Sodium fulvate organic fertilizer and preparation method thereof

Abstract

The invention relates to the field of fertilizers, and particularly discloses a sodium fulvate organic fertilizer and a preparation method thereof.The sodium fulvate organic fertilizer is prepared from, by weight, 25-35 parts of filler, 22-35 parts of synthetic chemical fertilizer, 10-15 parts of passivated sodium fulvate and 2.2-3.5 parts of microelements. The organic fertilizer provided by the invention contains various nutrient substances, can effectively improve the soil fertility, and reduces the release concentration to a certain extent and strengthens the protection on crops by performing protective resin passivation on the sodium fulvate; and the protective resin also has nitrogen adsorption sites forming coordinate bonds with empty orbits of calcium and magnesium ions, so that the flocculation phenomenon of the sodium fulvate in the hard water can be relieved by preferentially stabilizing metal ions in the hard water.

Description

Technical Field

[0001] The present invention belongs to the field of fertilizers, and particularly relates to a sodium fulvate organic fertilizer and a preparation method thereof. Background Art

[0002] Fertilizers are substances applied to the soil or sprayed on the above-ground parts of crops, which can directly or indirectly supply nutrients to crops, increase yields or improve soil properties. Classified by raw material sources, fertilizers can be divided into inorganic fertilizers and organic fertilizers. Inorganic fertilizers are mainly made from minerals, such as ammonium sulfate, potassium chloride, etc.; organic fertilizers are derived from plant and animal residues or excreta, such as compost, fish meal, etc. Compared with synthetic fertilizers, organic fertilizers are released more slowly, cause less nutrient loss, and help improve soil health and structure.

[0003] In the agricultural field, sodium fulvate, as an efficient fertilizer, can improve soil structure, increase crop yields and quality, and reduce the amount of pesticide used. It promotes plant absorption by activating nutrients in the soil, such as phosphorus, potassium, boron, etc., thereby enhancing the disease resistance and growth performance of crops. For example, patent application CN105367309A discloses a cotton foliar fertilizer containing sodium fulvate and a preparation method thereof, which can reduce the amount of pesticide applied, lower costs, improve the utilization rate of chemical fertilizers, and increase crop yields. Another example is that patent application CN 116063129A also discloses a special high-efficiency water-saving irrigation fertilizer for sugarcane containing sodium fulvate, and this water-saving irrigation fertilizer can promote the growth of sugarcane roots and increase the absorption area of sugarcane roots.

[0004] In the above-mentioned patent applications, sodium fulvate is directly mixed with other fertilizers for application. However, sodium fulvate is prone to form flocs under hard water conditions, and this flocculation phenomenon will hinder the effective absorption and utilization of sodium fulvate. Therefore, there is an urgent need in the market for a sodium fulvate organic fertilizer that is not sensitive to hard water and has a wide range of uses. Summary of the Invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a sodium fulvate organic fertilizer and a preparation method thereof. By passivating sodium fulvate with a protective resin, using the nitrogen adsorption sites in the protective resin that form coordination bonds with the empty orbitals of calcium and magnesium ions, the metal ions in hard water are preferentially stabilized, and the flocculation phenomenon of sodium fulvate in hard water is alleviated.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] On the one hand, the present invention provides a sodium fulvate organic fertilizer, which contains the following raw materials by weight: 25 - 35 parts of filler, 22 - 35 parts of synthetic chemical fertilizer, 10 - 15 parts of passivated sodium fulvate, and 2.2 - 3.5 parts of trace elements;

[0008] The preparation steps of the passivated sodium fulvate are as follows:

[0009] The reaction monomer, crosslinking agent and initiator are dissolved and mixed uniformly, reacted at 50-80° C. for 12-36 hours under nitrogen protection, washed with methanol to obtain a protective resin, mixed with sodium fulvic acid, dried and ground to obtain the passivated sodium fulvic acid.

[0010] The organic fertilizer provided by the present invention can increase the organic matter content in the soil, improve the water retention and air permeability of the soil, and has multiple functions such as improving soil structure, improving soil fertility and repairing soil pollution. Sodium humate has strong physiological activity, and its dosage is not completely proportional to the synergy of crops. On the contrary, too high a concentration will cause damage to crops. The present invention passivates sodium humate, reduces the release concentration by reducing contact with the outside world without affecting its physiological activity, and strengthens the protection of crops. In addition, the protective resin in the passivated sodium humate has a certain water absorption, and does not affect the release of sodium humate in the protective state.

[0011] Sodium humate contains functional groups such as carboxyl and phenolic hydroxyl groups, has strong complexation, chelation and surface adsorption capabilities, can reduce the loss of ammonium nitrogen, increase the movement distance of phosphorus in the soil, inhibit the fixation of water-soluble phosphorus by the soil, convert invalid phosphorus into effective phosphorus, and promote the absorption of phosphorus by the root system; it can also absorb and store potassium ions to increase the content of effective potassium. However, under hard water conditions, calcium and magnesium ions are prone to complexation reactions with functional groups such as carboxyl and phenolic hydroxyl groups in sodium humate to form flocs, and this flocculation phenomenon will hinder the effective absorption and utilization of sodium humate. The protective resin in the passivated sodium humate provided by the present invention can provide nitrogen adsorption sites that form coordination bonds with the empty orbitals of calcium and magnesium ions, preferentially stabilize these metal ions in hard water, and alleviate the flocculation phenomenon of sodium humate in hard water.

[0012] In some embodiments, the crosslinking agent comprises trimethylolpropane trimethacrylate and ethylene glycol dimethacrylate.

[0013] In some embodiments, the molar ratio of trimethylolpropane trimethacrylate to ethylene glycol dimethacrylate is 1:(0.7-1.3).

[0014] The invention uses specially selected trimethylolpropane trimethacrylate and ethylene glycol dimethacrylate as crosslinking agents, wherein the three-crosslinked product formed by trimethylolpropane trimethacrylate can reduce the amount of crosslinking agent used, reduce the coverage of the crosslinking agent on the active sites, and ensure the polymerization of the protective resin; ethylene glycol dimethacrylate can adjust the degree of crosslinking, improve the water absorption degree and reduce the mechanical strength of the protective resin, which is convenient for subsequent crushing.

[0015] In some embodiments, the reaction monomer comprises benzylvinyltrimethylammonium chloride and 1,4-butadiene.

[0016] In some embodiments, the molar ratio of benzylvinyltrimethylammonium chloride to 1,4-butadiene is 1:(0.4 - 0.6).

[0017] Through the specific selection of benzylvinyltrimethylammonium chloride in the reaction monomer, by utilizing the charge repulsion of quaternized N and the methyl steric hindrance, as many positively charged nitrogens as possible are oriented and exposed on the resin surface during the formation of the protective resin, improving the exposure rate of nitrogen adsorption sites of the protective resin, and further enhancing the stability of sodium fulvate in hard water. In addition, 1,4-butadiene in the reaction monomer can enhance the fluidity of the protective resin, facilitating the mixing with sodium fulvate.

[0018] In some embodiments, the molar ratio of the reaction monomer to the crosslinking agent is 1:(0.1 - 0.3).

[0019] In some embodiments, the mass ratio of the reaction monomer to the initiator is 1:(0.04 - 0.09).

[0020] In some embodiments, the trace elements comprise ammonium molybdate and ferrous sulfate.

[0021] Ammonium molybdate in the trace elements mainly promotes nitrogen metabolism and phosphorus absorption, while ferrous sulfate is mainly used to supplement iron elements and regulate soil acidity and alkalinity.

[0022] In some embodiments, the filler comprises bone meal and diatomite.

[0023] Bone meal in the filler is rich in phosphorus, calcium and a small amount of nitrogen, which has a significant promoting effect on the growth of plant roots, flowering and fruiting, helps to increase the yield of fruits and seeds, strengthen the root structure, and has a slow-release effect, capable of continuously releasing nutrients. Diatomite has characteristics such as porosity and strong adsorption capacity, can improve soil structure, increase soil water retention and air permeability, and at the same time provide silicon elements required by plants.

[0024] In some embodiments, the synthetic fertilizer comprises monoammonium phosphate, urea and potassium chloride.

[0025] On the other hand, the present invention provides a method for preparing the above sodium fulvate organic fertilizer, which specifically comprises the following steps: uniformly mixing the filler, synthetic fertilizer, passivated sodium fulvate and trace elements to obtain the sodium fulvate organic fertilizer.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention provides an organic fertilizer containing various nutrients, which has multiple functions such as improving soil structure, enhancing soil fertility, and repairing soil pollution. On this basis, sodium fulvate is passivated with a protective resin. Without affecting the physiological activity of sodium fulvate, the release concentration is reduced by decreasing the contact with the outside world, strengthening the protection of crops; this protective resin has a certain water absorption capacity and can release sodium fulvate in a protected state by watering; and this protective resin also has nitrogen adsorption sites that can form coordination bonds with the empty orbitals of calcium and magnesium ions, and can alleviate the flocculation phenomenon of sodium fulvate in hard water by preferentially stabilizing metal ions in hard water.

[0028] 2. By specifically selecting trimethylolpropane trimethacrylate and ethylene glycol dimethacrylate as crosslinking agents, the present invention can reduce the amount of crosslinking agent used, decrease the coverage of active sites by the crosslinking agent, and also increase the water absorption degree, reduce the mechanical strength of the protective resin, and facilitate subsequent pulverization.

[0029] 3. Through the specific selection of reaction monomers, during the formation of the protective resin, positively charged nitrogen is as much as possible oriented to expose on the resin surface, increasing the exposure rate of nitrogen adsorption sites of the protective resin, thereby enhancing the stability of sodium fulvate in hard water; it can also enhance the fluidity of the protective resin, facilitating mixing with sodium fulvate. Specific Embodiments

[0030] The following will illustrate the present invention in combination with specific implementation examples. It should be noted that the following examples are examples of the present invention, only used to illustrate the present invention, rather than to limit the present invention. Without departing from the gist or scope of the present invention, other combinations and various improvements within the concept of the present invention can be made.

[0031] It is worth noting that the raw materials used in the following preparation examples and examples, if not specifically stated, are from any commercially available manufacturer.

[0032] Preparation Example 1

[0033] The preparation steps of passivated sodium fulvate A are as follows:

[0034] Dissolve and mix the reaction monomers, crosslinking agent, and AIBN evenly, react at 70 °C for 24 h under nitrogen protection, rinse with methanol to obtain the protective resin, mix it with sodium fulvate, dry, and grind to obtain the passivated sodium fulvate;

[0035] The molar ratio of trimethylolpropane trimethacrylate to ethylene glycol dimethacrylate in the crosslinking agent is 1:1.1;

[0036] The molar ratio of benzylvinyltrimethylammonium chloride to 1,4-butadiene in the reaction monomers is 1:0.5;

[0037] The molar ratio of the reaction monomer to the crosslinking agent is 1:0.2;

[0038] The mass ratio of the reaction monomer to AIBN is 1:0.06;

[0039] The mass ratio of the protective resin to sodium fulvate is 1:0.8.

[0040] Preparation Example 2

[0041] The preparation steps of passivated sodium fulvate B are as follows:

[0042] The difference between this preparation example and Preparation Example 1 is that trimethylolpropane trimethacrylate in the crosslinking agent is replaced by an equal molar amount of ethylene glycol dimethacrylate.

[0043] Preparation Example 3

[0044] The preparation steps of passivated sodium fulvate C are as follows:

[0045] The difference between this preparation example and Preparation Example 1 is that ethylene glycol dimethacrylate in the crosslinking agent is replaced by an equal molar amount of trimethylolpropane trimethacrylate.

[0046] Preparation Example 4

[0047] The preparation steps of passivated sodium fulvate D are as follows:

[0048] The difference between this preparation example and Preparation Example 1 is that benzylvinyltrimethylammonium chloride in the reaction monomer is replaced by an equal molar amount of 1,4-butadiene.

[0049] Preparation Example 5

[0050] The preparation steps of passivated sodium fulvate E are as follows:

[0051] The difference between this preparation example and Preparation Example 1 is that 1,4-butadiene in the reaction monomer is replaced by an equal molar amount of benzylvinyltrimethylammonium chloride.

[0052] Example 1

[0053] A sodium fulvate organic fertilizer contains the following raw materials by weight: 30 parts of filler, 30 parts of synthetic chemical fertilizer, 13 parts of passivated sodium fulvate A, and 3 parts of trace elements;

[0054] The filler contains 6 parts of bone meal and 24 parts of diatomite;

[0055] The synthetic chemical fertilizer contains 9 parts of monoammonium phosphate, 14 parts of urea, and 7 parts of potassium chloride;

[0056] The trace elements include 0.1 part of ammonium molybdate and 2.9 parts of ferrous sulfate;

[0057] In this embodiment, the preparation method of the sodium fulvate organic fertilizer specifically includes the following steps: Mix the filler, synthetic chemical fertilizer, passivated sodium fulvate A and trace elements evenly to obtain the sodium fulvate organic fertilizer.

[0058] Example 2

[0059] A sodium fulvate organic fertilizer, by weight, comprises the following raw materials: 25 parts of filler, 22 parts of synthetic chemical fertilizer, 10 parts of passivated sodium fulvate A, and 2.2 parts of trace elements;

[0060] The filler includes 5 parts of bone meal and 20 parts of diatomite;

[0061] The synthetic chemical fertilizer includes 5 parts of monoammonium phosphate, 12 parts of urea, and 5 parts of potassium chloride;

[0062] The trace elements include 0.06 part of ammonium molybdate and 2.14 parts of ferrous sulfate;

[0063] In this embodiment, the preparation method of the sodium fulvate organic fertilizer is the same as that in Example 1.

[0064] Example 3

[0065] A sodium fulvate organic fertilizer, by weight, comprises the following raw materials: 35 parts of filler, 35 parts of synthetic chemical fertilizer, 15 parts of passivated sodium fulvate A, and 3.5 parts of trace elements;

[0066] The filler includes 10 parts of bone meal and 25 parts of diatomite;

[0067] The synthetic chemical fertilizer includes 10 parts of monoammonium phosphate, 15 parts of urea, and 10 parts of potassium chloride;

[0068] The trace elements include 0.2 part of ammonium molybdate and 3.3 parts of ferrous sulfate;

[0069] In this embodiment, the preparation method of the sodium fulvate organic fertilizer is the same as that in Example 1.

[0070] Example 4

[0071] This embodiment provides a sodium fulvate organic fertilizer and its preparation method. The specific implementation manner is the same as that in Example 1, except that: the passivated sodium fulvate A is replaced by an equal amount of passivated sodium fulvate B.

[0072] Example 5

[0073] This embodiment provides a sodium fulvate organic fertilizer and its preparation method. The specific implementation manner is the same as that in Example 1, except that: the passivated sodium fulvate A is replaced by an equal amount of passivated sodium fulvate C.

[0074] Example 6

[0075] This embodiment provides a sodium fulvate organic fertilizer and a preparation method thereof. The specific implementation manner is the same as that of Embodiment 1, except that: the passivated sodium fulvate A is replaced by an equal amount of passivated sodium fulvate D.

[0076] Example 7

[0077] This embodiment provides a sodium fulvate organic fertilizer and a preparation method thereof. The specific implementation manner is the same as that of Embodiment 1, except that: the passivated sodium fulvate A is replaced by an equal amount of passivated sodium fulvate E.

[0078] Comparative Example 1

[0079] This comparative example provides a sodium fulvate organic fertilizer and a preparation method thereof. The specific implementation manner is the same as that of Embodiment 1, except that: the passivated sodium fulvate A is replaced by sodium fulvate.

[0080] Performance test:

[0081] The sodium fulvate organic fertilizers provided in Embodiments 1 to 7 and Comparative Example 1 are subjected to the following experiments:

[0082] 1. Dissolution experiment

[0083] Each sodium fulvate organic fertilizer is mixed with 5 times its mass of water, filtered after standing for 1 h and 3 h, and the dissolution amount of sodium fulvate in the filtrate is detected by liquid phase analysis. The dissolution rate at different times is obtained through the formula dissolution rate % = (dissolution amount / added amount) × 100%.

[0084] 2. Stability

[0085] Each sodium fulvate organic fertilizer is mixed with 5 times its mass of hard water, and whether flocculation occurs is observed after standing for 1 h.

[0086] The test results are shown in Table 1.

[0087] Table 1 Performance test results

[0088]

[0089] As can be seen from the data in Table 1, the dissolution rate of sodium fulvate in the organic fertilizers of Embodiments 1 to 3 is stable after 1 h and 3 h, indicating that the passivation of sodium fulvate can effectively reduce the release concentration and strengthen the protection of crops; and the passivated sodium fulvate does not show flocculation in hard water.

[0090] Compared with Example 1, in Examples 4 to 5, instead of using a composite cross-linking agent, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate were used separately. From the data in the table, it can be seen that using ethylene glycol dimethacrylate alone will result in a relatively fast dissolution rate, causing the crop to come into contact with a high concentration of nutrients in a short time, leading to plant burns; while using trimethylolpropane trimethacrylate alone will significantly reduce the dissolution rate of sodium fulvate and there will be a trace of flocculation in hard water, making the fertilizer unable to provide sufficient nutrition for the crop within the validity period, thereby resulting in poor growth. The possible reason is that the three-crosslinked product of trimethylolpropane trimethacrylate improves the polymerization completion degree but also covers the active sites.

[0091] Compared with Example 1, in Examples 6 to 7, instead of using a composite reaction monomer, trimethylolpropane trimethacrylate and 1,4-butadiene were used separately. The protective resin obtained from the former has poor fluidity, which affects the mixing uniformity with sodium fulvate and slightly increases the dissolution rate of sodium fulvate; the flocculation phenomenon that appears in the latter in hard water indicates that the addition of benzylvinyltrimethylammonium chloride can effectively improve the stability of sodium fulvate in hard water.

[0092] Compared with Example 1, the sodium fulvate used in Comparative Example 1 was not passivated. Although it can dissolve well in water, attention should be paid to the dosage during use to avoid negative impacts on the crop. At the same time, it also shows an obvious flocculation phenomenon in hard water, indicating that it has certain requirements for the quality of the water used, otherwise it will not be able to provide an ideal effect.

[0093] The above-described examples and comparative examples do not impose any formal restrictions on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to the above-disclosed technical content to obtain equivalent embodiments with equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A sodium humate organic fertilizer, characterized in that: The raw materials are as follows: 25-35 parts of filler, 22-35 parts of synthetic fertilizer, 10-15 parts of passivated sodium fulvic acid, and 2.2-3.5 parts of trace elements. The preparation steps of the passivated sodium fulvic acid are as follows: The reaction monomer, crosslinking agent and initiator are dissolved and mixed uniformly, reacted at 50-80° C. for 12-36 hours under nitrogen protection, washed with methanol to obtain a protective resin, mixed with sodium fulvic acid, dried and ground to obtain the passivated sodium fulvic acid.

2. The sodium fulvic acid organic fertilizer according to claim 1, characterized in that The crosslinking agent comprises trimethylolpropane trimethacrylate and ethylene glycol dimethacrylate.

3. Sodium humate organic fertilizer according to claim 2, characterized in that, The molar ratio of trimethylolpropane trimethacrylate to ethylene glycol dimethacrylate is 1:(0.7-1.3).

4. The sodium fulvic acid organic fertilizer according to claim 1, characterized in that The reactive monomers include benzyl vinyl trimethyl ammonium chloride and 1,4-butadiene.

5. The sodium fulvic acid organic fertilizer according to claim 4, characterized in that The molar ratio of the benzyl vinyl trimethyl ammonium chloride to 1,4-butadiene is 1:(0.4-0.6).

6. The sodium humate organic fertilizer according to claim 1, characterized in that The molar ratio of the reactive monomer to the cross-linking agent is 1:(0.1-0.3).

7. The sodium fulvic acid organic fertilizer according to claim 1, characterized in that The mass ratio of the reaction monomer to the initiator is 1:(0.04-0.09).

8. The sodium fulvic acid organic fertilizer according to claim 1, characterized in that The trace elements include ammonium molybdate and ferrous sulfate.

9. The sodium fulvic acid organic fertilizer according to claim 1, characterized in that The filler includes bone meal and diatomaceous earth.

10. The sodium humate organic fertilizer according to claim 1, characterized in that: The synthetic fertilizer comprises monoammonium phosphate, urea and potassium chloride.

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