Medium trace element granular fertilizer

Abstract

The invention relates to the technical field of fertilizers, and provides a medium trace element granular fertilizer, which comprises the following raw materials by weight: 70-80 parts of clay mineral, 7-9 parts of a binder, 7-11 parts of an organic matter, 2-4 parts of modified sepiolite, 0.5-1.5 parts of calcium superphosphate, and 1-3 parts of potassium nitrate. Wherein the modified sepiolite is obtained by modifying sepiolite with an aromatic aminopropionic acid derivative. Through the technical scheme, the problems of single soil fertility and heavy metal cadmium ion pollution in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of fertilizer technology, specifically to a micronutrient granular fertilizer. Background Technology

[0002] With the rapid development of modern agriculture towards large-scale and intensive operations, the drawbacks of long-term excessive application of macronutrient fertilizers such as nitrogen, phosphorus, and potassium are becoming increasingly apparent. On the one hand, micronutrients such as calcium, magnesium, sulfur, iron, zinc, and boron are continuously being lost from the soil, leading to severe deficiencies. On the other hand, traditional fertilizers have limited nutrient content and low utilization rates, making it difficult to meet the growth needs of crops. Even more worrying is that in some areas, the combined effects of long-term irrational fertilization and industrial pollution have resulted in the continuous accumulation of cadmium in the soil. This not only hinders the absorption and translocation of micronutrients by crops but may also enter their bodies through the root system, thus threatening the quality and safety of agricultural products and human health. Therefore, developing a micronutrient granular fertilizer with strong synergistic effects and the ability to help reduce soil cadmium content has become an urgent need for the green and efficient development of modern agriculture. Summary of the Invention

[0003] This invention proposes a micronutrient granular fertilizer that solves the problems of single soil fertility and heavy metal cadmium ion pollution in existing technologies.

[0004] The technical solution of the present invention is as follows: This invention proposes a granular fertilizer containing trace elements, comprising the following raw materials in parts by weight: 70-80 parts clay minerals, 7-9 parts binder, 7-11 parts organic matter, 2-4 parts modified sepiolite, 0.5-1.5 parts superphosphate, and 1-3 parts potassium nitrate; wherein the modified sepiolite is obtained by modifying sepiolite with aromatic aminopropionic acid derivatives.

[0005] As a further technical solution, the mass ratio of aromatic aminopropionic acid derivative to sepiolite in the modified sepiolite is 3~7:100.

[0006] In this invention, the aromatic aminopropionic acid derivative in the micronutrient granular fertilizer modifies sepiolite. When the mass ratio of aromatic aminopropionic acid derivative to sepiolite is less than 3:100, the aromatic aminopropionic acid derivative is difficult to fully cover the active sites of sepiolite, resulting in limited modification effect. When the mass ratio of aromatic aminopropionic acid derivative to sepiolite is greater than 7:100, excessive aromatic aminopropionic acid derivative is prone to form agglomerates or multilayer coatings on the surface of sepiolite, which not only wastes the aromatic aminopropionic acid derivative but may also block the pore structure of sepiolite, reduce its specific surface area, and thus reduce the adsorption capacity of sepiolite. When the mass ratio of aromatic aminopropionic acid derivative to sepiolite is 3~7:100, the ability of sepiolite to adsorb heavy metal cadmium ions can be better improved.

[0007] As a further technical solution, the aromatic aminopropionic acid derivative includes one or more of 3-(3-aminophenyl)propionic acid, 3-amino-3-(3-hydroxyphenyl)-propionic acid, and 3-amino-3-(2,3-dihydroxyphenyl)-propionic acid.

[0008] As a further technical solution, the method for preparing modified sepiolite includes the following steps: dispersing an aromatic aminopropionic acid derivative evenly in ethanol, then adding sepiolite and mixing, followed by drying to obtain modified sepiolite; wherein the mass ratio of sepiolite to the aromatic aminopropionic acid derivative is 100:3~7, and the mass-to-volume ratio of sepiolite to ethanol is 1g:12mL. As a further technical solution, the particle size of the sepiolite is 40~50μm.

[0009] In this invention, when the sepiolite particle size in the micronutrient granular fertilizer is greater than 50 μm, the specific surface area is relatively small and the number of surface active sites is insufficient, which leads to a reduction in the contact area with aromatic aminopropionic acid derivatives, which is not conducive to the uniform loading and full reaction of the modifier. When the particle size is less than 40 μm, the particles are prone to agglomeration, increasing the difficulty of dispersion. When the sepiolite particle size is between 40 and 50 μm, it can ensure a certain specific surface area and sufficient active sites, which is conducive to effective binding and full reaction with aromatic aminopropionic acid derivatives, while reducing particle agglomeration, thereby ensuring the optimization of the modification effect.

[0010] As a further technical solution, the clay minerals include one or more of the following: kaolin, montmorillonite, illite, bentonite, talc, mica, vermiculite, chlorite, and borax.

[0011] As a further technical solution, the micronutrient granular fertilizer contains Si, Ca, Mg, S, Fe, Cu, Zn, Mn, and B. The mass ratio of each micronutrient is as follows: Si:Ca:Mg:S:Fe:Cu:Zn:Mn:B = (1~2):(10~14):(30~40):(12~14):(20~40):(0.07~0.09):(1~2):(0.2~0.4):(0.1~0.2).

[0012] In this invention, the micronutrient granular fertilizer contains calcium, magnesium, and iron, which are key elements for crop growth and development and can meet the needs of core physiological processes such as cell wall formation and photosynthesis; silicon can enhance crop stress resistance, sulfur participates in amino acid synthesis, and zinc helps in the synthesis of growth hormones, which are crucial for improving crop quality; copper, manganese, boron, etc. are indispensable in specific physiological functions such as pollen development. The overall ratio of Si:Ca:Mg:S:Fe:Cu:Zn:Mn:B = (1~2):(10~14):(30~40):(12~14):(20~40):(0.07~0.09):(1~2):(0.2~0.4):(0.1~0.2) in the micronutrients highlights the leading role of core elements such as magnesium and iron, while also taking into account the basic functions of elements such as calcium and sulfur. At the same time, the amount of micronutrients such as copper, manganese, and boron is precisely controlled so that each element can work synergistically. This can not only meet the multifaceted nutritional needs of crops, but also avoid the antagonistic effects between elements, thereby effectively promoting crop growth, improving stress resistance, and increasing crop yield and quality.

[0013] As a further technical solution, the components of the micronutrient granular fertilizer also include 1 to 5 parts of compound microbial inoculant.

[0014] The addition of compound microbial agents to the micronutrient granular fertilizer of this invention can play multiple roles: on the one hand, the microorganisms in the compound microbial agents can secrete organic acids and other substances, promoting the dissolution and transformation of micronutrients in the granular fertilizer, improving their effectiveness in the soil, and facilitating absorption and utilization by crop roots; on the other hand, these microorganisms can improve the soil micro-ecological environment, inhibit the reproduction of harmful pathogens, enhance soil aggregate structure, and improve soil fertility. At the same time, they can also stimulate crop growth by producing auxins, cytokinins and other substances, enhance crop stress resistance, and work synergistically with micronutrients to further improve the comprehensive efficacy of fertilizer, promote healthy crop growth and improve yield and quality.

[0015] As a further technical solution, the composite microbial agent is composed of Pseudomonas fluorescens and Bacillus natto.

[0016] As a further technical solution, the mass ratio of the fluorescent Pseudomonas to Bacillus natto is 1~3:7.

[0017] If the mass ratio of *Pseudomonas fluorescens* to *Bacillus natto* is less than 1:7, its effects in inhibiting soil-borne pathogens and secreting growth-promoting substances will be weakened, leading to a decline in soil disease control capabilities. If the mass ratio of *Pseudomonas fluorescens* to *Bacillus natto* is greater than 3:7, it cannot effectively improve crop yield. However, when the mass ratio of *Pseudomonas fluorescens* to *Bacillus natto* is between 1 and 3:7, *Pseudomonas fluorescens* can fully exert its disease resistance and growth-promoting advantages, while *Bacillus natto* can effectively decompose nutrients and improve soil. The synergistic effect of these two microbial agents can enhance soil microecological stability and improve fertilizer nutrient conversion efficiency, thus helping to further increase crop yield.

[0018] As a further technical solution, the binder is an aqueous urea solution, wherein the urea content in the aqueous urea solution is 45wt%~50wt%.

[0019] As a further technical solution, the organic matter includes one or more of soybean meal, wheat bran, and mushroom residue.

[0020] This invention also proposes a method for preparing a granular fertilizer containing trace elements, comprising the following steps: S1. After the components are mixed evenly, a premix is ​​obtained, and the contents of Si, Ca, Mg, S, Fe, Cu, Zn, Mn and B elements in the premix are determined. S2. Based on the test results, supplement the ingredients according to the target ratio of each element in the trace elements to obtain the mixture; S3. Add water to the mixture, stir evenly, and then granulate to obtain granular fertilizer containing micronutrients.

[0021] As a further technical solution, the mass ratio of water to the mixture is 15:1.

[0022] The working principle and beneficial effects of this invention are as follows: This invention prepares a micronutrient granular fertilizer using clay minerals, binders, organic matter, aromatic aminopropionic acid derivative-modified sepiolite, superphosphate, and potassium nitrate as raw materials. This fertilizer not only effectively replenishes micronutrients in the soil, making soil nutrients more diverse and thus improving soil fertility, but also possesses the ability to adsorb heavy metal cadmium. Sepiolite, with its large specific surface area, is a natural adsorbent for heavy metal cadmium. However, micronutrient granular fertilizers containing sepiolite tend to bind with soil colloids during use, exacerbating soil compaction. Modifying sepiolite with aromatic aminopropionic acid derivatives not only solves the compatibility problem between sepiolite and soil colloids, but also, the amino groups in the aromatic aminopropionic acid derivatives have strong complexing ability, which can more firmly fix heavy metal cadmium ions, thereby further improving the adsorption effect of the micronutrient granular fertilizer on heavy metal cadmium. Detailed Implementation

[0023] 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.

[0024] In the following examples and comparative examples: sepiolite, particle size 45μm; Bacillus natto, spore content 100 billion / g; Pseudomonas fluorescens, spore content 500 million / g; soybean meal, purchased from Shijiazhuang Gupan Biotechnology Co., Ltd.; wheat bran, purchased from Shijiazhuang Linnong Biotechnology Co., Ltd.; mushroom residue, purchased from Dezhou Fubang Agricultural Development Co., Ltd.

[0025] Example 1 A micronutrient granular fertilizer comprises the following raw materials in parts by weight: 70 parts clay minerals, 7 parts urea aqueous solution with a urea content of 47wt%, 7 parts soybean meal, 2 parts modified sepiolite, 0.5 parts superphosphate, and 1 part potassium nitrate; wherein the mass ratio of micronutrients is Si:Ca:Mg:S:Fe:Cu:Zn:Mn:B = 1:10:30:12:20:0.07:1:0.2:0.1; The method for preparing modified sepiolite includes the following steps: 3-(3-aminophenyl)propionic acid is added to ethanol and dispersed evenly, then sepiolite is added and mixed for 3 hours, and then dried to obtain modified sepiolite; wherein the mass ratio of sepiolite to 3-(3-aminophenyl)propionic acid is 100:3, and the mass-volume ratio of sepiolite to ethanol is 1g:12mL. A method for preparing a granular fertilizer containing trace elements includes the following steps: S1. After mixing the raw materials of each component evenly, a premix is ​​obtained. The contents of Si, Ca, Mg, S, Fe, Cu, Zn, Mn and B elements in the premix are determined. S2. Based on the content of various elements determined in the premix, supplement the ingredients according to the target ratio of each element in the trace elements to obtain the mixture; wherein the mass ratio of trace elements in the mixture is Si:Ca:Mg:S:Fe:Cu:Zn:Mn:B=1:10:30:12:20:0.07:1:0.2:0.1; S3. Add water to the mixture, stir evenly, and then granulate to obtain micronutrient granular fertilizer, wherein the mass ratio of water to the mixture is 15:1.

[0026] Example 2 A micronutrient granular fertilizer comprises the following raw materials in parts by weight: 75 parts clay minerals, 8 parts urea aqueous solution with a urea content of 47 wt%, 9 parts wheat bran, 3 parts modified sepiolite (same as in Example 1), 1 part superphosphate, and 2 parts potassium nitrate. A method for preparing a granular fertilizer containing trace elements includes the following steps: S1. After mixing the raw materials of each component evenly, a premix is ​​obtained. The contents of Si, Ca, Mg, S, Fe, Cu, Zn, Mn and B elements in the premix are determined. S2. Based on the content of various elements determined in the premix, supplement the ingredients according to the target ratio of each element in the trace elements to obtain the mixture. The mass ratio of trace elements in the mixture is Si:Ca:Mg:S:Fe:Cu:Zn:Mn:B=3:12:35:13:30:0.08:1.5:0.3:0.15. S3. Add water to the mixture, stir evenly, and then granulate to obtain micronutrient granular fertilizer, wherein the mass ratio of water to the mixture is 15:1.

[0027] Example 3 A micronutrient granular fertilizer comprises the following raw materials in parts by weight: 80 parts clay minerals, 9 parts urea aqueous solution with a urea content of 47wt%, 11 parts mushroom residue, 4 parts modified sepiolite (same as in Example 1), 1.5 parts superphosphate, and 3 parts potassium nitrate. A method for preparing a granular fertilizer containing trace elements includes the following steps: S1. After mixing the raw materials of each component evenly, a premix is ​​obtained. The contents of Si, Ca, Mg, S, Fe, Cu, Zn, Mn and B elements in the premix are determined. S2. Based on the content of various elements determined in the premix, supplement the ingredients according to the target ratio of each element in the trace elements to obtain the mixture. The mass ratio of trace elements in the mixture is Si:Ca:Mg:S:Fe:Cu:Zn:Mn:B=2:14:40:14:40:0.09:2:0.4:0.2. S3. Add water to the mixture, stir evenly, and then granulate to obtain micronutrient granular fertilizer, wherein the mass ratio of water to the mixture is 15:1.

[0028] Example 4 Compared with Example 2, the only difference in Example 4 is that 3-(3-aminophenyl)propionic acid is replaced with an equal amount of 3-amino-3-(3-hydroxyphenyl)-propionic acid.

[0029] Example 5 Compared with Example 2, the only difference in Example 5 is that 3-(3-aminophenyl)propionic acid is replaced with an equal amount of 3-amino-3-(2,3-dihydroxyphenyl)propionic acid.

[0030] Example 6 Compared with Example 4, the only difference in Example 6 is that the mass ratio of sepiolite to 3-amino-3-(3-hydroxyphenyl)-propionic acid in this example is 20:1.

[0031] Example 7 Compared with Example 4, the only difference in Example 7 is that the mass ratio of sepiolite to 3-amino-3-(3-hydroxyphenyl)-propionic acid in this example is 100:7.

[0032] Example 8 Compared with Example 2, the only difference in Example 8 is that this example also includes 3 samples of fluorescent Pseudomonas.

[0033] Example 9 Compared with Example 2, the only difference in Example 9 is that this example also includes 3 samples of Bacillus natto.

[0034] Example 10 Compared with Example 2, the only difference in Example 10 is that this example also includes 3 parts of compound microbial agent, which is composed of Pseudomonas fluorescens and Bacillus natto in a mass ratio of 1:7.

[0035] Example 11 Compared with Example 10, the only difference in Example 11 is that the compound microbial agent in this example is composed of Pseudomonas fluorescens and Bacillus natto in a mass ratio of 2:7.

[0036] Example 12 Compared with Example 10, the only difference in Example 12 is that the compound microbial agent in this example is composed of Pseudomonas fluorescens and Bacillus natto in a mass ratio of 3:7.

[0037] Comparative Example 1 Compared with Example 2, the only difference in Comparative Example 1 is that the modified sepiolite was replaced with an equal amount of sepiolite in this comparative example.

[0038] The micronutrient granular fertilizers in Examples 1-12 and Comparative Example 1 were tested according to the following method: 1. Determination of available cadmium content in soil: Cadmium-contaminated soil was divided into 8 portions, each weighing 100g, and placed in a 1L beaker. 500mL of deionized water was added, and 5g of modified sepiolite from Examples 1-7 and Comparative Example 1 was added to each portion. After stirring and treating for 14 days, the soil was dried. The cadmium-contaminated soil before and after treatment was tested according to HJ804-2016 "Determination of 8 available elements in soil by diethylenetriaminepentaacetic acid extraction-inductively coupled plasma atomic emission spectrometry" to determine the available cadmium content in the soil.

[0039] 2. Crop Yield Measurement: This experiment was conducted in a plastic greenhouse of Handan Yuanwo Fertilizer Technology Co., Ltd. The uniformly fertile soil was divided into 6 experimental zones, each treated with fertilizers specified in Examples 2 and 8-12. Each treatment had 3 plots, and each plot had an area of ​​4m². 2 The fertilizer application rate was 0.5 kg / plot. Four cucumber plants were selected at a fixed point in each plot for yield measurement. The total yield was recorded from the first harvest to the last harvest, and then the average yield of each experimental plot was calculated.

[0040] The measurement results are shown in Tables 1 and 2: Table 1. Results of determination of available cadmium content in soil in Examples 1-7 and Comparative Example 1

[0041] As shown in Table 1, the micronutrient granular fertilizer prepared by this invention can effectively reduce the available form of cadmium in the soil. A comparison between Examples 1-7 and Comparative Example 1 shows that the addition of aromatic aminopropionic acid derivative-modified sepiolite can significantly improve the adsorption capacity of the micronutrient granular fertilizer for available form of cadmium in the soil.

[0042] Table 2. Results of crop yield determination after application of micronutrient granular fertilizer in Examples 2, 8-12

[0043] As shown in Table 2, the micronutrient granular fertilizer prepared by this invention can effectively increase crop yield. Comparisons in Examples 2 and 8-12 demonstrate that the addition of compound microbial agents can significantly increase crop yield.

[0044] 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. A granular fertilizer containing trace elements, characterized in that, The micronutrient granular fertilizer comprises the following raw materials in parts by weight: 70-80 parts clay minerals, 7-9 parts binder, 7-11 parts organic matter, 2-4 parts modified sepiolite, 0.5-1.5 parts superphosphate, and 1-3 parts potassium nitrate; wherein the modified sepiolite is obtained by modifying sepiolite with aromatic aminopropionic acid derivatives.

2. The micronutrient granular fertilizer according to claim 1, characterized in that, The mass ratio of aromatic aminopropionic acid derivative to sepiolite in the modified sepiolite is 3~7:

100.

3. The micronutrient granular fertilizer according to claim 1, characterized in that, The aromatic aminopropionic acid derivatives include one or more of 3-(3-aminophenyl)propionic acid, 3-amino-3-(3-hydroxyphenyl)-propionic acid, and 3-amino-3-(2,3-dihydroxyphenyl)-propionic acid.

4. The micronutrient granular fertilizer according to claim 1, characterized in that, The sepiolite has a particle size of 40~50μm.

5. A micronutrient granular fertilizer according to claim 1, characterized in that, The clay minerals include one or more of the following: kaolin, montmorillonite, illite, bentonite, talc, mica, vermiculite, chlorite, and borax.

6. A micronutrient granular fertilizer according to claim 1, characterized in that, The micronutrient granular fertilizer contains Si, Ca, Mg, S, Fe, Cu, Zn, Mn, and B. The mass ratio of each micronutrient is as follows: Si:Ca:Mg:S:Fe:Cu:Zn:Mn:B = (1~2):(10~14):(30~40):(12~14):(20~40):(0.07~0.09):(1~2):(0.2~0.4):(0.1~0.2).

7. A micronutrient granular fertilizer according to claim 1, characterized in that, The components of the micronutrient granular fertilizer also include 1 to 5 parts of compound microbial agent; the compound microbial agent is composed of Pseudomonas fluorescens and Bacillus natto.

8. A micronutrient granular fertilizer according to claim 7, characterized in that, The mass ratio of *Pseudomonas fluorescens* to *Bacillus natto* is 1-3:

7.

9. The micronutrient granular fertilizer according to claim 1, wherein the binder is an aqueous urea solution, and the urea content in the aqueous urea solution is 45wt%~50wt%.

10. The micronutrient granular fertilizer according to claim 1, wherein the organic matter includes one or more of soybean meal, wheat bran, and mushroom residue.

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