A nutrient-balanced water-soluble fertilizer and its preparation method

Abstract

This invention relates to the field of agricultural application technology and proposes a nutrient-balanced water-soluble fertilizer and its preparation method, comprising the following steps: S1, reacting sodium alginate and fulvic acid under the action of a catalyst to obtain modified fulvic acid; S2, adding calcium ammonium nitrate to the modified fulvic acid and mixing to obtain calcium alginate-modified fulvic acid; S3, adding inorganic fertilizer to the calcium alginate-modified fulvic acid and mixing to obtain the nutrient-balanced water-soluble fertilizer; wherein the inorganic fertilizer in S3 contains nitrogen, phosphorus, and potassium elements. Through the above technical solution, the problems of incomplete nutrient content and unreasonable nutrient structure in existing water-soluble fertilizers are solved.

Description

Technical Field

[0001] This invention relates to the field of agricultural application technology, specifically to a nutrient-balanced water-soluble fertilizer and its preparation method. Background Technology

[0002] Fulvic acid is a water-soluble reddish-brown or grayish-black powdery substance that plays an important role in promoting plant growth, enhancing plant stress resistance, and drought resistance. Compared with humic acid, it has a smaller molecular weight, stronger water solubility, and is more easily absorbed by plants. However, when it coexists with a large amount of calcium and magnesium ions, it will also generate calcium (magnesium) fulvic acid over time, which will significantly reduce its water solubility and weaken the absorption by crops.

[0003] Calcium fertilizer can neutralize soil pH, improve the growth environment of soil microorganisms, increase soil nutrient retention capacity, and prevent soil compaction, making the soil looser. When planting cash crops, flowers, fruits, vegetables, and other crops, calcium fertilizer can prolong the flowering period, promote normal growth of roots, stems, and leaves, ensure vibrant fruit color, and increase fruit firmness.

[0004] However, due to the requirement of water solubility, water-soluble fertilizers are mainly composed of inorganic fertilizers, which leads to problems such as incomplete nutrient distribution and unreasonable nutrient structure. Therefore, there is a need to develop a nutrient-balanced water-soluble fertilizer to solve the above problems. Summary of the Invention

[0005] This invention proposes a nutrient-balanced water-soluble fertilizer and its preparation method, which solves the problems of incomplete nutrient content and unreasonable nutrient structure in related technologies.

[0006] The technical solution of the present invention is as follows: This invention proposes a method for preparing a nutrient-balanced water-soluble fertilizer, comprising the following steps: S1. Sodium alginate and fulvic acid are reacted under the action of a catalyst to obtain modified fulvic acid; S2. After adding calcium ammonium nitrate to the modified fulvic acid and mixing, calcium alginate modified fulvic acid is obtained. S3. After adding inorganic fertilizer to calcium alginate-modified fulvic acid and mixing, a nutrient-balanced water-soluble fertilizer is obtained. The inorganic fertilizer in S3 contains nitrogen, phosphorus, and potassium elements.

[0007] As a further technical solution, the structural formula of the modified humic acid is: ; As a further technical solution, the structural formula of the calcium alginate-modified fulvic acid is: ; In this invention, sodium alginate is used to modify fulvic acid. Taking advantage of fulvic acid's high water solubility, the water solubility of sodium alginate is increased. When mixed with calcium ammonium nitrate, the strong complexing ability of sodium alginate and calcium ions prevents the calcium ions from binding with fulvic acid, thus ensuring that the performance of fulvic acid is not affected. While calcium alginate is insoluble in water, the high water solubility of fulvic acid ensures that the entire calcium alginate-modified fulvic acid is soluble in water. This also ensures that fulvic acid and calcium ammonium nitrate can form a stable water-soluble fertilizer. This avoids the problems of phosphate and sulfate ions in inorganic fertilizers precipitating with calcium ions, affecting crop absorption of nitrogen, phosphorus, and potassium, leading to nutrient loss and soil compaction, and limiting the combination of macronutrients such as nitrogen, phosphorus, and potassium with calcium fertilizer. The modified fulvic acid in this invention can achieve the coexistence of nitrogen, phosphorus, potassium, and calcium fertilizers, forming a stable, nutritionally balanced water-soluble fertilizer. Through interaction, each component provides maximum nutrition to crops and improves the soil.

[0008] As a further technical solution, the catalyst in S1 includes one or both of zinc oxide and stannous chloride.

[0009] As a further technical solution, the inorganic fertilizer is composed of nitrogen- and phosphorus-containing inorganic fertilizer and potassium-containing inorganic fertilizer.

[0010] As a further technical solution, the mass ratio of the nitrogen-phosphorus inorganic fertilizer to the potassium-containing inorganic fertilizer is 0.75~1.5:1.

[0011] As a further technical solution, the nitrogen- and phosphorus-containing inorganic fertilizer includes one or two of monoammonium phosphate and diammonium phosphate; the potassium-containing inorganic fertilizer includes one or two of potassium sulfate and potassium chloride.

[0012] As a further technical solution, the mass ratio of fulvic acid to sodium alginate in S1 is 3~5:1.

[0013] As a further technical solution, the mass ratio of the catalyst in S1 to the combined mass of sodium alginate and fulvic acid is 0.1~0.3:1.

[0014] As a further technical solution, S1 involves fully dissolving sodium alginate in water, adding a water absorbent, fulvic acid, and a catalyst, and then reacting to obtain modified fulvic acid.

[0015] As a further technical solution, the rotation speed during dissolution is 300 r / min, and the stirring time is 1 h.

[0016] As a further technical solution, the absorbent is concentrated sulfuric acid.

[0017] As a further technical solution, the reaction temperature in S1 is 60~80℃, and the reaction time is 2~3h.

[0018] As a further technical solution, the mass ratio of calcium ammonium nitrate to fulvic acid is 0.7~1.5:1.

[0019] As a further technical solution, calcium ammonium nitrate in S2 is added at a uniform rate for 25-35 minutes, preferably 30 minutes.

[0020] As a further technical solution, the ammonium calcium nitrate is added at a speed of 500 r / min, and after the ammonium calcium nitrate is added, the stirring is continued at a speed of 500 r / min for 30 min.

[0021] As a further technical solution, the mass ratio of inorganic fertilizer to humic acid in S3 is 0.5~1.5:1.

[0022] As a further technical solution, the mixing speed in S3 is 500 r / min, and the mixing time is 30 min.

[0023] This invention also proposes a method for preparing a nutrient-balanced water-soluble fertilizer.

[0024] In this invention, the prepared nutrient-balanced water-soluble fertilizer can be applied to crops through fertigation, sprinkler irrigation, or drip irrigation. It can improve the soil, ensure the crop's production environment, and provide crops with comprehensive nutrients.

[0025] The working principle and beneficial effects of this invention are as follows: In this invention, the nutrient-balanced water-soluble fertilizer mainly includes inorganic fertilizers providing nitrogen, phosphorus, and potassium, calcium ammonium nitrate, and modified fulvic acid. The modified fulvic acid is obtained by modifying fulvic acid with sodium alginate, utilizing the strong water solubility of fulvic acid to increase the water solubility of sodium alginate. The resulting modified fulvic acid is mixed with calcium ammonium nitrate. The modified fulvic acid contains sodium alginate and calcium... 2+ Calcium alginate is generated, while fulvic acid and Ca are avoided. 2+ The combination of these two methods not only prevents the flocculation of fulvic acid in water but also allows for the full utilization of water-soluble calcium, maximizing fertility. Furthermore, due to the shielding effect of sodium alginate, it effectively solves the problems of phosphate and sulfate ions in inorganic fertilizers easily precipitating with calcium ions, affecting crop absorption of nitrogen, phosphorus, and potassium, causing nutrient loss and soil compaction. This reduces the limitations of inorganic fertilizer use and comprehensively combines the advantages of organic and inorganic fertilizers, giving the fertilizer a balanced and stable characteristic, achieving the goal of efficient fertilization. Attached Figure Description

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] Figure 1 This is a synthetic route diagram of calcium alginate-modified fulvic acid according to the present invention; In the figure, n represents the number of alginate units, and x represents the number of calcium ion complexes. Figure 2 The image shows the modified fulvic acid and its infrared spectrum in Example 1 of this invention. Detailed Implementation

[0028] 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.

[0029] In the following embodiments and comparative examples: Calcium ammonium nitrate: Jiaocheng County Zhibaowang Fertilizer Co., Ltd., yellow granules, nitrogen content: 15.5%, calcium content: 18.5%, particle size: 2-4mm, 91.85%; Fulvic acid: Shandong Huayuan Humic Acid Ecological Agriculture Technology Co., Ltd., black granules, fulvic acid content: 47.98%, moisture: 6.1%, pH: 10.5; Sodium alginate: Tianxin (Qingdao) Food Co., Ltd., white powder; Zinc oxide: Chifeng Boda Zinc Oxide Co., Ltd., white powder; Stannous chloride: Henan Angshe Chemical Technology Co., Ltd., white crystalline powder; Monoammonium phosphate: Hubei Liuguo Chemical Co., Ltd., white crystals, nitrogen content: 11.8%, phosphorus content: 61.5%; Diammonium phosphate: Hebei Jinqiao Agricultural Materials Co., Ltd., black granules, nitrogen content: 17.52%, phosphorus content: 47%; Potassium chloride: Hebei Jiabang Agricultural Technology Co., Ltd., white crystals, potassium content: 62.42%; Potassium sulfate: Chifeng Aoxin Chemical Co., Ltd., white powder, potassium content: 52.84%; Concentrated sulfuric acid: The mass fraction of H2SO4 is 98.3%. Density: 1.84 g / cm³ 3 .

[0030] Example 1 A nutrient-balanced water-soluble fertilizer and its preparation method, comprising the following steps: S1. Add 2g sodium alginate and 300mL water to a three-necked flask, stir at 300r / min for 1h, then add 0.4g concentrated sulfuric acid, 6g fulvic acid and 0.8g zinc oxide, react at 60℃ for 2h, and then cool to room temperature to obtain modified fulvic acid. S2. Transfer the modified fulvic acid to a beaker, and slowly and uniformly add 5g of calcium ammonium nitrate at 500 rpm for 30 minutes. After the addition is complete, stir at 500 rpm for another 30 minutes to obtain calcium alginate-modified fulvic acid. The synthesis route of calcium alginate-modified fulvic acid is shown below. Figure 1 As shown; S3. Add 2g of monoammonium phosphate and 2g of potassium sulfate to calcium alginate-modified fulvic acid, stir at 500 rpm for 30 minutes to obtain a nutrient-balanced water-soluble fertilizer.

[0031] Example 2 A nutrient-balanced water-soluble fertilizer and its preparation method, comprising the following steps: S1. Add 2g sodium alginate and 300mL water to a three-necked flask, stir at 300r / min for 1h, then add 0.4g concentrated sulfuric acid, 8g fulvic acid and 1g zinc oxide, react at 70℃ for 3h, and then cool to room temperature to obtain modified fulvic acid. S2. Transfer the modified fulvic acid to a beaker, and slowly and uniformly add 6g of calcium ammonium nitrate at 500r / min for 30min. After the addition is complete, stir at 500r / min for another 30min to obtain calcium alginate modified fulvic acid. S3. Add 3g of diammonium phosphate and 3g of potassium chloride to calcium alginate-modified fulvic acid, stir at 500r / min for 30min to obtain a nutrient-balanced water-soluble fertilizer.

[0032] Example 3 A nutrient-balanced water-soluble fertilizer and its preparation method, comprising the following steps: S1. Add 2g sodium alginate and 300mL water to a three-necked flask, stir at 300r / min for 1h, then add 0.4g concentrated sulfuric acid, 10g fulvic acid and 1.2g zinc oxide, react at 80℃ for 2h, and then cool to room temperature to obtain modified fulvic acid. S2. Transfer the modified fulvic acid to a beaker, and slowly and uniformly add 7g of calcium ammonium nitrate at 500r / min for 30min. After the addition is complete, stir at 500r / min for another 30min to obtain calcium alginate modified fulvic acid. S3. Add 4g of diammonium phosphate and 3g of potassium sulfate to calcium alginate-modified fulvic acid, stir at 500r / min for 30min to obtain a nutrient-balanced water-soluble fertilizer.

[0033] Example 4 A nutrient-balanced water-soluble fertilizer and its preparation method, comprising the following steps: S1. Add 2g sodium alginate and 300mL water to a three-necked flask, stir at 300r / min for 1h, then add 0.4g concentrated sulfuric acid, 6g fulvic acid and 1.6g zinc oxide, react at 60℃ for 2h, and then cool to room temperature to obtain modified fulvic acid. S2. Transfer the modified fulvic acid to a beaker, and slowly and uniformly add 8g of calcium ammonium nitrate at 500r / min for 30min. After the addition is complete, stir at 500r / min for another 30min to obtain calcium alginate modified fulvic acid. S3. Add 3g of diammonium phosphate and 4g of potassium sulfate to calcium alginate-modified fulvic acid, stir at 500r / min for 30min to obtain a nutrient-balanced water-soluble fertilizer.

[0034] Example 5 A nutrient-balanced water-soluble fertilizer and its preparation method, comprising the following steps: S1. Add 2g sodium alginate and 300mL water to a three-necked flask, stir at 300r / min for 1h, then add 0.4g concentrated sulfuric acid, 8g fulvic acid and 3g zinc oxide, react at 70℃ for 3h, and then cool to room temperature to obtain modified fulvic acid. S2. Transfer the modified fulvic acid to a beaker, and slowly and uniformly add 7g of calcium ammonium nitrate at 500r / min for 30min. After the addition is complete, stir at 500r / min for another 30min to obtain calcium alginate modified fulvic acid. S3. Add 4g of diammonium phosphate and 3g of potassium sulfate to calcium alginate-modified fulvic acid, stir at 500r / min for 30min to obtain a nutrient-balanced water-soluble fertilizer.

[0035] Example 6 A nutrient-balanced water-soluble fertilizer and its preparation method, comprising the following steps: S1. Add 2g sodium alginate and 300mL water to a three-necked flask, stir at 300r / min for 1h, then add 0.4g concentrated sulfuric acid, 10g fulvic acid and 3g zinc oxide, react at 80℃ for 3h, and then cool to room temperature to obtain modified fulvic acid. S2. Transfer the modified fulvic acid to a beaker, and slowly and uniformly add 8g of calcium ammonium nitrate at 500r / min for 30min. After the addition is complete, stir at 500r / min for another 30min to obtain calcium alginate modified fulvic acid. S3. Add 4g of diammonium phosphate and 4g of potassium chloride to calcium alginate-modified fulvic acid, stir at 500r / min for 30min to obtain a nutrient-balanced water-soluble fertilizer.

[0036] Comparative Example 1 The fertilizer used in this comparative example is humic acid.

[0037] Comparative Example 2 In this comparative example, the fertilizer is the modified fulvic acid prepared in step S1 of Example 1.

[0038] Comparative Example 3 In this comparative example, the fertilizer is calcium alginate modified fulvic acid prepared in step S2 of Example 1.

[0039] Comparative Example 4 The fertilizer used in this comparative example is calcium ammonium nitrate.

[0040] Comparative Example 5 In this comparative example, the fertilizer consists of monoammonium sulfate and potassium sulfate in a mass ratio of 1:1.

[0041] Comparative Example 6 In this comparative example, the fertilizer was prepared by uniformly mixing 2g sodium alginate, 6g humic acid, 5g calcium ammonium nitrate, 2g monoammonium phosphate, and 2g potassium sulfate.

[0042] Test case (1) Infrared spectroscopy was performed on the modified fulvic acid in Example 1. Modified fulvic acid and the infrared determination results of fulvic acid are as follows: Figure 2 As shown, analysis reveals: Modified fulvic acid: ~1680cm -1 The C=O stretching vibration shifts to ~1746cm -1 C=O stretching vibration; ~1160cm -1 The first absorption of COC asymmetric stretching vibration is the most useful characteristic absorption of esters, namely the successful modification of fulvic acid with sodium alginate.

[0043] Fulvic acid: ~1680cm -1 The C=O stretching vibration shifts to a lower wavenumber due to conjugation with the benzene ring; ~980 cm⁻¹ -1 The peak at ~980 cm⁻¹ is due to the OH bond on the carboxyl group. The OH group undergoes a non-planar rocking vibration, which is a characteristic peak. Modified humic acid does not exhibit this characteristic peak. -1 This indicates that the carboxyl group has reacted.

[0044] (2) The nutrient-balanced water-soluble fertilizers and fertilizers prepared in Examples 1-6 and Comparative Examples 1-6 were tested for performance, and water was set as a blank control. The specific test method was as follows: 2 kg of soil with vermiculite as the main material was placed in flower pots, and 3 seeds of four-season Chinese cabbage were planted in each flower pot. 2 g of fertilizer was weighed, diluted 2000 times, and 500 mL was taken for irrigation. The plants were cultured under the same conditions (temperature: 25±2℃, humidity: 50%). The leaf area of ​​each four-season Chinese cabbage was measured after 40 days of culture, and the mean was calculated. The results are shown in Table 1.

[0045] Table 1. Performance test results of the nutrient-balanced water-soluble fertilizers in Examples 1-6 and the fertilizers in Comparative Examples 1-6.

[0046] As shown in Table 1, the average leaf area of ​​each Chinese cabbage plant in Examples 1-6 over 40 days was greater than that in Comparative Examples 1-6 and the blank control, indicating that the nutrient-balanced water-soluble fertilizer prepared in this invention has the ability to promote growth and has a significant yield-increasing effect.

[0047] In Comparative Example 6, after inorganic and organic fertilizers were mixed by physical mixing, the average leaf area of ​​each Chinese cabbage leaf after 40 days was smaller than that in the Example. The inventors speculate that the reason may be that some calcium alginate, calcium sulfate and calcium phosphate were generated in Comparative Example 6, forming precipitates that are not conducive to crop absorption, thus resulting in the average leaf area of ​​each Chinese cabbage leaf after 40 days being smaller than that in the Example.

[0048] 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 method for preparing a nutrient-balanced water-soluble fertilizer, characterized in that, Includes the following steps: S1. Sodium alginate is fully dissolved in water, and then concentrated sulfuric acid, fulvic acid and zinc oxide are added and reacted to obtain modified fulvic acid. S2. After adding calcium ammonium nitrate to the modified fulvic acid and mixing, calcium alginate modified fulvic acid is obtained. S3. After adding inorganic fertilizer to calcium alginate-modified fulvic acid and mixing, a nutrient-balanced water-soluble fertilizer is obtained. The inorganic fertilizer in S3 contains nitrogen, phosphorus, and potassium elements; The mass ratio of fulvic acid to sodium alginate in S1 is 3~5:1; The reaction temperature is 60~80℃, and the reaction time is 2~3h; The mass ratio of zinc oxide to the sum of the masses of sodium alginate and fulvic acid in S1 is 0.1~0.3:1; The mass ratio of calcium ammonium nitrate to humic acid is 0.7~1.5:

1.

2. The method for preparing a nutrient-balanced water-soluble fertilizer according to claim 1, characterized in that, The inorganic fertilizer is composed of nitrogen- and phosphorus-containing inorganic fertilizers and potassium-containing inorganic fertilizers.

3. The method for preparing a nutrient-balanced water-soluble fertilizer according to claim 2, characterized in that, The nitrogen- and phosphorus-containing inorganic fertilizers include one or two of monoammonium phosphate and diammonium phosphate; the potassium-containing inorganic fertilizers include one or two of potassium sulfate and potassium chloride.

4. The method for preparing a nutrient-balanced water-soluble fertilizer according to claim 1, characterized in that, The mass ratio of inorganic fertilizer to humic acid in S3 is 0.5~1.5:

1.

5. A nutrient-balanced water-soluble fertilizer prepared by the method for preparing a nutrient-balanced water-soluble fertilizer according to any one of claims 1 to 4.

Images