymer chain length in the coating solution remains moderate, and the formed gel network can provide suitable outward diffusion resistance for urea molecules.

[0016] Preferably, the step of obtaining anti-loss sustained-release urea includes: Corn starch was dispersed in deionized water and gelatinized at 80-85°C for 30-45 minutes. Nitrogen gas was purged to remove oxygen and the temperature was lowered to 60-65°C. Acrylamide monomer, N,N'-methylenebisacrylamide, and potassium persulfate were added sequentially, and a graft copolymerization reaction was initiated at a constant temperature for 2.0-3.0 hours to obtain a prepolymer. After cooling to 25°C, micron-sized n-butylthiophosphoric triamine powder was added and stirred evenly at 300-400 rpm to obtain a composite coating solution. The composite coating solution was sprayed onto the surface of large-particle urea in a fluidized bed using a bottom sprayer, with the inlet air temperature controlled at 50-60°C and the spraying rate at 15-25 mL / min. After drying and curing, anti-loss slow-release urea with a coating rate of 5.0%-8.0% by mass was obtained.

[0017] By adopting the above technical solution, the graft copolymerization reaction temperature is controlled at 60 to 65°C, which can maintain a stable rate of free radical generation and avoid excessively violent reaction leading to explosive polymerization. Since n-butylthiophosphoric triamine exhibits certain thermosensitivity and will degrade and deactivate at high temperatures, the addition operation is delayed until the system is cooled to 25°C, which plays a role in protecting the integrity of the compound's chemical structure and inhibiting enzyme activity. The bottom-spray fluidized bed uses high-speed hot airflow to keep the urea particles in a suspended and dispersed state. The coating liquid droplets are sprayed upward countercurrently from the bottom nozzle. After the droplets contact the urea surface, the solvent evaporates quickly, which can form a relatively uniform coating on the surface.

[0018] Preferably, the step of placing the hybrid Napier grass seed stems into a cellar for storage includes: Multiple rigid PVC pipes with a diameter of 50 to 80 mm and a spacing of 80 to 100 cm are laid horizontally along the long axis at the bottom of the storage cellar. The pipes have ventilation holes with a diameter of 5 to 10 mm and are 30 to 40 cm above the ground at both ends. The cut seed stems are lightly sprayed with an antibacterial solution containing 0.3 to 0.8 wt% calcium propionate and 1.0 to 2.0 wt% sorbitol. The treated seed stems are then tightly packed into the cellar, with a thickness of 50 to 70 cm, covered with a 2 to 3 cm layer of straw, and then covered with 5 to 10 cm of soil.

[0019] By adopting the above technical solution, the rigid PVC ventilation pipe network arranged at the bottom of the cellar relies on the principle of passive ventilation to guide external air into the cellar bottom. Natural convection carries away the carbon dioxide and residual heat released by the respiration of the seed stems. The propionate ions dissociated from calcium propionate in the antibacterial solution can penetrate the cell wall of mold and interfere with the synthesis process of enzymes in fungal cells to exert an antibacterial effect. Sorbitol acts as an osmotic regulator, forming a moisturizing isolation layer on the cut surface, slowing down the rate of cell water loss and reducing the probability of plasmolysis, which is beneficial to maintaining the vitality of seed stem cells.

[0020] Preferably, the step of sterilizing the cut buds includes: Immerse in 75 vol% ethanol for 1.0 to 2.0 min, rinse with sterile water, then transfer to a compound disinfectant solution containing 1.5 to 2.5 wt% sodium hypochlorite and 0.05 to 0.15 wt% Tween 20, and shake on a shaker at 100 to 150 rpm for 10 to 12 min; remove and soak in 0.08 to 0.12 wt% ascorbic acid solution for 1.0 to 2.0 min and rinse.

[0021] By adopting the above technical solution, Tween 20 is introduced into the compound disinfectant as a nonionic surfactant to reduce the surface tension of the liquid, which facilitates the penetration of hypochlorite ions into the intercellular spaces and surface folds of plant epidermal cells, clearing away hidden and attached pathogenic microorganisms. Since sodium hypochlorite has strong oxidizing properties, it will cause phenolic substances in plant tissues to be oxidized to produce quinone polymers, causing browning and necrosis of explants. Subsequently, soaking with ascorbic acid solution is carried out, and the reducing properties of ascorbic acid are used to remove residual reactive oxygen free radicals on the tissue surface, promoting the reduction of quinone substances to phenols, reducing the risk of browning damage to explants.

[0022] Preferably, in the step of culturing to obtain tissue culture seedlings, the culture medium formula is limited to: The induction medium is formulated as follows: MS + 0.8 to 1.2 mg / L kinetin and 0.1 to 0.3 mg / L 1-naphthaleneacetic acid; the rooting medium is formulated as follows: 1 / 2 MS and 0.2 to 0.4 mg / L 1-naphthaleneacetic acid, with the addition of the paclobutrazol microemulsion to make the concentration of the active ingredient of paclobutrazol 0.2 to 0.4 mg / L.

[0023] By adopting the above technical solution, the concentration of kinetin in the induction medium is higher than that of 1-naphthacetic acid. The resulting ratio of cytokinin to auxin helps to break apical dominance and stimulate the differentiation and proliferation of axillary buds and adventitious buds. During the rooting stage, switching to 1 / 2MS medium with half the nutrient concentration can generate a moderate osmotic stress signal. Combined with the supplementation of 1-naphthacetic acid and paclobutrazol active ingredients in the rooting medium to inhibit excessive growth, it induces the vascular bundle cambium to differentiate towards the root primordia, promotes the lateral expansion and thickening of the root system, and provides a basic guarantee for the plant to cope with adverse environments during the later transplanting and hardening stage.

[0024] Preferably, the step of transplanting the tissue culture seedlings after tilling the red soil and applying base fertilizer includes: 15 to 20 days before sowing, plow the red soil to a depth of 30 to 40 cm, and apply 200 to 300 kg / mu of concentrated humic acid bio-organic fertilizer and 20 to 30 kg / mu of calcium magnesium phosphate fertilizer; transplant the tissue culture seedlings in furrows with a row spacing of 80 to 90 cm and a plant spacing of 50 to 60 cm.

[0025] By adopting the above technical solution, the concentrated humic acid bio-organic fertilizer contains active functional groups such as carboxyl groups and phenolic hydroxyl groups. After being applied to the soil, the functional groups can chelate and coordinate with free aluminum or iron ions in the red soil to form water-soluble complexes, thereby reducing aluminum toxicity and releasing some of the originally fixed ineffective phosphate ions. When combined with the application of alkaline calcium magnesium phosphate fertilizer, it can neutralize the acidic matrix of the red soil and create a rhizosphere micro-ecological environment with relatively good nutrient availability for the roots of forage grasses.

[0026] Preferably, the step of applying the anti-loss slow-release urea includes: When the grass layer reaches a height of 10 to 15 cm, apply 4.0 to 6.0 kg / mu of the anti-loss slow-release urea.

[0027] By adopting the above technical solution, after the grass layer grows to the predetermined height, anti-loss slow-release urea is applied. The vegetation canopy is used to reduce the surface temperature and slow down the volatilization of urea ammonia. The nitrogen released slowly by the coated urea is more in line with the fertilizer requirements of the forage grass, supporting nutrient retention and plant biomass conversion.

[0028] This invention provides a method for high-yield cultivation of forage grasses in barren red soil. It has the following beneficial effects: 1. This invention improves the root development of forage grass in the early stage of planting by preparing paclobutrazol technical material with low water solubility into a microemulsion and adding it to the rooting culture medium. The microemulsification treatment reduces the particle size of paclobutrazol, increases the uniformity of drug dispersion in the matrix and the tissue absorption rate. Combined with 1-naphthaleneacetic acid in the culture medium, it guides the transfer of plant assimilation products to the roots, promotes the development of short, thick and dense root networks in tissue culture seedlings, and enhances the rooting ability and survival rate of plants in arid and barren red soil environments.

[0029] 2. The composite coated slow-release urea prepared in this invention reduces the risk of nitrogen fertilizer loss through a combination of physical inhibition and chemical enzyme inhibition mechanisms. Corn starch and acrylamide monomers are grafted and copolymerized to form a three-dimensional network gel film layer, which can slow down the diffusion rate of internal urea molecules after absorbing water and swelling. The n-butylthiophosphoric triamine doped in it is released into the soil and competitively binds to and inhibits the activity of soil urease, thus slowing down the hydrolysis of urea to produce ammonia. This dual-effect synergistic mechanism is adapted to the environment of frequent rainfall in red soil areas and prolongs the effect time of fertilizer.

[0030] 3. This invention uses concentrated humic acid bio-organic fertilizer and calcium magnesium phosphate fertilizer applied before transplanting tissue culture seedlings. Relying on functional group complexation and acid-base neutralization, it reduces aluminum toxicity in red soil and enhances the effect of phosphorus. Combined with the shading effect of grass vegetation to slow down urea volatilization, it improves the overall yield and ecological stability of forage in barren areas. Attached Figure Description

[0031] Figure 1 This is a trend diagram showing the correlation between soil urease activity and corresponding fitted hydrolysis half-life at different monitoring time points after the slow-release urea of ​​the present invention is applied to red soil. Figure 2 This is a graph showing the dynamic wetting parameter variation trend of different disinfection systems of the present invention; Figure 3 This is a histogram of the extreme maximum temperature distribution in the central region of the cellar captured during the winter storage period of this invention. Figure 4 This is a line graph showing the mold rate of the seed tuber epidermis and the germination survival rate of the seed tubers in the cellar according to the present invention; Figure 5 A bar chart showing the proportion of miscellaneous bacteria and the phenomenon of vitrification necrosis in tissues in this invention; Figure 6 This is a comparison chart of the absolute number of roots induced from single buds in each group after the rooting culture medium of the present invention and the dispersion of population variation. Figure 7 This is a bar chart showing the outflow concentrations of total nitrogen and ammonia nitrogen in the first wave of surface runoff according to the present invention. Figure 8 This is a line graph showing the absolute residual level of available nitrogen in this invention and the final yield per acre of hybrid Napier grass in the field at the end of the growing season. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0034] Paclobutrazol, CAS No. 76738-62-0, has an active ingredient purity greater than 95.0 wt%. Polyoxyethylene castor oil ether EL-40, CAS number 61791-12-6; Alkylbenzene sulfonate calcium, CAS number 26264-06-2, active ingredient mass fraction greater than 70.0 wt%; Urea, CAS number 57-13-6, with a total nitrogen mass fraction greater than 46.0 wt%, using large-particle urea with a particle size range of 2.0 mm to 4.0 mm; Acrylamide, CAS number 79-06-1; N,N'-methylenebisacrylamide, CAS number 110-26-9; n-Butylthiophosphoric triamine, CAS No. 94317-64-3, purity greater than 97.0 wt%; Calcium propionate, CAS number 4075-81-4; Sodium hypochlorite aqueous solution, CAS number 7681-52-9, with an available chlorine mass fraction greater than 10.0 wt%. Twain 20, CAS number 9005-64-5; This concentrated humic acid bio-organic fertilizer contains more than 30.0 wt% free humic acid and is formulated with Bacillus amyloliquefaciens and Bacillus subtilis, with an effective viable count greater than 2.0 × 10⁻⁶. 8 CFU / g; Hybrid Napier grass seed stems are the stems of robust, mold-free living plants harvested in autumn, with the stubble height controlled to be 5cm to 8cm.

[0035] In this invention, the units of measurement for all materials and solvents are uniformly referred to as parts by weight.

[0036] Example 1: This embodiment provides a method for high-yield cultivation of forage grass in barren red soil, including the following steps: S1. Weigh out 10.0 wt% paclobutrazol technical, 15.0 wt% cyclohexanone, and 10.0 wt% composite emulsifier according to the following proportions: polyoxyethylene castor oil ether EL-40 to alkylbenzene sulfonate calcium in a mass ratio of 2:1; propylene glycol 3.0 wt%; and deionized water 62.0 wt%. Dissolve the paclobutrazol technical completely in cyclohexanone at 40°C to form a homogeneous oil phase. Add the composite emulsifier and maintain a constant temperature while stirring at 500 rpm for 20 min. Dissolve the propylene glycol in deionized water to form an aqueous phase. Under the action of a shear emulsifier at 2000 rpm, slowly add the aqueous phase to the oil phase at a dropping rate of 10 mL / min. After a phase transition occurs and blue fluorescence appears, continue shearing for 10 min and cool to room temperature to obtain a paclobutrazol microemulsion. S2. Weigh 10.0 parts corn starch, 30.0 parts acrylamide monomer, 0.05 parts N,N'-methylenebisacrylamide, 0.1 parts potassium persulfate, 0.5 parts n-butylthiophosphoric triamine, and 150.0 parts deionized water. Disperse the corn starch in deionized water and gelatinize at 80℃ for 30 min. Purge with nitrogen to remove oxygen and cool to 60℃. Add acrylamide monomer, N,N'-methylenebisacrylamide, and potassium persulfate sequentially. Initiate graft copolymerization at constant temperature for 2.0 h to obtain a prepolymer. After cooling to 25℃, add micron-sized n-butylthiophosphoric triamine powder and stir evenly at 300 rpm to obtain a composite coating solution. Use a bottom spray fluidized bed to spray the composite coating solution onto the surface of fluidized large-particle urea. The inlet air temperature is 50℃, the spraying rate is 15 mL / min, and the solution is dried and cured to obtain an anti-loss slow-release urea with a coating rate of 5.0% by mass. S3. Lay multiple rigid PVC pipes horizontally along the long axis at the bottom of the storage cellar. The pipes are 50mm in diameter and spaced 100cm apart. The pipe surfaces are drilled with 5mm diameter ventilation holes, and both ends of the pipes are 30cm above the ground surface. Cut the hybrid Napier grass seed stems and spray them with a mildly moisturizing solution containing 0.3wt% calcium propionate and 1.0wt% sorbitol. Place the treated seed stems tightly into the cellar to a thickness of 50cm, cover with a 2cm layer of straw, and then cover with 5cm of soil. Cut tender shoots and soak them in 75 vol% ethanol for 1.0 min. After rinsing with sterile water, transfer them to a compound disinfectant solution containing 1.5 wt% sodium hypochlorite and 0.05 wt% Tween 20 and shake on a shaker at 100 rpm for 10 min. Remove them and soak them in 0.08 wt% ascorbic acid solution for 1.0 min and rinse. Inoculate the tender shoots into an induction medium containing MS + 0.8 mg / L kinetin + 0.1 mg / L 1-naphthylacetic acid. After obtaining clustered shoots, cut single shoots and inoculate them into a rooting medium containing S1 microemulsion. The rooting medium contains 1 / 2 MS + 0.2 mg / L 1-naphthylacetic acid + 0.2 mg / L paclobutrazol active ingredient. 15 days before sowing, plow the red soil to a depth of 30cm and apply 200kg / mu of concentrated humic acid bio-organic fertilizer and 20kg / mu of calcium magnesium phosphate fertilizer; transplant the tissue culture seedlings in furrows with a row spacing of 80cm and a plant spacing of 50cm. When the grass layer reaches a height of 10cm, apply 4.0kg / mu of anti-loss slow-release urea prepared by S2.

[0037] Example 2: This embodiment provides a method for high-yield cultivation of forage grass in barren red soil, including the following steps: S1. Weigh out 12.5 wt% paclobutrazol technical, 17.5 wt% cyclohexanone, 12.5 wt% composite emulsifier, polyoxyethylene castor oil ether EL-40 to alkylbenzene sulfonate calcium in a mass ratio of 2:1, 4.0 wt% propylene glycol, and 53.5 wt% deionized water according to the following proportions: Dissolve paclobutrazol technical in cyclohexanone at 45℃ to form a homogeneous oil phase; add the composite emulsifier and maintain a constant temperature while stirring at 650 rpm for 25 min; dissolve propylene glycol in deionized water to form an aqueous phase; under the action of a shear emulsifier at 2500 rpm, slowly add the aqueous phase to the oil phase at a dropping rate of 12.5 mL / min; after a phase transition occurs and blue fluorescence appears, continue shearing for 12 min and cool to room temperature to obtain paclobutrazol microemulsion; S2. Weigh 12.5 parts corn starch, 35.0 parts acrylamide monomer, 0.075 parts N,N'-methylenebisacrylamide, 0.15 parts potassium persulfate, 0.75 parts n-butylthiophosphoric triamine, and 175.0 parts deionized water. Disperse the corn starch in deionized water and gelatinize at 82.5℃ for 37 min. Purge with nitrogen to remove oxygen and cool to 62.5℃. Add acrylamide monomer, N,N'-methylenebisacrylamide, and potassium persulfate sequentially. Initiate graft copolymerization at constant temperature for 2.5 h to obtain a prepolymer. After cooling to 25℃, add micron-sized n-butylthiophosphoric triamine powder and stir evenly at 350 rpm to obtain a composite coating solution. Use a bottom-spray fluidized bed to spray the composite coating solution onto the surface of fluidized large-particle urea. The inlet air temperature is 55℃, the spraying rate is 20 mL / min, and the solution is dried and cured to obtain an anti-loss slow-release urea with a coating rate of 6.5% by mass. S3. Lay multiple rigid PVC pipes horizontally along the long axis at the bottom of the storage cellar. The pipes are 65mm in diameter and 90cm apart. The pipe surfaces are drilled with 7.5mm diameter ventilation holes. The ends of the pipes are 35cm above the ground. Cut the hybrid Napier grass seed stems and spray them with a mildly moisturizing solution containing 0.55wt% calcium propionate and 1.5wt% sorbitol. Place the treated seed stems tightly into the cellar to a thickness of 60cm, cover with a 2.5cm layer of straw, and then cover with 7.5cm of soil. Cut tender shoots and soak them in 75 vol% ethanol for 1.5 min. After rinsing with sterile water, transfer them to a compound disinfectant solution containing 2.0 wt% sodium hypochlorite and 0.1 wt% Tween 20 and shake on a shaker at 125 rpm for 11 min. Remove them and soak them in 0.1 wt% ascorbic acid solution for 1.5 min and rinse. Inoculate the tender shoots into an induction medium containing MS + 1.0 mg / L kinetin + 0.2 mg / L 1-naphthaleneacetic acid. After obtaining clustered shoots, cut single shoots and inoculate them into a rooting medium containing S1 microemulsion. The rooting medium contains 1 / 2 MS + 0.3 mg / L 1-naphthaleneacetic acid + 0.3 mg / L paclobutrazol active ingredient. 17 days before sowing, plow the red soil to a depth of 35cm and apply 250kg / mu of concentrated humic acid bio-organic fertilizer and 25kg / mu of calcium magnesium phosphate fertilizer; transplant the tissue culture seedlings in furrows with a row spacing of 85cm and a plant spacing of 55cm. When the grass layer reaches a height of 12.5cm, apply 5.0kg / mu of anti-loss slow-release urea prepared by S2.

[0038] Example 3: This embodiment provides a method for high-yield cultivation of forage grass in barren red soil, including the following steps: S1. Weigh out 15.0 wt% paclobutrazol technical, 20.0 wt% cyclohexanone, and 15.0 wt% composite emulsifier according to the following proportions: polyoxyethylene castor oil ether EL-40 to alkylbenzene sulfonate calcium in a mass ratio of 2:1; propylene glycol 5.0 wt%; and deionized water 45.0 wt%. Dissolve the paclobutrazol technical completely in cyclohexanone at 50°C to form a homogeneous oil phase. Add the composite emulsifier and maintain a constant temperature while stirring at 800 rpm for 30 min. Dissolve the propylene glycol in deionized water to form an aqueous phase. Under the action of a shear emulsifier at 3000 rpm, slowly add the aqueous phase to the oil phase at a dropping rate of 15 mL / min. After a phase transition occurs and blue fluorescence appears, continue shearing for 15 min and cool to room temperature to obtain the paclobutrazol microemulsion. S2. Weigh 15.0 parts of corn starch, 40.0 parts of acrylamide monomer, 0.1 parts of N,N'-methylenebisacrylamide, 0.2 parts of potassium persulfate, 1.0 part of n-butylthiophosphoric triamine, and 200.0 parts of deionized water. Disperse the corn starch in deionized water and gelatinize at 85℃ for 45 min. Purge with nitrogen to remove oxygen and cool to 65℃. Add acrylamide monomer, N,N'-methylenebisacrylamide, and potassium persulfate sequentially. Initiate graft copolymerization at constant temperature for 3.0 h to obtain a prepolymer. After cooling to 25℃, add micron-sized n-butylthiophosphoric triamine powder and stir evenly at 400 rpm to obtain a composite coating solution. Use a bottom spray fluidized bed to spray the composite coating solution onto the surface of fluidized large-particle urea. The inlet air temperature is 60℃, the spraying rate is 25 mL / min, and the solution is dried and cured to obtain an anti-loss slow-release urea with a coating rate of 8.0% by mass. S3. Lay multiple rigid PVC pipes horizontally along the long axis at the bottom of the storage cellar. The pipes are 80mm in diameter and spaced 80cm apart. The pipe surfaces are drilled with 10mm diameter ventilation holes. Both ends of the pipes are 40cm above the ground surface. Cut the hybrid Napier grass seed stems and spray them with a mildly moisturizing solution containing 0.8wt% calcium propionate and 2.0wt% sorbitol. Place the treated seed stems tightly into the cellar to a thickness of 70cm, cover with a 3cm layer of straw, and then cover with 10cm of soil. Cut tender shoots and soak them in 75 vol% ethanol for 2.0 min. After rinsing with sterile water, transfer them to a compound disinfectant solution containing 2.5 wt% sodium hypochlorite and 0.15 wt% Tween 20 and shake on a shaker at 150 rpm for 12 min. Remove them and soak them in 0.12 wt% ascorbic acid solution for 2.0 min and rinse. Inoculate the tender shoots into MS medium containing 1.2 mg / L kinetin and 0.3 mg / L 1-naphthaleneacetic acid. After obtaining clustered shoots, cut single shoots and inoculate them into rooting medium containing S1 microemulsion. The rooting medium contains 1 / 2 MS medium containing 0.4 mg / L 1-naphthaleneacetic acid and 0.4 mg / L paclobutrazol active ingredient. Twenty days before sowing, plow the red soil to a depth of 40cm and apply 300kg / mu of concentrated humic acid bio-organic fertilizer and 30kg / mu of calcium magnesium phosphate fertilizer; transplant the tissue culture seedlings in furrows with a row spacing of 90cm and a plant spacing of 60cm. When the grass layer reaches a height of 15cm, apply 6.0kg / mu of anti-loss slow-release urea prepared by S2.

[0039] Comparative Example 1: Compared with Example 2, the differences are as follows: in the seed preservation step, rigid PVC pipes are not laid and surface micro-wetting spray treatment with antibacterial solution is not used; in the tissue culture step, Tween 20 is not added to the compound disinfectant solution, ascorbic acid solution soaking and reduction treatment is not performed, and the rooting medium does not add the paclobutrazol microemulsion prepared in S1, but adds ordinary commercially available paclobutrazol technical powder with the same effective concentration; in the urea application step, the anti-loss slow-release urea prepared in S2 is not applied, but ordinary naked urea with the same total nitrogen content is applied, and the rest are the same.

[0040] Comparative Example 2: Compared with Example 2, the difference is that in the seed stem preservation step, a rigid PVC pipe was not laid at the bottom of the storage cellar, and the seed stems were not treated with a micro-moistening spray of an antibacterial solution containing calcium propionate and sorbitol. The cut seed stems were directly placed into the cellar and covered with soil for preservation. All other steps are the same.

[0041] Comparative Example 3: Compared with Example 2, the difference is that Tween 20 is not added to the sodium hypochlorite compound disinfectant in the tissue culture step, and sterile water is used to rinse directly after disinfection, omitting the step of soaking and neutralizing with ascorbic acid solution. All other steps are the same.

[0042] Comparative Example 4: Compared with Example 2, the difference is that in the tissue culture induction and rooting culture steps, the paclobutrazol microemulsion prepared in S1 was not added to the rooting medium, but instead a commercially available paclobutrazol aqueous suspension with an equivalent concentration of paclobutrazol was directly added. All other steps are the same.

[0043] Comparative Example 5: Compared with Example 2, the difference is that in the urea application step, when the hybrid Napier grass layer reaches the required height, instead of applying the anti-loss slow-release urea prepared by S2, ordinary large-particle urea with the same total nitrogen content is applied. All other steps are the same.

[0044] Test Example 1: Take 5 mL of each of the paclobutrazol microemulsions prepared in Examples 1 to 3, dilute them 100 times with deionized water, and inject them into a quartz cuvette. Measure the average hydraulic particle size and polydispersity index using a dynamic light scattering instrument at 25°C. Take another 20 mL of each example microemulsion and place it in a graduated sealed glass test tube. Store it in a 54°C incubator for 14 days. After it is taken out and allowed to return to room temperature, read and record the volume percentage of the precipitated aqueous or oil phase to evaluate the antithermal flocculation physical stability of the microemulsion system.

[0045] The polymer coating layer on the surface of the sustained-release urea prepared in Examples 1 to 3 was manually peeled off and placed in a vacuum drying oven at 60°C for continuous baking until the mass was constant. The mass of the dry film was accurately weighed. The dried coating material was completely immersed in a beaker containing 200 mL of deionized water and left to stand at room temperature for 24 hours to allow the coating material to reach water absorption and swelling equilibrium. The swollen gel film was removed with stainless steel tweezers, and the free water adhering to the surface was quickly absorbed with qualitative filter paper and weighed immediately. The gel swelling ratio was obtained by calculating the ratio of the swollen mass to the initial mass of the dry film.

[0046] 500g of fresh field red soil samples that passed through a 2mm standard sieve were weighed and evenly mixed with the slow-release urea prepared in Examples 1 to 3. The amount of pure nitrogen added was uniformly 0.2g / kg of soil. The samples were placed in sealed plastic culture bottles, and sterile water was slowly added to adjust the soil moisture content to 60% of the field saturation water holding capacity. The bottles were placed in a 25℃ constant temperature biochemical incubator for cultivation in the dark and at constant humidity. On the 3rd and 7th days of the cultivation period, 5g samples were independently and destructively taken, and 1mL of toluene was added to instantly block the life activities of soil microorganisms. After centrifugation and extraction, the absorbance was measured at a wavelength of 630nm using the phenol-sodium hypochlorite colorimetric method. The soil urease activity was calculated and converted. Finally, the hydrolysis half-life of urea in the soil microenvironment was evaluated by fitting the multi-point continuous monitoring values.

[0047] Table 1: Summary of Physicochemical Performance Test Data of Paclobutrazol Microemulsion and Anti-Loss Sustained-Release Urea in Examples 1 to 3

[0048] As shown in Table 1, Example 2, prepared under moderate proportions and optimized process parameters, produced paclobutrazol microemulsions, forming extremely fine micelles with an average particle size of 42.1 nm. This microscopic scale indicates that the reaction system has completely overcome the energy barrier of phase inversion. Free aqueous molecules are highly stably embedded in the continuous phase interface under the tight encapsulation of the composite emulsifier. The polydispersity index is only 0.124, confirming the high homogeneity of the emulsion droplets in spatial distribution. This provides direct structural evidence for explaining the physical state of this group of samples maintaining zero stratification during the 54℃ extreme thermodynamic accelerated aging test. In contrast, Example 1, under the edge of the process conditions, is limited by the shear rate and surfactant concentration, showing a significant tendency for particle aggregation. The average particle size approaches the hundred nanometer scale, accompanied by trace phase separation. This difference in structural evolution essentially reflects the absolute dominant role of the preparation parameters in the dynamic balance of interfacial tension during the phase transformation process.

[0049] Looking at the performance of the slow-release urea surface polymer coating system in Table 1, the data objectively reveal the mechanical laws governing the response of the graft copolymer network to environmental water molecules. In Example 2, the gel swelling ratio increased to 28.6 g / g, demonstrating that a suitable monomer concentration allowed the hydrophilic segments of polyacrylamide to fully expand, constructing a robust three-dimensional hydrogel matrix. Once this physical form comes into contact with the soil water environment, it rapidly transforms into a gel state, firmly anchoring itself to the plant rhizosphere to resist erosion. Simultaneously, the porosity of the three-dimensional hydrogel matrix directly controls the permeation flux of internal active substances. Although Example 3 used an excessive amount of crosslinking agent to construct a thick coating layer, the overly dense polymer network limited the expansion space for hydration and inhibited the rate of enzyme release, leading to a decline in overall response performance. Biochemical monitoring data further validated the feasibility of transforming this physical barrier into agronomic effects.

[0050] According to Table 1 and Figure 1 It is known that during the critical hydrolysis peak periods on the 3rd and 7th days after fertilization, the soil urease activity in Example 2 was forcibly suppressed to extremely low levels of 0.15 and 0.22, pushing the entire urea degradation half-life to more than 18 days. Since conventional naked urea often explosively transforms into ammonia nitrogen and escapes with surface runoff within three to five days after entering red soil, this scheme precisely encapsulates micron-sized n-butylthiophosphoric triamine in a gel network to achieve slow leakage and continuously seize the active center of surrounding urease molecules. The superposition of this physical barrier delay mechanism and chemical targeted enzyme inhibition effect successfully shifts the peak of the fertilizer release curve backward, thus completely coinciding with the real nitrogen requirement rhythm of long-term pasture growth.

[0051] Test Example 2: Fresh shoots and stem segments of hybrid Napier grass with uniform growth were cut and fixed flat on a glass slide using double-sided tape. Under standard laboratory conditions at 25°C, pure sodium hypochlorite solution and the composite disinfectant solution prepared in Example 2 were respectively drawn up using a microsyringe of a contact angle measuring instrument. Two microliters of test solution were dropped onto the cuticle surface of the stem segment. The high-speed camera module of the instrument was activated to record dynamic spreading images of the droplets at 0, 5, 15, and 30 seconds after they contacted the surface. The static contact angle at different time points was calculated based on the Young-Laplace equation. Simultaneously, the initial liquid-gas interfacial tension of the two test solutions was measured on a surface tension meter using the pendant drop method.

[0052] Waste liquid from different stages of simulated tissue culture disinfection was collected. The collected liquid after being soaked and shaken with sodium hypochlorite and then rinsed with sterile water for the first time was measured separately, as well as the residual reaction mixture after being soaked in ascorbic acid solution of the required concentration in Example 2 for 1.5 minutes. 100 mL of the above water sample was transferred into an iodine flask, and 2 g of solid potassium iodide and 2 mL of glacial acetic acid were added in sequence. The flask was sealed with water and placed in the dark for 5 minutes to react. Then, it was titrated with 0.01 mol / L sodium thiosulfate standard titration solution. When the solution turned light yellow, starch indicator was added and titration continued until the blue color just disappeared. The volume consumed was recorded, and the residual effective chlorine concentration in the water sample was calculated accordingly.

[0053] Table 2: Dynamic wetting parameters and available chlorine residue test data for different disinfection systems

[0054] According to Table 2 and Figure 2 It is known that the surface tension of pure sodium hypochlorite solution is 72.1 mN / m. This data is basically equivalent to pure water in terms of physical properties. This interfacial tension characteristic is reflected in the wetting behavior of the material surface. It is shown that the contact angle of the droplet is still maintained at 86.1° after 30 seconds of contact with the plant cuticle. The slight attenuation indicates that the water droplet maintains the spherical cap shape of force balance. A common problem encountered in routine tissue culture sterilization operations is that the plant epidermis is often accompanied by hydrophobic micro-textures. The high-tension reagent liquid surface is physically blocked outside the fine pores, and parasitic fungi in the crevices or wrapped in wax have difficulty contacting the agent. The addition of Tween 20 to the composite disinfectant breaks the original interfacial stress state. In Example 2, the surface tension of the composite disinfectant is reduced to 31.8 mN / m. The contact angle of the droplet on the surface of the plant cuticle drops to 65.2° immediately, and then spreads and collapses to 15.4° within half a minute. The reconstruction of surface activity removes the physical resistance to liquid phase penetration, and hypochlorite ions can quickly invade the micro-gaps of the plant tissue surface with the carrier to carry out targeted lysis.

[0055] The deeper the drug penetrates, the higher the risk of cellular oxidative stress caused by subsequent detoxification. How to ensure complete removal after such high-penetration disinfection becomes a key variable determining the survival rate of tissue culture. Conventional sterile water dilution and rinsing, with a residual effective chlorine level of 154.3 mg / L in the waste liquid, exposes physical washing as extremely inefficient at removing adsorbed ions from tissue pores. In Example 2, after the ascorbic acid soaking process, the active electrons in its enediol structure undergo a transient directional transfer to hypochlorite ions. The redox reaction directly lowers the residual effective chlorine in the rinsing system to a nearly undetectable level of 1.8 mg / L. This chemically-based forced neutralization mechanism blocks the continuous damage of reactive oxygen species to plant protoplasts, mitigating the oxidative stress deficiency arising from the replacement of highly toxic drugs at the microscopic level.

[0056] Test Example 3: One week before the start of winter, storage cellars were excavated in a flat and well-drained outdoor site according to the cellar size parameters set in Examples 1 to 3 and Comparative Examples 1 and 2. Perforated PVC pipe networks were laid at the bottom of each cellar according to the spacing requirements in the examples. Three sets of K-type thermocouple temperature sensor probes were pre-embedded in the three-dimensional geometric center area and 0.5 meters around the perimeter of each test cellar. They were then connected to an externally arranged multi-channel data acquisition instrument. Subsequently, hybrid Napier grass seed stems, whether treated or untreated, were tightly arranged into the cellar to complete the straw covering and soil sealing operation.

[0057] The entire overwintering storage period lasts for 95 days from the date of sealing the cellar. During this period, the multi-channel data acquisition instrument continuously records the temperature fluctuation characteristics inside the cellar at a sampling frequency of once every 2 hours. Data collection ends after the beginning of spring in the following year. The maximum extreme temperature recorded by each group of sensors is extracted from the massive historical data to quantitatively assess the risk of thermal runaway inside the storage bed.

[0058] Around the time of the Awakening of Insects solar term, a unified inspection was conducted by opening the seed pits. After removing the soil and straw layer with a shovel, 500 seed stem sections were randomly selected from the middle and bottom layers of each pit. Using a handheld magnifying glass, the seed stems were examined one by one to see if there were obvious fungal hyphae or mold spots on the surface and cut surfaces. The mold rate of the surface was recorded and calculated in detail. After removing severely rotten samples, 300 seed stem sections with intact appearance were randomly selected from each group and laid flat in a standard river sand seedbed with a moisture content adjusted to 65%. The seed stems were placed in a greenhouse at 28℃ with a light cycle of 12h / 12h for unified germination. After 20 days, the number of seed stems that had sprouted and grown more than two healthy green leaves was counted, and the final germination survival rate was calculated.

[0059] Table 3: Data on Heat Control Monitoring and Live Seed Quality Assessment During Winter Storage of Seed Stems

[0060] According to Table 3 and Figure 3 and Figure 4 It can be seen that, due to the removal of the physical ventilation network at the bottom, Comparative Examples 1 and 2 experienced severe uncontrolled temperature rise in the core area of ​​the cellar during the overwintering period, with the extreme peak exceeding 40°C. The large-scale solid biomass did not cease its life activities in the closed accumulation state. The basic respiration metabolism of living cells continued to release latent heat and moisture. When this part of energy lacked an effective channeling path in the porous media bed, it induced a vicious positive feedback accumulation of temperature and humidity. This stuffy microenvironment directly broke the ecological balance in the cellar, triggering the germination and infection of a large number of spores of saprophytic fungi attached to the epidermis of the seed stems. Ultimately, the epidermal mold rate of the comparative examples soared to over 63%. Excessive consumption of internal nutrients and damage by pathogens caused the germination and survival rate to drop to less than 25%, basically losing its agronomical value for field planting. The passive heat and mass exchange channels constructed in Examples 1 to 3 fundamentally break this chain of deterioration. With the help of the pre-embedded perforated PVC pipe system, a stable convection circulation is formed between the cold and dry air on the ground and the hot and humid exhaust gas in the cellar due to the natural density difference. The residual heat from deep breathing is steadily carried out by the pure physical chimney effect, so that the highest temperature in the cellar is firmly controlled in the dormant safe range below 22.4℃.

[0061] Simple physical cooling is insufficient to completely eliminate the risk of mold growth caused by localized condensation. Therefore, surface spraying with an antibacterial solution provides a double layer of chemical protection. Calcium propionate in the antibacterial solution dissociates into highly lipid-soluble free propionic acid molecules at the cut surface and epidermal microenvironment of the seed stem. These molecules can penetrate the thick cell wall barrier of common contaminants such as Alternaria alternata, directly inhibiting the activity of intracellular pyruvate dehydrogenase and precisely disrupting the energy metabolism pathway of pathogens. Even under long-term cold and damp soil burial conditions, Example 2 still suppressed the risk of mold growth to an extremely low level of 3.2%, thereby preserving over 93% of the highly active seed source. This synergistic strategy of thermal control and anti-corrosion without additional energy consumption provides a solid material foundation for subsequent high-density large-scale planting in barren red soil areas.

[0062] Test Example 4: The paclobutrazol microemulsion and composite disinfection system prepared in Examples 1 to 3 were used to simultaneously prepare the tissue culture-related reagents and culture media required for Comparative Examples 1, 3, and 4. The top shoots and stem segments of high-quality hybrid Napier grass that germinated after overwintering in the same batch were cut as uniform explants. The surface disinfectant was shaken and the subsequent reduction, neutralization, and rinsing steps were completed according to the set procedures for each group. The treated explants were inoculated into their respective induction media and placed in a light incubator with a temperature set at 25°C and a light intensity of 2000 lx for constant temperature culture. On the 15th day after inoculation, the 200 explants in each group were destructively counted. The number of bottles contaminated with visible fungal or bacterial colonies was recorded. The number of virus-free seedlings that showed a translucent water-soaked appearance or browning necrosis due to oxidative stress was identified under a stereomicroscope. The contamination rate and the vitrification / browning rate of the tissue were calculated.

[0063] After the successfully detoxified and induced clustered shoots stabilized, they were separated into individual shoots in a sterile operating table. The individual shoots were then transferred to rooting media containing different forms of paclobutrazol for continuous light culture. After a 30-day rooting induction period, 50 well-growing test-tube seedlings were randomly selected from each test group. The agar substrate adhering to the roots was carefully cleaned using a dissecting needle and deionized water. The cleaned roots were laid flat on an observation plate with graduated lines. The number of independent primary roots and longer secondary roots emerging from the base of each tissue culture seedling was counted, and the average number of roots per plant was calculated. The data of each plant were collected, and the ratio of the standard deviation to the mean was calculated to obtain the coefficient of variation (CV) of the number of roots in the same test group.

[0064] Table 4: Data on the quality of tissue culture virus-free propagation and uniformity of rooting development

[0065] According to Table 4 and Figure 5It is known that latent contamination and pesticide damage faced during the plant tissue culture stage are often bottlenecks that limit the scale of propagation. Observation of the data of Comparative Example 3 shows that in the absence of the surfactant Tween 20, relying solely on conventional sodium hypochlorite soaking, the contamination rate of miscellaneous bacteria remains at a high level of 17.8%. The cuticle layer naturally attached to the explant naturally repels water-based disinfectant from entering the stomatal gaps, and external washing is difficult to reach the deep-seated pathogens. The system of the example instantly tears this physical barrier by means of interface wetting and reconstruction, allowing effective chloride ions to directly reach the target area to complete the lysis. This deep disinfection leads to the problem of oxidative stress byproducts that cannot be ignored. The strong oxidants that remain deep cannot be completely removed by rinsing with sterile water as in Comparative Example 1 or Comparative Example 3 alone. Hypochlorite ions continuously deprive the cell membrane system of electrons, resulting in increased vitrification and browning rates in the tissues of the comparative examples, with Comparative Example 3 exceeding 20%. However, after introducing ascorbic acid for elution and neutralization, the redox reaction that is completed instantly intercepts the electron demand of the residual oxidants, and the protoplasts are spared from deep damage. Example 2 reduced this kind of irreversible physiological damage to a safe level of 2.3%.

[0066] After solving the survival problem, the seedlings enter the rooting stage. The microscopic distribution of the regulator in the substrate determines the final growth of the seedlings. In Comparative Example 4, conventional suspension paclobutrazol was directly mixed into the culture medium. Large-sized insoluble active ingredient particles randomly aggregated and settled during the solidification of agar, and the effective concentration that the test-tube seedling roots came into contact with exhibited extreme spatial heterogeneity. The results showed that, in comparison, the average number of roots per plant in the tissue culture seedlings of Example 4 was only 9. More seriously, the coefficient of variation (CV) of the population increased dramatically to 28.9%. Seedlings in the same culture bottle even showed root entanglement or differentiation with no roots at all. The example utilized a high-shear phase transition mechanism to construct a thermodynamically stable nanoscale oil-in-water micelle system. The drug was tightly sealed in micro-regions of tens of nanometers and uniformly dispersed in the three-dimensional network of the culture medium, increasing the actual specific surface area of ​​the active ingredients in the drug in contact with plant cell membrane receptors. This homogeneous penetration at the molecular level prompted the seedlings in Example 2 to grow an average of 14.6 healthy primary roots. Moreover, the individual differences within the batch were converged and controlled within a low CV value range of 8.4%. The homogeneous and uniform root system enabled large-scale uniform planting under harsh environments such as nutrient deficiency, eliminating interference from inherently weak individuals.

[0067] Test Example 5: Typical red soil dryland with a slope of about 15 degrees was selected as the field test area. Each test plot was divided into independent test plots with an area of ​​50 square meters. Hybrid Napier grass tissue culture seedlings cultivated in Examples 1 to 3, Comparative Examples 1 and 5 were planted in the field area according to the designed row and plant spacing. After the hybrid Napier grass grass layer grew to a height of 10 to 15 cm, anti-loss slow-release urea prepared in Examples 1 to 3 and ordinary large-particle naked urea with the same total nitrogen content set in Comparative Examples 1 and 5 were applied to each test plot respectively.

[0068] Five days after fertilization, a short-term heavy rainfall scenario was simulated in the experimental area. A micro-sprinkler irrigation system was used to continuously supply water to each plot until stable surface runoff was generated. 500 mL of the first wave of surface runoff liquid was extracted from the runoff collection trough at the bottom of the plot. The water sample was tested using a portable multi-parameter water quality analyzer and a laboratory ultraviolet spectrophotometer. The peak loss concentrations of total nitrogen and ammonia nitrogen were read and recorded to assess the risk of non-point source pollution spillover in the early stage of fertilization.

[0069] After 30 days of natural growth and climatic influence, soil samples were collected from the rhizosphere of hybrid Napier grass at a depth of 10 to 15 cm using a five-point sampling method. The soil samples were air-dried, ground, and sieved. They were then extracted with a 2 mol / L potassium chloride solution, and the absolute residual amount of available nitrogen in the soil was determined using a flow injection analyzer.

[0070] When the forage is ready for fresh feeding at a suitable cutting height of 150 to 180 cm, three standard quadrats of 2 square meters are randomly selected in each field test plot. The above-ground parts are cut with a uniform stubble of 8 to 15 cm. The total fresh weight of the quadrats is accurately weighed and recorded, and the comprehensive fresh weight yield of forage per acre is calculated based on this.

[0071] Table 5: Data on runoff nutrient loss and comprehensive field crop promotion performance in red soil areas

[0072] According to Table 5 and Figure 7 and Figure 8 It is known that seasonal heavy rainfall in red soil areas poses a severe challenge to conventional agricultural fertilizer systems. Previous surveys have often found that once heavy rainfall occurs after fertilization, the water around the farmland will become eutrophic. The common large-particle naked urea applied in a 5-fold ratio directly exposed this defect in simulated rainfall runoff, with its total nitrogen loss peaking at 51.2 mg / L. This large-scale spillover is mainly attributed to the extremely high water solubility of naked urea, which causes it to physically dissolve and disintegrate the moment it comes into contact with surface runoff. The dissolved nitrogen, lacking spatial anchoring, drifts away from the interception range of the hybrid Napier grass root system. After the polymer coating system of the present invention intervenes, it cuts off the above-mentioned loss path. The polymer membrane containing the polyacrylamide network does not dissolve in the flood irrigation water, but quickly absorbs water and transforms into a highly viscous gel with high mechanical strength. This expanded three-dimensional hydrogel network not only blocks the high-speed leakage channel of internal urea, but also tightly anchors itself to the rough red soil particle gaps and weed root surface with the strong interfacial adhesion of the gel matrix, rigidly resisting the scouring and stripping of surface water dynamics. In Example 2, the peak values ​​of total nitrogen loss and ammonia nitrogen loss in runoff were strongly clamped to the low levels of 7.6 mg / L and 2.1 mg / L, respectively.

[0073] Retaining base fertilizer only establishes the basic environment; whether the release rhythm of nutrients in the later stages matches the physiological accumulation curve of the forage grass is the core factor determining the final biomass. By comparing the physicochemical state of the rhizosphere soil 30 days after fertilization, it can be seen that the available nitrogen residue in Example 2 remains at an abundant level of 62.8 mg / kg. The n-butylthiophosphoric triamine encapsulated in the micro-regions inside the gel continues to seep outward with slight water replacement, inhibiting the catalytic activity of free urease in the soil throughout the entire growth cycle, forcibly flattening the nitrogen supply life cycle. Combined with the homogeneous and robust seedlings induced by mild detoxification and microemulsification in the early stage, the hybrid Napier grass receives continuous and uninterrupted nutritional support throughout the vigorous growth period, promoting the accelerated conversion of photosynthetic products into leaf mesophyll and stem structure, ultimately resulting in a fresh grass yield of over 4800 kg per acre in Example 2. Compared with the control example 1, which suffered oxidative damage to plant tissues in the early stage and nutrient gap in the field in the later stage, the yield of hybrid Napier grass per mu shrank to less than half of that in Example 2. This obvious yield gap confirms that the closed-loop technology of this scheme, from tissue culture to detoxification and propagation to long-term nutrient control in the field, has extremely high feasibility for in-situ improvement of red soil barren areas.

[0074] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for high-yield cultivation of forage grass in barren red soil, characterized in that, The method includes the following steps: Paclobutrazol technical, cyclohexanone and composite emulsifier are mixed to form an oil phase, propylene glycol is dissolved in deionized water to form an aqueous phase, and phase transition occurs through shear emulsification to obtain paclobutrazol microemulsion; A prepolymer was obtained by graft copolymerization of corn starch, acrylamide monomer, N,N'-methylenebisacrylamide, potassium persulfate and deionized water. After cooling, n-butylthiophosphoric triamine was added and mixed evenly to prepare a composite coating liquid. The composite coating liquid was sprayed onto the surface of large urea particles in a fluidized bed and dried and cured to obtain anti-loss slow-release urea. Ventilation pipes were laid at the bottom of the storage cellar. The hybrid Napier grass seed stems were cut and treated with antibacterial spray before being placed into the cellar for storage. Tender shoots were cut, disinfected, and then inoculated sequentially into an induction medium and a rooting medium containing the paclobutrazol microemulsion to obtain tissue culture seedlings. The tissue culture seedlings were planted in red soil that had been tilled and treated with basal fertilizer. The grass growth height was dynamically monitored. When the grass reached a preset height threshold, the anti-loss slow-release urea was applied to match the fertilizer requirements of the forage and maximize the anti-loss performance of the coating fertilizer.

2. The method for high-yield cultivation of forage grass in barren red soil according to claim 1, characterized in that, The paclobutrazol microemulsion is made from the following raw materials in parts by weight: Paclobutrazol technical grade: 10.0 to 15.0 wt%; Cyclohexanone: 15.0 to 20.0 wt%; Composite emulsifier: 10.0 to 15.0 wt%, wherein the composite emulsifier is composed of polyoxyethylene castor oil ether EL-40 and calcium alkylbenzene sulfonate in a mass ratio of 2:1; Propylene glycol: 3.0 to 5.0 wt%; Deionized water: 45.0 to 62.0 wt%.

3. The method for high-yield cultivation of forage grass in barren red soil according to claim 1, characterized in that, The steps for obtaining the paclobutrazol microemulsion include: The paclobutrazol technical material was completely dissolved in cyclohexanone at 40 to 50°C to form a homogeneous oil phase. A composite emulsifier was added and the mixture was stirred at 500 to 800 rpm for 20 to 30 minutes while maintaining a constant temperature. Propylene glycol is dissolved in deionized water to form an aqueous phase; Under the action of a shear emulsifier at 2000 to 3000 rpm, the aqueous phase is slowly added to the oil phase at a dropping rate of 10 to 15 mL / min. After the phase transition occurs and blue fluorescence is observed, shearing is continued for 10 to 15 min, and the mixture is cooled to room temperature to obtain paclobutrazol microemulsion.

4. The method for high-yield cultivation of forage grass in barren red soil according to claim 1, characterized in that, The raw materials for preparing the composite coating solution comprise the following components in parts by weight: Corn starch: 10.0 to 15.0 parts; Acrylamide monomer: 30.0 to 40.0 parts; N,N'-Methylenebisacrylamide: 0.05 to 0.1 parts; Potassium persulfate: 0.1 to 0.2 parts; n-Butylthiophosphoric triamine: 0.5 to 1.0 parts; Deionized water: 150.0 to 200.0 parts.

5. The method for high-yield cultivation of forage grass in barren red soil according to claim 1, characterized in that, The steps for obtaining anti-loss sustained-release urea include: Corn starch was dispersed in deionized water and gelatinized at 80 to 85°C for 30 to 45 minutes. Nitrogen gas was purged to remove oxygen and the temperature was lowered to 60 to 65°C. Acrylamide monomer, N,N'-methylenebisacrylamide and potassium persulfate were added sequentially. The graft copolymerization reaction was initiated at a constant temperature for 2.0 to 3.0 hours to obtain the prepolymer. After cooling to 25°C, add micron-sized n-butylthiophosphoric triamine powder and stir at 300 to 400 rpm to obtain a composite coating solution. A bottom-spray fluidized bed was used to spray the composite coating liquid onto the surface of large urea particles in a fluidized state. The inlet air temperature was controlled at 50 to 60°C and the spraying rate was 15 to 25 mL / min. After drying and curing, anti-loss slow-release urea with a coating rate of 5.0% to 8.0% by mass was obtained.

6. The method for high-yield cultivation of forage grass in barren red soil according to claim 1, characterized in that, The step of placing the hybrid Napier grass seed stems into a cellar for storage includes: Multiple rigid PVC pipes with a diameter of 50 to 80 mm and a spacing of 80 to 100 cm are laid horizontally along the long axis at the bottom of the storage cellar. Ventilation holes with a diameter of 5 to 10 mm are drilled on the surface of the pipes, and both ends of the pipes are 30 to 40 cm above the ground. The cut seed tubers were treated with a micro-moistening spray containing an antibacterial solution of 0.3 to 0.8 wt% calcium propionate and 1.0 to 2.0 wt% sorbitol. The treated seed stalks are tightly packed into the pit, with a thickness of 50 to 70 cm, covered with a 2 to 3 cm layer of straw, and then covered with 5 to 10 cm of soil.

7. The method for high-yield cultivation of forage grass in barren red soil according to claim 1, characterized in that, The step of sterilizing the cut tender shoots includes: Immerse in 75 vol% ethanol for 1.0 to 2.0 min, rinse with sterile water, and then transfer to a compound disinfectant solution containing 1.5 to 2.5 wt% sodium hypochlorite and 0.05 to 0.15 wt% Tween 20. Shake at 100 to 150 rpm for 10 to 12 min. After removal, immerse in 0.08 to 0.12 wt% ascorbic acid solution for 1.0 to 2.0 min and rinse.

8. The method for high-yield cultivation of forage grass in barren red soil according to claim 1, characterized in that, In the step of obtaining tissue culture seedlings, the culture medium formula is limited to: The induction medium formulation is: MS + 0.8 to 1.2 mg / L kinetin and 0.1 to 0.3 mg / L 1-naphthaleneacetic acid; The rooting medium is formulated as follows: 1 / 2 MS with 0.2 to 0.4 mg / L 1-naphthaleneacetic acid, and the paclobutrazol microemulsion is added to make the concentration of the paclobutrazol active ingredient 0.2 to 0.4 mg / L.

9. A method for high-yield cultivation of forage grass in barren red soil according to claim 1, characterized in that, The steps of tilling the red soil, applying base fertilizer, and then transplanting the tissue culture seedlings include: 15 to 20 days before sowing, plow the red soil to a depth of 30 to 40 cm, and apply 200 to 300 kg / mu of concentrated humic acid bio-organic fertilizer and 20 to 30 kg / mu of calcium magnesium phosphate fertilizer; transplant the tissue culture seedlings in furrows with a row spacing of 80 to 90 cm and a plant spacing of 50 to 60 cm.

10. A method for high-yield cultivation of forage grass in barren red soil according to claim 1, characterized in that, The steps for applying the aforementioned anti-loss slow-release urea include: When the grass layer reaches a height of 10 to 15 cm, apply 4.0 to 6.0 kg / mu of the anti-loss slow-release urea.

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