A method for precise fertilization of corn throughout the whole growth period

Abstract

The present application relates to the technical field of corn fertilization, and provides a corn whole growth period precise fertilization method, which comprises the following steps: S1, applying base fertilizer containing nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, brown algal polysaccharide, calcium ammonium nitrate, zinc citrate, potassium humate and gamma-polyglutamic acid between corn rows when corn is sowed; S2, spraying leaf fertilizer containing potassium dihydrogen phosphate, magnesium sulfate, alginic acid and polyaspartic acid during the corn filling stage; the base fertilizer is slow-release fertilizer, and after granulation, the base fertilizer is coated with a polyester composite layer and a wax layer in sequence. According to the present application, the base fertilizer is made into double-layer coated slow-release particles and applied with sowing, the outer layer of furfural / wax forms a hydrophobic barrier to inhibit the burst release and salt damage during the seedling stage, and the inner layer of polyester composite layer forms controllable water channels and slowly hydrolyzes with time, so that nutrients are supplied in stages in a platform mode during the corn growth period, and precise fertilization and efficient utilization are achieved during the whole growth period.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of corn fertilization, in particular to a corn whole growth period precise fertilization method. BACKGROUND

[0002] As an important corn production area in China, the northwest region plays a crucial role in ensuring national food security. However, due to the natural conditions such as drought climate and poor soil, the improvement of corn yield and quality faces many challenges.

[0003] With the continuous development of agricultural technology, precise fertilization technology has gradually become an important means to improve crop yield and quality. By scientifically and reasonably applying fertilizers, the nutrient needs of crops at different growth stages can be met, the fertilizer utilization rate can be improved, and environmental pollution can be reduced.

[0004] Currently, the fertilization technology for corn in the northwest region still has problems such as inaccurate fertilization amount, unreasonable fertilization period, and single type of fertilizer, resulting in low fertilizer utilization rate and high production cost. Therefore, it is of great practical significance to develop a precise fertilization nutrition technology scheme for corn in the whole growth period in the northwest region. SUMMARY

[0005] Therefore, the present application provides a corn whole growth period precise fertilization method with high fertilizer utilization rate and yield increase.

[0006] The technical scheme of the present application is realized as follows: The present application provides a corn whole growth period precise fertilization method, which comprises the following steps:

[0007] S1, applying base fertilizer containing nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, fucoidan, calcium ammonium nitrate, zinc citrate, potassium humate, and gamma-polyglutamic acid in the corn row at the time of corn sowing;

[0008] Through the synergistic effect of nitrogen, phosphorus, potassium, fucoidan, calcium ammonium nitrate, zinc citrate, potassium humate, and gamma-polyglutamic acid, the dual goals of nutrient supply and physiological regulation are achieved. Nitrogen, phosphorus, and potassium provide the nutritional basis for the vegetative growth and reproductive growth of corn, fucoidan activates the rhizosphere microbial activity, promotes root hair growth, and improves the water and nutrient absorption capacity of the root system; calcium ammonium nitrate (used after drying) provides available calcium to prevent new leaf "edge burning" and weak stems; zinc citrate as an organic zinc source efficiently prevents the common zinc deficiency "white seedling" phenomenon of corn; potassium humate and gamma-polyglutamic acid synergistically enhance the soil water and fertilizer retention capacity, improve the nutrient interception efficiency of the root system, alleviate drought stress, and ensure full development of the ear, laying the key structural foundation for high yield.

[0009] S2, spraying leaf fertilizer at the corn filling stage, the components of the leaf fertilizer including potassium dihydrogen phosphate, magnesium sulfate, alginic acid, and polyaspartic acid;

[0010] Leaf fertilizer is sprayed at the grain filling stage, taking potassium dihydrogen phosphate and magnesium sulfate as the core, supplemented with alginic acid and polyaspartic acid, mainly playing the role of rapid nourishment, delaying aging and improving grain weight. Potassium dihydrogen phosphate rapidly replenishes phosphorus and potassium at the key period of grain filling, promotes the translocation of photosynthate to the grain, and increases the thousand-grain weight; magnesium sulfate corrects magnesium deficiency prone to occur in the middle and late stages, and maintains the photosynthetic function of leaves; alginic acid and polyaspartic acid as biological stimulants can activate the antioxidant system, enhance the tolerance of plants to adversity such as high temperature and drought, delay leaf senescence, prolong the grain filling time, and significantly improve the grain fullness and quality, which is the last guarantee to realize "stable yield and quality improvement".

[0011] The base fertilizer is a slow-release fertilizer, which is coated with a polyester composite layer and a wax layer after granulation; the raw materials of the polyester composite layer include polybutylene succinate, betaine and sodium alginate, and the raw materials of the wax layer include furfuryl alcohol, microcrystalline wax, polybutylene adipate / terephthalate and ethyl acetate.

[0012] The inner-layer polyester composite coating structure realizes precise release effect: polybutylene succinate (PBS) is used as a hydrophobic matrix to form a continuous and dense film, which effectively blocks the rapid penetration of water and nutrients, and provides a basic slow-release barrier. In the PBS matrix, hydrophilic microdomains rich in betaine are dispersed by sodium alginate through W / O emulsification technology, which can actively absorb moisture and dissolve under drought conditions, locally increase the osmotic pressure, activate the microscale mass transfer channel, and realize "drought activation"; while in a humid environment, the density of PBS still limits the overall diffusion rate, maintaining delayed release, so as to achieve the intelligent response of "drought activation, wet delay", matching the nutrient demand peak of corn from the jointing to the large bell stage.

[0013] The outer-layer wax coating constructs an efficient physical protection barrier to enhance the overall weather resistance: the hydrophobic layer composed of furfuryl alcohol and microcrystalline wax provides a hydrophobic, low-surface-energy protective shell, mainly controlling the initial wetting and entry rate of water, which is equivalent to adding an external flow resistance to the system. Polybutylene adipate / terephthalate as a key compatibilizer, its polar groups form a strong interfacial interaction with the inner-layer PBS, effectively preventing the wax layer from falling off, and ensuring the integrity of the coating structure.

[0014] On the basis of the above technical scheme, preferably, in the base fertilizer of step S1, the mass ratio of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, brown algae polysaccharide, calcium ammonium nitrate, zinc citrate, potassium humate and γ-polyglutamic acid is 5-7.5:1.5-2.5:4-6:0.04-0.1:0.6-1.2:0.08-0.15:0.2-0.5:0.05-0.15, and the fertilization amount is 40-60 kg / mu.

[0015] On the basis of the above technical scheme, preferably, the nitrogen fertilizer is one or both of ammonium bicarbonate and urea, the phosphorus fertilizer is one or both of superphosphate and calcium-magnesium phosphate, and the potassium fertilizer is one or more of potassium chloride, potassium sulfate and potassium nitrate.

[0016] On the basis of the above technical scheme, preferably, in the foliar fertilizer of step S2, the potassium dihydrogen phosphate is 1.0wt%-1.5wt%, the magnesium sulfate is 0.5wt%-1.0wt%, the alginic acid is 0.05wt%-0.15wt%, and the polyaspartic acid is 0.05wt%-0.15wt%, and the solvent is water.

[0017] On the basis of the above technical scheme, preferably, the preparation method of the polyester composite layer comprises the following steps:

[0018] S11, organic phase preparation: dissolve polybutylene succinate in a mixed solvent of ethyl acetate and ethanol at 50-55℃, and then reduce to 20-30℃ to obtain an oil phase:

[0019] S12, water phase preparation: dissolve sodium alginate in deionized water, add betaine and stir until clear to obtain a water phase;

[0020] S13, mixing: slowly add the water phase to the organic phase, high-speed shear and then filter to obtain a polyester composite layer mixture.

[0021] On the basis of the above technical scheme, preferably, in step S11, the volume ratio of ethyl acetate to ethanol is 15.6-19:1, and the amount of polybutylene succinate is 18wt%-20wt% of the total amount of ethyl acetate and ethanol; in step S12, the mass ratio of polybutylene succinate, sodium alginate and betaine is 90-100:5-8:1-3.

[0022] On the basis of the above technical scheme, preferably, the preparation method of the wax layer is: heat ethyl acetate to 70-80℃, and then sequentially add microcrystalline wax, furfural and polybutylene succinate / butylene terephthalate to obtain a wax layer mixture.

[0023] On the basis of the above technical scheme, preferably, the mass ratio of furfural, microcrystalline wax and polybutylene succinate / butylene terephthalate is 45-60:35-50:5-7, and the amount of ethyl acetate is 2.8-3.3 times the total weight of the three. The amount of ethyl acetate is calculated according to m=ρ×V.

[0024] Based on the above technical solutions, the preferred coating method is as follows: the granulated fertilizer is placed in a fluidized bed coating machine and heated to 40-45℃. Then, the polyester composite layer mixture is sprayed onto the fertilizer surface, with a spraying amount of 5.5%-7.5% of the initial fertilizer mass. After the polyester composite layer dries, the wax layer mixture is sprayed, with a spraying amount of 3%-4.5% of the initial fertilizer mass.

[0025] The method for precise fertilization of maize throughout its entire growth period, as proposed in this invention, has the following advantages over existing technologies:

[0026] This method involves preparing the base fertilizer into double-coated slow-release granules and applying it during sowing. The outer layer of rice bran wax / microcrystalline wax and the compatible modified poly(adipic acid) / butylene terephthalate form a hydrophobic barrier, which inhibits sudden release and salt damage during the seedling stage. The inner layer of polybutylene succinate, combined with betaine and sodium alginate, constructs a controllable water channel and slow-release network, enabling the release of nitrogen, phosphorus, and potassium as needed from the seedling stage to the jointing stage. Nitrogen drives leaf formation and assimilation, phosphorus ensures root extension and energy metabolism, and potassium enhances drought resistance and promotes osmotic regulation. Calcium ammonium nitrate provides readily available Ca and nitrate N in the early and mid-stages, strengthens cell walls and stem toughness, and reduces leaf edge scorching. Zinc citrate maintains high availability in an organic complex state, continuously preventing zinc deficiency bleaching and promoting meristematic tissue activity. Potassium humate and γ-polyglutamic acid increase soil cation exchange capacity and water and fertilizer retention capacity, enhance the rhizosphere's interception of NPK and micronutrients, and buffer against drought and flood fluctuations. Brown algae polysaccharides and betaine work together as biostimulants to activate rhizosphere microorganisms and root hair differentiation, solidify the early root framework, and improve carbon and nitrogen metabolism efficiency under stress. During the grain-filling stage, potassium dihydrogen phosphate, magnesium sulfate, alginic acid, and polyaspartic acid are used to provide targeted P and Mg to promote grain filling, thereby achieving precise fertilization throughout the entire growth period from seedling emergence to maturity, including low initial release, plateau supply, and late-stage top supplementation. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] The γ-polyglutamic acid (solid) used in this invention was purchased from Shandong Peptide and Biotechnology Co., Ltd., product model 301, with a PGA content ≥30%. Polyaspartic acid (solid) was purchased from Shandong Yuanlian Chemical Co., Ltd., and polybutylene succinate was purchased from Xuke New Materials (Shandong) Co., Ltd. Polybutylene adipate / terephthalate was purchased from Maclean's, model P729139, in powder form.

[0029] The base fertilizer is mixed with 1wt% of the binder (sodium lignosulfonate) and 3wt% of the bentonite, granulated by a machine to form spherical particles with a diameter of 4-6mm.

[0030] Example 1

[0031] The corn whole growth period precision fertilization method of the embodiment comprises the following steps:

[0032] S1, base fertilizer containing nitrogen fertilizer (urea), phosphorus fertilizer (superphosphate), potassium fertilizer (potassium sulfate), fucoidan, calcium ammonium nitrate, zinc citrate, potassium humate and gamma-polyglutamic acid is applied when corn is sown. The mass ratio of the nitrogen fertilizer, the phosphorus fertilizer, the potassium fertilizer, the fucoidan, the calcium ammonium nitrate, the zinc citrate, the potassium humate and the gamma-polyglutamic acid is 6:2:5:0.5:1:0.1:0.3:0.1, and 40kg is configured. The base fertilizer is applied with the corn seeds according to the use amount of 40kg per mu.

[0033] The base fertilizer is a slow-release fertilizer, which is coated with a polyester composite layer and a wax layer in sequence after granulation. The preparation method of the slow-release fertilizer is as follows:

[0034] S11, preparation of the polyester composite layer material:

[0035] Preparation of the organic phase: 90g of polybutylene succinate is dissolved in 450mL of ethyl acetate and 50mL of ethanol mixed solvent under the condition of 55℃, and then cooled to 25℃ to obtain the oil phase.

[0036] Preparation of the aqueous phase: 7g of sodium alginate is dissolved in 80mL of deionized water, and 2g of betaine is added and stirred until clear to obtain the aqueous phase.

[0037] Mixing: the aqueous phase is slowly added to the organic phase, and after high-speed shearing at 10000rpm, the polyester composite layer mixture is obtained by filtering through a 20μm filter membrane.

[0038] S12, preparation of the wax layer material: 300mL of ethyl acetate is heated to 75℃, and then 45g of microcrystalline wax, 45g of furfuryl alcohol and 6.5g of polybutylene succinate are sequentially added to obtain the wax layer mixture.

[0039] S13, coating: the granulated base fertilizer is placed in a blender, heated to 40℃, and then the polyester composite layer mixture is sprayed onto the surface of the fertilizer, with a spraying amount of 6% of the initial fertilizer mass. After the polyester composite layer is dried, the wax layer mixture is sprayed, with a spraying amount of 4% of the initial fertilizer mass.

[0040] The base fertilizer application method is to apply the fertilizer between the rows of corn seeds, with a distance of 10cm from the seeds, and a fertilization depth of 15-20cm.

[0041] S2, foliar fertilization is carried out by using a plant protection unmanned aerial vehicle during the corn filling stage, and the components of the foliar fertilizer include potassium dihydrogen phosphate, magnesium sulfate, alginic acid and polyaspartic acid. Among them, the mass fraction of potassium dihydrogen phosphate is 1.3%, the mass fraction of magnesium sulfate is 0.8%, the mass fraction of alginic acid is 0.1%, and the mass fraction of polyaspartic acid is 0.1%, and the solvent is water.

[0042] Example 2

[0043] The precise fertilization method for corn during the whole growth period of the embodiment includes the following steps:

[0044] S1, base fertilizer containing nitrogen fertilizer (mass ratio of ammonium bicarbonate to urea 1:3), phosphorus fertilizer (mass ratio of superphosphate to calcium magnesium phosphate 1:1), potassium fertilizer (mass ratio of potassium chloride, potassium sulfate and potassium nitrate 1:1:1), brown algae polysaccharide, calcium ammonium nitrate, zinc citrate, potassium humate and γ-polyglutamic acid is applied when corn is sown; wherein the mass ratio of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, brown algae polysaccharide, calcium ammonium nitrate, zinc citrate, potassium humate and γ-polyglutamic acid is 7.5:2.5:6:0.04:1.2:0.15:0.5:0.15, 50 kg is configured, and the amount of 50 kg per mu is applied together with the sowing of corn. The fertilization method is: fertilization is carried out in the row of corn, the distance between the seed and the seed is 10 cm, and the fertilization depth is 15-20 cm.

[0045] S2, foliar fertilization is carried out by using a plant protection unmanned aerial vehicle during the corn filling stage, and the components of the foliar fertilizer include potassium dihydrogen phosphate, magnesium sulfate, alginic acid and polyaspartic acid. Among them, the mass fraction of potassium dihydrogen phosphate is 1.0%, the mass fraction of magnesium sulfate is 0.5%, the mass fraction of alginic acid is 0.05%, and the mass fraction of polyaspartic acid is 0.05%, and the solvent is water.

[0046] The above base fertilizer is a slow-release fertilizer, which is coated with a polyester composite layer and a wax layer after granulation. The preparation method of the slow-release fertilizer is as follows:

[0047] S11, preparation of polyester composite layer material:

[0048] Preparation of organic phase: 100 g of polybutylene succinate is dissolved in 475 mL of ethyl acetate and 25 mL of ethanol mixed solvent under the condition of 50°C, and then cooled to 30°C to obtain an oil phase.

[0049] Preparation of aqueous phase: 8 g of sodium alginate is dissolved in 80 mL of deionized water, 3 g of betaine is added and stirred until clear to obtain an aqueous phase.

[0050] Mixing: the aqueous phase is slowly added to the organic phase, and after high-speed shearing at 10000 rpm, the polyester composite layer mixture is filtered through a 20 μm filter membrane.

[0051] S12, Preparation of wax layer material: 350 mL of ethyl acetate was heated to 80℃, and 35 g of microcrystalline wax, 60 g of furfuryl alcohol and 7 g of polybutylene succinate were sequentially added to obtain a wax layer mixture.

[0052] S13, Coating: The granulated fertilizer was placed in a blender and heated to 45℃, then the polyester composite layer mixture was sprayed onto the surface of the fertilizer, the spraying amount was 5.5% of the initial fertilizer mass; after the polyester composite layer was dried, the wax layer mixture was sprayed, the spraying amount was 3% of the initial fertilizer mass.

[0053] Example 3

[0054] The corn full growth period precision fertilization method of the embodiment includes the following steps:

[0055] S1, Base fertilizer containing nitrogen fertilizer (urea), phosphorus fertilizer (calcium magnesium phosphate), potassium fertilizer (potassium chloride), fucoidan, calcium ammonium nitrate, zinc citrate, potassium humate and γ-polyglutamic acid is applied when corn is sown; wherein the mass ratio of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, fucoidan, calcium ammonium nitrate, zinc citrate, potassium humate and γ-polyglutamic acid is 5:1.5:4:0.1:0.6:0.08:0.2:0.05, 60 kg is configured, and the amount of 60 kg per mu is applied together with the sowing of corn. The fertilization method is: fertilization is carried out between the rows of corn, the distance from the seed is 10 cm, and the fertilization depth is 15-20 cm.

[0056] S2, Leaf fertilizer is applied by plant protection unmanned aerial vehicle during corn filling period, the components of leaf fertilizer include potassium dihydrogen phosphate, magnesium sulfate, alginic acid and polyaspartic acid. Potassium dihydrogen phosphate 1.5wt%, magnesium sulfate 1.0wt%, alginic acid 0.15wt% and polyaspartic acid 0.15wt%, the solvent is water.

[0057] The above base fertilizer is slow-release fertilizer, which is coated with polyester composite layer and wax layer in turn after granulation, and the preparation method of slow-release fertilizer is as follows:

[0058] S11, Preparation of polyester composite layer material

[0059] Preparation of organic phase: 95 g of polybutylene succinate was dissolved in 460 mL of ethyl acetate and 40 mL of ethanol mixed solvent at 55℃, and then cooled to 25-30℃ to obtain the oil phase.

[0060] Preparation of aqueous phase: 5 g of sodium alginate was dissolved in 80 mL of deionized water, 1 g of betaine was added and stirred until clear to obtain the aqueous phase.

[0061] Mixing: the aqueous phase was slowly added to the organic phase, and after high-speed shearing at 10000 rpm, the polyester composite layer mixture was obtained by filtering through a 20 μm filter membrane.

[0062] S12, Preparation of wax layer material: 350 mL of ethyl acetate was heated to 70℃, and 42 g of microcrystalline wax, 50 g of furfuryl alcohol and 5 g of polybutylene succinate were sequentially added to obtain a wax layer mixture.

[0063] S13, Coating: The granulated fertilizer was placed in a blender and heated to 45℃, then the polyester composite layer mixture was sprayed onto the surface of the fertilizer, the spraying amount was 7.5% of the initial fertilizer mass; after the polyester composite layer was dried, the wax layer mixture was sprayed, the spraying amount was 4.5% of the initial fertilizer mass.

[0064] Example 4

[0065] The corn full growth period precision fertilization method of the present embodiment comprises the following steps:

[0066] S1, Base fertilizer containing nitrogen fertilizer (ammonium bicarbonate), phosphorus fertilizer (calcium magnesium phosphate), potassium fertilizer (potassium nitrate), fucoidan, calcium ammonium nitrate, zinc citrate, potassium humate and γ-polyglutamic acid was applied when corn was sown; wherein the mass ratio of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, fucoidan, calcium ammonium nitrate, zinc citrate, potassium humate and γ-polyglutamic acid was 6:2:3.5:0.1, 7:2.5:6:0.1:1.2:0.15:0.5:0.15, 45 kg was configured, and the amount of 45 kg per mu was applied together with the sowing of corn. The fertilization method is: fertilization is carried out in the row of corn, the distance between the seed and the fertilizer is 10 cm, and the fertilization depth is 15-20 cm.

[0067] S2, Leaf fertilizer was sprayed by plant protection unmanned aerial vehicle during corn filling period, the components of leaf fertilizer included potassium dihydrogen phosphate, magnesium sulfate, alginic acid and polyaspartic acid. Potassium dihydrogen phosphate 1.0wt%, magnesium sulfate 1.0wt%, alginic acid 0.1wt% and polyaspartic acid 0.15wt%, solvent was water.

[0068] The above base fertilizer is slow-release fertilizer, which is coated with polyester composite layer and wax layer after machine mixing and granulation (diameter 3-5 mm), and the preparation method of slow-release fertilizer is as follows:

[0069] S11, Preparation of polyester composite layer material:

[0070] Preparation of organic phase: 96 g of polybutylene succinate was dissolved in 470 mL of ethyl acetate and 30 mL of ethanol mixed solvent at 55℃, then cooled to 30℃ to obtain the oil phase.

[0071] Preparation of aqueous phase: 6 g of sodium alginate was dissolved in 80 mL of deionized water, 2.5 g of betaine was added and stirred until clear to obtain the aqueous phase.

[0072] Mixing: the water phase was slowly added into the organic phase, and the polyester composite layer mixture was obtained by filtering through a 20 μm filter membrane after high-speed shearing at 10000 rpm.

[0073] S12, Preparation of the wax layer material: 300 mL of ethyl acetate was heated to 70℃, and 35 g of microcrystalline wax, 55 g of furfuryl alcohol and 6 g of polybutylene adipate / terephthalate were sequentially added to obtain the wax layer mixture after dissolution.

[0074] S13, Coating: the granulated fertilizer was placed in a blender and heated to 45℃, and then the polyester composite layer mixture was sprayed onto the surface of the fertilizer, with a spraying amount of 7% of the initial fertilizer mass; after the polyester composite layer was dried, the wax layer mixture was sprayed, with a spraying amount of 4% of the initial fertilizer mass.

[0075] Comparative Example 1

[0076] The difference between Comparative Example 1 and Example 1 is that the base fertilizer does not include alginate, and the rest is the same as Example 1.

[0077] Comparative Example 2

[0078] The difference between Comparative Example 2 and Example 1 is that the base fertilizer does not include γ-polyglutamic acid, and the rest is the same as Example 1.

[0079] Comparative Example 3

[0080] The difference between Comparative Example 3 and Example 1 is that the foliar fertilizer does not include alginic acid and polyaspartic acid, and the rest is the same as Example 1.

[0081] Comparative Example 4

[0082] The difference between Comparative Example 4 and Example 1 is that the base fertilizer is only granulated, without coating the polyester composite layer and the wax layer, and the rest is the same as Example 1.

[0083] Comparative Example 5

[0084] The difference between Comparative Example 5 and Example 1 is that the base fertilizer is only coated with the polyester composite layer, and the rest is the same as Example 1.

[0085] Comparative Example 6

[0086] The difference between Comparative Example 6 and Example 1 is that the polyester composite layer material does not contain betaine, and the rest is the same as Example 1.

[0087] Comparative Example 7

[0088] The difference between Comparative Example 7 and Example 1 is that the wax layer material does not contain polybutylene adipate / terephthalate, and the rest is the same as Example 1.

[0089] Comparative Example 8

[0090] The difference between Comparative Example 8 and Example 1 is that the content of sodium alginate exceeds the limited range, specifically 14 g, and the rest is the same.

[0091] Comparative Example 9

[0092] The difference between Comparative Example 9 and Example 1 is that the content of betaine exceeds the limited range, specifically 6 g, and the rest is the same.

[0093] Comparative Example 10

[0094] The difference between Comparative Example 10 and Example 1 is that the content of polybutylene adipate / terephthalate exceeds the limited range, specifically 14 g, and the rest is the same.

[0095] The test field of the present application is located in Gulang County, Wuwei City, Gansu Province, the soil fertility is consistent, the corn planted is spring corn, the variety is Jingke 968, and the machine sowing is carried out on April 20, 2024, and the harvesting is carried out on August 30. The planting density is 60 cm in row spacing and 25 cm in plant spacing. The corn planting area of each example or comparative example is 60 m 2 , during the growth period, normal pest control, watering, pesticide spraying amount and watering amount are almost equal, the field management of examples and comparative examples is consistent, and external factor interference is excluded.

[0096] After the corn emerges, the emergence rate is detected, and the corn root length and final yield are detected at the time of harvesting. The corn root length detection method: five points are taken in each example and comparative example test field by five-point method, and the final average value is taken. The results are shown in Table 1.

[0097] Table 1 Corn growth and yield

[0098]

[0099] It can be known from Example 1 and Comparative Examples 1-3 that the brown algal polysaccharide in base fertilizer, the gamma-polyglutamic acid in topdressing, and the sodium alginate and polyaspartic acid in foliar fertilizer all have a greater impact on yield. Among them, the impact of brown algal polysaccharide and gamma-polyglutamic acid is the greatest.

[0100] It can be known from Comparative Examples 4 and 5 that without coating or only coating a polyester composite layer, the fertilizer is released too fast in the early stage and the fertilizer efficiency is insufficient in the later stage, which cannot meet the growth of corn in the later stage, thereby leading to yield reduction.

[0101] Water resistance test of slow-release fertilizer: 20 g of slow-release fertilizer prepared in the above-mentioned Example 1 and Comparative Examples 5-10 is soaked in 500 g of water, respectively, and placed in a 25℃ constant temperature box for 60 days, and then the urea dissolution rate is determined according to the standard GB / T 23348-2009 slow-release fertilizer, and the test results are shown in Table 2.

[0102] Table 2 Urea dissolution rate (%)

[0103]

[0104] Table 2 shows that Comparative Example 5 lacks a hydrophobic wax layer, which results in fast initial water absorption and accelerated urea dissolution; Comparative Example 6 lacks betaine, and the emulsion is unstable, the coating is uneven, and water rapidly penetrates, which in turn leads to faster initial dissolution and overall faster dissolution; Comparative Example 7 lacks polybutylene adipate terephthalate, and the wax layer is poorly attached and easily falls off, which leads to accelerated urea dissolution; Comparative Example 8 has an excessive amount of sodium alginate (hydrophilic phase), which leads to an increase in porosity and permeability coefficient, and thus accelerated urea dissolution; Comparative Example 9 also has an excessive amount of betaine (hydrophilic salt), which also leads to accelerated urea dissolution; and Comparative Example 10 has an excessive amount of polar grafting material (polybutylene adipate terephthalate), which changes the wax phase crystal type and brittleness, and thus leads to accelerated urea dissolution.

[0105] The optimal window for double-layer coating is that the inner layer is a moderately hydrophilic polyester composite layer (sodium alginate and betaine are within a limited range), and the outer layer contains a small amount of polybutylene adipate terephthalate (PBAT) in the wax phase, which together achieve low initial release and smooth long-period release. Any change that weakens the hydrophobic barrier of the outer layer or destroys the adhesion between the layers will significantly worsen water resistance; similarly, an excessive amount of sodium alginate and betaine will lead to excessive porosity and advanced release. The data of Example 1 represent a good level of water resistance against burst release and full coverage during the growth period, which is more in line with the fertilizer requirement law of corn in the northwest region of China from the jointing to the grouting stage.

[0106] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for precision fertilization of corn throughout the whole growth period, characterized in that, The method comprises the following steps: S1, applying base fertilizer containing nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, brown algae polysaccharide, zinc citrate and humic acid potassium between corn rows when corn is sown; S2, spraying foliage fertilizer at the corn filling stage, the components of the foliage fertilizer including potassium dihydrogen phosphate, magnesium sulfate, alginic acid and polyaspartic acid; The base fertilizer is slow-release fertilizer, and after granulation, a polyester composite layer and a wax layer are coated in sequence; The raw materials of the polyester composite layer include polybutylene succinate, betaine and sodium alginate, and the raw materials of the wax layer include furfurfuryl alcohol, microcrystalline wax, polybutylene succinate and ethyl acetate; The preparation method of the polyester composite layer comprises the following steps: S11, organic phase preparation: polybutylene succinate is dissolved in a mixed solvent of ethyl acetate and ethanol under the condition of 50-55 DEG C, and then reduced to 20-30 DEG C to obtain an oil phase: S12, water phase preparation: sodium alginate is dissolved in deionized water, and betaine is added and stirred until clear to obtain a water phase; S13, mixing: the water phase is slowly added to the organic phase, and after high-speed shearing, a polyester composite layer mixture is obtained by filtration; The preparation method of the wax layer is as follows: ethyl acetate is heated to 70-80 DEG C, and then microcrystalline wax, furfurfuryl alcohol and polybutylene succinate are sequentially added and dissolved to obtain a wax layer mixture.

2. The method for precise fertilization of the whole growth period of corn according to claim 1, characterized in that: In the base fertilizer of step S1, the mass ratio of the nitrogen fertilizer, the phosphorus fertilizer, the potassium fertilizer, the brown algae polysaccharide, the calcium ammonium nitrate, the zinc citrate, the humic acid potassium and the gamma-polyglutamic acid is 5-7.5:1.5-2.5:4-6:0.04-0.1:0.6-1.2:0.08-0.15:0.2-0.5:0.05-0.15, and the fertilization amount is 40-60 kg / mu.

3. The method for precise fertilization of the whole growth period of corn according to claim 2, characterized in that: In the foliage fertilizer of step S2, the potassium dihydrogen phosphate is 1.0wt%-1.5wt%, the magnesium sulfate is 0.5wt%-1.0wt%, the alginic acid is 0.05wt%-0.15wt%, and the polyaspartic acid is 0.05wt%-0.15wt%, and the solvent is water.

4. The method for precision fertilization of the whole growth period of corn according to claim 1, characterized in that: In step S11, the volume ratio of ethyl acetate and ethanol is 15.6-19:1, and the mass of polybutylene succinate is 18wt%-20wt% of the total mass of ethyl acetate and ethanol.

5. The method for precision fertilization of the whole growth period of corn according to claim 1, characterized in that: In step S12, the mass ratio of polybutylene succinate, sodium alginate and betaine is 90-100:5-8:1-3.

6. The method for precision fertilization of the whole growth period of corn according to claim 1, characterized in that: The mass ratio of furfurfuryl alcohol, microcrystalline wax and polybutylene succinate is 45-60:35-50:5-7, and the amount of ethyl acetate is 2.8-3.3 times the total weight of the three.

7. The method for precision fertilization of the whole growth period of corn according to claim 1, characterized in that: The coating method is as follows: after granulation, the fertilizer is placed in a fluidized bed coating machine, heated to 40-45 DEG C, then the polyester composite layer mixture is sprayed onto the surface of the fertilizer, and the spraying amount is 5.5%-7.5% of the mass of the initial fertilizer; after the polyester composite layer is dried, the wax layer mixture is sprayed, and the spraying amount is 3%-4.5% of the mass of the initial fertilizer.

8. The method for precision fertilization of the whole growth period of corn according to claim 1, characterized in that: The nitrogen fertilizer is one or both of ammonium bicarbonate and urea, the phosphorus fertilizer is one or both of superphosphate and calcium-magnesium phosphate fertilizer, and the potassium fertilizer is one or more of potassium chloride, potassium sulfate and potassium nitrate.

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