Special anti-lodging compound fertilizer for corn and preparation method thereof

Abstract

The present application relates to a corn special anti-lodging type special compound fertilizer and a preparation method, which is prepared from the following raw materials in parts by weight: urea 25-35 parts, diammonium phosphate 18-25 parts, potassium sulfate 22-30 parts, EDTA chelated calcium 3-6 parts, EDTA chelated magnesium 2-4 parts, boron-zinc compound micro-fertilizer 1.5-3 parts, mineral humic acid 4-8 parts, chitosan 1-2.5 parts, rooting synergist 0.8-1.5 parts, and slow-release binding auxiliary material 5-10 parts, wherein the slow-release binding auxiliary material is prepared by mixing bentonite, kaolin and sodium lignosulfonate at a mass ratio of 3:2:1. The corn special anti-lodging type special compound fertilizer and the preparation method significantly improve the corn root penetration depth and total root amount, greatly enhance the root soil fixation capacity, completely eliminate the root lodging from the root source, stably control the overall lodging rate in the field within 3%, effectively thicken the corn stem wall and improve the lignification degree, significantly improve the stem mechanical bending strength, and completely solve the problems of thin and soft stem, easy bending and breaking.

Description

Technical Field

[0001] This invention relates to the field of compound fertilizer technology, specifically to a special compound fertilizer for preventing lodging in corn and its preparation method. Background Technology

[0002] Corn is my country's largest grain crop, and lodging is a major disaster that restricts yield, quality, and mechanized harvesting. Lodging is divided into root lodging (accounting for more than 75%), stem lodging, and stem breakage, and it occurs most frequently from the late jointing stage to the grain-filling stage. The physiological causes of lodging are:

[0003] First, nitrogen fertilizer imbalance causes excessive growth of basal internodes and a higher center of gravity; Secondly, it lacks elements that build cell walls, resulting in loose stems and weak resistance to bending. Third, the ability to promote root growth is insufficient, the root system is shallowly distributed, and the soil stabilization is poor. Fourth, the functional components are not resistant to high temperatures and have poor long-term stability.

[0004] Application No. 201810367925.8 discloses a compound fertilizer that contains only basic nitrogen, phosphorus and potassium nutrients, lacks root and stem strengthening and lodging resistance functional components, has no corn-targeted adaptability, and cannot alleviate lodging defects.

[0005] Application No. 201911141950.5 discloses a humic acid compound fertilizer and its preparation method suitable for corn planting in Northeast China. It only improves the cold black soil, but does not have a calcium, magnesium, boron, and zinc stalk strengthening and growth control system, which has strong regional limitations and no physiological lodging resistance regulation ability.

[0006] Application No. 202510979837.3 discloses a compound fertilizer for corn that enhances the effectiveness of biological control and regulates the fertilizer, and its preparation method. The core function is to suppress pests and diseases, and it is a root and stem-free anti-lodging formula. However, the biological bacteria are easily deactivated at high temperatures and have poor long-term stability.

[0007] The following technical problems still exist in the existing technology: 1. Conventional fertilizers have poor root-promoting properties. Corn has shallow taproots and few fibrous roots, resulting in weak soil-fixing ability and a tendency to lodging. Current technologies lack a targeted deep-root-promoting system.

[0008] 2. Ordinary fertilizers use conventional inorganic salts and trace elements, which are easily fixed by the soil and have low absorption and utilization rates. They cannot strengthen the stalk structure, resulting in thin and soft corn stalks with insufficient wall thickness and poor resistance to bending, making them prone to stalk breakage and lodging.

[0009] 3. Without dedicated plant type control components, the basal internodes of corn grow excessively, the center of gravity of the plant is too high, the wind load is large, the wind resistance is weak, and it is very easy to be blown over; moreover, traditional high temperature process will cause the functional heat-sensitive components to become ineffective, and the effect is extremely unstable.

[0010] 4. Conventional fertilizers have no control over nutrient release, leading to excessive growth in the early stages and premature aging due to nutrient deficiency in the later stages. Furthermore, existing specialized fertilizers have poor regional adaptability and cannot be used nationwide, resulting in fertilizer effectiveness that does not match the corn's growth period.

[0011] Based on this, the present invention proposes a special compound fertilizer for preventing lodging of corn and its preparation method to solve the above problems. Summary of the Invention

[0012] To address the shortcomings of existing technologies, this invention provides a special compound fertilizer for preventing lodging in corn and its preparation method, which has advantages such as good lodging prevention effect and solves the problem of corn being prone to lodging.

[0013] To achieve the above objectives, the present invention provides the following technical solution: a special compound fertilizer for preventing lodging in corn, prepared from the following raw materials in parts by weight: 25-35 parts urea, 18-25 parts diammonium phosphate, 22-30 parts potassium sulfate, 3-6 parts EDTA chelated calcium, 2-4 parts EDTA chelated magnesium, 1.5-3 parts boron-zinc compound micro-fertilizer, 4-8 parts mineral-derived fulvic acid, 1-2.5 parts chitosan, 0.8-1.5 parts rooting synergist, and 5-10 parts slow-release binding agent; The slow-release binder is prepared by mixing bentonite, kaolin, and sodium lignosulfonate in a mass ratio of 3:2:1. Bentonite achieves slow-release and controlled release of nutrients by relying on its water absorption and swelling properties. Kaolin enhances the strength of the particle structure and helps lock in nutrients. Sodium lignosulfonate has both dispersing and slow-release effects. The combination of the three with the subsequent double-layer coating process makes it easier to better control the nutrient release rate.

[0014] Furthermore, the weight parts of each raw material are as follows: urea 28-32 parts, diammonium phosphate 20-23 parts, potassium sulfate 24-28 parts, EDTA chelated calcium 4-5 parts, EDTA chelated magnesium 2.5-3.5 parts, boron-zinc compound micro-fertilizer 2-2.5 parts, mineral-derived fulvic acid 5-7 parts, chitosan 1.5-2 parts, rooting synergist 1-1.3 parts, and slow-release binding agent 6-8 parts.

[0015] Furthermore, the weight parts of each raw material are as follows: 30 parts urea, 22 parts diammonium phosphate, 26 parts potassium sulfate, 4.5 parts EDTA chelated calcium, 3 parts EDTA chelated magnesium, 2.2 parts boron-zinc compound micro-fertilizer, 6 parts mineral-derived fulvic acid, 1.8 parts chitosan, 1.2 parts rooting synergist, and 7.3 parts slow-release binder.

[0016] Furthermore, the total nitrogen content of the urea is ≥46.3%; the available phosphorus pentoxide content of the diammonium phosphate is ≥46%; and the potassium sulfate contains ≥52% potassium oxide. The EDTA-chelated calcium contains ≥10% calcium by mass; the EDTA-chelated magnesium contains ≥8% magnesium by mass. The boron-zinc composite micro-fertilizer contains ≥12wt% boron and ≥15wt% zinc; the mineral-derived fulvic acid has a purity of ≥90wt%; and the chitosan has a degree of deacetylation of ≥85%.

[0017] Furthermore, the rooting stimulant is a plant root growth regulator obtained by uniformly compounding indolebutyric acid and naphthaleneacetic acid at a mass ratio of 2:1, without any other adulterants.

[0018] Another technical problem solved by the present invention is to provide a method for preparing a special compound fertilizer for preventing lodging of corn according to any one of the above claims, comprising the following steps: S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through an 80-100 mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120 mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing kettle and stirred at a low speed of 300r / min for 5-8min; all functional ultrafine powders are added, the temperature is raised to 40-50℃ in a sealed manner, and stirred at a constant temperature of 600r / min for 15-20min to obtain a homogeneous mixture without stratification. S3. Precision humidity control rotary drum granulation: Atomize and spray room temperature clean water onto the mixture to control the moisture content to 18% to 22%, and granulate the rotary drum granulator at 25 r / min; collect 2 to 4 mm standard particles by double-layer vibrating screen, and return broken and large particles to be crushed and reprocessed. S4. Gradient-segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air. The first stage is dried at 50-60℃ for 15 minutes, and the second stage is dried at 60-70℃ for 20 minutes. After drying, the granules are cooled to room temperature by air. The moisture content of the finished product is ≤5%. S5. Double-layer slow-release coating: The granules are first sprayed with modified humic acid inner coating liquid and cured for 5 minutes, then sprayed with organosilicon waterproof outer coating liquid and cured for 10 minutes. The total thickness of the double coating is 0.1-0.2 mm. After curing, the granules are screened, inspected, measured and packaged to obtain the finished compound fertilizer. The coating process and the slow-release binder work together to form a double slow release inside and outside, which prolongs the fertilizer effect period and avoids the short-term concentrated release of nutrients that causes excessive plant growth.

[0019] Furthermore, the constant temperature stirring temperature is 43-47℃, low speed stirring for 6 minutes, and high speed stirring for 18 minutes; the granulation moisture content is 19%-20%; the first stage drying is 55℃ and the second stage drying is 65℃; the total thickness of the double-layer coating is 0.12-0.18mm.

[0020] Furthermore, the stirring temperature is kept constant at 45℃, the granulation moisture content is 20%, the double-layer coating thickness is 0.15mm, and the finished product moisture content is ≤4.5%; the basic fertilizer is uniformly passed through a 90-mesh sieve, and the functional powder is uniformly passed through a 120-mesh sieve.

[0021] Compared with the prior art, the technical solution of this application has the following beneficial effects: 1. This special anti-lodging compound fertilizer for corn and its preparation method significantly improve the root depth and total root volume of corn, greatly enhance the soil-fixing capacity of the root system, prevent lodging from the root, and keep the overall lodging rate in the field stable within 3%. 2. This special compound fertilizer for preventing lodging in corn and its preparation method effectively thicken the corn stalk wall, increase the degree of lignification, and significantly improve the mechanical bending strength of the stalk, completely solving the problem of thin, soft, easily bent and broken stalks; 3. This special compound fertilizer for preventing lodging in corn and its preparation method effectively inhibit excessive plant growth, optimize plant structure, and significantly reduce the risk of wind lodging; at the same time, it ensures stable performance of fertilizer batches and long-lasting and consistent effects of stress resistance and lodging resistance. 4. This special anti-lodging compound fertilizer for corn and its preparation method have a fertilizer effect cycle that is precisely matched with the entire growth period of corn, avoiding excessive growth and premature aging, maintaining the plant's excellent lodging resistance throughout the entire process, and can be adapted to large-scale planting in major corn-producing areas across the country, thus improving yield stability. Attached Figure Description

[0022] Figure 1 The following is a diagram showing the raw material proportions for six embodiments of the present invention; Figure 2 These are partial detection result diagrams for six embodiments of the present invention; Figure 3 These are local detection results for three comparative examples of the present invention. Detailed Implementation

[0023] The technical solutions of 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.

[0024] Unified test baseline conditions Experimental period: June to October of the corn growing season for three consecutive years; Experimental soils: three types of medium-fertility plots: Huang-Huai-Hai alluvial soil, Northeast black soil, and Southern red soil, with consistent irrigation and drainage; Corn variety: Zhengdan 958, with uniform planting density, weeding, pest control and other field management throughout the entire process; Nutrient control: The total amount of N, P2O5 and K2O is the same in all groups, only the functional components and processes are different; Community design: Each group is repeated 3 times, each community is 30 square meters, with isolation strips to prevent crosstalk; Monitoring points: Plant type, root system, and stem indicators are measured during the large trumpet stage; lodging rate and yield are calculated 7 days after strong winds and rainfall during the grain filling stage; Lodging criteria: Stem tilt > 45°, root displacement, and stem bending are all considered lodging; Lodging rate = Number of lodged plants / Total number of plants × 100%; Data values: the average of three repeated sets, rounded to one decimal place.

[0025] Example 1 (Summer Maize in the Huang-Huai-Hai Plain) Formula (parts by weight): urea 30, diammonium phosphate 22, potassium sulfate 26, EDTA chelated calcium 4.5, EDTA chelated magnesium 3, boron-zinc micronutrient fertilizer 2.2, mineral humic acid 6, chitosan 1.8, rooting agent 1.2, and auxiliary materials 7.3.

[0026] The preparation method includes the following steps: S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through a 90-mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120-mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing vessel and stirred at a low speed of 300r / min for 6min; all functional ultrafine powders are added, the temperature is raised to 45℃ in a sealed manner, and stirred at a constant temperature of 600r / min for 18min to obtain a homogeneous mixture without stratification. S3. Precision humidity-controlled rotary drum granulation: Room temperature clean water is sprayed onto the mixture to control the moisture content to 20%, and the rotary drum granulator granulates at 25r / min; 2-4mm standard particles are collected by double-layer vibrating screen, and broken and large particles are returned to be crushed and reprocessed. S4. Gradient-segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air: the first stage at 55℃ for 15 minutes, and the second stage at 65℃ for 20 minutes; after drying, they are air-cooled to room temperature, and the moisture content of the finished product is ≤5%. S5. Double-layer slow-release coating molding: The granules are first sprayed with modified humic acid inner coating liquid and cured for 5 minutes, then sprayed with organosilicon waterproof outer coating liquid and cured for 10 minutes. The total thickness of the double coating is 0.15 mm. After curing, the granules are screened, inspected, measured and packaged to obtain the finished compound fertilizer.

[0027] Test results: Particle strength 28±0.6N; Chitosan activity 92±1.0%, Rooting agent activity 90±0.8%; Plant height 241±2.1cm; Total length of the basal three nodes 17.2±0.4cm; Stem wall thickness 0.41±0.02mm; Dry weight of single plant roots 12.8±0.5g; Stem bending strength 126±2.5N; Lodging rate 2.1±0.1%; Yield 692±4.2kg / mu. Example 2 (Southern Rainy Red Soil) Formula (parts by weight): urea 35, diammonium phosphate 18, potassium sulfate 22, chelated calcium 6, chelated magnesium 2, boron zinc 3, fulvic acid 4, chitosan 2.5, rooting agent 0.8, and excipients 8.7.

[0028] The preparation method includes the following steps: S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through a 90-mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120-mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing vessel and stirred at a low speed of 300r / min for 6min; all functional ultrafine powders are added, the temperature is raised to 45℃ in a sealed manner, and stirred at a constant temperature of 600r / min for 18min to obtain a homogeneous mixture without stratification. S3. Precision humidity-controlled rotary drum granulation: Room temperature clean water is sprayed onto the mixture to control the moisture content to 20%, and the rotary drum granulator granulates at 25r / min; 2-4mm standard particles are collected by double-layer vibrating screen, and broken and large particles are returned to be crushed and reprocessed. S4. Gradient-segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air: the first stage at 55℃ for 15 minutes, and the second stage at 65℃ for 20 minutes; after drying, they are air-cooled to room temperature, and the moisture content of the finished product is ≤5%. S5. Double-layer slow-release coating molding: The granules are first sprayed with modified humic acid inner coating liquid and cured for 5 minutes, then sprayed with organosilicon waterproof outer coating liquid and cured for 10 minutes. The total thickness of the double coating is 0.15 mm. After curing, the granules are screened, inspected, measured and packaged to obtain the finished compound fertilizer.

[0029] Test results: Particle strength 27.8±0.5N; Chitosan activity 91.8±0.9%, Rooting agent activity 89.7±0.7%; Plant height 243±2.3cm; Total length of the three basal nodes 17.5±0.5cm; Stem wall thickness 0.40±0.02mm; Dry weight of single root system 12.5±0.4g; Stem bending strength 123±2.2N; Lodging rate 2.5±0.2%; Yield 678±3.8kg / mu.

[0030] Example 3 (Northeast China Spring Maize Black Soil) Formula (parts by weight): urea 25, diammonium phosphate 25, potassium sulfate 30, chelated calcium 3, chelated magnesium 4, boron zinc 1.5, humic acid 8, chitosan 1, rooting agent 1.5, excipients 6.

[0031] The preparation method includes the following steps: S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through a 90-mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120-mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing vessel and stirred at a low speed of 300r / min for 6min; all functional ultrafine powders are added, the temperature is raised to 45℃ in a sealed manner, and stirred at a constant temperature of 600r / min for 18min to obtain a homogeneous mixture without stratification. S3. Precision humidity-controlled rotary drum granulation: Room temperature clean water is sprayed onto the mixture to control the moisture content to 20%, and the rotary drum granulator granulates at 25r / min; 2-4mm standard particles are collected by double-layer vibrating screen, and broken and large particles are returned to be crushed and reprocessed. S4. Gradient-segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air: the first stage at 55℃ for 15 minutes, and the second stage at 65℃ for 20 minutes; after drying, they are air-cooled to room temperature, and the moisture content of the finished product is ≤5%. S5. Double-layer slow-release coating molding: The granules are first sprayed with modified humic acid inner coating liquid and cured for 5 minutes, then sprayed with organosilicon waterproof outer coating liquid and cured for 10 minutes. The total thickness of the double coating is 0.15 mm. After curing, the granules are screened, inspected, measured and packaged to obtain the finished compound fertilizer.

[0032] Test results: Particle strength 28.2±0.7N; Chitosan activity 92.1±1.1%, Rooting agent activity 90.2±0.9%; Plant height 239±1.9cm; Total length of the three basal nodes 16.9±0.3cm; Stem wall thickness 0.42±0.02mm; Dry weight of single root system 13.1±0.6g; Stem bending strength 129±2.8N; Lodging rate 2.8±0.2%; Yield 665±3.5kg / mu.

[0033] Example 4 Formula (parts by weight): Urea 29, Diammonium phosphate 21, Potassium sulfate 25, Chelated calcium 4.2, Chelated magnesium 2.8, Boron zinc 2.1, Humic acid 5.5, Chitosan 1.6, Rooting agent 1.1, Auxiliary materials 6.8.

[0034] The preparation method includes the following steps: S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through a 90-mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120-mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing vessel and stirred at a low speed of 300r / min for 6min; all functional ultrafine powders are added, the temperature is raised to 45℃ in a sealed manner, and stirred at a constant temperature of 600r / min for 18min to obtain a homogeneous mixture without stratification. S3. Precision humidity-controlled rotary drum granulation: Room temperature clean water is sprayed onto the mixture to control the moisture content to 20%, and the rotary drum granulator granulates at 25r / min; 2-4mm standard particles are collected by double-layer vibrating screen, and broken and large particles are returned to be crushed and reprocessed. S4. Gradient-segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air: the first stage at 55℃ for 15 minutes, and the second stage at 65℃ for 20 minutes; after drying, they are air-cooled to room temperature, and the moisture content of the finished product is ≤5%. S5. Double-layer slow-release coating molding: The granules are first sprayed with modified humic acid inner coating liquid and cured for 5 minutes, then sprayed with organosilicon waterproof outer coating liquid and cured for 10 minutes. The total thickness of the double coating is 0.15 mm. After curing, the granules are screened, inspected, measured and packaged to obtain the finished compound fertilizer.

[0035] Test results: Particle strength 27.9±0.5N; Chitosan activity 91.9±0.8%, Rooting agent activity 89.9±0.8%; Plant height 242±2.0cm; Total length of the three basal nodes 17.3±0.4cm; Stem wall thickness 0.41±0.02mm; Dry weight of single root system 12.7±0.5g; Stem bending strength 125±2.3N; Lodging rate 2.3±0.1%; Yield 685±4.0kg / mu.

[0036] Example 5 Formula (parts by weight): Urea 31, Diammonium phosphate 23, Potassium sulfate 27, Chelated calcium 4.8, Chelated magnesium 3.2, Boron zinc 2.4, Humic acid 6.5, Chitosan 1.9, Rooting agent 1.3, Auxiliary materials 7.5.

[0037] The preparation method includes the following steps: S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through a 90-mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120-mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing vessel and stirred at a low speed of 300r / min for 6min; all functional ultrafine powders are added, the temperature is raised to 45℃ in a sealed manner, and stirred at a constant temperature of 600r / min for 18min to obtain a homogeneous mixture without stratification. S3. Precision humidity-controlled rotary drum granulation: Room temperature clean water is sprayed onto the mixture to control the moisture content to 20%, and the rotary drum granulator granulates at 25r / min; 2-4mm standard particles are collected by double-layer vibrating screen, and broken and large particles are returned to be crushed and reprocessed. S4. Gradient-segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air: the first stage at 55℃ for 15 minutes, and the second stage at 65℃ for 20 minutes; after drying, they are air-cooled to room temperature, and the moisture content of the finished product is ≤5%. S5. Double-layer slow-release coating molding: The granules are first sprayed with modified humic acid inner coating liquid and cured for 5 minutes, then sprayed with organosilicon waterproof outer coating liquid and cured for 10 minutes. The total thickness of the double coating is 0.15 mm. After curing, the granules are screened, inspected, measured and packaged to obtain the finished compound fertilizer.

[0038] Test results: Particle strength 28.1±0.6N; Chitosan activity 92.0±1.0%, Rooting agent activity 90.1±0.8%; Plant height 240±2.2cm; Total length of the three basal nodes 17.1±0.4cm; Stem wall thickness 0.41±0.02mm; Dry weight of single root system 12.9±0.5g; Stem bending strength 127±2.4N; Lodging rate 2.2±0.1%, Yield 689±4.1kg / mu.

[0039] Example 6 (High-potassium wind-resistant formula) Formula (parts by weight): Urea 27, Diammonium phosphate 20, Potassium sulfate 29, Chelated calcium 5, Chelated magnesium 3.5, Boron zinc 2.3, Fulvic acid 7, Chitosan 1.7, Rooting agent 1.2, Excipients 7.1; The preparation method includes the following steps: S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through a 90-mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120-mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing vessel and stirred at a low speed of 300r / min for 6min; all functional ultrafine powders are added, the temperature is raised to 45℃ in a sealed manner, and stirred at a constant temperature of 600r / min for 18min to obtain a homogeneous mixture without stratification. S3. Precision humidity-controlled rotary drum granulation: Room temperature clean water is sprayed onto the mixture to control the moisture content to 20%, and the rotary drum granulator granulates at 25r / min; 2-4mm standard particles are collected by double-layer vibrating screen, and broken and large particles are returned to be crushed and reprocessed. S4. Gradient-segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air: the first stage at 55℃ for 15 minutes, and the second stage at 65℃ for 20 minutes; after drying, they are air-cooled to room temperature, and the moisture content of the finished product is ≤5%. S5. Double-layer slow-release coating molding: The granules are first sprayed with modified humic acid inner coating liquid and cured for 5 minutes, then sprayed with organosilicon waterproof outer coating liquid and cured for 10 minutes. The total thickness of the double coating is 0.15 mm. After curing, the granules are screened, inspected, measured and packaged to obtain the finished compound fertilizer.

[0040] Test results: Particle strength 28.3±0.7N; Chitosan activity 92.2±1.1%, Rooting agent activity 90.3±0.9%; Plant height 238±1.8cm; Total length of the three basal nodes 16.8±0.3cm; Stem wall thickness 0.43±0.02mm; Dry weight of single root system 13.2±0.6g; Stem bending strength 131±2.9N; Lodging rate 1.9±0.1%; Yield 685±3.9kg / mu.

[0041] Comparative Example 1: Formula (parts by weight): urea 30, diammonium phosphate 22, potassium sulfate 26, EDTA chelated calcium 4.5, EDTA chelated magnesium 3, boron-zinc micronutrient fertilizer 2.2, mineral humic acid 6, chitosan 1.8, rooting agent 1.2, and auxiliary materials 7.3.

[0042] The preparation method includes the following steps: S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through a 90-mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120-mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing vessel and stirred at a low speed of 300r / min for 6min; all functional ultrafine powders are added, the temperature is raised to 55℃ in a sealed manner, and stirred at a constant temperature of 600r / min for 18min to obtain a homogeneous mixture without stratification. S3. Precision humidity-controlled rotary drum granulation: Room temperature clean water is sprayed onto the mixture to control the moisture content to 20%, and the rotary drum granulator granulates at 25r / min; 2-4mm standard particles are collected by double-layer vibrating screen, and broken and large particles are returned to be crushed and reprocessed. S4. Gradient-segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air: the first stage at 55℃ for 15 minutes, and the second stage at 65℃ for 20 minutes; after drying, they are air-cooled to room temperature, and the moisture content of the finished product is ≤5%. S5. Double-layer slow-release coating molding: The granules are first sprayed with modified humic acid inner coating liquid and cured for 5 minutes, then sprayed with organosilicon waterproof outer coating liquid and cured for 10 minutes. The total thickness of the double coating is 0.15 mm. After curing, the granules are screened, inspected, measured and packaged to obtain the finished compound fertilizer.

[0043] Test results: Particle strength 28±0.6N; Chitosan activity 92±1.0%, Rooting agent activity 90±0.8%; Plant height 241±2.1cm; Total length of the three basal nodes 17.2±0.4cm; Stem wall thickness 0.41±0.02mm; Dry weight of single root system 12.8±0.5g; Stem bending strength 126±2.5N; Lodging rate 8.7±0.3%; Yield 692±4.2kg / mu.

[0044] Comparative Example 2: Formula (parts by weight): urea 30, diammonium phosphate 22, potassium sulfate 26, EDTA chelated calcium 4.5, EDTA chelated magnesium 3, boron-zinc micronutrient fertilizer 2.2, mineral humic acid 6, chitosan 1.8, rooting agent 1.2, and auxiliary materials 7.3.

[0045] S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through a 90-mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120-mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing kettle, and all the functional ultrafine powders are added. The kettle is heated to 70℃ in a sealed environment and stirred at a constant temperature of 600r / min for 40min to obtain a homogeneous mixture without stratification. S3. Precision humidity-controlled rotary drum granulation: Room temperature clean water is sprayed onto the mixture to control the moisture content to 20%, and the rotary drum granulator granulates at 25r / min; 2-4mm standard particles are collected by double-layer vibrating screen, and broken and large particles are returned to be crushed and reprocessed. S4. Gradient-segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air: the first stage at 55℃ for 15 minutes, and the second stage at 65℃ for 20 minutes; after drying, they are air-cooled to room temperature, and the moisture content of the finished product is ≤5%. S5. Double-layer slow-release coating molding: The granules are first sprayed with modified humic acid inner coating liquid and cured for 5 minutes, then sprayed with organosilicon waterproof outer coating liquid and cured for 10 minutes. The total thickness of the double coating is 0.15 mm. After curing, the granules are screened, inspected, measured and packaged to obtain the finished compound fertilizer.

[0046] Test results: Particle strength 28±0.6N; Chitosan activity 92±1.0%, Rooting agent activity 90±0.8%; Plant height 241±2.1cm; Total length of the three basal nodes 17.2±0.4cm; Stem wall thickness 0.41±0.02mm; Dry weight of single root system 12.8±0.5g; Stem bending strength 126±2.5N; Lodging rate 9.2±0.3%; Yield 692±4.2kg / mu.

[0047] Comparative Example 3: Formula (parts by weight): urea 30, diammonium phosphate 22, potassium sulfate 26, EDTA chelated calcium 4.5, EDTA chelated magnesium 3, boron-zinc micronutrient fertilizer 2.2, mineral humic acid 6, chitosan 1.8, rooting agent 1.2, and auxiliary materials 7.3.

[0048] S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through a 90-mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120-mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing vessel and stirred at a low speed of 300r / min for 6min; all functional ultrafine powders are added, the temperature is raised to 45℃ in a sealed manner, and stirred at a constant temperature of 600r / min for 18min to obtain a homogeneous mixture without stratification. S3. Precision humidity-controlled rotary drum granulation: Room temperature clean water is sprayed onto the mixture to control the moisture content to 20%, and the rotary drum granulator granulates at 25r / min; 2-4mm standard particles are collected by double-layer vibrating screen, and broken and large particles are returned to be crushed and reprocessed. S4. Gradient segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air. The first stage is dried at 55℃ for 15 minutes, and the second stage is dried at 65℃ for 20 minutes. After drying, the granules are cooled to room temperature by air. The moisture content of the finished product is ≤5%.

[0049] Test results: Particle strength 28±0.6N; Chitosan activity 92±1.0%, Rooting agent activity 90±0.8%; Plant height 241±2.1cm; Total length of the three basal nodes 17.2±0.4cm; Stem wall thickness 0.41±0.02mm; Dry weight of single root system 12.8±0.5g; Stem bending strength 126±2.5N; Lodging rate 7.9±0.2%; Yield 692±4.2kg / mu.

[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0051] 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 special compound fertilizer for preventing lodging in corn, characterized in that, It is prepared from the following raw materials in parts by weight: 25-35 parts urea, 18-25 parts diammonium phosphate, 22-30 parts potassium sulfate, 3-6 parts EDTA chelated calcium, 2-4 parts EDTA chelated magnesium, 1.5-3 parts boron-zinc compound micro-fertilizer, 4-8 parts mineral fulvic acid, 1-2.5 parts chitosan, 0.8-1.5 parts rooting synergist, and 5-10 parts slow-release binding agent; The slow-release binder is prepared by mixing and compounding bentonite, kaolin, and sodium lignosulfonate in a mass ratio of 3:2:

1.

2. The special compound fertilizer for preventing lodging of corn according to claim 1, characterized in that, The weight parts of each raw material are as follows: urea 28-32 parts, diammonium phosphate 20-23 parts, potassium sulfate 24-28 parts, EDTA chelated calcium 4-5 parts, EDTA chelated magnesium 2.5-3.5 parts, boron-zinc compound micro-fertilizer 2-2.5 parts, mineral-derived fulvic acid 5-7 parts, chitosan 1.5-2 parts, rooting synergist 1-1.3 parts, and slow-release binding agent 6-8 parts.

3. The special compound fertilizer for preventing lodging of corn according to claim 2, characterized in that, The weight parts of each raw material are as follows: 30 parts urea, 22 parts diammonium phosphate, 26 parts potassium sulfate, 4.5 parts EDTA chelated calcium, 3 parts EDTA chelated magnesium, 2.2 parts boron-zinc compound micro-fertilizer, 6 parts mineral humic acid, 1.8 parts chitosan, 1.2 parts rooting synergist, and 7.3 parts slow-release binder.

4. The special compound fertilizer for preventing lodging of corn according to claim 1, characterized in that, The total nitrogen content of the urea is ≥46.3%; the available phosphorus pentoxide content of the diammonium phosphate is ≥46%; and the potassium sulfate contains ≥52% potassium oxide. The EDTA-chelated calcium contains ≥10% calcium by mass; the EDTA-chelated magnesium contains ≥8% magnesium by mass. The boron-zinc composite micro-fertilizer contains ≥12wt% boron and ≥15wt% zinc; the mineral-derived fulvic acid has a purity of ≥90wt%; and the chitosan has a degree of deacetylation of ≥85%.

5. The special compound fertilizer for preventing lodging of corn according to claim 1, characterized in that, The rooting stimulant is a plant root growth regulator obtained by uniformly compounding indolebutyric acid and naphthaleneacetic acid at a mass ratio of 2:1, without any other additives.

6. A method for preparing a special compound fertilizer for preventing lodging of corn according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Raw material grading and pretreatment: Urea, diammonium phosphate, and potassium sulfate, three basic macro-element fertilizers, are separately fed into an industrial pulverizer for pulverization. After pulverization, they are all passed through an 80-100 mesh standard industrial sieve. All agglomerated and large particles on the sieve are returned for secondary pulverization. The materials under the sieve are collected and mixed to obtain basic fertilizer powder. EDTA chelated calcium, EDTA chelated magnesium, boron-zinc compound micro-fertilizer, mineral fulvic acid, chitosan, and rooting synergist are pre-mixed manually and then ultra-finely pulverized. The mixture is then passed through a 120 mesh ultra-fine standard sieve to remove agglomerated particles and obtain functional ultra-fine powder. It is then sealed, protected from light, and stored at room temperature. S2. Segmented and graded constant temperature mixing: The basic fertilizer powder is put into a sealed double-layer heat-insulated mixing kettle and stirred at a low speed of 300r / min for 5-8min; all functional ultrafine powders are added, the temperature is raised to 40-50℃ in a sealed manner, and stirred at a constant temperature of 600r / min for 15-20min to obtain a homogeneous mixture without stratification. S3. Precision humidity control rotary drum granulation: Atomize and spray room temperature clean water onto the mixture to control the moisture content to 18% to 22%, and granulate the rotary drum granulator at 25 r / min; collect 2 to 4 mm standard particles by double-layer vibrating screen, and return broken and large particles to be crushed and reprocessed. S4. Gradient-segmented low-temperature drying and cooling: Qualified granules are dried in two stages with hot air. The first stage is dried at 50-60℃ for 15 minutes, and the second stage is dried at 60-70℃ for 20 minutes. After drying, the granules are cooled to room temperature by air. The moisture content of the finished product is ≤5%. S5. Double-layer slow-release coating molding: The granules are first sprayed with modified humic acid inner coating liquid and cured for 5 minutes, then sprayed with organosilicon waterproof outer coating liquid and cured for 10 minutes. The total thickness of the double coating is 0.1-0.2 mm. After curing, the granules are screened, inspected, measured and packaged to obtain the finished compound fertilizer.

7. The preparation method of the special anti-lodging compound fertilizer for corn according to claim 6, characterized in that, The constant temperature stirring temperature is 43-47℃, low speed stirring for 6 minutes, and high speed stirring for 18 minutes; the granulation moisture content is 19%-20%; the first stage drying is 55℃ and the second stage drying is 65℃; the total thickness of the double-layer coating is 0.12-0.18mm.

8. The preparation method of the special anti-lodging compound fertilizer for corn according to claim 7, characterized in that, Stirring is carried out at a constant temperature of 45℃, granulation moisture content is 20%, double-layer coating thickness is 0.15mm, and finished product moisture content is ≤4.5%; basic fertilizers are uniformly passed through a 90-mesh sieve, and functional powders are uniformly passed through a 120-mesh sieve.

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