A slow-release fertilizer and a method for loading the same on a seedling tray

Abstract

The application discloses a slow-release fertilizer and a method for loading the slow-release fertilizer on a seedling raising tray, and belongs to the technical field of slow-release fertilizers. The slow-release fertilizer is a slow-release fertilizer particle, which comprises a nutrient component and other components; the nutrient component is divided into a first nutrient component and a second nutrient component with the same component; and the slow-release fertilizer particle comprises, from inside to outside, an inner layer, a middle layer, a disintegration layer and an outer layer. The slow-release fertilizer particle can realize periodical and quantitative release of nutrients, matches the growth rule of seedlings, and realizes the purpose of accurately providing nutrients. In addition, the application adopts a specific method to load the slow-release fertilizer particle in the seedling raising tray in a seedling raising tray forming process, solves the problem of insufficient seedling raising fertilizer efficiency of the existing seedling raising tray, does not change the original production line of the seedling raising tray, is simple and convenient, can meet the basic growth requirement of seedlings, has low requirement on the nutrient component of a nutrient substrate in actual production and application, and is suitable for popularization and use.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, and in particular to a slow-release fertilizer and a method for loading it onto a seedling tray. Background Technology

[0002] Slow-release fertilizers, as a type of green and environmentally friendly fertilizer with low pollution, can effectively control the release rate of nutrients, extend the fertilization period, meet the nutrient needs of crops throughout their entire growth cycle, maximize fertilizer utilization, and improve the economic, social, and environmental benefits of fertilization.

[0003] Most existing slow-release fertilizers are in coated form. Their nutrient release principle is the process of solid fertilizer nutrients turning into liquid, and the release rate depends on the nutrient concentration difference inside and outside the membrane. Therefore, in the early stages of fertilization, the concentration difference is large, and the nutrient release rate is relatively fast. However, many crops absorb nutrients slowly in the early stages of growth (the soil itself can provide some basic nutrients, and crop growth is slow in the early stages), easily leading to a mismatch between nutrient release and crop growth patterns. Although the existing industry standard (HG / T 4215-2011 Controlled-Release Fertilizers) limits the initial nutrient release rate of controlled-release fertilizers to no more than 12%, for many crops (such as rice and wheat), minimizing the initial nutrient release rate is crucial to ensuring that nutrient release matches the crop's growth pattern as closely as possible, promoting crop growth, and further improving fertilizer utilization. In the later stages of fertilization, as crop growth accelerates, the crop's nutrient demand increases, requiring a nutrient release rate that is maximized.

[0004] Furthermore, with the development of agricultural mechanization, machine transplanting has become widespread. Seedling raising is a crucial step in the success of machine transplanting, and it requires higher standards than conventional manual transplanting seedling raising equipment. Seedling trays are an important carrier for seedling raising.

[0005] The applicant previously developed a fully degradable rice seedling tray in a mat-like shape and its application (CN202211125892.9), which simultaneously achieves full degradation, stable tray formation, good water permeability and retention, short seedling establishment period, rapid greening, and high yield. However, because it is divided into multiple pots, the space for storing nutrient substrate in the tray is relatively small (compared to ordinary flat trays), resulting in insufficient fertilizer efficiency during seedling cultivation. Furthermore, the specifications of commercially available nutrient substrates are generally standardized. If a higher nutrient concentration is required, a separate nutrient substrate must be prepared, which demands higher nutrient content from the substrate, causing inconvenience in actual production and application, and making standardization difficult.

[0006] Invention patent CN201910978528.9 discloses a method for preparing and applying a fully nutritious biodegradable straw seedling substrate block. The prepared seedling substrate block not only has good biodegradability, but also contains a slow-release nutrient conditioner. After it is attached to the inner surface of carbonized rice husk, the rice growth nutrition in the early stage mainly comes from the seed endosperm. The nutrient controllable slow-release conditioner carrier can slowly release all the nutrients required for seedling growth in the later stage of seedling growth, so that the seedlings can continuously absorb nutrients. No additional fertilization is required in the seedling raising process, achieving precise full nutrient modulation and storage form control. This patent has the following defects: (1) It is a straw seedling substrate block, not a seedling tray, and cannot obtain seedlings with an upper pot and lower mat on the basis of ensuring full nutrition and biodegradability; (2) Its nutrient release is not precise and controllable. In the early stage of seedling, the nutrients in the slow-release nutrient conditioner are also easily released by osmosis, only the amount of release is a problem.

[0007] Invention patent CN 201910906240.0 discloses a water-resistant, acid-resistant, biodegradable biomass seedling tray and its preparation method. It uses straw to prepare a biodegradable biomass seedling tray and sets up several pots. Nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and other fertilizers are added to the raw materials for preparing the seedling tray to ensure the nutritional components for plant growth during seedling raising. This patent has the following defects: (1) The biodegradable seedling tray with pots in this patent is different from the fully degradable rice pot-shaped blanket machine transplanting seedling tray in CN 202211125892.9 in terms of raw materials and molding process, resulting in different performance (strength, water permeability and water retention) and nutrient release of the seedling tray; (2) The fertilizer in this patent is ordinary fertilizer, which is difficult to match with the growth pattern of seedlings and cannot achieve regular and quantitative nutrient release.

[0008] To address the above problems, this invention provides a controlled-release fertilizer and a method for loading it onto a seedling tray. This method not only enables the quantitative and periodic release of nutrients from the controlled-release fertilizer, matching its growth pattern with that of seedlings, but also enables the loading of the controlled-release fertilizer onto the seedling tray, thus solving the problem of insufficient fertilizer efficiency in existing seedling trays. Summary of the Invention

[0009] The purpose of this invention is to provide a controlled-release fertilizer and a method for loading it onto a seedling tray. By preparing the controlled-release fertilizer granules into a structure containing an inner layer, a middle layer, a disintegrating layer, and an outer layer, it can achieve periodic and quantitative nutrient release, matching the growth pattern of seedlings and achieving precise nutrient delivery. Furthermore, this invention employs a specific method in the seedling tray forming process to load the controlled-release fertilizer granules into the seedling tray, solving the problem of insufficient fertilizer efficiency in existing seedling trays while maintaining the original production line. This method is simple and convenient, and the resulting seedling tray containing controlled-release fertilizer granules can meet the basic growth needs of seedlings. In practical production applications, the requirements for the nutrient composition of the substrate are not high, making it suitable for widespread use.

[0010] The objective of this invention is achieved as follows:

[0011] A controlled-release fertilizer includes nutrient components and other ingredients. The controlled-release fertilizer is a controlled-release fertilizer granule. The nutrient components are divided into a first nutrient component and a second nutrient component with the same composition. The controlled-release fertilizer granule includes, from the inside out, an inner layer, a middle layer, a disintegrating layer, and an outer layer with a mass ratio of (2-3):(2-4):(0.3-0.6):(0.4-0.7). The inner layer includes the first nutrient component and starch with a mass ratio of 1:(0.05-0.1). The middle layer includes the second nutrient component, sepiolite powder, polyvinyl alcohol, and an unsaturated oil film material with a mass ratio of 1:(1-2):(0.2-0.4):(0.03-0.05). The disintegrating layer includes a disintegrant and a natural film material with a mass ratio of (0.15-0.3):1. The outer layer includes wax and a porous material with a mass ratio of 1:(0.1-0.25).

[0012] Preferably, the nutrient release period of the controlled-release fertilizer granules is 7-25 days, and the nutrient components include any combination of phosphate fertilizer (selected from superphosphate, triple superphosphate or ammonium phosphate), nitrogen fertilizer (selected from urea, ammonium nitrate, ammonium nitrate phosphate or ammonium bicarbonate), potassium fertilizer (potassium chloride, potassium sulfate or potassium dihydrogen phosphate) and trace elements (silicon, zinc, boron or selenium).

[0013] Preferably, the unsaturated oil film material comprises vegetable oil and plant-based lipid amino acids in a mass ratio of 1:(0.2-0.4), the disintegrant is one or more of dextrin, polyvinylpyrrolidone or sodium carboxymethyl starch, the natural film material is molasses, the wax is beeswax, and the porous material is one or more of molecular sieve, pumice powder, zeolite powder, and activated carbon, with a porosity of 50-80%.

[0014] Preferably, in the unsaturated oil film material, the vegetable oil is linoleic acid, and the plant-based lipid amino acid is N-linolenic acid.

[0015] The present invention also provides a method for preparing the controlled-release fertilizer, comprising the following steps:

[0016] (1) Inner layer preparation: Mix starch and water (10-30% of the starch mass) evenly, then add the first nutrient component and mix well, and then granulate into (60-80 mesh) granules 1 through a granulator;

[0017] (2) Intermediate layer covering: Add water to the second nutrient component (the amount added is 5-10 times that of the second nutrient component) and stir to dissolve. Then add sepiolite powder and let it stand for adsorption. After standing for 30-60 minutes, evaporate the water. Then add granules 1, polyvinyl alcohol, and water (the amount added is 4-8% of the mass of polyvinyl alcohol) and mix evenly. Place it in a granulator to form granules 2. Then heat the unsaturated oil film material (30-40℃) and spray it evenly onto the surface of granules 2. Cool to obtain granules 3.

[0018] (3) Disintegration layer coverage: After heating the natural membrane material (40-60℃), mix it evenly with the disintegrating agent, then spray it evenly onto the surface of particle 3, dry and cool it to obtain particle 4;

[0019] (4) Outer layer coating: Mix the molten wax (70°C) with the porous material evenly, then spray it evenly onto the surface of the particles 4, and cool it to obtain the controlled-release fertilizer.

[0020] The present invention also provides a method for loading the controlled-release fertilizer onto a seedling tray, comprising the following steps:

[0021] S1. Spray anionic compound solution onto the surface of the controlled-release fertilizer granules and then dry them to obtain the treated controlled-release fertilizer granules.

[0022] S2. In the vacuum forming step of the seedling tray preparation process, the theoretical load of slow-release fertilizer granules is put into the slurry tank, stirred evenly, and then the slurry in the slurry tank is trapped on the surface of the mold screen by the suction of the vacuum forming machine.

[0023] S3. After drying the molded product, place it in a hot press to shape it, and you will get the finished seedling tray loaded with slow-release fertilizer.

[0024] Preferably, the amount of the anionic compound solution sprayed is 2-4% of the mass of the controlled-release fertilizer granules, and the anionic compound solution is prepared by mixing potassium azeloyl diglycinate with 5-10 times the amount of water.

[0025] Preferably, the theoretical loading capacity of the controlled-release fertilizer granules in the seedling tray is 10-24 g / tray, and the porous material in the outer layer of the controlled-release fertilizer granules is pumice powder (density 0.3-0.35 g / cm³). 3The vacuum forming machine has a vacuum degree of 0.3-0.5MPa, the slurry in the slurry tank has a pH of 6.3-7.0, and the mass concentration of the controlled-release fertilizer particles in the slurry is controlled to be 0.03-0.06% (through periodic feeding and pump circulation).

[0026] The present invention also provides a closed-cell pumice powder for use in the method of loading the controlled-release fertilizer on the seedling tray. The closed-cell pumice powder is added together with porous materials when preparing the outer layer of the controlled-release fertilizer particles. The mass ratio of the closed-cell pumice powder to wax is (0.2-0.4):1. The preparation method of the closed-cell pumice powder includes the following steps: mixing molten higher fatty acids and rosin esters evenly to obtain a mixture, then spraying it onto the surface of the pumice powder while hot, and then quickly cooling it at 0-5°C after spraying to obtain the closed-cell pumice powder.

[0027] The mass ratio of the higher fatty acid to the rosin ester is 1:(0.01-0.04), and the amount of the mixture injected is 4-8% of the mass of the pumice powder. The higher fatty acid is behenic acid, and the rosin ester is ethyl rosin ester.

[0028] The present invention also provides the application of the controlled-release fertilizer or the seedling tray loaded with the controlled-release fertilizer in the cultivation of rice seedlings, rapeseed seedlings, vegetable seedlings or flower seedlings.

[0029] The seedling tray of the present invention has the following beneficial effects:

[0030] (1) The controlled-release fertilizer provided by this invention uses all green and environmentally friendly materials as raw materials, which do not pollute the environment and are biodegradable in the soil. The method of loading the controlled-release fertilizer onto the seedling tray is simple and convenient. It does not require changing the original production line of the seedling tray, nor does it require adding another production line. The controlled-release fertilizer particles are directly put into the slurry tank in the seedling tray forming step, and then the slurry in the slurry tank is trapped on the surface of the mold screen by the suction of the vacuum forming machine. It is simple and easy to operate, and convenient for practical application and production promotion.

[0031] (2) The controlled-release fertilizer granules of the present invention consist of an inner layer, a middle layer, a disintegrating layer, and an outer layer, arranged sequentially from the inside out. The outer layer is made of wax and porous material. By controlling the amount and specifications of the porous material, the rate at which water seeps from the outer layer into the disintegrating layer can be controlled, allowing the disintegrating layer to disintegrate and rupture in about 7 days, and then the nutrients in the middle layer begin to be released. The middle layer contains a second nutrient component adsorbed by sepiolite powder. By controlling the amount of sepiolite powder added and combining it with the unsaturated oil film material on the surface, the nutrients can be slowly released into the soil in 8-18 days. After the polyvinyl alcohol binder in the middle layer is dissolved by the water in the soil, the other substances in the middle layer disperse, and the nutrients in the inner layer begin to be released rapidly in about 19 days. By controlling the ratio of starch to the first nutrient component, the nutrients in the inner layer can be completely released in 7 days. Therefore, the present invention can better control the release pattern of nutrients in the controlled-release fertilizer to match the growth pattern of seedlings, promote seedling growth, and improve seedling raising efficiency.

[0032] (3) The middle layer surface of the controlled-release fertilizer of the present invention is provided with an unsaturated oil film material, which is composed of plant oil and plant-based lipid amino acids. On the one hand, it forms a slow release of the second nutrient component in the middle layer, and on the other hand, it prevents the disintegration layer from sticking to the middle layer and plays a release role, preventing the disintegration layer from carrying the middle layer material during the disintegration and rupture process, thus affecting the release pattern of the nutrients in the middle layer.

[0033] The unsaturated oil film material of this invention further selects a certain ratio of linoleic acid and N-linolenic acid, which can form a certain water-oil balance film on the surface of the seedling substrate, thereby controlling the release of the second nutrient. In addition, the surface activity of N-linolenic acid can promote the dispersion and coating of the unsaturated oil film material on the surface of the controlled-release fertilizer. Furthermore, both linoleic acid and N-linolenic acid are plant-based materials, which are green and environmentally friendly. After decomposition in the soil, N-linolenic acid can also provide certain amino acid nutrition.

[0034] (4) In the vacuum forming step of the seedling tray, the slow-release fertilizer particles are added to the slurry tank. Due to the presence of pumice powder in the slow-release fertilizer particles, the slow-release fertilizer particles can be suspended near the water surface. Under the suction of the vacuum forming machine, the suspended slow-release fertilizer particles are formed together with the slurry and can be quickly loaded into the seedling tray to obtain a seedling tray containing slow-release fertilizer particles. This solves the problem of insufficient fertilizer effect in the seedling raising process of ordinary seedling trays. Therefore, the seedling tray containing slow-release fertilizer particles of the present invention can meet the basic growth needs of seedlings through the slow-release fertilizer effect performance of the slow-release fertilizer particles. In actual use, depending on the actual application, it is possible to choose not to use nutrient substrate (only use materials such as vermiculite for fixing the root system) or only use a small amount of nutrient substrate. The requirements for the nutrient composition of the nutrient substrate are not high, and it is suitable for promotion and use.

[0035] (5) The present invention further anionizes the controlled-release fertilizer granules before placing them into the slurry tank, which can promote the dispersion of the controlled-release fertilizer granules in the slurry. The anionic compound of the present invention is further selected as potassium azeloyl diglycinate (which contains glycine molecules at both ends and a hydrocarbon group in the middle), which can form a protective layer on the surface of the controlled-release fertilizer granules, ensuring the integrity of the controlled-release fertilizer granules in the slurry tank; in addition, it can also enhance the adhesion of the controlled-release fertilizer granules when loaded in the seedling tray.

[0036] (6) The present invention also controls the pH of the slurry in the slurry tank to be 6.3-7.0. If the pH is too low, it will affect the anion content of potassium azeloyl diglycinate. If the pH is too high, it will increase the alkalinity of the seedling tray and affect the absorption of nutrients by the seedlings. Therefore, it is necessary to control the pH of the water in the container within a suitable range.

[0037] (7) Since the outer layer of the controlled-release fertilizer granules needs to be controlled for 7 days before it begins to release, the content of pumice powder in the outer layer cannot be too high, otherwise too many pores will shorten the release period of the outer layer; however, the content of pumice powder will affect the suspension of the controlled-release fertilizer granules in the slurry when loaded on the seedling tray, resulting in a low load of fertilizer granules. Therefore, this invention also adds some closed-cell pumice powder to the outer layer of the controlled-release fertilizer granules to solve the problem of the original pumice powder content being limited.

[0038] The closed-cell pumice powder of the present invention is surface coated with a mixture of high fatty acids and rosin esters, which can effectively close the pores of the pumice powder and prevent external moisture from entering. The high fatty acids have good coating properties and the rosin esters have good thickening effect, so that a strong sealing layer is formed on the surface of the prepared closed-cell pumice powder.

[0039] (8) The rosin ester of the present invention is further selected as ethyl rosin ester, which not only improves the surface hydrophobicity of closed-cell pumice powder, but also prevents higher fatty acids from penetrating into the pores of pumice powder, thus avoiding affecting the suspension of closed-cell pumice powder. In addition, both behenic acid and ethyl rosin ester used are derived from natural green materials. Ethyl rosin ester is easily hydrolyzed into rosin and ethanol in soil, which is environmentally friendly. Attached Figure Description

[0040] Figure 1 This is a graph showing the cumulative nutrient release rate of the controlled-release fertilizer of the present invention at different times. Detailed Implementation

[0041] The present invention will be further described below with reference to the embodiments and 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. It should be noted that the accompanying drawings of the present invention are all simplified and non-precise scales, used only for convenient and clear illustration of the present invention. Example 1

[0042] This embodiment provides a controlled-release fertilizer, comprising nutrient components and other ingredients. The nutrient components are divided into a first nutrient component and a second nutrient component with identical components. The controlled-release fertilizer is a controlled-release fertilizer granule, which, from the inside out, comprises an inner layer, a middle layer, a disintegrating layer, and an outer layer with a mass ratio of 2:2:0.3:0.4. The inner layer comprises the first nutrient component and starch with a mass ratio of 1:0.05. The middle layer comprises the second nutrient component, sepiolite powder, polyvinyl alcohol, and an unsaturated oil film material (linoleic acid and N-linolenic acid with a mass ratio of 1:0.2) with a mass ratio of 1:1:0.2:0.03. The disintegrating layer comprises a disintegrant (dextrin) and a natural film material (molasses) with a mass ratio of 0.15:1. The outer layer comprises wax (beeswax) and a porous material (4A molecular sieve with a porosity of 50%) with a mass ratio of 1:0.1.

[0043] The nutrient components include any combination of phosphate fertilizer (selected from superphosphate, triple superphosphate or ammonium phosphate), nitrogen fertilizer (selected from urea, ammonium nitrate, ammonium nitrate or ammonium bicarbonate), potassium fertilizer (potassium chloride, potassium sulfate or potassium dihydrogen phosphate) and trace elements (silicon, zinc, boron or selenium), with ammonium nitrate being the preferred nutrient component.

[0044] The method for preparing the controlled-release fertilizer includes the following steps:

[0045] (1) Preparation of materials: Weigh the raw materials according to the above formula;

[0046] (2) Inner layer preparation: Mix starch and water (10% of the starch mass) evenly, then add the first nutrient component and mix well, and then granulate into (60 mesh) granules 1 by a granulator;

[0047] (3) Middle layer covering: Add water (the amount added is 5 times that of the second nutrient component) to the second nutrient component and stir to dissolve. Then add sepiolite powder and let it stand for adsorption. After standing for 30 minutes, evaporate the water. Then add granules 1, polyvinyl alcohol, and water (the amount added is 4% of the mass of polyvinyl alcohol) and mix evenly. Place it in a granulator to form granules 2. Then heat the unsaturated oil film material (30°C) and spray it evenly onto the surface of granules 2. Cool to obtain granules 3.

[0048] (4) Disintegration layer coverage: After heating the natural membrane material (40°C), mix it evenly with the disintegrating agent, then spray it evenly onto the surface of particle 3, dry and cool it to obtain particle 4;

[0049] (5) Outer layer coating: Mix the molten wax (70°C) with the porous material evenly, then spray it evenly onto the surface of the particles 4, and cool it to obtain the controlled-release fertilizer. Example 2

[0050] This embodiment provides a controlled-release fertilizer, wherein the porous material in the outer layer of the fertilizer granules is pumice powder (porosity 70%, density 0.3-0.35 g / cm³). 3 The rest is the same as in Example 1.

[0051] This embodiment also provides a method for loading the controlled-release fertilizer onto a seedling tray, including the following steps:

[0052] S1. Spray anionic compound solution onto the surface of controlled-release fertilizer granules and then dry them. The amount of spraying is 2% of the mass of the controlled-release fertilizer granules, to obtain the treated controlled-release fertilizer granules. The anionic compound solution is prepared by mixing potassium azeloyl diglycinate with 5 times the amount of water.

[0053] S2. In the vacuum forming step of the seedling tray preparation process (the preparation process and specifications of the seedling tray refer to patent CN 202211125892.9), the theoretical load (10g / tray) of controlled-release fertilizer granules is put into the slurry tank (slurry mass concentration is 0.4%). The pH of the slurry in the slurry tank is controlled at 6.3. (Through periodic feeding and pump circulation) the mass concentration of controlled-release fertilizer granules in the slurry is controlled at 0.03%. After stirring evenly, the slurry in the slurry tank is trapped on the surface of the mold screen by the suction of the vacuum forming machine (0.3MPa).

[0054] S3. After drying the molded product (to a moisture content of 10-15%), place it in a hot press for shaping to obtain the finished seedling tray loaded with slow-release fertilizer. Example 3

[0055] Based on Example 2, this example provides a slow-release fertilizer, wherein the outer layer comprises wax (beeswax), porous material (pumice powder), and closed-cell pumice powder in a mass ratio of 1:0.1:0.2.

[0056] The preparation method of the closed-cell pumice powder includes the following steps: molten behenic acid and ethyl rosin ester at a mass ratio of 1:0.01 are mixed evenly, and then sprayed onto the surface of the pumice powder while hot, with the spraying amount being 4% of the mass of the pumice powder. After spraying, the mixture is quickly placed at 0°C to cool, thereby obtaining the closed-cell pumice powder.

[0057] The rest is the same as in Example 2. Example 4

[0058] This embodiment provides a controlled-release fertilizer, including nutrient components and other ingredients. The controlled-release fertilizer is a controlled-release fertilizer granule. The nutrient components are divided into a first nutrient component and a second nutrient component with the same composition. The controlled-release fertilizer granule includes, from the inside out, an inner layer, a middle layer, a disintegrating layer, and an outer layer with a mass ratio of 2.5:3:0.45:0.55. The inner layer includes the first nutrient component and starch with a mass ratio of 1:0.08. The middle layer includes the second nutrient component, sepiolite powder, polyvinyl alcohol, and unsaturated oil film material (linoleic acid and N-linolenic acid with a mass ratio of 1:0.3) with a mass ratio of 1:1.5:0.3:0.04. The disintegrating layer includes a disintegrant (polyvinylpyrrolidone) and a natural film material (molasses) with a mass ratio of 0.2:1. The outer layer includes wax (beeswax), porous material (pumice powder), and closed-cell pumice powder with a mass ratio of 1:0.18:0.3.

[0059] The nutrient components include any combination of phosphate fertilizer (selected from superphosphate, triple superphosphate or ammonium phosphate), nitrogen fertilizer (selected from urea, ammonium nitrate, ammonium nitrate or ammonium bicarbonate), potassium fertilizer (potassium chloride, potassium sulfate or potassium dihydrogen phosphate) and trace elements (silicon, zinc, boron or selenium), with ammonium nitrate being the preferred nutrient component.

[0060] The preparation method of the closed-cell pumice powder includes the following steps: molten behenic acid and ethyl rosin ester are mixed evenly in a mass ratio of 1:0.025, and then sprayed onto the surface of the pumice powder while hot, with the spraying amount being 6% of the mass of the pumice powder. After spraying, the mixture is quickly placed at 2°C to cool, thereby obtaining the closed-cell pumice powder.

[0061] The method for preparing the controlled-release fertilizer includes the following steps:

[0062] (1) Preparation of materials: Weigh the raw materials according to the above formula;

[0063] (2) Inner layer preparation: Mix starch and water (20% of the starch mass) evenly, then add the first nutrient component and mix well, and then granulate into (70 mesh) granules 1 through a granulator;

[0064] (3) Intermediate layer covering: Add water (the amount added is 8 times that of the second nutrient component) to the second nutrient component and stir to dissolve. Then add sepiolite powder and let it stand for adsorption. After standing for 45 minutes, evaporate the water. Then add granules 1, polyvinyl alcohol, and water (the amount added is 6% of the mass of polyvinyl alcohol) and mix evenly. Place it in a granulator to form granules 2. Then heat the unsaturated oil film material (35°C) and spray it evenly onto the surface of granules 2. Cool to obtain granules 3.

[0065] (4) Disintegration layer coverage: After heating the natural membrane material (50°C), mix it evenly with the disintegrating agent, then spray it evenly onto the surface of particle 3, dry and cool it to obtain particle 4;

[0066] (5) Outer layer coating: Mix the molten wax (70°C) with porous material and closed-cell pumice powder evenly, then spray it evenly onto the surface of particle 4 and cool it to obtain the slow-release fertilizer.

[0067] This embodiment also provides a method for loading the controlled-release fertilizer onto a seedling tray, including the following steps:

[0068] S1. Spray anionic compound solution onto the surface of controlled-release fertilizer granules and then dry them. The amount of spraying is 3% of the mass of the controlled-release fertilizer granules, to obtain the treated controlled-release fertilizer granules. The anionic compound solution is prepared by mixing potassium azeloyl diglycinate with 8 times the amount of water.

[0069] S2. In the vacuum forming step of the seedling tray preparation process, the theoretical load (17g / tray) of slow-release fertilizer granules is put into the slurry tank (the mass concentration of the slurry is 0.5%). The pH of the slurry in the slurry tank is controlled at 6.6. (Through periodic feeding and pump circulation) the mass concentration of the slow-release fertilizer granules in the slurry is controlled at 0.045%. After stirring evenly, the slurry in the slurry tank is trapped on the surface of the mold screen by the suction of the vacuum forming machine (0.4MPa).

[0070] S3. After drying the molded product (to a moisture content of 10-15%), place it in a hot press for shaping to obtain the finished seedling tray loaded with slow-release fertilizer.

[0071] The rest is the same as in Example 3. Example 5

[0072] This embodiment provides a controlled-release fertilizer, including nutrient components and other ingredients. The controlled-release fertilizer is a controlled-release fertilizer granule. The nutrient components are divided into a first nutrient component and a second nutrient component with the same composition. The controlled-release fertilizer granules include, from the inside out, an inner layer, a middle layer, a disintegrating layer, and an outer layer with a mass ratio of 3:4:0.6:0.7. The inner layer includes the first nutrient component and starch with a mass ratio of 1:0.1. The middle layer includes the second nutrient component, sepiolite powder, polyvinyl alcohol, and unsaturated oil film material (linoleic acid and N-linolenic acid with a mass ratio of 1:0.4) with a mass ratio of 1:2:0.4:0.05. The disintegrating layer includes a disintegrant (sodium carboxymethyl starch) and a natural film material (molasses) with a mass ratio of 0.3:1. The outer layer includes wax (beeswax), porous material (pumice powder), and closed-cell pumice powder with a mass ratio of 1:0.25:0.4.

[0073] The nutrient components include any combination of phosphate fertilizer (selected from superphosphate, triple superphosphate or ammonium phosphate), nitrogen fertilizer (selected from urea, ammonium nitrate, ammonium nitrate phosphate or ammonium bicarbonate), potassium fertilizer (potassium chloride, potassium sulfate or potassium dihydrogen phosphate) and trace elements (silicon, zinc, boron or selenium). The preferred nutrient components include urea and ammonium phosphate in a mass ratio of 4:1.

[0074] The preparation method of the closed-cell pumice powder includes the following steps: molten behenic acid and ethyl rosin ester are mixed evenly in a mass ratio of 1:0.04, and then sprayed onto the surface of the pumice powder while hot, with the spraying amount being 8% of the mass of the pumice powder. After spraying, the mixture is quickly placed at 5°C to cool, thereby obtaining the closed-cell pumice powder.

[0075] The method for preparing the controlled-release fertilizer includes the following steps:

[0076] (1) Preparation of materials: Weigh the raw materials according to the above formula;

[0077] (2) Inner layer preparation: Mix starch and water (30% of the starch mass) evenly, then add the first nutrient component and mix well, and then granulate into (80 mesh) granules 1 through a granulator;

[0078] (3) Middle layer covering: Add water to the second nutrient component (the amount added is 10 times that of the second nutrient component) and stir to dissolve. Then add sepiolite powder and let it stand for adsorption. After standing for 60 minutes, evaporate the water. Then add granules 1, polyvinyl alcohol, and water (the amount added is 8% of the mass of polyvinyl alcohol) and mix evenly. Place it in a granulator to form granules 2. Then heat the unsaturated oil film material (40°C) and spray it evenly onto the surface of granules 2. Cool to obtain granules 3.

[0079] (4) Disintegration layer coverage: After heating the natural membrane material (60°C), mix it evenly with the disintegrating agent, then spray it evenly onto the surface of particle 3, dry and cool it to obtain particle 4;

[0080] (5) Outer layer coating: Mix the molten wax (70°C) with porous material and closed-cell pumice powder evenly, then spray it evenly onto the surface of particle 4 and cool it to obtain the slow-release fertilizer.

[0081] This embodiment also provides a method for loading the controlled-release fertilizer onto a seedling tray, including the following steps:

[0082] S1. Spray anionic compound solution onto the surface of controlled-release fertilizer granules and then dry them. The amount of spraying is 4% of the mass of the controlled-release fertilizer granules, to obtain the treated controlled-release fertilizer granules. The anionic compound solution is prepared by mixing potassium azeloyl diglycinate with 10 times the amount of water.

[0083] S2. In the vacuum forming step of the seedling tray preparation process, the theoretical load (24g / tray) of slow-release fertilizer granules is put into the slurry tank (the mass concentration of the slurry is 0.6%). The pH of the slurry in the slurry tank is controlled at 7.0. (Through periodic feeding and pump circulation) the mass concentration of the slow-release fertilizer granules in the slurry is controlled at 0.06%. After stirring evenly, the slurry in the slurry tank is trapped on the surface of the mold screen by the suction of the vacuum forming machine (0.5MPa).

[0084] S3. After drying the molded product (to a moisture content of 10-15%), place it in a hot press for shaping to obtain the finished seedling tray loaded with slow-release fertilizer.

[0085] The rest is the same as in Example 3.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 3 is that the inner and middle layers of the controlled-release fertilizer granules are combined together. The preparation method of the combined layer is as follows: the first and second nutrient components are dissolved in water by stirring, then sepiolite powder is added and allowed to stand for adsorption. After standing for 30-60 minutes, the water is evaporated. Then starch, polyvinyl alcohol and water are added and mixed evenly. The mixture is placed in a granulator to form granules 2. Then, unsaturated oil film material is heated and evenly sprayed onto the surface of granules 2. After cooling, granules 3 are obtained.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 3 is that the middle layer of the controlled-release fertilizer granules does not include unsaturated oil film material.

[0090] Comparative Example 3

[0091] The difference between this comparative example and Example 3 is that the unsaturated oil film material in the middle layer of the controlled-release fertilizer granules is linoleic acid.

[0092] Comparative Example 4

[0093] The difference between this comparative example and Example 3 is that the linoleic acid in the middle layer of the controlled-release fertilizer granules is replaced with palm oil.

[0094] Comparative Example 5

[0095] The difference between this comparative example and Example 3 is that the N-linolenic acid in the middle layer of the controlled-release fertilizer granules is replaced with cocoyl glutamic acid.

[0096] Comparative Example 6

[0097] The difference between this comparative example and Example 3 is that the mass ratio of wax to porous material in the outer layer of the controlled-release fertilizer granules is 1:0.05.

[0098] Comparative Example 7

[0099] The difference between this comparative example and Example 3 is that the mass ratio of wax to porous material in the outer layer of the controlled-release fertilizer granules is 1:0.3.

[0100] Comparative Example 8

[0101] The difference between this comparative example and Example 3 is that the method of loading the slow-release fertilizer onto the seedling tray does not include step S1, that is, the slow-release fertilizer particles are not treated.

[0102] Comparative Example 9

[0103] The difference between this comparative example and Example 3 is that the porous material on the outer layer of the controlled-release fertilizer granules is a molecular sieve.

[0104] Comparative Example 10

[0105] The difference between this comparative example and Example 3 is that in step S1 of the method of loading the controlled-release fertilizer onto the seedling tray, the anionic compound is sodium dodecylbenzenesulfonate.

[0106] Comparative Example 11

[0107] The difference between this comparative example and Example 3 is that in step S1 of the method of loading the controlled-release fertilizer onto the seedling tray, the anionic compound is sodium myristoyl glutamate.

[0108] Comparative Example 12

[0109] The difference between this comparative example and Example 3 is that the pH of the slurry in the slurry tank is controlled at 6.1.

[0110] Comparative Example 13

[0111] The difference between this comparative example and Example 3 is that the pH of the slurry in the slurry tank is controlled at 7.2.

[0112] Comparative Example 14

[0113] The difference between this comparative example and Example 3 is that the theoretical loading amount of the controlled-release fertilizer granules in the seedling tray is 8g / tray.

[0114] Comparative Example 15

[0115] The difference between this comparative example and Example 3 is that the theoretical loading amount of the controlled-release fertilizer granules in the seedling tray is 26g / tray.

[0116] Comparative Example 16

[0117] The difference between this comparative example and Example 3 is that rosin ester is not added in the preparation steps of closed-cell pumice powder.

[0118] Comparative Example 17

[0119] The difference between this comparative example and Example 3 is that, in the preparation steps of the closed-cell pumice powder, the rosin ester is rosin glycerol ester.

[0120] Comparative Example 18

[0121] The difference between this comparative example and Example 3 is that, in the preparation steps of the closed-cell pumice powder, the higher fatty acid is stearic acid.

[0122] I. Controlled-release performance of the slow-release fertilizer of the present invention

[0123] Slow-release fertilizers were prepared according to the methods of Examples 3-5 and Comparative Examples 1-7 of this invention. Referring to the method for determining nutrient release rate in standard HG / T4215-2011 (Controlled-Release Fertilizers), the cumulative nutrient release rate of the fertilizers at different times at 25°C was tested. The results are shown in Table 1 below. Figure 1 .

[0124] Table 1. Cumulative nutrient release rate (%) at different times

[0125]

[0126] Based on Table 1 Figure 1 The results show that the controlled-release fertilizers prepared in Examples 3-5 of this invention have a nutrient release period of 7-25 days. The cumulative nutrient release rate is 0% in the first 7 days. The second nutrient component begins to release slowly from day 8, and is essentially fully released within 18 days, meeting the initial growth pattern of seedlings. The first nutrient component begins to release rapidly from day 19, and is essentially fully released within 25 days, conforming to the later growth pattern of seedlings. Therefore, this invention can effectively control the release pattern of nutrients in the controlled-release fertilizer to match the growth pattern of seedlings.

[0127] Compared with Example 3, Comparative Examples 1-7 changed the raw material composition and preparation method of the controlled-release fertilizer, resulting in deviations between the nutrient release pattern of the fertilizer and the seedling growth. In Comparative Example 1, the release rate was basically the same in the early and late stages, and it could not be completely released within 25 days. In Comparative Examples 2, 5, and 7, the nutrient release rate was faster in the early stage, so that the second nutrient component was completely released in less than 18 days. In Comparative Examples 3, 4, and 6, the nutrient release rate was slower in the early stage, so that the second nutrient component could not be completely released within 18 days, and the cumulative nutrient release rate within 25 days was reduced.

[0128] II. Loading of the controlled-release fertilizer granules of the present invention in the seedling tray

[0129] According to the methods of Examples 2-5 and Comparative Examples 8-13 and 16-18 of this invention, controlled-release fertilizer granules were loaded onto seedling trays. After molding, the mass of the finished product was weighed. Based on the mass of the finished seedling tray (patent CN 202211125892.9) made under the same process conditions without controlled-release fertilizer granules, the actual loading amount of controlled-release fertilizer granules in the seedling tray was calculated. Ten parallel groups were set up, and the results are shown in Table 2.

[0130] Wherein, actual load = mass of the finished seedling tray loaded with controlled-release fertilizer granules - mass of the finished seedling tray without controlled-release fertilizer granules.

[0131] Table 2

[0132]

[0133] The actual loading of the controlled-release fertilizer granules in the seedling trays of Examples 2-5 of this invention is close to the theoretical loading, accounting for more than 80% of the theoretical loading, especially Examples 3-5 which reach more than 98%. This shows that the present invention can successfully load the controlled-release fertilizer granules onto the seedling trays with small variance and high stability.

[0134] Based on Example 2, Example 3 adds closed-cell pumice powder to the outer layer of the controlled-release fertilizer granules, which improves the suspension of the fertilizer granules in the slurry pool and significantly increases the actual load of fertilizer in the seedling tray.

[0135] Compared with Example 3, Comparative Examples 8-13 changed the method of loading the slow-release fertilizer granules on the seedling tray, and Comparative Examples 16-18 changed the preparation method of closed-cell pumice powder. The actual loading amount was reduced and the variance was increased, indicating a reduction in the loading effect.

[0136] III. Effects of using the seedling tray loaded with controlled-release fertilizer granules of the present invention on rice seedling cultivation

[0137] Test location: A field in Lianwei Town, Xinjian District, Nanchang City, Jiangxi Province.

[0138] Rice variety: Xiangzaoxian 45.

[0139] Seedling trays: Seedling trays prepared according to patent CN 202211125892.9 (control group), and seedling trays loaded with slow-release fertilizer granules prepared by the methods of Examples 2-5 and Comparative Examples 1-18 of this invention.

[0140] Experimental method: Rice seeds were germinated in a dark place and then sown at a rate of 1000-1400 seeds per tray. Each tray contained 800g of seedling substrate (vermiculite was selected in this experiment). Seedlings were raised in mud in the field, with non-woven fabric laid under the seedling trays. Other management measures were the same. Ten trays were sown in parallel in the same experimental group.

[0141] The germination rate of seedlings and the growth indicators of seedlings after 25 days of seedling cultivation were monitored. The results are shown in Table 3.

[0142] Table 3

[0143]

[0144] As shown in Table 3, compared with the control group (seedling trays without controlled-release fertilizer granules), the seedling trays loaded with controlled-release fertilizer granules in Examples 2-5 of the present invention can significantly improve the germination rate, seedling height, stem base width, number of roots, chlorophyll, chlorophyll SPAD and other growth indicators of seedlings, and no additional nutrient substrate is required (only vermiculite is added to stabilize the root system).

[0145] Based on Example 2, Example 3 further added closed-cell pumice powder to the outer layer of the controlled-release fertilizer granules, which increased the actual load of fertilizer in the seedling tray, and further improved the growth indicators of the seedlings.

[0146] Compared with Example 3, Comparative Examples 1-7 changed the raw material composition and preparation method of the controlled-release fertilizer, which affected the controlled-release performance of the fertilizer; Comparative Examples 8-13 changed the method of loading the controlled-release fertilizer granules on the seedling tray; Comparative Examples 14 and 15 changed the theoretical loading amount of the controlled-release fertilizer granules in the seedling tray; and Comparative Examples 16-18 changed the preparation method of the closed-cell pumice powder, which affected the actual loading amount of the fertilizer in the seedling tray. Ultimately, the growth indicators of the seedlings all showed a decrease to varying degrees.

[0147] IV. Water absorption of the closed-cell pumice powder prepared by this invention

[0148] Closed-cell pumice powder was prepared according to Examples 3-5 and Comparative Examples 16-19 of the present invention. Its water absorption rate was measured after being immersed in water at room temperature for 24 hours. The results are shown in Table 4 below.

[0149] Table 4

[0150]

[0151] As shown in Table 4, the water absorption rate of the closed-cell pumice powder prepared by this invention is 0.001-0.002%, which is low and the closed-cell effect is good.

[0152] Compared with Example 3, Comparative Examples 16-18 changed the preparation method of closed-cell pumice powder, and the water absorption rate increased and the closed-cell effect deteriorated.

[0153] It should be noted that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A controlled-release fertilizer, comprising nutrient components and other ingredients, characterized in that: The controlled-release fertilizer is a controlled-release fertilizer granule. The nutrient components are divided into a first nutrient component and a second nutrient component with the same composition. The controlled-release fertilizer granules, from the inside out, include an inner layer, a middle layer, a disintegrating layer, and an outer layer with a mass ratio of (2-3):(2-4):(0.3-0.6):(0.4-0.7). The inner layer includes the first nutrient component and starch with a mass ratio of 1:(0.05-0.1). The middle layer includes the second nutrient component, sepiolite powder, polyvinyl alcohol, and unsaturated oil film material with a mass ratio of 1:(1-2):(0.2-0.4):(0.03-0.05). The disintegrating layer includes a disintegrant and a natural film material with a mass ratio of (0.15-0.3):

1. The outer layer includes wax, pumice powder, and closed-cell pumice powder with a mass ratio of 1:(0.1-0.25):(0.2-0.4). The porosity of the pumice powder is 50-80%. The unsaturated oil film material comprises vegetable oil and plant-based lipid amino acids in a mass ratio of 1:(0.2-0.4), wherein the vegetable oil in the unsaturated oil film material is linoleic acid, and the plant-based lipid amino acid is N-linolenic acid. The preparation method of the closed-cell pumice powder includes the following steps: molten higher fatty acids and rosin esters are mixed evenly, and then sprayed onto the surface of pumice powder while hot. After spraying, the mixture is quickly placed at 0-5℃ to cool, thereby obtaining the closed-cell pumice powder. The mass ratio of the higher fatty acid to the rosin ester is 1:(0.01-0.04), and the amount of the mixture injected is 4-8% of the mass of the pumice powder. The higher fatty acid is behenic acid, and the rosin ester is ethyl rosin ester.

2. The controlled-release fertilizer according to claim 1, characterized in that: The nutrient release period of the controlled-release fertilizer granules is 7-25 days, and the nutrient components include any combination of phosphate fertilizer, nitrogen fertilizer, potassium fertilizer and trace elements.

3. The controlled-release fertilizer according to claim 1, characterized in that: The disintegrant is one or more of dextrin, polyvinylpyrrolidone, or sodium carboxymethyl starch, the natural membrane material is molasses, and the wax is beeswax.

4. A method for preparing a controlled-release fertilizer according to any one of claims 1-3, characterized in that: Includes the following steps: (1) Inner layer preparation: Mix starch and water evenly, then add the first nutrient component and mix well, and then granulate into granules 1 by a granulator; (2) Middle layer covering: Add water to the second nutrient component and stir to dissolve. Then add sepiolite powder and let it stand for adsorption. After standing for 30-60 minutes, evaporate the water. Then add granules 1, polyvinyl alcohol and water and mix evenly. Place it in a granulator to form granules 2. Then heat the unsaturated oil film material and spray it evenly onto the surface of granules 2. Cool to obtain granules 3. (3) Disintegration layer coverage: After heating the natural membrane material, mix it evenly with the disintegrating agent, then spray it evenly onto the surface of particle 3, dry and cool it to obtain particle 4; (4) Outer layer coating: Mix the molten wax, pumice powder and closed-cell pumice powder evenly, then spray evenly onto the surface of particle 4 and cool to obtain the slow-release fertilizer.

5. A method for loading the controlled-release fertilizer according to claim 1 onto a seedling tray, characterized in that: Includes the following steps: S1. Spray anionic compound solution onto the surface of the controlled-release fertilizer granules and then dry them to obtain the treated controlled-release fertilizer granules. S2. In the vacuum forming step of the seedling tray preparation process, the theoretical load of slow-release fertilizer granules is put into the slurry tank, stirred evenly, and then the slurry in the slurry tank is trapped on the surface of the mold screen by the suction of the vacuum forming machine. S3. After drying the molded product, place it in a hot press to shape it, and you will get the finished seedling tray loaded with slow-release fertilizer.

6. The method according to claim 5, characterized in that: The amount of the anionic compound solution sprayed is 2-4% of the mass of the controlled-release fertilizer granules. The anionic compound solution is prepared by mixing potassium azeloyl diglycinate with 5-10 times the amount of water.

7. The method according to claim 5, characterized in that: The theoretical loading capacity of the controlled-release fertilizer granules in the seedling tray is 10-24 g / tray. The porous material in the outer layer of the controlled-release fertilizer granules is pumice powder. The pH of the slurry in the slurry tank is controlled at 6.3-7.0, and the mass concentration of the controlled-release fertilizer granules in the slurry is controlled at 0.03-0.06%.

8. The application of a controlled-release fertilizer as described in claim 1 or a seedling tray loaded with controlled-release fertilizer as described in claim 5 in the cultivation of rice seedlings, rapeseed seedlings, vegetable seedlings or flower seedlings.

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