A method of using a nutritional supplement to increase yield of a corn crop

Abstract

The present application belongs to the field of agricultural technology, and relates to a method for using a nutrient agent to increase the yield of a corn crop, aiming to solve the problem that the number of grains per ear and the number of rows of ears are difficult to be synergistically improved in the prior art. The method forms a five-stage dynamic intervention system through seed coating, rhizosphere regulation, and three key period leaf spraying, accurately couples 6-BA, GA3, brassinolide, methyl jasmonate and other signal molecules with nutrient elements and biological source protective agents, and directionally strengthens the development of female ears without changing the variety and the basic water and fertilizer conditions. The present application can increase the number of grains per ear by 21.5-28.9%, increase the yield by 18.7-24.3% on average, and significantly reduce the lodging rate and biological stress loss.

Description

Technical Field

[0001] This invention relates to the field of agricultural technology, and in particular to a method for using a nutrient to increase corn crop yield. Background Technology

[0002] In modern agricultural production systems, maize, as one of the world's three major staple crops, has a yield that directly impacts national food security and agricultural economic benefits. For a long time, the core pathways to increasing maize yield have focused on two dimensions: genetic breeding improvement and cultivation management optimization. Cultivation management generally follows the traditional concept of "adjusting fertilizer with water and promoting growth with fertilizer," emphasizing coordinated water and fertilizer regulation during key growth stages such as jointing, tasseling, and silking to ensure robust vegetative development and support normal differentiation of ear organs. Within this framework, widely adopted yield-increasing strategies often revolve around increasing planting density to increase the number of ears per unit area, or using a single basal application of compound fertilizer combined with subsequent nitrogen topdressing to meet the concentrated nutrient demands of reproductive growth. These methods have indeed achieved phased success under specific ecological zones and varietal conditions. Their technical logic is based on a deep understanding of the light energy utilization efficiency and nitrogen response patterns of maize populations, possessing clear physiological basis and operability.

[0003] However, as high-yield breeding goals evolve towards efficient coordination of the "source-sink-flow" system, and the frequent occurrence of extreme weather events places higher demands on crop resilience and yield stability, the aforementioned traditional technical approaches are gradually revealing deep-seated structural contradictions at the principle level. Specifically, while existing water and fertilizer management models can effectively promote vegetative growth, they struggle to precisely intervene in the critical window period of maize ear primordia differentiation—namely, the early jointing stage to the small trumpet stage. This stage is a physiologically sensitive period determined by the number of ear rows and spikelet primordia, and its developmental quality directly restricts the final upper limit of the number of grains per ear. However, conventional fertilization, due to the difficulty in matching the nutrient release rhythm and root absorption kinetics with the demand for this brief but intense endogenous hormone regulation, leads to insufficient early development of the reproductive system. Even with sufficient water and fertilizer later on, it is impossible to reverse the inherent limitation of the number of grains per ear, thereby reducing the stability of the population yield. Summary of the Invention

[0004] This invention provides a method for using nutrients to increase maize crop yield. The method constructs a complex nutrient intervention system based on the key physiological window period of maize reproductive organ development throughout the entire growth cycle, combined with soil physicochemical properties, meteorological conditions, and the dynamics of pests and diseases. This system consists of three synergistic stages: seed treatment, rhizosphere regulation, and precise foliar delivery. This system aims to achieve targeted enhancement of the number of rows and grains per ear, thereby significantly increasing yield per unit area without altering the genetic background of the variety or the basic water and fertilizer input.

[0005] To achieve the above-mentioned objectives, the "method of applying a nutrient agent to increase corn crop yield" of this invention includes the following technical steps: First, the corn seeds are coated before sowing. The coating solution contains 0.5-2.0 g / L of 6-benzylaminopurine (6-BA), 1.0-3.0 g / L of gibberellic acid A3 (GA3), 0.8-1.5 g / L of brassinolide (BRs), and 5.0-10.0 g / L of a sodium alginate oligosaccharide mixture, wherein the average molecular weight of the sodium alginate oligosaccharide mixture is 1500-3000 Da, and the monosaccharides... The composition is that the molar ratio of mannuronic acid to guluronic acid is 1.2:1; the coating solution also contains 0.3% by mass of the film-forming agent polyvinyl alcohol (PVA, degree of polymerization 1700, degree of alcoholysis ≥98%) and 0.1% by mass of the surfactant sodium dodecyl sulfate (SDS). The mass ratio of coating solution to seeds is 1:100. After coating, the seeds are dried at 25±2℃ and 60% relative humidity for 24 hours to form a slow-release coating layer with a thickness of 15-25μm.

[0006] Secondly, a rhizosphere-regulating nutrient substrate is applied simultaneously at sowing. This substrate is composed of the following components mixed in the following mass percentages: 30-40% potassium humate (content ≥50%, pH 8.5-9.5), and biochar (particle size 0.5-2.0 mm, specific surface area ≥300 m²). 2 / g, pore volume ≥0.2cm 3 20-30% ( / g), 15-25% (SiO2≥45%, CaO≥20%, MgO≥8%), and 10-15% (microcapsule particles loaded with Bacillus subtilis CGMCCNo.1.1089 strain); the microcapsule particles are prepared by sodium alginate-chitosan double-layer encapsulation method, and the core is a 1×10⁻⁶ m² / g core. 9 The bacterial suspension contains CFU / g, with the outer cross-linking agent being a 0.1mol / L CaCl2 solution. The microcapsule particle size is 300-500μm, and the encapsulation rate is ≥90%. The nutrient substrate is applied to the sowing hole at a rate of 15-20g per hole, at the same position as the seeds, to a depth of 5-8cm. After covering with soil, the soil is compacted.

[0007] Third, the first foliar spray should be applied during the early jointing stage to the small trumpet stage (V6-V8 leaf age). The foliar spray solution contains the following components: potassium nitrate (KNO3, purity ≥99%) 3.0-5.0 g / L, potassium dihydrogen phosphate (KH2PO4, purity ≥98%) 2.0-4.0 g / L, chelated zinc (Zn-EDTA, Zn content ≥15%) 0.8-1.2 g / L, and chelated boron (B-EDTA, B content ≥10%) 0.5- The spray solution contains 0.8 g / L of methyl jasmonate (MeJA) and 0.1-0.3 g / L of phosphate buffer. The pH of the spray solution is adjusted to 6.2-6.8, and ionic strength is maintained using 0.1 mol / L phosphate buffer. Spraying is carried out within 2 hours after sunrise or 2 hours before sunset, with a spraying rate of 450-600 L / ha. The median droplet diameter (VMD) is controlled at 150-200 μm to ensure that the upper leaves of the canopy are evenly moistened on both sides without droplets sliding off.

[0008] Fourth, a second foliar spray should be applied during the large trumpet stage (V12-V14 leaf age stage). The spray solution contains: urea (purity ≥99.5%) 8.0-12.0 g / L, magnesium sulfate (MgSO4·7H2O, purity ≥98%) 3.0-5.0 g / L, chelated iron (Fe-EDDHA, Fe content ≥6%) 1.0-1.5 g / L, and a concentration of 0.05-0.15 g / L. The spray solution contains g / L salicylic acid (SA); simultaneously, it is formulated with a plant-derived insecticide composed of matrine and azadirachtin, wherein the concentration of matrine is 0.8-1.2 g / L and the concentration of azadirachtin is 0.03-0.05 g / L; the conductivity of the spray solution is controlled at 1.8-2.5 mS / cm, the spraying rate is 500-650 L / ha, and the droplet coverage density is not less than 80 droplets / cm. 2 .

[0009] Fifth, a third foliar spray is applied during the tasseling and silking stage (R1 stage). The spray solution contains: potassium chloride (KCl, purity ≥99%) 5.0-7.0 g / L, ammonium molybdate ((NH4)6Mo7O 24The spray solution contains 0.05-0.10 g / L of 4H₂O (purity ≥98%) and 0.2-0.4 g / L of abscisic acid (ABA); in addition, a bird and snail repellent compound composed of tea saponin and rotenone is added to the spray solution, wherein the concentration of tea saponin is 1.0-1.5 g / L and the concentration of rotenone is 0.02-0.04 g / L; the spraying operation should avoid high temperature periods (temperature > 32℃), and the spraying rate is 400-500 L / ha, focusing on covering the husk and silk areas of the female ear. The above five-stage intervention measures constitute a complete dynamic response system, the core of which lies in precisely regulating the key window of differentiation of maize female ear primordia through the spatiotemporal coupling supply of exogenous signaling molecules and nutrient elements.

[0010] Specifically, during seed germination, 6-BA and GA3 synergistically activate the expression of cyclin-dependent kinases (CDKs), promoting meristematic cell division; brassinolide enhances cell elongation by upregulating the BZR1 transcription factor; and sodium alginate oligosaccharides act as elicitors to induce acquired resistance (SAR), establishing an immune barrier in advance. In rhizosphere microenvironment construction, potassium humate and biochar synergistically improve soil aggregate structure, increasing cation exchange capacity (CEC) to 15-20 cmol / kg; silicate-calcium-magnesium minerals slowly release Si, Ca, and Mg ions, enhancing cell wall mechanical strength and inhibiting fungal infection; Bacillus subtilis colonizes the root surface, secreting iturin A lipopeptide antibiotics, effectively inhibiting spore germination of Fusarium and Pythium.

[0011] During the V6-V8 leaf stage, potassium nitrate and potassium dihydrogen phosphate provide high-energy nitrogen and phosphorus sources to support RNA and protein synthesis. Zinc ions act as a cofactor for RNA polymerase, while boron ions participate in sugar transport and cell wall synthesis; together, they ensure the normal differentiation of spikelet primordia. Methyl jasmonic acid acts as a key signaling hub at this stage, activating the MYC2 transcription factor, upregulating the cytokinin oxidase (CKX) repressor gene, and prolonging the half-life of endogenous cytokinins, thereby increasing the number of cells in the meristematic zone of the spikelet primordia. Experimental data show that treatment at this stage can increase the number of spikelet rows by 1.2-1.8 rows and the number of spikelet primordia by 18-25%.

[0012] During the V12-V14 stage, urea provides a rapid nitrogen source to support tassel development and pollen viability; magnesium ions, as a core component of chlorophyll, maintain photosynthetic efficiency; iron ions ensure the function of the electron transport chain; salicylic acid induces PR-1 protein expression at this stage, enhancing indirect resistance to corn borers and aphids; matrine blocks acetylcholine receptors at insect neural synapses, while azadirachtin interferes with ecdysone synthesis. Together, they achieve highly efficient control of lepidopteran and homoptera pests, with a control efficacy of over 85% and no risk of pesticide resistance.

[0013] In the R1 stage, potassium chloride maintains osmotic pressure balance and promotes simultaneous filament elongation and pollination; molybdenum, as a cofactor of nitrate reductase, optimizes nitrogen assimilation efficiency; abscisic acid accumulates moderately in this stage, regulating stomatal opening to reduce water transpiration, while inducing LEA protein expression to enhance drought resistance during the grain-filling period; tea saponin produces a feeding refusal effect by destroying taste receptors in birds, while rotenone has a paralyzing effect on the snail's nervous system. Both can effectively repel feeding animals in the ear at low concentrations, with a protection rate of over 90%.

[0014] The method described in this invention further includes a dynamic adjustment mechanism based on a field sensor network. Before sowing, the pH value, organic matter content, available nitrogen, phosphorus, and potassium content, and soil moisture content of the 0-20cm soil layer are measured using a portable soil multi-parameter instrument. If the pH is <5.5, an additional 5% limestone powder (CaCO3, 200 mesh) is added to the rhizosphere control substrate. If the organic matter content is <1.0%, the potassium humate ratio is increased to 45%. If the available nitrogen content is <80mg / kg, the potassium nitrate concentration is increased to 6.0g / L in the first foliar spray. In stage V6, the normalized difference vegetation index (NDVI) and chlorophyll fluorescence parameters (Fv / Fm) are acquired using a drone equipped with a multispectral camera. If the NDVI is <0.65 or Fv / Fm is <0.75, urea is increased to 15.0g / L in the second spray, and 0.1g / L of glutathione (GSH) is supplemented to alleviate oxidative stress. Seven days before the male reproductive process, data from the regional meteorological station is accessed. If the forecast indicates that the daily maximum temperature will remain at or above 35°C for the next 10 days, the concentration of abscisic acid will be increased to 0.5 g / L in the third application, and 0.3 g / L of proline will be added as an osmotic regulator.

[0015] In a preferred embodiment of the present invention, 6-BA, GA3, and brassinolide in the seed coating solution are microencapsulated using β-cyclodextrin inclusion technology at a molar ratio of 1:1 and an inclusion efficiency ≥85%, to delay their release rate in the soil and ensure continuous release of effective concentrations within 72 hours after the radicle breaks through the seed coat. The microencapsulation process is achieved through the following steps: 6-BA, GA3, and brassinolide are dissolved separately in anhydrous ethanol to prepare a mixed solution with a total concentration of 10 g / L; β-cyclodextrin is dissolved in deionized water to prepare a 20 g / L solution; the organic phase is slowly added dropwise to the aqueous phase at 40°C and a stirring speed of 300 rpm at a dropping rate of 2 mL / min; after the addition is complete, stirring continues for 2 hours, followed by cooling to room temperature and freeze-drying to obtain a white powder, which is the microencapsulated active ingredient.

[0016] In another preferred embodiment of the present invention, the surface of the Bacillus subtilis microcapsule particles in the rhizosphere regulation matrix is ​​modified with a maize root exudate mimic, wherein the mimic is a 1:3 molar mixture of phenylalanine (Phe) and malic acid (Mal). The modification method involves suspending the microcapsules in a 0.5 mmol / L mimic solution, incubating at 4°C for 12 hours, centrifuging, collecting, and vacuum drying. This modification significantly enhances the chemotaxis of the bacteria to maize roots, increasing the colonization efficiency by 3.2 times.

[0017] In another preferred embodiment of the present invention, the salicylic acid and matrine in the second foliar spray form a molecular complex that coexists stably through hydrogen bonding, with a complex ratio of 1:8 (mass ratio). The complex exhibits a 40% increase in solubility and a 2.5-fold increase in bioavailability at pH 6.5. The formation of this complex was verified by infrared spectroscopy: at 3300 cm⁻¹... -1 A broad peak appears at 1650 cm⁻¹ (OH stretching vibration). -1 A new peak appears (characteristic absorption of C=O...HN hydrogen bonds).

[0018] In a further preferred embodiment of the present invention, the tea saponin and rotenone in the third foliar spray are delivered using a nanoemulsion carrier. The nanoemulsion is composed of an oil phase (rotenone dissolved in isopropyl myristate), an aqueous phase (tea saponin aqueous solution), a surfactant (Tween 80), and a co-surfactant (n-butanol) in a mass ratio of 10:70:15:5. It is prepared by cycling three times under high pressure at 80 MPa using a homogenizer, with an average particle size of 85 nm, a Zeta potential of -32 mV, and drug loadings of 12% and 0.4%, respectively. This nanoemulsion can significantly improve the adhesion rate and penetration rate of hydrophobic components on the leaf surface, extending the effective period to 14 days.

[0019] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions: This invention integrates five major technical modules: seed physiological activation, rhizosphere microecological reconstruction, key window period signal regulation, full-process biological protection, and intelligent dynamic response. It constructs a replicable, scalable, and monitorable method for applying maize yield-enhancing nutrients, which solves the structural contradictions in existing technologies such as "emphasizing nutrition while neglecting signaling," "emphasizing above-ground factors while neglecting underground factors," and "emphasizing static formulation while neglecting dynamic response." It achieves precise, efficient, and sustainable enhancement of maize yield components—the number of rows per ear and the number of grains per ear.

[0020] In implementing the method described in this invention, the concentration and timing of each active ingredient are strictly limited to avoid phytotoxicity or ecological risks. For example, a concentration of 6-BA exceeding 2.5 g / L can lead to embryonic malformation, so the upper limit is set at 2.0 g / L; methyl jasmonate, when applied after the V10 stage, inhibits male spike development, so it is only used during the V6-V8 stages; rotenone is highly toxic to bees, but because it is only locally sprayed on the female spike during the R1 stage at a concentration below 0.05 g / L, it has no significant effect on pollinating insects.

[0021] The above overview is for illustrative purposes only and is not intended to be limiting in any way. Further aspects, embodiments, and features of the invention will become readily apparent from the following detailed description, in addition to the illustrative aspects, embodiments, and features described above. Detailed Implementation

[0022] The following is a detailed description of the embodiments of this disclosure.

[0023] It should be understood that the following specific examples illustrate the implementation of this disclosure, and those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0024] This invention provides a method for applying nutrients to increase maize crop yield. This method constructs a complex nutrient intervention system based on the key physiological window period of maize reproductive organ development throughout the entire growth cycle, combined with soil physicochemical properties, meteorological conditions, and the dynamics of pests and diseases. This system consists of three synergistic stages: seed treatment, rhizosphere regulation, and precise foliar delivery. This system aims to achieve targeted enhancement of the number of rows and grains per ear, thereby significantly increasing yield per unit area without altering the genetic background of the variety or the basic water and fertilizer input.

[0025] Before sowing, the corn seeds are first coated. The coating solution contains 0.5-2.0 g / L of 6-benzylaminopurine (6-BA), 1.0-3.0 g / L of gibberellic acid A3 (GA3), 0.8-1.5 g / L of brassinolide (BRs), and 5.0-10.0 g / L of a sodium alginate oligosaccharide mixture. The sodium alginate oligosaccharide mixture has an average molecular weight of 1500-3000 Da, and the monosaccharide composition is a molar ratio of mannuronic acid to guluronic acid of 1.2:1. The coating solution also contains 0.3% by mass of a film-forming agent, polyvinyl alcohol (PVA, degree of polymerization 1700, degree of alcoholysis ≥98%), and 0.1% by mass of a surfactant, sodium dodecyl sulfate (SDS). The mass ratio of coating solution to seeds is 1:100. After coating, the seeds are dried at 25±2℃ and 60% relative humidity for 24 hours to form a sustained-release coating layer with a thickness of 15-25 μm. In a preferred embodiment of the invention, 6-BA, GA3, and brassinolide are microencapsulated using β-cyclodextrin inclusion technology, with an inclusion ratio of 1:1 (molar ratio) and an inclusion efficiency ≥85%. The specific steps of the microencapsulation process are as follows: 6-BA, GA3, and brassinolide are dissolved separately in anhydrous ethanol to prepare a mixed solution with a total concentration of 10 g / L; β-cyclodextrin is dissolved in deionized water to prepare a 20 g / L solution; the organic phase is slowly added dropwise to the aqueous phase at 40℃ and a stirring speed of 300 rpm, with a dropping rate of 2 mL / min; after the addition is complete, stirring continues for 2 hours, the mixture is cooled to room temperature, and freeze-dried to obtain a white powder, which is the microencapsulated active ingredient. This microencapsulated structure can slow down the release rate of active ingredients in the soil, ensuring a continuous release of effective concentrations within 72 hours after the radicle breaks through the seed coat, thus maintaining the physiological needs for cell division and elongation.

[0026] Apply a rhizosphere-regulating nutrient substrate simultaneously at sowing. The nutrient substrate is composed of the following components mixed in the following mass percentages: potassium humate (≥50%, pH 8.5-9.5) 30-40%, biochar (particle size 0.5-2.0 mm, specific surface area ≥300 m²). 2 / g, pore volume ≥0.2cm 3 20-30% ( / g) of silica-calcium-magnesium composite mineral powder (SiO2≥45%, CaO≥20%, MgO≥8%), 15-25% of microcapsule particles loaded with Bacillus subtilis CGMCC No.1.1089 strain. The microcapsule particles are prepared using a sodium alginate-chitosan double-layer encapsulation method, with a core containing a concentration of 1×10⁻⁶. 9The bacterial suspension contains CFU / g of microcapsules with an outer cross-linking agent of 0.1 mol / L CaCl2 solution. The microcapsule particle size is 300-500 μm, and the encapsulation efficiency is ≥90%. In another preferred embodiment of the invention, the surface of the microcapsule particles is modified with a maize root exudate mimic, which is a 1:3 molar mixture of phenylalanine (Phe) and malic acid (Mal). The modification method involves suspending the microcapsules in a 0.5 mmol / L mimic solution, allowing them to stand at 4°C for 12 hours, centrifuging, and then vacuum drying. This modification significantly enhances the chemotaxis of the bacteria towards maize roots, increasing colonization efficiency by 3.2 times. The nutrient substrate is applied at a rate of 15-20 g per hole, placed in the same position as the seeds, at a depth of 5-8 cm, covered with soil, and compacted. This matrix forms a stable microenvironment in the soil. Potassium humate and biochar synergistically improve soil aggregate structure and increase cation exchange capacity (CEC) to 15-20 cmol / kg. The silica-calcium-magnesium minerals slowly release Si, Ca, and Mg ions, enhancing the mechanical strength of the cell wall and inhibiting fungal infection. Bacillus subtilis colonizes the root surface and secretes iturin A-type lipopeptide antibiotics, effectively inhibiting the spore germination of Fusarium and Pythium.

[0027] The first foliar spraying should be carried out during the early jointing stage to the small trumpet stage (V6-V8 leaf age). The foliar spray solution contains the following components: potassium nitrate (KNO3, purity ≥99%) 3.0-5.0 g / L, potassium dihydrogen phosphate (KH2PO4, purity ≥98%) 2.0-4.0 g / L, chelated zinc (Zn-EDTA, Zn content ≥15%) 0.8-1.2 g / L, chelated boron (B-EDTA, B content ≥10%) 0.5-0.8 g / L, and methyl jasmonate (MeJA) at a concentration of 0.1-0.3 g / L. The pH of the spray solution should be adjusted to 6.2-6.8, and the ionic strength should be maintained using 0.1 mol / L phosphate buffer. Spraying should be carried out within 2 hours after sunrise or 2 hours before sunset, at a rate of 450-600 L / ha, with a median droplet diameter (VMD) controlled at 150-200 μm to ensure uniform wetting of both sides of the upper canopy leaves without droplet slippage. This stage is a critical window for the differentiation of female spike primordia. Potassium nitrate and potassium dihydrogen phosphate provide high-energy nitrogen and phosphorus sources to support RNA and protein synthesis; zinc ions act as cofactors for RNA polymerase, and boron ions participate in sugar transport and cell wall synthesis, both working together to ensure normal differentiation of spikelet primordia; methyl jasmonic acid acts as a key signaling hub at this stage, activating the MYC2 transcription factor, upregulating the cytokinin oxidase (CKX) repressor gene, and prolonging the half-life of endogenous cytokinin, thereby increasing the number of cells in the meristematic zone of the spikelet primordia. Experimental data show that treatment at this stage can increase the number of spike rows by 1.2-1.8 rows and the number of spikelet primordia by 18-25%. A second foliar spray is applied during the large trumpet stage (V12-V14 leaf age). The spray solution contains: 8.0-12.0 g / L urea (purity ≥99.5%), 3.0-5.0 g / L magnesium sulfate (MgSO4·7H2O, purity ≥98%), 1.0-1.5 g / L chelated iron (Fe-EDDHA, Fe content ≥6%), and 0.05-0.15 g / L salicylic acid (SA). Simultaneously, a plant-derived insecticide composed of matrine and azadirachtin is added to the spray solution, wherein the concentration of matrine is 0.8-1.2 g / L and the concentration of azadirachtin is 0.03-0.05 g / L.

[0028] In another preferred embodiment of the present invention, the salicylic acid and matrine form a molecular complex that coexists stably through hydrogen bonding, with a complex ratio of 1:8 (mass ratio). This complex exhibits a 40% increase in solubility and a 2.5-fold increase in bioavailability at pH 6.5. The formation of the complex is verified by infrared spectroscopy: a broad peak (OH stretching vibration) appears at 3300 cm⁻¹, and at 1650 cm⁻¹... -1A new peak appears (characteristic absorption of C=O...HN hydrogen bonds). The conductivity of the spray solution is controlled at 1.8-2.5 mS / cm, the spraying rate is 500-650 L / ha, and the droplet coverage density is not less than 80 droplets / cm. 2 .

[0029] During this stage, urea provides a rapid nitrogen source to support tassel development and pollen viability; magnesium ions, as a core component of chlorophyll, maintain photosynthetic efficiency; iron ions ensure the function of the electron transport chain; salicylic acid induces PR-1 protein expression, enhancing indirect resistance to corn borers and aphids; matrine blocks acetylcholine receptors at insect neural synapses, while azadirachtin interferes with ecdysone synthesis. Together, they achieve highly efficient control of lepidopteran and homoptera pests, with a control efficacy of over 85% and no risk of pesticide resistance.

[0030] A third foliar spray is applied during the tasseling and silking stage (R1 stage). The spray solution contains: potassium chloride (KCl, purity ≥99%) 5.0-7.0 g / L, ammonium molybdate ((NH4)6Mo7O 24 The spray solution contains 0.05-0.10 g / L of 4H₂O (purity ≥98%) and 0.2-0.4 g / L of abscisic acid (ABA). In addition, a bird and snail repellent compound composed of tea saponin and rotenone is added to the spray solution, wherein the concentration of tea saponin is 1.0-1.5 g / L and the concentration of rotenone is 0.02-0.04 g / L.

[0031] As a further preferred embodiment of the present invention, the tea saponin and rotenone are delivered using a nanoemulsion carrier. The nanoemulsion is composed of an oil phase (rotenone dissolved in isopropyl myristate), an aqueous phase (tea saponin aqueous solution), a surfactant (Tween 80), and a co-surfactant (n-butanol) in a mass ratio of 10:70:15:5. It is prepared by homogenizing under high pressure at 80 MPa for three cycles, resulting in an average particle size of 85 nm, a Zeta potential of -32 mV, and drug loadings of 12% and 0.4%, respectively. This nanoemulsion can significantly improve the adhesion rate and penetration rate of hydrophobic components on the leaf surface, extending the effective period to 14 days. Spraying should be avoided during high-temperature periods (air temperature > 32℃), with a spraying rate of 400-500 L / ha, focusing on covering the husks and silks of the female ear. During this stage, potassium chloride maintains osmotic pressure balance and promotes simultaneous filament elongation and pollination; molybdenum, as a cofactor of nitrate reductase, optimizes nitrogen assimilation efficiency; abscisic acid accumulates moderately, regulating stomatal opening to reduce water transpiration, while simultaneously inducing LEA protein expression to enhance drought resistance during the grain-filling period; tea saponins produce a feeding refusal effect by damaging avian taste receptors, while rotenone has a paralyzing effect on the snail's nervous system. Both can effectively repel feeding animals in the ear at low concentrations, with a protection rate of over 90%.

[0032] The above five-stage intervention measures constitute a complete dynamic response system. Its core lies in precisely regulating the key window of maize ear primordia differentiation through the spatiotemporal coupling supply of exogenous signaling molecules and nutrient elements.

[0033] This invention further includes a dynamic adjustment mechanism based on a field sensor network. Before sowing, the pH value, organic matter content, available nitrogen, phosphorus, and potassium content, and soil moisture content of the 0-20cm soil layer are measured using a portable soil multi-parameter instrument. If the pH is <5.5, an additional 5% limestone powder (CaCO3, 200 mesh) is added to the rhizosphere control substrate. If the organic matter content is <1.0%, the potassium humate ratio is increased to 45%. If the available nitrogen content is <80mg / kg, the potassium nitrate concentration is increased to 6.0g / L in the first foliar spray. In stage V6, the normalized difference vegetation index (NDVI) and chlorophyll fluorescence parameters (Fv / Fm) are acquired using a drone equipped with a multispectral camera. If the NDVI is <0.65 or Fv / Fm is <0.75, urea is increased to 15.0g / L in the second spray, and 0.1g / L of glutathione (GSH) is supplemented to alleviate oxidative stress. Seven days before the male reproductive process, data from the regional meteorological station is accessed. If the forecast indicates that the daily maximum temperature will remain at or above 35°C for the next 10 days, the concentration of abscisic acid will be increased to 0.5 g / L in the third application, and 0.3 g / L of proline will be added as an osmotic regulator.

[0034] To verify the technical effectiveness of this invention, field trials were conducted in multiple regions. The trials employed a randomized block design, with each treatment replicated three times, and each plot measuring 30 m². 2 The planting density was 67,500 plants / ha, and the variety was Zhengdan 958. The control group used conventional local fertilization and plant protection methods, without applying the nutrient system described in this invention. The example groups strictly followed the above five-stage plan and made local optimizations based on the dynamic adjustment mechanism. Comparative Example 1 only implemented seed coating and rhizosphere substrate, omitting three foliar sprays; Comparative Example 2 only implemented three foliar sprays, omitting seed coating and rhizosphere substrate; Comparative Example 3 used conventional foliar fertilizer (urea + potassium dihydrogen phosphate) instead of the three foliar spray solutions of this invention, with the remaining steps being the same.

[0035] The experimental results are shown in the table below: Data shows that the average yield increase in the example group was 23.7%, with a 27.1% increase in the number of grains per ear, a 4.5% increase in thousand-grain weight, a 42.9% decrease in lodging rate, a decrease in the rate of corn borer damage to 4.1%, and bird damage and snail feeding losses below 2%. The yield increases in Comparative Examples 1 and 2 were significantly lower than those in the examples, indicating that seed treatment, rhizosphere regulation, and foliar spraying are all indispensable and must work synergistically to achieve the maximum yield potential. Although Comparative Example 3 included foliar nutrition, it lacked signaling molecules and biological protective components; its number of grains per ear and stress resistance indicators were significantly inferior to those in the examples, demonstrating the necessity of the "signal-nutrient-protection" three-in-one system described in this invention.

[0036] In implementing the method described in this invention, the concentration and timing of each active ingredient are strictly limited to avoid phytotoxicity or ecological risks. For example, a concentration of 6-BA exceeding 2.5 g / L can lead to embryonic malformation, therefore the upper limit is set at 2.0 g / L; methyl jasmonate, when applied after the V10 stage, inhibits male spike development, therefore it is only used during the V6-V8 stages; rotenone is highly toxic to bees, but because it is only locally sprayed on the female spike during the R1 stage at a concentration below 0.05 g / L, it has no significant effect on pollinating insects.

[0037] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A method for applying a nutrient agent to increase corn crop yield, characterized in that, Includes the following steps: (1) Before sowing, the corn seeds are coated. The coating solution contains 6-benzylaminopurine at a concentration of 0.5-2.0 g / L, gibberellic acid at a concentration of 1.0-3.0 g / L, brassinolide at a concentration of 0.8-1.5 g / L, a mixture of sodium alginate oligosaccharides at a concentration of 5.0-10.0 g / L, a polyvinyl alcohol film-forming agent at a mass fraction of 0.3%, and sodium dodecyl sulfate at a mass fraction of 0.1%. The average molecular weight of the sodium alginate oligosaccharide mixture is 1500-3000 Da, the molar ratio of mannuronic acid to guluronic acid is 1.2:1, and the mass ratio of the coating solution to the seeds is 1:

100. After coating, the seeds are dried at 25±2℃ and 60% relative humidity for 24 hours to form a slow-release coating layer with a thickness of 15-25 μm. (2) Apply rhizosphere-regulating nutrient substrate simultaneously at the time of sowing. The nutrient substrate is composed of 30-40% potassium humate, 20-30% biochar, 15-25% silicon-calcium-magnesium composite mineral powder and 10-15% microcapsule particles loaded with Bacillus subtilis in a mass percentage. The microcapsule particles are prepared by sodium alginate-chitosan double-layer encapsulation method, with a particle size of 300-500μm and an encapsulation rate of ≥90%. The nutrient substrate is applied to the sowing hole at a dosage of 15-20g per hole, at the same position as the seeds, at a depth of 5-8cm. (3) The first foliar spray is applied to the corn from the early jointing stage to the small trumpet stage. The spray solution contains 3.0-5.0 g / L potassium nitrate, 2.0-4.0 g / L potassium dihydrogen phosphate, 0.8-1.2 g / L chelated zinc, 0.5-0.8 g / L chelated boron and 0.1-0.3 g / L methyl jasmonate. The pH of the spray solution is 6.2-6.8, the spraying rate is 450-600 L / ha, and the median droplet diameter is 150-200 μm. (4) At the large trumpet stage, a second foliar spray is applied. The spray solution contains 8.0-12.0 g / L urea, 3.0-5.0 g / L magnesium sulfate, 1.0-1.5 g / L chelated iron, 0.05-0.15 g / L salicylic acid, 0.8-1.2 g / L matrine, and 0.03-0.05 g / L azadirachtin. The conductivity of the spray solution is 1.8-2.5 mS / cm, the spraying rate is 500-650 L / ha, and the droplet coverage density is not less than 80 droplets / cm. 2 ; (5) During the tasseling and silking stage, a third foliar spray is applied. The spray solution contains 5.0-7.0 g / L potassium chloride, 0.05-0.10 g / L ammonium molybdate, 0.2-0.4 g / L abscisic acid, 1.0-1.5 g / L tea saponin and 0.02-0.04 g / L rotenone. The spraying amount is 400-500 L / ha, focusing on covering the female ear bracts and silk area.

2. The method of using the nutrient agent to increase corn crop yield according to claim 1, characterized in that, In step (1), 6-benzylaminopurine, gibberellic acid and brassinolide are encapsulated with β-cyclodextrin in a microencapsulation ratio of 1:1 and an encapsulation efficiency of ≥85%. The microencapsulated active ingredients continue to release effective concentrations within 72 hours after the radicle breaks through the seed coat.

3. The method for using the nutrient agent to increase corn crop yield according to claim 1, characterized in that, In step (2), the surface of the microcapsule particles is modified with a corn root secretion mimic, which is a 1:3 mixture of phenylalanine and malic acid. After modification, the colonization efficiency of Bacillus subtilis on corn roots is increased by 3.2 times.

4. The method of using the nutrient agent to increase corn crop yield according to claim 1, characterized in that, In step (4), salicylic acid and matrine form a molecular complex in a mass ratio of 1:

8. This complex coexists stably through hydrogen bonding. Under pH 6.5 conditions, its solubility is increased by 40% and its bioavailability is increased by 2.5 times.

5. The method of using the nutrient agent to increase corn crop yield according to claim 1, characterized in that, In step (5), tea saponin and rotenone are delivered using a nanoemulsion carrier. The nanoemulsion consists of an oil phase, an aqueous phase, Tween 80 and n-butanol in a mass ratio of 10:70:15:5, with an average particle size of 85 nm, a zeta potential of -32 mV, and drug loading of 12% and 0.4%, respectively, extending the duration of efficacy to 14 days.

6. The method of using the nutrient agent to increase corn crop yield according to claim 1, characterized in that, The method also includes a dynamic adjustment mechanism based on a field sensor network: if the soil pH is less than 5.5 before sowing, an additional 5% limestone powder is added to the rhizosphere regulation substrate. If organic matter content is less than 1.0%, the potassium humate ratio should be increased to 45%; if available nitrogen content is less than 80 mg / kg, the potassium nitrate concentration should be increased to 6.0 g / L in the first foliar spray. In the V6 stage, if the normalized vegetation index (NDVI) is less than 0.65 or the chlorophyll fluorescence parameter (Fv / Fm) is less than 0.75, the urea concentration should be increased to 15.0 g / L and 0.1 g / L glutathione should be added in the second spraying. If the forecast indicates that the daily maximum temperature will remain at or above 35°C for the next 10 days, the abscisic acid concentration will be increased to 0.5 g / L and 0.3 g / L proline will be added during the third spraying.

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