Spring corn high yield method

Abstract

The application relates to the field of agricultural planting technology and discloses a high-yield method for spring corn close planting, which comprises the following steps: adopting film mulching drip irrigation seeding and performing normal water and fertilizer management; in the jointing stage, a nutrient solution containing self-extrusion slow-release microspheres, zinc sodium ethylenediaminetetraacetate and compound amino acids is pressed into a root area with tail water, water supply is stopped to maintain moderate water deficit, a first regulation liquid containing amine fresh ester and ethylene is sprayed on a leaf surface; in the big trumpet stage, water supply is restored and a second regulation liquid containing a compound light shield film agent is sprayed; before male flowering, soil matric potential is monitored, when reaching a drought threshold, a third regulation liquid containing 14-hydroxy brassinosteroid and fluid boron is sprayed; and in the early filling stage, a fourth regulation liquid containing the compound light shield film agent is sprayed. By introducing self-adaptive release microspheres and a film agent for improving light transmittance, combining water management and chemical regulation, the anti-lodging capacity of the close planting population is improved, the bare tip rate caused by water shortage is reduced, leaf early senescence is slowed down, and the dry matter fullness of grains is ensured.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, specifically a method for high-yield dense planting of spring maize. Background Technology

[0002] As a major grain crop in my country, the steady increase in spring maize yield is of great significance to ensuring agricultural security. With limited arable land resources, increasing planting density has become a core cultivation approach to break through the yield ceiling per unit area. As plant density continues to increase, the light, heat, water, and fertilizer resources allocated to each individual maize plant are squeezed. This high-density environment easily triggers intense competition for light within the plant population, thereby disrupting the plant's original water and carbon metabolic balance. This places higher agronomical demands on the entire lifecycle management of maize, from vegetative growth to reproductive development.

[0003] For field management in densely planted corn cultivation, current agricultural production mostly adopts traditional techniques combining conventional chemical growth regulators with regular water and fertilizer replenishment. During the vegetative growth stage, plant growth regulators are typically applied foliar to forcibly inhibit the longitudinal elongation of corn stalks. After entering the reproductive development and grain-filling stages, regular topdressing and mulching irrigation are mainly carried out according to a pre-set agricultural calendar. In some production areas, to prevent nutrient deficiency later on, a large amount of base fertilizer is applied once in the early stage, or the frequency of field irrigation is passively increased after visible drought symptoms occur, in order to maintain the basic developmental needs of the plants.

[0004] Existing traditional management methods, relying solely on foliar chemical growth control, can only temporarily suppress above-ground growth. After the effects of the chemicals wear off, plants often experience a secondary rebound in vertical growth. Because they fail to guide nutrients to the soil, the shallow root system cannot provide sufficient mechanical anchoring force. Densely planted maize plants still face a high risk of lodging during windy and rainy weather. Regular watering cannot accurately match the physiological critical point of water stress in plants. During the tasseling and pollination stage, high temperatures and drought cause extensive stomata closure, leading to rapid dehydration of floral organs and obstruction of fertilization channels, directly causing severe ear tip barrenness. Furthermore, in densely planted maize, the lower leaves remain in a closed state for extended periods. With the gradual depletion of available soil nutrients, carbon assimilation enzymes within the leaves degrade rapidly, making the photosynthetic function of the entire plant population highly susceptible to irreversible premature aging. Premature leaf aging cuts off the source of assimilated products transported to the grains, and insufficient dry matter accumulation ultimately limits overall yield. Therefore, this invention provides a high-yield method for densely planted spring maize to address the shortcomings of existing technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-yield method for dense planting of spring maize. This method solves the problems of excessive vertical growth and a high center of gravity in densely planted spring maize plants due to the high density of the canopy, which leads to light starvation in the middle and lower leaves and heat shock to the top leaves, increasing the risk of lodging later on. In addition, when encountering drought, conventional free trace elements are easily physically fixed by the soil, making them unabsorbable by the roots. Furthermore, dehydration of the floral organs during the tasseling and pollen shedding period leads to barren ears.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for high-yield dense planting of spring maize, comprising the following steps: S1. Spring corn is sown using drip irrigation under mulch film, and conventional water and fertilizer management is carried out from emergence to jointing. S2, during the jointing stage, before the end of the last drip irrigation, a nutrient solution containing self-extruding slow-release microspheres sensitive to water tension, sodium zinc ethylenediaminetetraacetate, and a mixture of compound amino acids is injected into the 0-40cm root zone with the tail water; then the water is stopped to maintain a moderate water deficit in the soil layer, and after the water is stopped, the aboveground parts are sprayed with a first regulating solution containing potassium dihydrogen phosphate, amino acid ester, and ethephon. S3. Restore water supply and spray the leaves with a second regulating solution containing compound light shield film agent, potassium dihydrogen phosphate, compound amino acid mixture and 14-hydroxybrassinosteroid during the large trumpet stage. S4. Before male emergence, monitor the soil matrix potential and spray a third regulating solution containing potassium dihydrogen phosphate, 14-hydroxybrassinosteroidol and fluid boron when the drought threshold is reached. S5. In the initial stage of grouting, spray the fourth regulating solution containing composite light shield film agent, potassium dihydrogen phosphate, 14-hydroxybrassinosteroidol and sodium zinc ethylenediaminetetraacetate.

[0007] By employing the above technical solution, this invention deeply integrates the spatially decoupled application of intelligent response materials and chemical signaling substances with physical environmental management, reshaping the morphological structure and physiological metabolic direction of plants at different growth stages. Its specific reaction mechanism is manifested as follows: During the jointing stage, corn enters a period of vigorous vegetative growth. Ethephon, applied via foliar spraying, degrades in the cytoplasm, releasing ethylene molecules. This forces the microfibrils within the meristematic cell walls to shift from longitudinal to transverse deposition, inhibiting longitudinal elongation of the above-ground internodes and promoting stem thickening. Simultaneously, self-pressurized slow-release microspheres applied via tailwater drainage penetrate deep into the soil. During subsequent water cutoff, the decreased surface soil matrix potential triggers dehydration and shrinkage of the polymer chains within the microspheres. The microspheres utilize the significant internal stress from this physical deformation to forcefully pump available zinc, silicon, and other elements from the core layer into the rhizosphere microzone, completely overcoming the limitations of ion solidification under drought conditions. These targeted-release elements act as cofactors, activating tryptophan synthase and promoting the synthesis of large amounts of indoleacetic acid in the deep root tips, forcing photosynthetic products to be primarily transported to the deep root system.

[0008] As development progresses to the large trumpet stage and grain-filling stage, the canopy density of the plant reaches its peak. The foliar sprayed composite light shield film agent constructs a physical interface layer on the leaf surface that actively intervenes in the light radiation conduction path: the high reflectivity nanocrystals within the interface reflect near-infrared thermal radiation over a wide angle, stripping away the heat load of the top leaves and avoiding cellular oxidative damage caused by high-temperature heat shock; at the same time, the doped carbon quantum dots utilize the downconversion luminescence mechanism to convert high-energy short-wavelength light into red and blue wavelengths that plants can directly utilize, and combined with the scattering effect of nanoparticles, the light beam penetrates and is guided into the depths of the canopy, greatly increasing the overall photosynthetically effective radiation input near the panicle leaves, thus resolving the natural light starvation contradiction caused by dense planting from a physical and optical perspective.

[0009] After entering the tasseling stage, the soil matrix potential reaches the drought threshold as an objective trigger condition, and fluid boron and brassinolide are precisely sprayed. Fluid boron penetrates the epidermis, releasing boric acid molecules that cross-link with pectin in the pollen tube cell wall through ester bonds, maintaining the integrity of the fertilization channel structure. Combined with 14-hydroxybrassinolide sterol, it upregulates the expression of vacuolar membrane aquaporins and forms osmotic pressure regulation, forcibly maintaining the necessary water for the floral organs. Later, zinc and potassium dihydrogen phosphate are supplemented to maintain the chloroplast lamellae structure and the energy supply for photosynthetic phosphorylation, opening up the source-sink transport pathway, thereby effectively delaying premature leaf senescence and greatly reducing the rate of barren tips on the ears.

[0010] Preferably, the nutrient solution, the first regulating solution, the second regulating solution, the third regulating solution, and the fourth regulating solution are prepared from the following components in parts by mass: The nutrient solution is prepared by mixing 20-30 parts of self-extruded slow-release microspheres, 10-16 parts of sodium zinc ethylenediaminetetraacetate, 12-18 parts of a complex amino acid mixture, and 2000-3000 parts of water. The first conditioning solution is prepared by mixing 120-180 parts potassium dihydrogen phosphate, 1.5-3.5 parts aminoethyl ester, 6.0-9.0 parts ethephon and 20,000-30,000 parts water; The second regulating solution is prepared by mixing 70-90 parts of composite light shield film agent, 120-180 parts of potassium dihydrogen phosphate, 12-18 parts of composite amino acid mixture, 0.0003-0.0006 parts of 14-hydroxybrassinosteroidol and 20,000-30,000 parts of water; The third regulating solution is prepared by mixing 120-180 parts potassium dihydrogen phosphate, 0.0003-0.0006 parts 14-hydroxybrassinosteroidol, 66-137 parts fluid boron and 20,000-30,000 parts water; The fourth regulating solution is prepared by mixing 40-60 parts of composite light shield film agent, 120-180 parts of potassium dihydrogen phosphate, 0.0003-0.0006 parts of 14-hydroxybrassinosteroidol, 7-13 parts of sodium zinc ethylenediaminetetraacetate and 20,000-30,000 parts of water.

[0011] By adopting the above technical solutions, the feeding ratio of intelligent materials, chemical regulatory substances and nutrients required at each stage is limited, ensuring that the relevant components maintain appropriate concentrations and optical film thickness inside and outside the plant, and ensuring the stable operation of morphological remodeling and microclimate regulation processes.

[0012] Preferably, in step S1, the drip irrigation under the film is specifically carried out by sowing using a single-strip drip irrigation system with wide and narrow rows under the film, and the seedling density is controlled at 5800 to 6500 plants per mu; the relative soil moisture content is maintained at 70% to 80% from emergence to jointing.

[0013] Preferably, in step S2: the tailwater is injected 15-20 minutes before the end of the last drip irrigation system operation; the water is cut off to maintain the relative moisture content of the 0-40cm soil layer at 60%-65% for 7-10 days; and the first regulating solution is sprayed within 1-2 days after the water source is cut off.

[0014] Preferably, in step S4, the drought threshold is defined as soil matrix potential being monitored between -50 kPa and -45 kPa for three consecutive days. Clearly defining the physical parameter limits for water rescue during the reproductive period avoids indiscriminate pesticide application and improves the targeted nature of control measures.

[0015] Preferably, the preparation method of the self-extrusion sustained-release microspheres includes: adding sodium alginate and polyacrylic acid to deionized water and heating to dissolve them to form a base solution; adding nano-silica and sodium zinc ethylenediaminetetraacetate to the base solution and ultrasonically dispersing them to obtain a core layer suspension; dropping the core layer suspension into a crosslinking curing bath containing calcium chloride and surfactant, allowing it to stand for crosslinking, washing it, and freeze-drying it to obtain the microspheres.

[0016] By employing the above technical solution, free trace elements are encapsulated using sodium alginate with excellent hydration properties and a polyacrylic acid backbone. When the environment encounters water deficit, the water tension-sensitive properties of the polymer backbone are activated, and the strong self-compression effect generated by volume shrinkage can actively push the effective elements into the rhizosphere microzone of plants, breaking through the bottleneck of traditional fertilizers' inability to diffuse in arid soils.

[0017] Preferably, the preparation method of the composite light shield film includes: stirring carbon quantum dot solution, melatonin and deionized water to form a homogeneous solution; adding nano-titanium dioxide powder modified with silane coupling agent for high shear dispersion and emulsification; adding polyethylene glycol and stirring to remove air to obtain the final product.

[0018] By adopting the above technical solution, a heat shielding layer is constructed using the light scattering and heat reflection properties of nano-titanium dioxide. Combined with the photoluminescence properties of carbon quantum dots, efficient reconstruction of the full spectrum is achieved. Polyethylene glycol provides flexible film formation guarantee, enabling the film agent to adhere seamlessly to the leaf surface after spraying and actively regulate the physical radiation field inside the plant population.

[0019] Preferably, the composite amino acid mixture is prepared by mixing L-glutamic acid, L-proline and glycine at room temperature in a mass ratio of 1.5-2:1-1.5:1-1.5; the fluid boron is prepared by reacting xylitol or mannitol with boric acid in deionized water at a constant temperature of 80°C.

[0020] By adopting the above technical solution, a targeted anti-osmotic protective substrate was provided, and a sugar alcohol complex boron fertilizer that can penetrate the plant epidermal structure was synthesized to ensure that boron can quickly migrate to the flower organs to play a role in structural stability during drought in the reproductive period.

[0021] Preferably, in the first regulating solution, the mass ratio of ethephon to aminoethyl ester is 2.5:1 to 4:1; in S2 to S5, the regulating solution is applied to the aboveground parts of corn by uniform foliar spraying, and the total amount of solution applied per acre is controlled between 20 and 30 kg each time.

[0022] This invention provides a method for high-yield, densely planted spring maize. It has the following beneficial effects: 1. This invention combines moderate water deficit with foliar spraying of ethephon and aminoethyl esters during the jointing stage to inhibit longitudinal elongation of the above-ground internodes. Simultaneously, a nutrient solution containing self-extruding slow-release microspheres is applied with the final irrigation water. As soil moisture decreases, the self-extruding slow-release microspheres shrink due to water loss in their polymer chains, actively squeezing the available zinc within into the rhizosphere microzone. This treatment ensures root absorption of micronutrients under drought conditions, promotes deep root development, and effectively improves the lodging resistance of densely planted populations by lowering the plant's center of gravity.

[0023] 2. This invention involves spraying a composite light shield film agent during the tasseling and grain-filling stages. The nano-titanium dioxide and carbon quantum dots in the film agent reflect thermal radiation and convert the spectrum, improving light transmittance within the densely planted canopy, reducing canopy temperature, and alleviating insufficient light caused by canopy closure. Combined with pre-tasseling spraying of fluid boron and 14-hydroxybrassinosteroids triggered by soil matrix potential monitoring, this maintains the osmotic pressure of floral organs and pollen tube cell structure under water stress, ensuring normal fertilization and effectively reducing the rate of barren tips on the ears.

[0024] 3. This invention involves foliar spraying with a regulating solution containing 14-hydroxybrassinosteroids, sodium zinc EDTA, and potassium dihydrogen phosphate during the early grain-filling stage. Through the synergistic effect of nutrients and plant growth regulators, the stability of chloroplast structure in leaves is maintained during the later stages of growth. This step slows down the degradation rate of carbon assimilation enzymes, providing essential inorganic phosphorus and metabolic energy for the transmembrane transport of photosynthetic products to the grains, mitigating premature senescence of lower leaves in the plant population, and increasing the dry matter accumulation and seed setting rate of the grains. Attached Figure Description

[0025] Figure 1 This is a flowchart of the preparation method of the present invention; Figure 2 This is a schematic diagram illustrating the correlation between plant morphology and field lodging rate in this invention. Figure 3 This is a graph showing the response of ear development traits and seed setting rate in this invention. Figure 4 This is a schematic diagram of the ion release pump effect trajectory of forced dehydration at the microsphere interface of the present invention; Detailed Implementation 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.

[0026] 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.

[0027] The spring maize variety tested was Xianyu 1483.

[0028] Potassium dihydrogen phosphate has a CAS number of 7778-77-0 and a purity of ≥99%.

[0029] The chemical name of amino acid ester is diethylaminoethanol hexanoate, and its CAS number is 10369-83-2.

[0030] Ethephon's chemical name is 2-chloroethylphosphonic acid, and its CAS number is 16672-87-0.

[0031] The CAS number for 14-hydroxybrassinosteroid is 457603-63-3.

[0032] The CAS number for sodium zinc ethylenediaminetetraacetate is 14025-21-9.

[0033] The CAS number for boric acid is 10043-35-3; the CAS number for xylitol is 87-99-0; the CAS number for mannitol is 69-65-8; the CAS number for L-glutamic acid is 56-86-0; the CAS number for L-proline is 147-85-3; the CAS number for glycine is 56-40-6; the CAS number for melatonin (N-acetyl-5-methoxytryptamine) is 73-31-4; both nano-titanium dioxide and nano-silica are commercially available industrial-grade nanopowders; and carbon quantum dots are commercially available water-soluble carbon nanomaterials.

[0034] Preparation Example 1: This preparation example provides a method for preparing a complex amino acid mixture, comprising the following steps: Add 30 parts by weight of L-glutamic acid, 20 parts by weight of L-proline and 20 parts by weight of glycine to a powder mixer and mix continuously at a stirring speed of 200 rpm for 30 minutes at room temperature. The resulting product is a uniform powdered compound amino acid mixture.

[0035] Preparation Example 2: This preparation example provides a method for preparing a complex amino acid mixture, comprising the following steps: 35 parts by weight of L-glutamic acid, 25 parts by weight of L-proline and 25 parts by weight of glycine were added to a powder mixer and mixed continuously at a stirring speed of 200 rpm for 30 minutes at room temperature. The resulting product was a uniform powdered compound amino acid mixture.

[0036] Preparation Example 3: This preparation example provides a method for preparing a complex amino acid mixture, comprising the following steps: 40 parts by weight of L-glutamic acid, 30 parts by weight of L-proline and 30 parts by weight of glycine were added to a powder mixer and mixed continuously at a stirring speed of 200 rpm for 30 minutes at room temperature. The resulting product was a uniform powdered compound amino acid mixture.

[0037] Preparation Example 4: This preparation example provides a method for preparing fluid boron, including the following steps: 152 parts by mass of xylitol were added to a reactor containing 500 parts by mass of deionized water. Stirring was started and the stirring speed was set to 150 rpm. The temperature was raised to 60 degrees Celsius to completely dissolve the xylitol and make it clear. Then, 62 parts by mass of boric acid were added while stirring, and the temperature inside the reactor was raised to 80 degrees Celsius. The reaction was carried out at this temperature with stirring for 2 hours. After the liquid in the reactor became transparent and there were no solid particles, the heating was stopped and the mixture was allowed to cool naturally to room temperature to obtain fluid boron.

[0038] Preparation Example 5: This preparation example provides a method for preparing fluid boron, including the following steps: 182 parts by mass of mannitol were added to a reactor containing 500 parts by mass of deionized water. Stirring was started and the stirring speed was set to 150 rpm. The temperature was raised to 60 degrees Celsius to completely dissolve the mannitol and make it clear. Then, 62 parts by mass of boric acid were added while stirring, and the temperature inside the reactor was raised to 80 degrees Celsius. The reaction was carried out at this temperature with stirring for 2 hours. After the liquid in the reactor became transparent and there were no solid particles, the heating was stopped and the mixture was allowed to cool naturally to room temperature to obtain fluid boron.

[0039] Preparation Example 6: This preparation example provides a method for preparing self-extruded sustained-release microspheres, including the following steps: Heat 50 parts by weight of deionized water to 60 degrees Celsius, add 4 parts by weight of sodium alginate and 2 parts by weight of polyacrylic acid, and stir continuously until completely dissolved to form a viscous base liquid. 1.5 parts by mass of nano-silica and 3 parts by mass of sodium zinc ethylenediaminetetraacetate were ultrasonically dispersed in the base solution and stirred evenly to obtain a core layer suspension. The above core layer suspension was dripped into a crosslinking curing bath containing 5% calcium chloride and 0.5% surfactant Tween-20 in the form of droplets using a micro-injection pump, and allowed to stand at room temperature for 30 minutes for crosslinking. The generated microspheres were filtered out, washed three times with deionized water, and dried in a freeze dryer for 24 hours to obtain self-extrusion sustained-release microspheres with water tension sensitivity.

[0040] Preparation Example 7: This preparation example provides a method for preparing a composite light shield film agent, including the following steps: 100 parts by mass of deionized water, 0.5 parts by mass of carbon quantum dot solution and 1.2 parts by mass of melatonin were added to the reaction vessel and stirred at 40 degrees Celsius for 30 minutes to form a homogeneous solution; Add 2.5 parts by weight of nano-titanium dioxide powder modified with silane coupling agent, and disperse it for 45 minutes at a speed of 5000 rpm using a high shear dispersing emulsifier; Add 0.8 parts by weight of polyethylene glycol as a flexible film-forming aid, stir for 20 minutes to degas, and obtain a stable carbon quantum dot-nano titanium dioxide-melatonin composite light shield film.

[0041] See attached document Figure 1 Example 1: This embodiment provides a method for high-yield, densely planted spring maize, including the following steps: S1. Select the Xianyu 1483 spring maize variety. Sow in the field using a single-strip drip irrigation system with wide and narrow rows under plastic film, with a seedling density of 6150 plants per mu. Apply conventional base fertilizer and maintain the relative soil moisture content at 75% from emergence to jointing.

[0042] S2. One day before the planned water deficit is implemented, the last drip irrigation operation of the jointing stage is carried out on the day the corn enters the jointing stage. Within 15 minutes before the drip irrigation system ends, a micro-pulse nutrient solution is injected into the root zone depth of 0-40 cm using a fertigation system. This micro-pulse nutrient solution is prepared by uniformly mixing 25 parts by weight of the self-extruded slow-release microspheres obtained in Preparation Example 6, 13 parts by weight of sodium zinc ethylenediaminetetraacetate, 15 parts by weight of the composite amino acid mixture obtained in Preparation Example 2, and 2500 parts by weight of water. After the operation, the drip irrigation water source is cut off, maintaining a moderate water deficit of 62% relative moisture content in the 0-40 cm soil layer for 8 days. On the second day after the water source is cut off, the first regulating solution is uniformly sprayed onto the aboveground parts of the corn. This first regulating solution is prepared by uniformly mixing 150 parts by weight of potassium dihydrogen phosphate, 2.5 parts by weight of amino acid ester, 7.5 parts by weight of ethephon, and 25000 parts by weight of water.

[0043] S3. After the water deficit period ends, resume the drip irrigation program under the film. Stop ethephon input and spray the corn leaves evenly with a second regulating solution at the corn tasseling stage; wherein, the second regulating solution is prepared by uniformly mixing 80 parts by weight of the composite light shield sol obtained in Preparation Example 7, 150 parts by weight of potassium dihydrogen phosphate, 15 parts by weight of the composite amino acid mixture, 0.00045 parts by weight of 14-hydroxybrassinosteroidol and 25,000 parts by weight of water.

[0044] S4. During the phenological stage when 50% of the plants are about to produce male spikes but have not yet emerged, the soil matrix potential is continuously monitored using a soil tensiometer pre-buried in the 40cm soil layer. If the soil matrix potential is monitored to be -48kPa for 3 consecutive days, the application of the third regulating solution to the leaves is triggered. The third regulating solution is prepared by uniformly mixing 150 parts by mass of potassium dihydrogen phosphate, 0.00045 parts by mass of 14-hydroxybrassinosteroidol, 99 parts by mass of fluid boron obtained from Preparation Example 4 containing 1.5 parts by mass of pure boron, and 25,000 parts by mass of water.

[0045] S5. After the corn has finished pollinating and entered the early stage of grain filling, spray the corn leaves evenly with the fourth regulating solution; wherein the fourth regulating solution is made of 50 parts by mass of the composite light shield sol obtained in Preparation Example 7, 150 parts by mass of potassium dihydrogen phosphate, 0.00045 parts by mass of 14-hydroxybrassinosteroidol, 10 parts by mass of sodium zinc ethylenediaminetetraacetate and 25,000 parts by mass of water.

[0046] Example 2: This embodiment provides a method for high-yield, densely planted spring maize, including the following steps: S1. Select the Xianyu 1483 spring maize variety. Sow in the field using a single-strip drip irrigation system with wide and narrow rows under plastic film, with a seedling density of 5800 plants per mu. Apply conventional base fertilizer and maintain the relative soil moisture content at 70% from emergence to jointing.

[0047] S2. One day before the planned water deficit is implemented, and the corn enters the jointing stage, the final drip irrigation is performed. Fifteen minutes before the end of drip irrigation, a micro-pulse nutrient solution is injected into the 0-40cm root zone via a fertigation system. This nutrient solution is composed of 20 parts by weight of the self-extruded slow-release microspheres obtained in Example 6, 10 parts by weight of sodium zinc ethylenediaminetetraacetate, 12 parts by weight of a compound amino acid mixture, and 2000 parts by weight of water. After the operation, the water supply is cut off, maintaining a moderate water deficit of 60% relative moisture content in the 0-40cm soil layer for 7 days. On the second day after the water cut-off, the first regulating solution is sprayed: composed of 120 parts by weight of potassium dihydrogen phosphate, 2.0 parts by weight of amino acid ester, 6.0 parts by weight of ethephon, and 20000 parts by weight of water.

[0048] S3. Resume water supply after the water deficit ends. Spray the second regulating solution during the large bell mouth period: it is made from 70 parts by weight of the composite light shield sol obtained in Example 7, 120 parts by weight of potassium dihydrogen phosphate, 12 parts by weight of the composite amino acid mixture, 0.0003 parts by weight of 14-hydroxybrassinosteroidol and 20,000 parts by weight of water.

[0049] S4. When 50% of the plants are about to produce male spikes, monitor the soil matrix potential for 3 consecutive days until it is -45 kPa, and spray the third regulating solution: containing 120 parts by weight of potassium dihydrogen phosphate, 0.0003 parts by weight of 14-hydroxybrassinosteroidol, 80 parts by weight of fluid boron and 20,000 parts by weight of water.

[0050] S5. In the early stage of grouting, spray the fourth conditioning solution: it is made of 40 parts by weight of the composite light shield sol obtained in Example 7, 120 parts by weight of potassium dihydrogen phosphate, 0.0003 parts by weight of 14-hydroxybrassinosteroidol, 8 parts by weight of sodium zinc ethylenediaminetetraacetate and 20,000 parts by weight of water.

[0051] Example 3: This embodiment provides a method for high-yield, densely planted spring maize, including the following steps: S1. Select Xianyu 1483 spring maize, with a seedling density of 6300 plants per mu. Maintain the relative soil moisture content at 80% from emergence to jointing.

[0052] S2. One day before the planned water deficit at the jointing stage, administer the final drip irrigation, injecting nutrient solution 15 minutes before the end. This nutrient solution is composed of 30 parts by weight of Preparation Example 6 microspheres, 15 parts by weight of sodium zinc EDTA, 18 parts by weight of a compound amino acid mixture, and 3000 parts by weight of water. Water is withheld to maintain the relative soil moisture content at 65% for 9 days. On the second day after water withholding, spray the first regulating solution: composed of 180 parts by weight of potassium dihydrogen phosphate, 3.0 parts by weight of amino acid ester, 9.0 parts by weight of ethephon, and 30000 parts by weight of water.

[0053] S3. After water supply is restored, spray the second regulating solution during the large funnel-shaped mouth period: it is made of 90 parts by weight of the light shield sol prepared in Example 7, 180 parts by weight of potassium dihydrogen phosphate, 18 parts by weight of the complex amino acid mixture, 0.0006 parts by weight of 14-hydroxybrassinosteroidol and 30,000 parts by weight of water.

[0054] S4. During the early stage of male emergence, the soil matrix potential was monitored for three consecutive days and kept at -50 kPa. The third regulating solution was sprayed, containing 180 parts by weight of potassium dihydrogen phosphate, 0.0006 parts by weight of 14-hydroxybrassinosteroidol, 120 parts by weight of fluid boron and 30,000 parts by weight of water.

[0055] S5. In the initial stage of grouting, spray the fourth conditioning solution: it is made from 60 parts by weight of the light shield sol prepared in Example 7, 180 parts by weight of potassium dihydrogen phosphate, 0.0006 parts by weight of 14-hydroxybrassinosteroidol, 12 parts by weight of sodium zinc ethylenediaminetetraacetate and 30,000 parts by weight of water.

[0056] Example 4: This embodiment provides a method for high-yield, densely planted spring maize, including the following steps: S1. Select the Xianyu 1483 spring maize variety. Sow in the field using a single-strip drip irrigation system with wide and narrow rows under plastic film, with a seedling density of 6200 plants per mu. Apply conventional base fertilizer and maintain the relative soil moisture content at 78% from emergence to jointing.

[0057] S2. One day before the planned water deficit is implemented, the last drip irrigation operation of the jointing stage is carried out on the day the corn enters the jointing stage. Fifteen minutes before the drip irrigation system ends, a micro-pulse nutrient solution is injected into the root zone depth of 0-40 cm using a fertigation system. This micro-pulse nutrient solution is prepared by uniformly mixing 28 parts by weight of the self-extruded slow-release microspheres obtained in Preparation Example 6, 14 parts by weight of sodium zinc ethylenediaminetetraacetate, 16 parts by weight of the composite amino acid mixture obtained in Preparation Example 2, and 2800 parts by weight of water. After the operation, the drip irrigation water source is cut off, maintaining a moderate water deficit of 63% relative moisture content in the 0-40 cm soil layer for 8 days. On the second day after the water source is cut off, the first regulating solution is uniformly sprayed onto the aboveground parts of the corn. This first regulating solution is prepared by uniformly mixing 160 parts by weight of potassium dihydrogen phosphate, 2.8 parts by weight of amino acid ester, 8.0 parts by weight of ethephon, and 28000 parts by weight of water.

[0058] S3. After the water deficit period ends, resume the drip irrigation program under the film, stop the input of ethephon, and spray the corn leaves evenly with the second regulating solution at the corn tasseling stage; wherein, the second regulating solution is prepared by uniformly mixing 85 parts by mass of the composite light shield sol obtained in Preparation Example 7, 160 parts by mass of potassium dihydrogen phosphate, 16 parts by mass of the composite amino acid mixture, 0.0005 parts by mass of 14-hydroxybrassinosteroidol and 28000 parts by mass of water.

[0059] S4. During the phenological stage when 50% of the plants are about to produce male spikes but have not yet emerged, the soil matrix potential is continuously monitored using a soil tensiometer pre-buried in the 40cm soil layer. If the soil matrix potential is monitored to be -48kPa for 3 consecutive days, the application of the third regulating solution to the leaves is triggered; the third regulating solution contains 160 parts by mass of potassium dihydrogen phosphate, 0.0005 parts by mass of 14-hydroxybrassinosteroidol, 100 parts by mass of the fluid boron obtained in Preparation Example 4, and 28,000 parts by mass of water.

[0060] S5. After the corn has finished pollinating and entered the early stage of grain filling, spray the corn leaves evenly with the fourth regulating solution; wherein the fourth regulating solution is made of 55 parts by mass of the composite light shield sol obtained in Preparation Example 7, 160 parts by mass of potassium dihydrogen phosphate, 0.0005 parts by mass of 14-hydroxybrassinosteroidol, 11 parts by mass of sodium zinc ethylenediaminetetraacetate and 28,000 parts by mass of water.

[0061] Comparative Example 1: Compared with Example 1, the seedling density was the conventional 4500 plants / acre, the water deficit of S2 was not implemented throughout the entire growth period, and no regulatory liquid, self-extruded microspheres, or light shield sol were sprayed. Only conventional water and fertilizer management was performed.

[0062] Comparative Example 2: Compared with Example 1, the seedling density was increased to 6150 plants / acre, but the water deficit of S2 was not implemented throughout the entire growth period, and no regulatory liquid, self-extruded microspheres, or light shield sol were sprayed. Only conventional water and fertilizer management was performed.

[0063] Comparative Example 3: Compared with Example 1, the seedling density was 6150 plants / acre, and the water deficit of S2 was only implemented during the jointing stage, but no nutrient solution, self-extruded microspheres, light shield sol were added, and no foliar conditioning solution was sprayed.

[0064] Comparative Example 4: The difference from Example 1 is that the first conditioning solution containing aminoethyl ester and ethephon is not sprayed in step S2, but otherwise it is exactly the same.

[0065] Comparative Example 5: Compared with Example 1, the difference is that 14-hydroxybrassinosteroidol is not added to the conditioning solution in steps S3, S4 and S5, but the rest are exactly the same.

[0066] Comparative Example 6: The difference from Example 1 is that step S4 is missing; otherwise, they are exactly the same.

[0067] Comparative Example 7: Compared with Example 1, the difference is that in the root zone micropulse nutrient solution of step S2, the self-extrusion sustained-release microspheres obtained in Preparation Example 6 are not added, but equal amounts of free nano-silicon and free sodium zinc ethylenediaminetetraacetate are directly added, and the rest of the steps are exactly the same.

[0068] Comparative Example 8: Compared with Example 1, the difference is that in steps S3 and S5, the composite light shield sol obtained in Preparation Example 7 is not added to the control solution, and only a conventional mixture of potassium dihydrogen phosphate, amino acids and brassinolide is sprayed, while the rest is exactly the same.

[0069] Test Example 1: Test Description: This test case aims to explore the differences in the effects of different planting densities and control modes on the spatial structure of maize plants and the actual risk of lodging in the field. By obtaining morphological parameters, the effectiveness of the example scheme and the comparative scheme in resisting lodging damage under dense planting conditions is evaluated.

[0070] Test steps: The experimental subjects were maize plants in the milk-ripe stage in the experimental plots of Examples 1-4 and Comparative Examples 1-8.

[0071] Three measurement quadrats were randomly selected within each experimental plot to exclude plants affected by edge effects.

[0072] Plant height was measured from the base of the plant stem to the top of the tassel using standard measuring tools. At the same time, the vertical distance from the ground to the uppermost effective tassel node was measured to obtain the ear height. 52 to 55 valid samples were randomly obtained from each treatment group and the arithmetic mean was calculated.

[0073] Closely record the plant condition throughout the entire growth period until full maturity and harvest. Plants with stems tilted at an angle exceeding 45 degrees vertically or with broken stems are included in the lodging category. Finally, calculate the overall field lodging rate for each plot.

[0074] The experimental data are shown in Table 1: Table 1: Statistics on plant morphology and lodging rate in different treatment groups

[0075] See attached document Figure 2 Compared with the data in Table 1, in Comparative Example 2, under the condition of significantly increasing the number of plants per unit area without targeted intervention, the plant height and ear height showed an excessive elongation trend. The upward shift of the plant center of gravity, accompanied by the increase in the mechanical load on the stem, led to a serious degradation of the stability of the field population structure, and its actual lodging rate has exceeded the warning level of conventional agricultural production.

[0076] Comparative Example 4 failed to block the signal transduction of excessive growth induced by dense planting, resulting in the failure of plant shape control. Examples 1 to 4 effectively inhibited excessive longitudinal elongation of internode cells by combining physical water deficit manipulation at specific growth stages with the input of chemical regulatory substances. This synergistic effect based on the cross-communication between water and exogenous hormones resulted in a compact spatial structure with moderate plant height and a lower center of gravity in the final population.

[0077] Comparative Example 7 was limited by the lack of environmentally responsive slow-release microspheres, and the plant stems failed to obtain sufficient concentrations of trace elements such as silicon and zinc during the critical developmental period for cell wall lignification and silicification reinforcement.

[0078] Test Example 2: Test Description: This test case explores the impact of changes in light nutrient distribution within a densely planted population on the integrity of ear development during the reproductive growth stage. By assessing the condition of barren tips and differences in the grain filling ratio, it verifies the protective effects of the example scheme and the comparative scheme on the silk pollination and grain filling process.

[0079] Test steps: The experimental subjects were maize ears that had developed to maturity in the experimental plots of Examples 1-4 and Comparative Examples 1-8.

[0080] Fifty valid maize ears from each treatment group were randomly selected to analyze traits, avoiding areas prone to interference from the edges.

[0081] The vertical length from the base of the unfruited part at the top of the ear to the tip of the ear is measured using vernier calipers and recorded as the length of the bare tip.

[0082] The seed setting rate is obtained by dividing the actual number of full and plump grains in each ear by the total number of attachment points remaining at the base of all the silks.

[0083] The experimental data are shown in Table 2: Table 2: Test data of maize ear traits in different treatment groups

[0084] See attached document Figure 3 According to the data in Table 2, in Comparative Example 2, the high degree of shading in the population severely obstructs the synthesis and transport channels of assimilates. The silks at the tip of the ear often fail to complete normal fertilization or even cause grain abortion due to delayed silking or a shortage of carbohydrate supply. Ultimately, it exhibits the dual deterioration characteristics of extremely long barren tips and extremely low seed setting rate.

[0085] Comparative Example 8 also revealed corresponding reproductive development defects. Due to the sharp shrinkage of photosynthetic products produced at the source end of the middle and lower leaves, the limited nutrients could not be allocated to the top of the ear after meeting the survival needs of the vegetative body itself. The imbalance between source and sink inevitably led to a significant drop in the seed setting rate.

[0086] Examples 1 to 4 relied on a series of comprehensive interventions to maintain high pollination quality and efficient nutrient unloading at the pollen sink under high-density conditions. Systematic physical and material interventions ensured the supply of trace elements and carbon skeletons required for pollen tube elongation, and the optimization of the source-sink relationship reduced tip barrenness to an extremely small extent, ensuring a high stability in the number of effective grains per ear.

[0087] Test Example 3: Test Description: This test case aims to evaluate the dynamic differences between polymer composite microspheres and conventional free elements on the supply level of available micronutrients in the rhizosphere of plants during soil moisture deficit.

[0088] The experimental subjects were soil samples at a depth of 20-40cm from the experimental plots of Example 1 and Comparative Example 7, as well as the rhizosphere environment of maize.

[0089] On the first day after the water deficit operation was carried out during the jointing stage, soil samples closely attached to the maize root system were extracted to determine the baseline concentration.

[0090] Rhizosphere soil samples with the same depth and location characteristics were extracted on the 8th day of continuous water deprivation stress.

[0091] After air-drying, grinding, and sieving, the soil samples were extracted with DTPA extractant by shaking. The extract was then centrifuged, filtered, and sent to an inductively coupled plasma mass spectrometer to determine the concentrations of available zinc and available silicon.

[0092] The experimental data are shown in Table 3: Table 3: Results of rhizosphere available element concentrations before and after water deficit operation (mg / kg)

[0093] See attached document Figure 4 Compared with the data in Table 3, in Comparative Example 7, the soil moisture content dropped to the drought threshold on the eighth day after water withholding due to the application of free elements. The sharp reduction of liquid water in soil pores led to the obstruction of ion cross-phase migration channels. A large number of free elements underwent adsorption and precipitation reactions on the soil solid phase surface, resulting in a precipitous drop in the concentrations of available zinc and available silicon. This conventional physicochemical solidification phenomenon completely blocked the plant's access to essential micronutrients during the stress period.

[0094] In Example 1, the concentrations of available zinc and available silicon not only did not decrease with decreasing water content under water-deficient conditions, but actually increased significantly. The test data reflects that the specific environmental stress parameters have transcended their negative limiting factor properties and have essentially transformed into a trigger for nutrient release.

[0095] As the soil continues to lose water and the matrix potential decreases, dehydration and shrinkage occur between the polymer chain segments inside the microspheres, causing violent volume collapse. The microspheres rely on the huge internal stress generated by the physical deformation of the material to force the metal ions and nanoparticles loaded in the core layer to the micro-region near the root epidermis. This physical release mechanism, which is not dominated by concentration gradient, overcomes the limitation of the decay of the ion diffusion coefficient in arid soil.

[0096] Test Example 4: Test Description: This test case explores the reverse remodeling effect of a specific sol material spread on the leaf surface on the microclimate characteristics of the canopy and the physiological stress level of plants in high-density plant communities.

[0097] Test steps: The experimental subjects were the canopy leaves of the test plots of Example 1 and Comparative Example 8.

[0098] Instantaneous microclimate parameters were collected at midday on a clear, cloudless day during the corn silking stage in midsummer.

[0099] High-resolution infrared thermal imaging thermometers were used to vertically scan the surface of the top layer of leaves in the test plot to determine canopy temperature data.

[0100] Insert the photosynthetically active radiation sensor probe with cosine correction into the ear-leaf height position inside the population and read the instantaneous PAR value.

[0101] The top functional leaves of the cells were simultaneously collected and temperature-controlled, and then quickly immersed in liquid nitrogen for solidification and refrigeration. Subsequently, the activity of superoxide dismutase, which reflects the level of cellular oxidative stress, was extracted and measured.

[0102] The experimental data are shown in Table 4: Table 4: Measurement data of meteorological and physical indicators and physiological stress indicators of maize canopy

[0103] Referring to the data in Table 4, the surface temperature of the top leaves far exceeded the upper limit of the plant's suitable physiological temperature during periods of strong solar radiation. This high-temperature heat shock led to a large accumulation of reactive oxygen species (ROS) in the plant cells. Under survival pressure, the plant exhibited a compensatory surge in superoxide dismutase activity to cope with the heat shock oxidative damage. At the same time, the severely shaded middle and lower canopy layers intercepted low amounts of photosynthetically active radiation, exhibiting a typical light-starved state in a closed-canopy environment.

[0104] Example 1: By introducing a composite light shield film agent during a specific growth period, a physical interface layer is constructed on the leaf surface that can actively intervene in the light radiation conduction path. The film structure composed of high reflectivity nanocrystals in the interface has a wide-angle reflection effect on the incident near-infrared thermal radiation, cutting off the main heat source and effectively stripping the heat load from the top of the canopy, so that the temperature of the top leaf surface is stably maintained within the normal range of efficient operation of the photosynthetic enzyme system.

[0105] The carbon nanomaterials deliberately doped into the interface coating utilize a downconversion luminescence mechanism to convert some of the potentially destructive high-energy short-wavelength bands into red and blue wavelengths that can be directly utilized by plant photosynthesis. Combined with the multiple scattering effect of dispersed phase nanoparticles, the redirected diffuse beam penetrates and is directed deep into the canopy, increasing the overall photosynthetically active radiation input near the panicle leaves. This resolves the natural contradiction between high canopy density and the need for high light efficiency per plant from a physical-optical intervention perspective.

[0106] 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, densely planted spring maize, characterized in that, Includes the following steps: S1. Spring corn is sown using drip irrigation under mulch film, and conventional water and fertilizer management is carried out from emergence to jointing. S2, during the jointing stage, before the end of the last drip irrigation, a nutrient solution containing self-extruding slow-release microspheres sensitive to water tension, sodium zinc ethylenediaminetetraacetate, and a mixture of compound amino acids is injected into the 0-40cm root zone with the tail water; then the water is stopped to maintain a moderate water deficit in the soil layer, and after the water is stopped, the aboveground parts are sprayed with a first regulating solution containing potassium dihydrogen phosphate, amino acid ester, and ethephon. S3. Restore water supply and spray the leaves with a second regulating solution containing compound light shield film agent, potassium dihydrogen phosphate, compound amino acid mixture and 14-hydroxybrassinosteroid during the large trumpet stage. S4. Before male emergence, monitor the soil matrix potential and spray a third regulating solution containing potassium dihydrogen phosphate, 14-hydroxybrassinosteroidol and fluid boron when the drought threshold is reached. S5. In the initial stage of grouting, spray the fourth regulating solution containing composite light shield film agent, potassium dihydrogen phosphate, 14-hydroxybrassinosteroidol and sodium zinc ethylenediaminetetraacetate.

2. The high-yield method for dense planting of spring maize according to claim 1, characterized in that, The nutrient solution, first regulating solution, second regulating solution, third regulating solution, and fourth regulating solution are composed of the following components in parts by mass: The nutrient solution is prepared by mixing 20-30 parts of self-extruded slow-release microspheres, 10-16 parts of sodium zinc ethylenediaminetetraacetate, 12-18 parts of a complex amino acid mixture, and 2000-3000 parts of water. The first conditioning solution is prepared by mixing 120-180 parts potassium dihydrogen phosphate, 1.5-3.5 parts aminoethyl ester, 6.0-9.0 parts ethephon and 20,000-30,000 parts water; The second regulating solution is prepared by mixing 70-90 parts of composite light shield film agent, 120-180 parts of potassium dihydrogen phosphate, 12-18 parts of composite amino acid mixture, 0.0003-0.0006 parts of 14-hydroxybrassinosteroidol and 20,000-30,000 parts of water; The third regulating solution is prepared by mixing 120-180 parts potassium dihydrogen phosphate, 0.0003-0.0006 parts 14-hydroxybrassinosteroidol, 66-137 parts fluid boron and 20,000-30,000 parts water; The fourth regulating solution is prepared by mixing 40-60 parts of composite light shield film agent, 120-180 parts of potassium dihydrogen phosphate, 0.0003-0.0006 parts of 14-hydroxybrassinosteroidol, 7-13 parts of sodium zinc ethylenediaminetetraacetate and 20,000-30,000 parts of water.

3. The high-yield method for dense planting of spring maize according to claim 1, characterized in that, In step S1, the drip irrigation under the film is specifically carried out by sowing using a single-strip drip irrigation system with wide and narrow rows under the film, and the seedling density is controlled at 5800 to 6500 plants per mu; the relative soil moisture content is maintained at 70% to 80% from emergence to jointing.

4. The high-yield method for dense planting of spring maize according to claim 1, characterized in that, The specific process parameters in step S2 are as follows: Before the last drip irrigation ends, specifically within 15 to 20 minutes before the drip irrigation system finishes running; A moderate water deficit state is defined as maintaining the relative moisture content of the 0-40cm soil layer at 60%-65% for 7-10 days. The timing for spraying the first regulating solution on the above-ground parts after water cut-off is within 1 to 2 days after the water source is cut off.

5. The high-yield method for dense planting of spring maize according to claim 1, characterized in that, In step S4, the drought threshold is defined as the soil matrix potential being monitored to be between -50 kPa and -45 kPa for three consecutive days.

6. The high-yield method for dense planting of spring maize according to claim 1, characterized in that, The method for preparing the self-extrusion sustained-release microspheres includes: Sodium alginate and polyacrylic acid are added to deionized water and heated to dissolve them to form a base solution; Nano-silica and sodium zinc ethylenediaminetetraacetate were added to the base solution and ultrasonically dispersed to obtain a core layer suspension. The core layer suspension is dropped into a crosslinking curing bath containing calcium chloride and surfactant. After standing for crosslinking, it is washed and freeze-dried to obtain the final product.

7. The high-yield method for dense planting of spring maize according to claim 1, characterized in that, The preparation method of the composite light shield film includes: The carbon quantum dot solution, melatonin, and deionized water were stirred to form a homogeneous solution. High-shear dispersion and emulsification were carried out by adding nano-titanium dioxide powder modified with silane coupling agent; Polyethylene glycol was added and stirred to remove air, thus obtaining a carbon quantum dot-nano titanium dioxide-melatonin composite light shield film.

8. The high-yield method for dense planting of spring maize according to claim 1, characterized in that, The composite amino acid mixture is prepared by mixing L-glutamic acid, L-proline and glycine at room temperature in a mass ratio of 1.5-2:1-1.5:1-1.5; the fluid boron is prepared by reacting xylitol or mannitol with boric acid in deionized water at a constant temperature of 80°C.

9. The high-yield method for dense planting of spring maize according to claim 2, characterized in that, In the first conditioning solution, the mass ratio of ethephon to aminoethyl ester is 2.5:1 to 4:

1.

10. The method for high-yield dense planting of spring maize according to claim 1, characterized in that, In S2, S3, S4 and S5, the control liquid is applied to the aboveground parts of corn by uniform foliar spraying, and the total amount of liquid applied per acre is controlled between 20 and 30 kg each time.

Images