Preparation method and application of an organic-inorganic micro-particle compound fertilizer

Abstract

This invention relates to the field of agricultural application technology, and proposes a method for preparing and applying an organic-inorganic micro-particle compound fertilizer, comprising a slow-release layer and a fast-release layer arranged sequentially from the inside out. The fast-release layer comprises the following components by weight: 4-6 parts nitrogen-potassium compound fertilizer, 1-5 parts dipotassium hydrogen phosphate, 8-10 parts urea, 0.4-0.5 parts boric acid, 0.3-0.5 parts EDTA-Fe, and 0.1-0.2 parts starch. The slow-release layer comprises the following components by weight: 7-10 parts formaldehyde urea, 10-20 parts trehalose-modified humic acid, and 0.4-0.5 parts slow-release acid-adjusting substance. This technical solution solves the problems of low fertilizer utilization and short-term fertilizer effect in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of agricultural application technology, specifically to a method for preparing and applying an organic-inorganic micro-particle compound fertilizer. Background Technology

[0002] Inorganic fertilizers have a single nutrient composition and do not contain organic matter, so they are mostly used as top dressing. Inorganic fertilizers have low utilization rates, require large quantities, are labor-intensive, and long-term application can easily lead to soil compaction.

[0003] Humic acid is a polycyclic aromatic hydrocarbon containing carbon, hydrogen, oxygen, and nitrogen. Due to the presence of active groups such as aromatic nuclei, hydroxyl groups, carboxyl groups, carbonyl groups, quinone groups, and methoxy groups, humic acid exhibits certain viscosity and adsorption properties. Humic acid can regulate physiological and ecological changes in crops, thereby enhancing their stress resistance. When soil contains high levels of salt and heavy metal ions, humic acid can enhance the activity of enzymes related to reactive oxygen species metabolism in plants, thus having a dual effect of improving soil and stimulating crop growth, making it an excellent slow-release organic fertilizer.

[0004] To improve fertilizer utilization, enrich the soil, meet the growth needs of different crops, control the nutrient release cycle to the greatest extent, and improve crop yield and quality, it is of great significance to develop an organic-inorganic micro-particle compound fertilizer that can improve fertilizer utilization and has a long-lasting effect. Summary of the Invention

[0005] This invention proposes a method for preparing and applying an organic-inorganic micro-particle compound fertilizer, which solves the problems of low fertilizer utilization and short fertilizer effect in related technologies.

[0006] The technical solution of the present invention is as follows:

[0007] This invention proposes an organic-inorganic micro-particle compound fertilizer, comprising a slow-release layer and a fast-release layer arranged sequentially from the inside out;

[0008] The quick-release layer comprises the following components in parts by weight: 4-6 parts nitrogen-potassium compound fertilizer, 1-5 parts dipotassium hydrogen phosphate, 8-10 parts urea, 0.4-0.5 parts boric acid, 0.3-0.5 parts EDTA-Fe, and 0.1-0.2 parts starch;

[0009] The sustained-release layer comprises the following components in parts by weight: 7-10 parts formaldehyde urea, 10-20 parts trehalose-modified humic acid, and 0.4-0.5 parts sustained-release acid-adjusting substance;

[0010] The structural formula of the trehalose-modified humic acid is:

[0011]

[0012] As a further technical solution, the preparation method of the trehalose-modified humic acid is as follows: humic acid is dissolved in a solvent, POCl3 is added under ice bath conditions, the mixture is stirred evenly, trehalose and catalyst are added in sequence, and the reaction is carried out to obtain the trehalose-modified humic acid.

[0013] As a further technical solution, the mass ratio of humic acid to trehalose is 1:1-3.

[0014] As a further technical solution, the catalyst is a sodium hydroxide solution, and the mass fraction of the sodium hydroxide solution is 5%-15%.

[0015] As a further technical solution, the mass ratio of humic acid to POCl3 is 100:3-5, and the mass ratio of humic acid to sodium hydroxide solution is 100:1-3.

[0016] As a further technical solution, the solvent is N,N-dimethylformamide or dimethyl sulfoxide.

[0017] As a further technical solution, the reaction temperature is 60-80℃ and the time is 4-6h.

[0018] As a further technical solution, the slow-release acid-regulating substance is limestone powder or calcium bicarbonate.

[0019] This invention also proposes a method for preparing the aforementioned organic-inorganic micro-particle compound fertilizer, comprising the following steps:

[0020] S1. Trehalose-modified humic acid is coated on the surface of formaldehyde urea, a slow-release acid-adjusting substance and water are added, mixed evenly, granulated, and dried to obtain slow-release layer particles.

[0021] S2. Mix nitrogen-potassium compound fertilizer, dipotassium hydrogen phosphate, urea, boric acid, EDTA-Fe, and starch with water until uniform, coat the surface of the slow-release layer particles, granulate, and dry to obtain organic-inorganic micro-particle compound fertilizer.

[0022] As a further technical solution, in step S1, the rotation speed is 200-400 rpm during granulation, and the temperature is 80-90℃ during drying.

[0023] As a further technical solution, in step S2, the rotation speed is 100-300 rpm during granulation, and the temperature is 80-100℃ during drying.

[0024] This invention also proposes the application of the aforementioned organic-inorganic micro-particle compound fertilizer in agricultural fertilization.

[0025] The working principle and beneficial effects of this invention are as follows:

[0026] 1. In this invention, the organic-inorganic micro-particle compound fertilizer includes a slow-release layer and a fast-release layer, which combines the advantages of organic and inorganic fertilizers, giving the fertilizer a balanced and stable characteristic, providing a stable growth environment for crops, and achieving the goals of improving fertilizer utilization, extending fertilizer effectiveness time, and providing efficient fertilizer supply. Wherein:

[0027] (1) The quick-release layer contains the three elements of nitrogen, phosphorus and potassium required by crops. It has the characteristics of rapid decomposition and rapid fertilizer effect. It is easily absorbed and utilized by crops in the early stage, which can ensure the healthy growth of plants.

[0028] (2) In the slow-release layer, formaldehyde urea can serve as a slow-release nitrogen source, providing continuous nutrition for the later crop growth. The addition of trehalose-modified humic acid ensures that trehalose and formaldehyde urea are tightly bound together, and can also undergo ion exchange, adsorption, and complexation with heavy metal ions in the soil, achieving the dual effect of improving the soil and stimulating crop growth. On the other hand, trehalose can form a protective film on the crop roots, effectively protecting the stable growth of the crop. In addition, the slow-release acid-regulating substances can increase the pH value of acidic soil within a certain period of time, accelerating the fixation of heavy metal ions.

[0029] 2. In this invention, the two-step granulation process of the immediate-release layer and the slow-release layer avoids the mixed use of a large number of elements, prevents soil compaction and fertility reduction, further improves fertility utilization, and further extends the fertilizer effect time. Attached Figure Description

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0031] Figure 1 This is a schematic diagram of the reaction of trehalose-modified humic acid in Example 1;

[0032] Figure 2 The infrared spectrum of trehalose-modified humic acid in Example 1 is shown. Detailed Implementation

[0033] 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 some embodiments of the present invention, and not all 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.

[0034] Unless otherwise specified, in the following examples and comparative examples, the nitrogen-potassium compound fertilizer was purchased from Tianfeng Chemical (Shanxi) Group Co., Ltd., with a nitrate nitrogen content ≥13.5% and a potassium oxide content ≥46%; dipotassium hydrogen phosphate was purchased from Hefei Shengrun Biological Products Co., Ltd.; urea was purchased from Jinan Xinying Chemical Co., Ltd., with a total nitrogen content ≥46.0%; boric acid was purchased from Jinan Huiteng Chemical Co., Ltd.; EDTA-Fe was purchased from Jinan Qiansheng Chemical Co., Ltd., with an Fe content ≥13.0%; the starch was corn starch, purchased from Jinan Aotai Chemical Co., Ltd.; the formaldehyde urea, with the product number CGSL018726, was purchased from Wuhan Yunhong Agricultural Chemical Technology Development Co., Ltd.; trehalose was purchased from Shaanxi Rankang Biotechnology Co., Ltd., with a trehalose content ≥99.0% on a dry basis; humic acid was purchased from Wuhan Jushun Chemical Co., Ltd.; limestone powder was purchased from Lingshou County Huixin Mining Processing Plant, with a calcium content ≥97%; and calcium bicarbonate was purchased from Lingshou County Nanyu Mineral Products Processing Plant.

[0035] Example 1

[0036] A method for preparing an organic-inorganic micro-particle compound fertilizer includes the following steps:

[0037] S1. Coat 10 parts of trehalose-modified humic acid onto the surface of 7 parts of formaldehyde urea, add 0.4 parts of limestone powder and 1 part of water and mix evenly. After granulation by a disc granulator with a rotation speed of 200 rpm, dry at 80°C to obtain slow-release layer particles.

[0038] S2. Mix 4 parts nitrogen-potassium compound fertilizer, 1 part dipotassium hydrogen phosphate, 8 parts urea, 0.4 parts boric acid, 0.3 parts EDTA-Fe, 0.1 parts starch and 2 parts water evenly, coat the surface of the slow-release layer particles, granulate them in a disc granulator at 100 rpm, and dry them at 80℃ to obtain organic-inorganic micro-particle compound fertilizer.

[0039] The preparation method of trehalose-modified humic acid is as follows: 5 parts of humic acid are placed in a three-necked flask, and 0.15 parts of POCl3 are slowly added dropwise under ice bath conditions using N,N-dimethylformamide as solvent. After stirring evenly at room temperature, 5 parts of trehalose and 0.05 parts of sodium hydroxide solution (mass fraction of 5%) are added, and the mixture is reacted at 60℃ for 4 hours to obtain trehalose-modified humic acid.

[0040] Figure 1 This is a schematic diagram of the reaction between trehalose and humic acid. Figure 2 The infrared spectrum of trehalose-modified humic acid.

[0041] Example 2

[0042] A method for preparing an organic-inorganic micro-particle compound fertilizer includes the following steps:

[0043] S1. Coat 15 parts of trehalose-modified humic acid onto the surface of 8 parts of formaldehyde urea, add 0.5 parts of calcium bicarbonate and 2 parts of water and mix evenly. After granulation by a disc granulator with a speed of 400 rpm, dry at 90°C to obtain slow-release layer particles.

[0044] S2. Mix 5 parts nitrogen-potassium compound fertilizer, 2 parts dipotassium hydrogen phosphate, 9 parts urea, 0.5 parts boric acid, 0.4 parts EDTA-Fe, 0.2 parts starch and 3 parts water evenly, coat the surface of the slow-release layer particles, granulate them in a disc granulator at 300 rpm, and dry them at 100℃ to obtain organic-inorganic micro-particle compound fertilizer.

[0045] The preparation method of trehalose-modified humic acid is as follows: 5 parts of humic acid are placed in a three-necked flask, and 0.2 parts of POCl3 are slowly added dropwise under ice bath conditions using N,N-dimethylformamide as solvent. After stirring evenly at room temperature, 10 parts of trehalose and 0.1 parts of sodium hydroxide solution (mass fraction of 5%) are added, and the mixture is reacted at 70℃ for 5 hours to obtain trehalose-modified humic acid.

[0046] Example 3

[0047] A method for preparing an organic-inorganic micro-particle compound fertilizer includes the following steps:

[0048] S1. Coat 20 parts of trehalose-modified humic acid onto the surface of 9 parts of formaldehyde urea, add 0.4 parts of limestone powder and 2 parts of water and mix evenly. After granulation by a disc granulator with a speed of 400 rpm, dry at 80°C to obtain slow-release layer particles.

[0049] S2. Mix 6 parts nitrogen-potassium compound fertilizer, 3 parts dipotassium hydrogen phosphate, 10 parts urea, 0.4 parts boric acid, 0.5 parts EDTA-Fe, 0.1 parts starch and 3 parts water evenly, coat the surface of the slow-release layer particles, granulate them in a disc granulator at 300 rpm, and dry them at 100℃ to obtain organic-inorganic micro-particle compound fertilizer.

[0050] The preparation method of trehalose-modified humic acid is as follows: 5 parts of humic acid are placed in a three-necked flask, and 0.25 parts of POCl3 are slowly added dropwise under ice bath conditions using N,N-dimethylformamide as solvent. After stirring evenly at room temperature, 15 parts of trehalose and 0.15 parts of sodium hydroxide solution (mass fraction of 5%) are added, and the mixture is reacted at 80℃ for 6 hours to obtain trehalose-modified humic acid.

[0051] Example 4

[0052] A method for preparing an organic-inorganic micro-particle compound fertilizer includes the following steps:

[0053] S1. Coat 10 parts of trehalose-modified humic acid onto the surface of 10 parts of formaldehyde urea, add 0.5 parts of limestone powder and 1 part of water and mix evenly. After granulation by a disc granulator with a rotation speed of 300 rpm, dry at 80°C to obtain slow-release layer particles.

[0054] S2. Mix 6 parts nitrogen-potassium compound fertilizer, 4 parts dipotassium hydrogen phosphate, 10 parts urea, 0.4 parts boric acid, 0.3 parts EDTA-Fe, 0.2 parts starch and 2 parts water evenly, coat the surface of the slow-release layer particles, granulate them in a disc granulator at 300 rpm, and dry them at 100℃ to obtain organic-inorganic micro-particle compound fertilizer.

[0055] The preparation method of trehalose-modified humic acid is as follows: 5 parts of humic acid are placed in a three-necked flask, and 0.15 parts of POCl3 are slowly added dropwise under ice bath conditions using N,N-dimethylformamide as solvent. After stirring evenly at room temperature, 5 parts of trehalose and 0.15 parts of sodium hydroxide solution (mass fraction of 5%) are added, and the mixture is reacted at 70℃ for 5 hours to obtain trehalose-modified humic acid.

[0056] Example 5

[0057] A method for preparing an organic-inorganic micro-particle compound fertilizer includes the following steps:

[0058] S1. Coat 15 parts of trehalose-modified humic acid onto the surface of 10 parts of formaldehyde urea, add 0.4 parts of calcium bicarbonate and 2 parts of water and mix evenly. After granulation by a disc granulator with a rotation speed of 200 rpm, dry at 90°C to obtain slow-release layer particles.

[0059] S2. Mix 5 parts nitrogen-potassium compound fertilizer, 5 parts dipotassium hydrogen phosphate, 10 parts urea, 0.5 parts boric acid, 0.4 parts EDTA-Fe, 0.1 parts starch and 2 parts water evenly, coat the surface of the slow-release layer particles, granulate them in a disc granulator at 300 rpm, and dry them at 100℃ to obtain organic-inorganic micro-particle compound fertilizer.

[0060] The preparation method of trehalose-modified humic acid is as follows: 5 parts of humic acid are placed in a three-necked flask, and 0.2 parts of POCl3 are slowly added dropwise under ice bath conditions using N,N-dimethylformamide as solvent. After stirring evenly at room temperature, 15 parts of trehalose and 0.1 parts of sodium hydroxide solution (mass fraction of 5%) are added, and the mixture is reacted at 80℃ for 6 hours to obtain trehalose-modified humic acid.

[0061] Example 6

[0062] A method for preparing an organic-inorganic micro-particle compound fertilizer includes the following steps:

[0063] S1. Coat 20 parts of trehalose-modified humic acid onto the surface of 10 parts of formaldehyde urea, add 0.5 parts of calcium bicarbonate and 2 parts of water and mix evenly. After granulation by a disc granulator with a speed of 400 rpm, dry at 90°C to obtain slow-release layer particles.

[0064] S2. Mix 6 parts nitrogen-potassium compound fertilizer, 5 parts dipotassium hydrogen phosphate, 10 parts urea, 0.5 parts boric acid, 0.5 parts EDTA-Fe, 0.2 parts starch and 3 parts water evenly, coat the surface of the slow-release layer particles, granulate them in a disc granulator at 300 rpm, and dry them at 100℃ to obtain organic-inorganic micro-particle compound fertilizer.

[0065] The preparation method of trehalose-modified humic acid is as follows: 5 parts of humic acid are placed in a three-necked flask, and 0.25 parts of POCl3 are slowly added dropwise under ice bath conditions using N,N-dimethylformamide as solvent. After stirring evenly at room temperature, 15 parts of trehalose and 0.15 parts of sodium hydroxide solution (mass fraction of 5%) are added, and the mixture is reacted at 80℃ for 6 hours to obtain trehalose-modified humic acid.

[0066] Example 7

[0067] The only difference between this embodiment and Embodiment 1 is that, in this embodiment, the mass fraction of sodium hydroxide solution is 15% when preparing trehalose-modified humic acid.

[0068] Comparative Example 1

[0069] A method for preparing an organic-inorganic micro-particle compound fertilizer includes the following steps:

[0070] 10 parts trehalose, 7 parts formaldehyde urea, 4 parts nitrogen-potassium compound fertilizer, 1 part dipotassium hydrogen phosphate, 8 parts urea, 0.4 parts boric acid, 0.3 parts EDTA-Fe, 0.1 parts starch, 0.4 parts limestone powder and 3 parts water are mixed evenly, granulated by a disc granulator at 200 rpm and dried at 80℃ to obtain organic-inorganic micro-granular compound fertilizer.

[0071] Comparative Example 2

[0072] A method for preparing an organic-inorganic micro-particle compound fertilizer includes the following steps:

[0073] S1. Coat 10 parts of humic acid onto the surface of 7 parts of formaldehyde urea, add 0.4 parts of limestone powder and 1 part of water and mix evenly. After granulation by a disc granulator with a speed of 200 rpm, dry at 80°C to obtain slow-release layer particles.

[0074] S2. Mix 4 parts nitrogen-potassium compound fertilizer, 1 part dipotassium hydrogen phosphate, 8 parts urea, 0.4 parts boric acid, 0.3 parts EDTA-Fe, 0.1 parts starch and 2 parts water evenly, coat the surface of the slow-release layer particles, granulate them in a disc granulator at 100 rpm, and dry them at 80℃ to obtain organic-inorganic micro-particle compound fertilizer.

[0075] Comparative Example 3

[0076] A method for preparing an organic-inorganic micro-particle compound fertilizer includes the following steps:

[0077] S1. Coat 5 parts of humic acid onto the surface of 5 parts of trehalose and 7 parts of formaldehyde urea, add 0.4 parts of limestone powder and 1 part of water and mix evenly. After granulation by a disc granulator with a speed of 200 rpm, dry at 80°C to obtain slow-release layer particles.

[0078] S2. Mix 4 parts nitrogen-potassium compound fertilizer, 1 part dipotassium hydrogen phosphate, 8 parts urea, 0.4 parts boric acid, 0.3 parts EDTA-Fe, 0.1 parts starch and 2 parts water evenly, coat the surface of the slow-release layer particles, granulate them in a disc granulator at 100 rpm, and dry them at 80℃ to obtain organic-inorganic micro-particle compound fertilizer.

[0079] Comparative Example 4

[0080] A method for preparing an organic-inorganic micro-particle compound fertilizer includes the following steps:

[0081] 10 parts of trehalose-modified humic acid, 7 parts of formaldehyde urea, 4 parts of nitrogen-potassium compound fertilizer, 1 part of dipotassium hydrogen phosphate, 8 parts of urea, 0.4 parts of boric acid, 0.3 parts of EDTA-Fe, 0.1 parts of starch, 0.4 parts of limestone powder and 3 parts of water were mixed evenly, granulated by a disc granulator at 200 rpm, and dried at 80℃ to obtain organic-inorganic micro-granular compound fertilizer.

[0082] The preparation method of trehalose-modified humic acid is as follows: 5 parts of humic acid are placed in a three-necked flask, and 0.15 parts of POCl3 are slowly added dropwise under ice bath conditions using N,N-dimethylformamide as solvent. After stirring evenly at room temperature, 5 parts of trehalose and 0.05 parts of sodium hydroxide solution (mass fraction of 5%) are added, and the mixture is reacted at 60℃ for 4 hours to obtain trehalose-modified humic acid.

[0083] Using four-season Chinese cabbage as the experimental material, the organic-inorganic micro-particle compound fertilizer prepared in Examples 1-7 was mixed with the soil (the mass ratio of fertilizer to soil was 1:500). 5 kg was weighed as base fertilizer and placed in flower pots. Chinese cabbage seeds were placed 2 cm deep in the soil. The germination time and the mass of the four-season Chinese cabbage after 20 days were recorded. The results are shown in Table 1 below.

[0084] Table 1. Germination time and quality of *Bok choy* after 20 days in Examples 1-7

[0085]

[0086] As can be seen from the data in the table, the organic-inorganic micro-particle compound fertilizer prepared by this invention can significantly reduce the germination time of crops and significantly increase crop yield. This indicates that the macro-elements in the quick-release layer play a key role in the early growth stage of crops, and the components in the slow-release layer can enable crops to continue to grow for a certain period of time, thereby improving fertilizer utilization.

[0087] Using four-season Chinese cabbage as the experimental material, the organic-inorganic micro-particle compound fertilizer prepared in Comparative Examples 1-4 was mixed with the soil (the mass ratio of fertilizer to soil was 1:500). 5 kg was weighed as base fertilizer and placed in flower pots. Chinese cabbage seeds were placed 2 cm deep in the soil. The mass of the four-season Chinese cabbage was recorded after 20 days. The results are shown in Table 2 below.

[0088] Table 2 shows the quality of Chinese cabbage from Comparative Examples 1-4 after 20 days.

[0089]

[0090] Comparisons 1-3 with Example 1 show that trehalose-modified humic acid can prolong the fertilizer effect time, stimulate crop growth in the later stages, and improve fertilizer utilization. Comparison 4 with Example 1 shows that two-step granulation with an immediate-release layer and a slow-release layer further improves fertilizer utilization and prolongs the fertilizer effect time.

[0091] The above are merely preferred embodiments of the present invention and are 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. An organic-inorganic micro-particle compound fertilizer, characterized in that, It includes a sustained-release layer and an immediate-release layer arranged sequentially from the inside out; The quick-release layer comprises the following components in parts by weight: 4-6 parts nitrogen-potassium compound fertilizer, 1-5 parts dipotassium hydrogen phosphate, 8-10 parts urea, 0.4-0.5 parts boric acid, 0.3-0.5 parts EDTA-Fe, and 0.1-0.2 parts starch; The sustained-release layer comprises the following components in parts by weight: 7-10 parts formaldehyde urea, 10-20 parts trehalose-modified humic acid, and 0.4-0.5 parts sustained-release acid-adjusting substance; The structural formula of the trehalose-modified humic acid is: ； The preparation method of the trehalose-modified humic acid is as follows: humic acid is dissolved in a solvent, POCl3 is added under ice bath conditions, the mixture is stirred evenly, trehalose and catalyst are added in sequence, and the reaction is carried out to obtain the trehalose-modified humic acid. The mass ratio of humic acid to trehalose is 1:1-3; The catalyst is a sodium hydroxide solution, and the mass fraction of the sodium hydroxide solution is 5%-15%. The mass ratio of humic acid to POCl3 is 100:3-5, and the mass ratio of humic acid to sodium hydroxide solution is 100:1-3. The solvent is N,N-dimethylformamide or dimethyl sulfoxide; The reaction is carried out at a temperature of 60-80℃ for 4-6 hours. The slow-release acid-regulating substance is limestone powder or calcium bicarbonate.

2. A method for preparing an organic-inorganic micro-particle compound fertilizer as described in claim 1, characterized in that, Includes the following steps: S1. Trehalose-modified humic acid is coated on the surface of formaldehyde urea, a slow-release acid-adjusting substance and water are added, mixed evenly, granulated, and dried to obtain slow-release layer particles. S2. Mix nitrogen-potassium compound fertilizer, dipotassium hydrogen phosphate, urea, boric acid, EDTA-Fe, and starch with water until uniform, coat the surface of the slow-release layer particles, granulate, and dry to obtain organic-inorganic micro-particle compound fertilizer.

3. The application of the organic-inorganic micro-particle compound fertilizer according to claim 1 or the organic-inorganic micro-particle compound fertilizer obtained by the preparation method according to claim 2 in agricultural fertilization.

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