Synergistic humic acid stress-resistant quality-improving rooting chemical fertilizer rich in VC (Vitamin C) and preparation method thereof

Abstract

The invention relates to a VC-rich synergistic humic acid stress-resistant quality-improving rooting chemical fertilizer and a preparation method thereof. According to the VC-rich synergistic humic acid stress-resistant quality-improving rooting chemical fertilizer and the preparation method thereof, the VC-rich synergistic humic acid stress-resistant quality-improving rooting chemical fertilizer comprises the following components in parts by weight: 30-50 parts of synergistic humic acid and 100-160 parts of a nitrogen-phosphorus-potassium base fertilizer, the preparation method of the synergistic humic acid comprises the following steps: heating a humic acid solution composed of humic acid and deionized water to 45-60 DEG C, uniformly adding polyglutamic acid, then adding gulonic acid, then dropwise adding sulfuric acid until the gulonic acid in the system is less than or equal to 0.5%, and naturally cooling to obtain the synergistic humic acid. According to the invention, gulonic acid and polyglutamic acid are synergetic and are used as synergistic components of humic acid, polyglutamic acid is used as a carrier to guarantee the stability and utilization rate of the components, gulonic acid is catalytically converted into VC through sulfuric acid, and the VC and humic acid jointly realize rooting, cold resistance, quality improvement, disease resistance, yield increase and synergy.

Description

Technical Field

[0001] This invention belongs to the field of fertilizer technology, specifically relating to a vitamin C-rich, nutrient-enhancing, stress-resistant, quality-improving, and root-promoting fertilizer with humic acid and its preparation method. Background Technology

[0002] Chemical fertilizers are an indispensable basic material in agricultural production, playing a crucial role in increasing crop yields. However, the long-term excessive use of traditional chemical fertilizers has led to a series of problems, such as soil compaction and decreased organic matter content, while also causing a decline in crop quality and resilience. Humic acid fertilizers have received widespread attention due to their ability to improve soil, stimulate crop growth, and enhance fertilizer utilization, becoming one of the important development directions for green agriculture.

[0003] Currently, most humic acid fertilizers on the market are based on simple physical blending, mixing humic acid with basic fertilizers such as nitrogen, phosphorus, and potassium and then granulating. These products have significant drawbacks: First, their function is relatively singular; they lack targeted effective ingredients and a clear mechanism of action in addressing increasingly frequent abiotic stresses, especially low-temperature damage, resulting in unstable effects. When crops encounter low temperatures, excessive reactive oxygen species accumulate within them, damaging cell membrane systems, and conventional humic acid fertilizers cannot effectively alleviate this oxidative damage caused by low temperatures.

[0004] Secondly, humic acid and its potential highly active synergistic components (such as vitamin C and other biostimulants) are easily destroyed and degraded during the high-temperature granulation process in fertilizer production, resulting in low or even completely ineffective content of active ingredients in the final product, which seriously affects the actual use effect of the product. Summary of the Invention

[0005] The purpose of this invention is to provide a vitamin C-rich, enhanced humic acid fertilizer for stress resistance, quality improvement, and root development, and its preparation method, in order to solve the above-mentioned problems.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] The first aspect of this invention provides a vitamin C-enhanced humic acid fertilizer for stress resistance, quality improvement and root promotion, comprising the following components in parts by weight: 30-50 parts of enhanced humic acid and 100-160 parts of nitrogen, phosphorus and potassium base fertilizer.

[0008] Specifically, per 100 kg, the raw materials for preparing the enhanced humic acid consist of 47-53 kg of humic acid, 14-18 kg of polyglutamic acid, 12-19 kg of gulonic acid, 1.8-3 kg of sulfuric acid, and 15-25 kg of deionized water.

[0009] The method for preparing the enhanced humic acid is as follows: a humic acid solution composed of humic acid and deionized water is heated to 45-60°C, polyglutamic acid is added uniformly, followed by gulonic acid, and then sulfuric acid is added dropwise until the gulonic acid content in the system is ≤0.5%. The solution is then allowed to cool naturally to obtain the enhanced humic acid.

[0010] As a further optimization of the present invention, the preparation method of the enhanced humic acid is specifically as follows:

[0011] (1) Add deionized water to the corrosion-resistant reaction vessel, heat to 45-60℃, stir at 400-500r / min, slowly add humic acid while stirring, and form a uniform mixture.

[0012] (2) Maintain the temperature and stirring speed, add polyglutamic acid, and continue stirring until the pH of the system is 5.0-5.5;

[0013] (3) Maintain the temperature, adjust the stirring speed to 500-600 r / min, add gulonic acid, stir until completely dissolved, slowly add 98% sulfuric acid, stir after the addition is complete, the pH of the system is 2.5-3.0, and when the residual amount of gulonic acid in the system is ≤0.5%, let it cool down naturally.

[0014] As a further optimization of the present invention, in step (1), the humic acid is added in 3-4 portions, with an interval of 5 minutes between each addition. In step (2), the humic acid is either fulvic acid or potassium fulvicate; the molecular weight of the polyglutamic acid is 100-300 kDa.

[0015] The second aspect of this invention provides the application of a vitamin C-rich, enhanced humic acid fertilizer for stress resistance, quality improvement, and root development in improving the cold resistance of crops.

[0016] The third aspect of this invention provides a method for preparing a vitamin C-enhanced humic acid fertilizer for stress resistance, quality improvement, and root development. The nitrogen, phosphorus, and potassium base fertilizer is a water-soluble base fertilizer. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth and then mixed with the nitrogen, phosphorus, and potassium base fertilizer.

[0017] The fourth aspect of this invention provides a method for preparing a VC-rich, enhanced humic acid fertilizer for stress resistance, quality improvement, and root development. The nitrogen, phosphorus, and potassium base fertilizer is a long-acting solid base fertilizer. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth, and the filtrate is spray-dried, pulverized, sieved, and mixed with the nitrogen, phosphorus, and potassium base fertilizer.

[0018] As a further optimization of the present invention, the inlet air temperature of the dryer is 150-160°C and the outlet air temperature is 75-80°C.

[0019] The fifth aspect of this invention also provides a method for preparing a vitamin C-enhanced humic acid fertilizer for stress resistance, quality improvement, and root development. The nitrogen, phosphorus, and potassium base fertilizer is a long-acting solid base fertilizer. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth, and a portion is fully mixed with biochar. The mixture is then heated to 70-90°C and mixed with snail pulverized material. After drying and pulverizing, another portion of the enhanced humic acid is added and mixed with snail pulverized material again. After drying, the mixture is pulverized and sieved, and then mixed with the nitrogen, phosphorus, and potassium base fertilizer.

[0020] As a further optimization of the present invention, the biochar includes, but is not limited to, corn cob char, corn stalk char, rice straw char, or rice husk char; the mass ratio of the biochar to the total synergistic humic acid is 1:2.0-2.2.

[0021] As a further optimization of the present invention, the snail powder is obtained by grinding farmed snails after they have been crushed, steamed at 100°C, frozen, and then ground; the mass ratio of the snail powder to the total synergistic humic acid is 1:4.0-5.0.

[0022] The sixth aspect of this invention provides a method for preparing a vitamin C-enhanced humic acid fertilizer for stress resistance, quality improvement, and root promotion, and the application of the prepared fertilizer in saline-alkali land.

[0023] As a further optimization of the present invention, the fertilizer increases the available nitrogen, available phosphorus, and organic matter in saline-alkali land, and reduces the pH and soluble salts in saline-alkali land.

[0024] The seventh aspect of this invention provides a method for preparing a vitamin C-rich, enhanced humic acid fertilizer for stress resistance, quality improvement, and root development, and the application of the prepared fertilizer in improving the cold resistance, disease resistance, and survival rate of crops.

[0025] As a further optimization of the present invention, the crops are wheat, corn, rice, fruit vegetables and leafy greens.

[0026] The beneficial effects of this invention are as follows:

[0027] (1) In this invention, gulonic acid and polyglutamic acid are used as synergistic components of humic acid. Polyglutamic acid is used as a carrier to ensure the stability and utilization rate of the components. Gulongic acid is converted into VC by sulfuric acid catalysis, and together with humic acid, it can achieve rooting and cold resistance, quality improvement and disease resistance and increased yield.

[0028] By loading synergistic humic acid onto a carrier, a slow-release effect is achieved. When applied to long-acting base fertilizers, the adsorption of biochar and humic acid helps fix excess salt in the soil. The organic acids produced from the decomposition of snail fragments alleviate salt damage and also have antibacterial effects. Furthermore, using snail fragments as fertilizer increases soil fertility and water retention, improves soil quality, and promotes plant growth and development. The fertilizer prepared by this invention has stronger adsorption and regulation capabilities, effectively reducing the risk of salt stress to crop roots. Detailed Implementation

[0029] The present application will now be described in further detail. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0030] At least one embodiment of the present invention discloses a vitamin C-enhanced humic acid fertilizer for stress resistance, quality improvement and root promotion, containing the following components in parts by weight: 30-50 parts of enhanced humic acid and 100-160 parts of nitrogen, phosphorus and potassium base fertilizer; it may also include other functional ingredients.

[0031] The raw materials for preparing synergistic humic acid, per 100 kg, consist of 47-53 kg of humic acid, 14-18 kg of polyglutamic acid, 12-19 kg of gulonic acid, 1.8-3 kg of sulfuric acid, and 15-25 kg of deionized water. The preparation method of synergistic humic acid is as follows: heat the humic acid solution composed of humic acid and deionized water to 45-60℃, add polyglutamic acid evenly, then add gulonic acid, and then add sulfuric acid dropwise. After the addition is complete, stir until the gulonic acid content in the system is ≤0.5%, and then allow it to cool naturally to obtain synergistic humic acid.

[0032] Specifically:

[0033] (1) Add deionized water to the corrosion-resistant reaction vessel, heat to 45-60℃, stir at 400-500r / min, slowly add humic acid while stirring, and form a uniform mixture.

[0034] (2) Maintain the temperature and stirring speed, add polyglutamic acid, and continue stirring until the pH of the system is 5.0-5.5;

[0035] (3) Maintain the temperature, adjust the stirring speed to 500-600 r / min, add gulonic acid, stir until completely dissolved, slowly add 98% sulfuric acid, stir after the addition is complete, the pH of the system is 2.5-3.0, when the residual amount of gulonic acid in the system is ≤0.5%, let it cool down naturally.

[0036] In step (1), humic acid is added in 3-4 portions, with a 5-minute interval between each addition.

[0037] In step (3), the sulfuric acid is added at a rate of 60-100 mL / min.

[0038] The main raw materials of the synergistic humic acid in this invention include humic acid, gulonic acid, polyglutamic acid, and sulfuric acid. In a heated acidic environment, gulonic acid undergoes partial degradation to generate small molecule carboxylic acids (such as oxalic acid and malic acid); on the other hand, sulfuric acid can act as a catalyst to promote esterification side reactions of gulonic acid to generate ascorbic acid (VC).

[0039] The acidity of sulfuric acid breaks down the hydrogen bonds and hydrophobic interactions between humic acid molecules, transforming the previously insoluble bound humic acid into a more reactive form that readily interacts with other substances, thus activating humic acid. Simultaneously, the temperature of 45-60℃, combined with the weak oxidizing effect of sulfuric acid, causes some large humic acid molecules to undergo slight degradation, breaking down into smaller humic acid fragments. Unlike nitric acid, sulfuric acid does not drastically destroy the functional group structure of humic acid. These smaller humic acid molecules are the key beneficial components; compared to large humic acid molecules, they are more water-soluble and mobile, making them easier for crop roots to absorb. They also more efficiently adsorb heavy metal ions from the soil, reducing the harmful effects of heavy metals on crops. Furthermore, the carboxyl and hydroxyl groups on the activated humic acid molecules are more easily exposed, enhancing their binding capacity with soil minerals and improving the soil structure-improving effect of humic acid.

[0040] The polyglutamic acid backbone is linked by γ-amide bonds, which readily undergo hydrolysis in acidic systems at 45-60℃. This temperature is close to its initial acidic degradation temperature range, causing it to degrade into low molecular weight polyglutamic acid and a small amount of glutamic acid monomers without undergoing severe oxidation or cross-linking reactions, thus better preserving its nitrogen-containing functional groups.

[0041] First, low molecular weight polyglutamic acid and glutamic acid monomers contain nitrogen elements that can serve as a high-quality organic nitrogen source for crops, and the chelating properties of polyglutamic acid can also reduce the loss of nutrients from chemical fertilizers. Second, the small molecule carboxylic acids produced by the degradation of gulonic acid can regulate the slightly acidic environment of the soil, promote the dissolution of mineral nutrients such as phosphorus and calcium in the soil, and improve the nutrient utilization rate of chemical fertilizers. Third, the residual gulonic acid and its conversion products in the system can work synergistically with humic acid and polyglutamic acid degradation products to form a composite component that combines organic nutrition and adsorption properties, thereby enhancing the slow-release effect of chemical fertilizers and extending the nutrient supply time.

[0042] At least one embodiment of the present invention discloses a method for preparing a VC-rich enhanced humic acid fertilizer for stress resistance, quality improvement and root promotion. When the nitrogen, phosphorus and potassium base fertilizer is a water-soluble base fertilizer, the enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth and mixed with the nitrogen, phosphorus and potassium base fertilizer. Granulation or liquid state can be used.

[0043] At least one embodiment of this invention discloses a method for preparing a vitamin C-rich, enhanced humic acid fertilizer for stress resistance, quality improvement, and root development. When the nitrogen, phosphorus, and potassium base fertilizer is a long-acting solid base fertilizer, the enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth. The filtrate is then spray-dried (inlet air temperature 150-160℃, outlet air temperature 75-80℃), pulverized, sieved, and mixed with the nitrogen, phosphorus, and potassium base fertilizer.

[0044] At least one embodiment of this invention discloses a method for preparing a vitamin C-rich, synergistic humic acid fertilizer for stress resistance, quality improvement, and root development. When the nitrogen, phosphorus, and potassium base fertilizer is a long-acting solid base fertilizer, the synergistic humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth. A portion of this humic acid is thoroughly mixed with biochar, and then mixed with snail pellets at a temperature of 70-90°C. After drying and pulverizing, another portion of the synergistic humic acid is added, and the mixture is then mixed with the snail pellets again. This repeated mixing ensures that the humic acid completely enters the biochar, and the snail pellets effectively seal the pores in the biochar, allowing the humic acid to be slowly released into the soil. After drying, the mixture is pulverized, sieved, and then mixed with the nitrogen, phosphorus, and potassium base fertilizer. The mass ratio of biochar to total synergistic humic acid is 1:2.0-2.2, and the mass ratio of snail pellets to total synergistic humic acid is 1:4.0-5.0.

[0045] It should be noted that the "humic acid" mentioned in this invention refers to fulvic acid, which has higher activity; it can also be potassium fulvicate extracted and purified from weathered coal or lignite. The "water-soluble nitrogen, phosphorus, and potassium base fertilizer" consists of 37.5% potassium dihydrogen phosphate, 25% potassium nitrate, and 37.5% urea; the "long-acting solid nitrogen, phosphorus, and potassium base fertilizer" consists of 42% urea-formaldehyde resin-coated urea, 26% monoammonium phosphate, and 32% potassium chloride. "Biocharcoal" includes, but is not limited to, corn cob charcoal, corn stalk charcoal, rice straw charcoal, or rice husk charcoal. The biomass is placed in a muffle furnace and roasted at 450-500℃ for 1-2 hours in an oxygen-deficient state, then cooled and pulverized to 80 mesh. "Snail pulverized material" and "shrimp and crab pulverized material" are obtained by pulverizing farmed snails or farmed shrimp and crabs, steaming them at 100℃, adding a preservative (0.01% potassium sorbate), freezing, and then grinding them into powder.

[0046] Cologne was purchased from Zhengzhou Aikem Chemical Co., Ltd.

[0047] Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art, and all reagents and materials used are commercially available products, and all instruments used are conventional instruments known to those skilled in the art.

[0048] Example 1

[0049] The vitamin C-rich, synergistic humic acid fertilizer for stress resistance, quality improvement, and root promotion in this embodiment consists of 42 parts by weight of synergistic humic acid and 158 parts by weight of nitrogen, phosphorus, and potassium base fertilizer. The synergistic humic acid is prepared from 50 kg of humic acid, 15 kg of polyglutamic acid, 13.2 kg of gulonic acid, 1.8 kg of sulfuric acid, and 20 kg of deionized water. The preparation method of the synergistic humic acid is as follows:

[0050] Add deionized water to the corrosion-resistant reactor, heat to 50-55℃, stir at 400r / min, add humic acid powder slowly in 3 portions, 5min apart each time, stirring continuously for 60min to form a homogeneous mixture (a small amount of microparticles are allowed, which will be further dispersed in the subsequent reaction).

[0051] Maintain a temperature of 50-55℃ and a stirring speed of 400 rpm, add polyglutamic acid (molecular weight 100-300 kDa), and continue stirring for 50 min. In the acidic precursor system, polyglutamic acid will form hydrogen bonds with the phenolic hydroxyl groups of humic acid through the carboxyl groups, forming a stable humic acid-polyglutamic acid composite matrix.

[0052] Maintain a temperature of 50-55℃ and adjust the stirring speed to 550 rpm. Add gulonic acid and stir for 20 minutes until completely dissolved. Slowly add 98% sulfuric acid at a rate of 100 mL / min to avoid local over-acidity that could cause humic acid to coagulate. After the addition is complete, stir for 30 minutes until the pH of the system drops to 2.5-3.0. When the residual gulonic acid content is ≤0.5% (sample for testing), allow it to cool naturally, filter it through a 100-mesh filter cloth, and then mix it with water-soluble nitrogen, phosphorus, and potassium base fertilizer to obtain the fertilizer.

[0053] Comparative Example 1

[0054] The fertilizer in this comparative example, by weight, consists of 44 parts humic acid and 160 parts nitrogen, phosphorus, and potassium base fertilizer. 80 kg of humic acid is mixed with 20 kg of deionized water, filtered through a 100-mesh filter cloth, and then mixed with water-soluble nitrogen, phosphorus, and potassium base fertilizer to obtain the fertilizer.

[0055] Comparative Example 2

[0056] The fertilizer in this comparative example, by weight, consists of 42 parts humic acid and 160 parts nitrogen, phosphorus, and potassium base fertilizer. The raw materials for preparing humic acid consist of 65 kg humic acid, 14 kg gulonic acid, 2 kg sulfuric acid, and 19 kg deionized water. The preparation method of humic acid is as follows:

[0057] Add deionized water to the corrosion-resistant reactor, heat to 50-55℃, stir at 400r / min, add humic acid powder slowly in 3 portions, 5min apart each time, stirring continuously for 60min to form a homogeneous mixture.

[0058] Maintain a temperature of 50-55℃, adjust the stirring speed to 500 rpm, add gulonic acid, and stir for 20 minutes until completely dissolved. Slowly add 98% sulfuric acid at a rate of 100 mL / min to avoid local over-acidity that could cause humic acid to coagulate. After the addition is complete, stir for 30 minutes until the pH of the system drops to 2.5-3.0. When the residual gulonic acid content is ≤0.5% (sample for testing), allow it to cool naturally, filter it through a 100-mesh filter cloth, and then mix it with water-soluble nitrogen, phosphorus, and potassium base fertilizer to obtain the fertilizer.

[0059] Comparative Example 3

[0060] The fertilizer in this comparative example, by weight, consists of 42 parts of humic acid II and 156 parts of nitrogen, phosphorus, and potassium base fertilizer. The raw materials for preparing humic acid II consist of 62 kg of humic acid, 18 kg of polyglutamic acid, and 20 kg of deionized water. The preparation method of humic acid II is as follows:

[0061] Add deionized water to the corrosion-resistant reactor, heat to 50-55℃, stir at 400r / min, add humic acid powder slowly in 3-4 portions, 5min apart each time, stirring continuously for 60min to form a homogeneous mixture (a small amount of microparticles are allowed, which will be further dispersed in subsequent reactions).

[0062] Maintain a temperature of 50-55℃ and a stirring speed of 400 rpm. Add polyglutamic acid (molecular weight 100-300 kDa) and continue stirring for 50 minutes. Allow the mixture to cool naturally, filter it through a 100-mesh filter cloth, and then mix it with water-soluble nitrogen, phosphorus, and potassium base fertilizer to obtain chemical fertilizer.

[0063] Comparative Example 4

[0064] The fertilizer in this comparative example, by weight, consists of 42 parts of humic acid (trihydrate) and 158 parts of nitrogen, phosphorus, and potassium base fertilizer. The raw materials for preparing humic acid (trihydrate) consist of 52 kg of humic acid, 15 kg of glutamic acid, 14 kg of gulonic acid, 2 kg of sulfuric acid, and 17 kg of deionized water. The preparation method of humic acid (trihydrate) is as follows:

[0065] Add deionized water to the corrosion-resistant reactor, heat to 50-55℃, stir at 400r / min, add humic acid powder slowly in 3 portions, 5min apart each time, stirring continuously for 60min to form a homogeneous mixture.

[0066] Maintain a temperature of 50-55℃ and a stirring speed of 400 rpm, add glutamic acid, and continue stirring for 50 minutes.

[0067] Maintain a temperature of 50-55℃, adjust the stirring speed to 500 rpm, add gulonic acid, and stir for 20 minutes until completely dissolved. Slowly add 98% sulfuric acid at a rate of 100 mL / min to avoid local over-acidity that could cause humic acid to coagulate. After the addition is complete, stir for 30 minutes until the pH of the system drops to 2.5-3.0. When the residual gulonic acid content is ≤0.5% (sample for testing), allow it to cool naturally, filter it through a 100-mesh filter cloth, and then mix it with water-soluble nitrogen, phosphorus, and potassium base fertilizer to obtain the fertilizer.

[0068] Comparative Example 5

[0069] The fertilizer in this comparative example, by weight, consists of 42 parts of humic acid tetrahydrate and 158 parts of nitrogen, phosphorus, and potassium base fertilizer. The raw materials for preparing humic acid tetrahydrate consist of 50 kg of humic acid, 15 kg of polyglutamic acid, 13.2 kg of gulonic acid, 1.8 kg of sulfuric acid, and 20 kg of deionized water. The preparation method of humic acid tetrahydrate is as follows:

[0070] Dissolve humic acid in deionized water, heat to 50-55℃, and stir at 400 rpm. Then, add polyglutamic acid, gulonic acid, and sulfuric acid (add sulfuric acid at multiple points to prevent explosion) to the humic acid system simultaneously, stir at 500 rpm for 60 minutes, allow to cool naturally, filter through a 100-mesh filter cloth, and mix with water-soluble nitrogen, phosphorus, and potassium base fertilizer to obtain fertilizer.

[0071] Comparative Example 6

[0072] The fertilizer in this comparative example consists of 40 parts of humic acid quinone and 155 parts of nitrogen, phosphorus, and potassium base fertilizer. The raw materials for preparing humic acid quinone consist of 50 kg of humic acid, 15 kg of polyglutamic acid, 15 kg of ascorbic acid, and 20 kg of deionized water. The preparation method of humic acid quinone is as follows:

[0073] Add deionized water to the corrosion-resistant reactor, heat to 50-55℃, stir at 400r / min, add humic acid powder slowly in 3-4 portions, with an interval of 5min between each addition, stirring continuously for 60min to form a homogeneous mixture.

[0074] Maintain a temperature of 50-55℃ and a stirring speed of 400 rpm, add polyglutamic acid, and continue stirring for 50 minutes.

[0075] Maintain the temperature and stirring speed, add ascorbic acid, and stir for 30 minutes. At this time, the pH of the system drops to 2.5-3.0. After natural cooling, filter the mixture through a 100-mesh filter cloth and mix it with water-soluble nitrogen, phosphorus, and potassium base fertilizer to obtain chemical fertilizer.

[0076] The fertilizers obtained in Example 1 and Comparative Examples 1-6 were tested.

[0077] ① Take 5.0 g of each of the fertilizers prepared in Example 1 and Comparative Examples 1-6, add them to 500 mL beakers, add 495 mL of deionized water at 25 °C, and stir on a magnetic stirrer at 150 rpm for 5 min. After standing for 5 min, observe the state of the solution and determine the water-insoluble content according to GB / T34763-2017 Water-soluble Fertilizers - Determination of Water-Insoluble Matter Content.

[0078] Table 1. Water solubility of fertilizers

[0079]

[0080] The results above show that the synergistic humic acid prepared by this invention does not affect solubility. The fully water-soluble formula and extremely low insoluble content ensure that the fertilizer can flow smoothly in any fertigation facility without clogging the drippers. It is suitable for modern high-tech agricultural technology and can be applied in large quantities.

[0081] ② The experiment began in mid-October 2023 in Sujiatun District, Shenyang City, Liaoning Province, where the local temperature ranged from 4℃ to 16℃. The experimental fields were divided into plots based on their shape, with each plot measuring approximately 10m × 2m. Mulch was laid along the ridges between adjacent experimental fields to prevent seepage. The experimental crop was wheat, specifically the variety Mi 808.

[0082] The fertilizer samples obtained in Example 1 and Comparative Examples 1-6 were processed at a rate of 0.5 kg / m³. 2 The fertilizer was applied evenly to the experimental field after deep tillage, with a blank control (no fertilizer applied). The experimental field was then rotary tilled, followed by irrigation. The irrigation amount could be determined based on local experience, ensuring the soil remained moist within a 20cm depth. Wheat seeds were sown in the experimental field in mid-to-late October. After planting, irrigation was adjusted according to local conditions, with no additional fertilizer applied.

[0083] The growth of wheat in different experimental fields was statistically analyzed. The results are shown in Table 2.

[0084] Table 2. Wheat growth

[0085]

[0086] Statistical analysis shows that the fertilizer prepared using this invention exhibits outstanding performance in four key indicators for wheat: emergence rate, overwintering plant height, disease resistance (disease incidence during flowering), and yield (thousand-grain weight). Polyglutamic acid acts as a carrier to ensure the stability and utilization rate of the components. Guronic acid is converted into vitamin C through sulfuric acid catalysis, working together with humic acid to promote root development, cold resistance, improve quality and disease resistance, and increase yield and efficiency. Directly adding vitamin C to fertilizers is costly and easily oxidized. Using gulonic acid to replace high-priced vitamin C achieves similar results with more balanced indicators, especially the lowest disease incidence, making it more suitable for large-scale industrial production.

[0087] It can be concluded that using humic acid, polyglutamic acid, and gulonic acid in combination as fertilizers can not only increase the cold resistance and disease resistance of wheat, but also enable wheat to have balanced nutrition, thereby increasing yield.

[0088] ③ The experiment began in early April 2024 at a vegetable base in Sujiatun District, Shenyang City, Liaoning Province. The experimental crop was tomato (Tianci 575). Tomato seedlings of uniform growth (three-leaf-one-heart stage) were divided into four groups of 30 plants each. Fertilizers from Example 1 and Comparative Examples 1-6 (2g / plant) were applied, with a blank control (no fertilizer). After 7 days of normal management, the seedlings were placed in an artificial climate chamber for low-temperature stress treatment: day / night temperatures were set at 8℃ / 4℃, with 12 hours of light for 3 consecutive days. After the low-temperature treatment, the following measurements were taken:

[0089] Electrolyte permeability: Leaves from the same part of each group of seedlings were taken and measured using the conductivity method to reflect the degree of cell membrane damage. The higher the permeability, the more severe the membrane damage and the worse the cold resistance.

[0090] Chlorophyll fluorescence parameter (Fv / Fm): The maximum photochemical efficiency of leaves after dark adaptation was determined using a portable chlorophyll fluorometer. This value is a core indicator reflecting the activity of photosynthetic system II (PSII), and it decreases under stress.

[0091] Fresh weight of above-ground parts: After harvesting the seedlings, quickly rinse the above-ground parts to remove impurities, absorb the surface moisture with filter paper, and weigh with an electronic balance.

[0092] Fresh weight of underground parts: Carefully peel off the soil from the roots (you can gently rinse with clean water), absorb the moisture with filter paper, and weigh with an electronic balance.

[0093] Root activity: The reduction method using triphenyltetrazolium chloride (TTC) was employed, and the reduction products were detected. This reflects the root system's ability to absorb water and nutrients; a higher value indicates stronger root metabolic activity at low temperatures, ensuring biomass accumulation.

[0094] Vitamin C (VC) content: The seedling samples were weighed by fresh weight of the aboveground and underground parts, ground, and then the extraction solvent was added. After extraction, the samples were filtered through a 0.45 μm filter membrane to remove impurities and obtained by high performance liquid chromatography.

[0095] The experimental results are shown in Tables 3 and 4:

[0096] Table 3. Electrolyte osmotic rate and Fv / Fm in tomatoes after low temperature stress

[0097]

[0098] Tomato seedlings treated with the fertilizer in Example 1 showed significantly lower electrolyte permeability after low-temperature stress compared to other groups, indicating the least cell membrane damage and the strongest cold resistance. Simultaneously, their Fv / Fm values ​​were the highest, suggesting that their photosynthetic function was least affected by low temperatures and that they had a stronger recovery ability. This demonstrates that the addition of gulonic acid and polyglutamic acid can achieve a similar cold resistance effect to directly adding vitamin C in tomatoes.

[0099] Table 4. Fresh weight, root activity, and vitamin C content of tomatoes after low temperature stress

[0100]

[0101] This invention utilizes polyglutamic acid and humic acid to form a stable composite substrate, enhancing nutrient adsorption and slow release. Guronic acid degrades under acidic conditions to produce small-molecule carboxylic acids, activating humic acid and supplementing organic nutrients. A step-by-step feeding process avoids humic acid aggregation, maximizing the retention of active ingredients. Under low-temperature stress, root vitality and vitamin C content were significantly higher than other groups, demonstrating stress resistance, root growth, and quality improvement effects.

[0102] In Comparative Example 1, humic acid was not activated, had poor water solubility, and low nutrient utilization. Root metabolism was weak at low temperatures, resulting in low biomass accumulation and insufficient VC synthesis; all indicators were close to the blank control. In Comparative Example 2, the lack of polyglutamic acid's chelating and slow-release effects led to easy nutrient loss. Root activity and biomass were better than in Comparative Example 1, but lower than in Example 1; VC content was slightly increased due to gulonic acid conversion. In Comparative Example 3, polyglutamic acid formed a complex with humic acid, but the humic acid was not activated under acidic conditions, resulting in a low proportion of small-molecule humic acid. Root development was slightly better than in Comparative Example 2, but VC synthesis lacked the promotion of gulonic acid degradation products, resulting in lower VC content. In Comparative Example 4, glutamic acid was a monomer, lacking the high-molecular-weight chelating and slow-release properties of polyglutamic acid, and could not form a stable composite substrate. Although a nitrogen source was supplemented, the synergistic effect was weaker than in Example 1, and all indicators were slightly lower than in Example 1. In Comparative Example 5, the lack of stepwise feeding led to localized over-acidity, slight humic acid aggregation, insufficient exposure of active ingredients, and a reduced synergistic effect. In Comparative Example 6, ascorbic acid directly supplemented vitamin C, but lacked the activation effect of small molecule carboxylic acids produced by gulonic acid degradation on humic acid. The vitamin C content exceeded that of Example 1, but root activity and biomass were slightly lower due to insufficient humic acid activation.

[0103] Example 2

[0104] The vitamin C-rich, enhanced humic acid fertilizer for stress resistance, quality improvement, and root development in this embodiment consists of 42 parts of enhanced humic acid and 158 parts of nitrogen, phosphorus, and potassium base fertilizer. The preparation method of the enhanced humic acid is the same as in Example 1. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth, and the filtrate is spray-dried, pulverized, sieved, and then mixed with long-acting solid nitrogen, phosphorus, and potassium base fertilizer.

[0105] Example 3

[0106] The vitamin C-rich, enhanced humic acid fertilizer for stress resistance, quality improvement, and root development in this embodiment consists of 42 parts enhanced humic acid and 158 parts nitrogen, phosphorus, and potassium base fertilizer. The preparation method of the enhanced humic acid is the same as in Example 1. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth, and 80% is thoroughly mixed with biochar (corn cob char, with a mass ratio of biochar to total enhanced humic acid of 1:2.0). This mixture is then mixed with snail pulverizer at 80°C, dried, pulverized, and then the remaining 20% ​​of enhanced humic acid is added. This mixture is then mixed with snail pulverizer (mass ratio of snail pulverizer to total enhanced humic acid of 1:4.0), dried, pulverized, and sieved before being mixed with long-acting solid nitrogen, phosphorus, and potassium base fertilizer.

[0107] Example 4

[0108] The fertilizer in this embodiment consists of 42 parts of enhanced humic acid and 158 parts of nitrogen, phosphorus, and potassium base fertilizer. The preparation method of the enhanced humic acid is the same as in Example 1. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth and then thoroughly mixed with biochar (corn cob char, with a mass ratio of biochar to total enhanced humic acid of 1:2.0). After drying, it is pulverized and sieved, and then mixed with long-acting solid nitrogen, phosphorus, and potassium base fertilizer.

[0109] Example 5

[0110] The vitamin C-rich, enhanced humic acid fertilizer for stress resistance, quality improvement, and root development in this embodiment consists of 42 parts enhanced humic acid and 158 parts nitrogen, phosphorus, and potassium base fertilizer. The preparation method of the enhanced humic acid is the same as in Example 1. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth, and 80% is thoroughly mixed with bentonite (the mass ratio of bentonite to total enhanced humic acid is 1:2.0). This mixture is then mixed with snail pulverizer at 80°C, dried, pulverized, and then the remaining 20% ​​of enhanced humic acid is added. This mixture is then mixed with snail pulverizer (the mass ratio of snail pulverizer to total enhanced humic acid is 1:4.0), dried, pulverized, and sieved before being mixed with long-acting solid nitrogen, phosphorus, and potassium base fertilizer.

[0111] Example 6

[0112] The vitamin C-rich, enhanced humic acid fertilizer for stress resistance, quality improvement, and root development in this embodiment consists of 42 parts enhanced humic acid and 158 parts nitrogen, phosphorus, and potassium base fertilizer. The preparation method of the enhanced humic acid is the same as in Example 1. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth, and 80% is thoroughly mixed with biochar (corn cob char, with a mass ratio of biochar to total enhanced humic acid of 1:2.0). This mixture is then mixed with shrimp and crab pulverized material at 80°C, dried, pulverized, and then the remaining 20% ​​of enhanced humic acid is added. This mixture is then mixed with the shrimp and crab pulverized material (mass ratio of shrimp and crab pulverized material to total enhanced humic acid of 1:4.0), dried, pulverized, and sieved before being mixed with long-acting solid nitrogen, phosphorus, and potassium base fertilizer.

[0113] The fertilizer obtained in the above embodiments was tested.

[0114] ④ The experiment was conducted in early April 2024 at the vegetable base in Sujiatun District, Shenyang City, Liaoning Province. The experimental crops were wheat (Mi 808), corn (Shenyu 31), rice (Shennong 2100), tomato (Tianci 575), cucumber (Chunfeng 2), and winter spinach (Donglv 1). The experimental plots were divided into groups according to the shape of the experimental fields. Each plot of wheat, corn, and rice was about 10m × 2m, and each plot of tomato, cucumber, and winter spinach was about 5m × 1m. The ridges between adjacent experimental fields were covered with plastic film to prevent seepage.

[0115] Seedlings of uniform growth (three-leaf stage) were divided into four groups of 30 plants each. Each group was treated with the fertilizers described in Examples 2-6 (2g / plant), with a blank control group receiving no fertilizer. After 7 days of normal management, the seedlings were placed in an artificial climate chamber for low-temperature stress treatment: day / night temperature set at 8℃ / 4℃, 12 hours of light per day, for 3 consecutive days. The seedlings were then replanted in the experimental field, and the successfully replanted crops were inoculated with different pathogens (inoculation sites were randomized, more than 10 sites), and the fertilizers described in Examples 2-6 (2g / plant) were applied again. The disease incidence rate was tested after 7 days. The results are shown in Table 5.

[0116] Table 5. Disease incidence rate of each crop / %

[0117]

[0118] This invention utilizes biochar as a carrier for synergistic humic acid, leveraging its porous structure to adsorb pathogens, improve the rhizosphere microenvironment, and reduce disease proliferation. Snail powder, rich in protein, minerals, and natural antibacterial components, directly inhibits pathogen activity while simultaneously supplementing crop nutrition and strengthening immunity. Furthermore, a step-by-step mixing process ensures the antibacterial components fully combine with the synergistic humic acid, extending its effective period.

[0119] In Example 2, the disease incidence rate was generally between 23% and 39%, which was better than the blank control, but it lacked biochar and animal-derived antibacterial components, and its disease resistance was far inferior to that of Example 3. The disease incidence rate in Example 4 was higher than in Example 2, indicating that the adsorption effect of biochar alone cannot compensate for the lack of animal-derived antibacterial components, and may even affect crop immunity due to the adsorption of some nutrients. In Example 5, using bentonite instead of biochar, the disease incidence rate was better than in Examples 2, 4, and 6, but lower than in Example 3. The core reason is that bentonite can only retain water and fertilizer, lacking the porous adsorption and antibacterial synergistic effects of biochar, thus reducing the synergistic effect. In Example 6, using shrimp and crab powder instead of snail powder, the disease incidence rate was the highest among all examples, with some crops (such as winter spinach and cucumber) even approaching the blank control. It is speculated that the antibacterial component content of shrimp and crab powder is low, or that it has poor compatibility with humic acid and biochar, thus failing to exert its antibacterial effect.

[0120] Tomatoes and wheat are the most sensitive to the fertilizer of this invention. The incidence rate of tomatoes is only 9.5% and that of wheat is 11.8%, which is the largest reduction compared to other embodiments, indicating that the fertilizer has the most significant effect on improving the immunity of these two crops.

[0121] ⑤ The experiment was conducted in early April 2024 in Guanbaowopu Village, Kangping County, Shenyang City, Liaoning Province. The physicochemical properties of the soil in the experimental field are shown in Table 6.

[0122] Table 6. Soil physicochemical properties of the experimental field (0-20cm)

[0123]

[0124] Note: Soluble salts are mainly sodium chloride, sulfate, and carbonate.

[0125] An experimental group and a control group were set up, and a randomized block design was adopted. The experimental fields were divided into blocks according to their shape, with each block measuring approximately 10m × 2m. The field ridges between adjacent experimental fields were covered with plastic film to prevent seepage. The experimental crop was maize, and the maize variety was Chengyu 20.

[0126] Fertilizer samples prepared for the experimental and control groups were prepared at a ratio of 0.75 kg / m³. 2 The fertilizer was applied evenly to the experimental field, with a blank control (no fertilizer). The experimental field was then rotary tilled, followed by irrigation. The irrigation amount could be determined based on local experience, ensuring the soil remained moist within a 20cm depth. Planting could be done using conventional methods. After planting, irrigation was adjusted according to local conditions, with no additional fertilizer applied.

[0127] Thirty days later, the soil water holding capacity and water retention rate of the experimental field were measured, and the results are shown in Table 7.

[0128] Table 7. Soil water holding capacity and water retention rate

[0129]

[0130] As shown in Table 6, compared with the control group, the fertilizer of this invention improves both the water-holding and water-retention capacity of saline-alkali soil. When applied to the soil, it increases the soil's water-holding capacity and improves soil compaction. Even after 30 days, the soil water retention rate of the long-acting granular fertilizer remains above 18%. Clearly, adding the fertilizer prepared according to this invention to the soil can not only improve the water-holding capacity of saline-alkali soil but also enhance its water-retention capacity, thereby effectively improving the compaction of saline-alkali soil and demonstrating promising application prospects.

[0131] The corn in the experimental field was harvested in mid-October 2024, and the soil in the experimental field was measured and analyzed. The results are shown in Table 8.

[0132] Table 8. Soil Analysis

[0133]

[0134] It can be seen that the fertilizer prepared by this invention can significantly increase soil nutrient content, increase organic matter, and reduce soluble salts, making it highly suitable for the improvement and restoration of saline-alkali land. The adsorption effect of biochar and humic acid can fix excess salt in the soil, and the organic acids produced by the decomposition of snail fragments can alleviate salt damage. Furthermore, using snail shells as fertilizer can increase soil fertility and water retention, improve soil quality, and promote plant growth and development. Snail shells also have insect-repellent properties, reducing the number of pathogens and parasites in the soil and increasing crop yield and quality. The fertilizer prepared by this invention has stronger adsorption and regulation capabilities, effectively reducing the risk of salt stress to crop roots.

[0135] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A vitamin C-rich, synergistic humic acid fertilizer for stress resistance, quality improvement, and root promotion, characterized in that... It includes the following components by weight: 30-50 parts of enhanced humic acid and 100-160 parts of nitrogen, phosphorus and potassium base fertilizer; Specifically, per 100 kg, the raw materials for preparing the enhanced humic acid consist of 47-53 kg of humic acid, 14-18 kg of polyglutamic acid, 12-19 kg of gulonic acid, 1.8-3 kg of sulfuric acid, and 15-25 kg of deionized water. The method for preparing the enhanced humic acid is as follows: a humic acid solution composed of humic acid and deionized water is heated to 45-60°C, polyglutamic acid is added uniformly, followed by gulonic acid, and then sulfuric acid is added dropwise until the gulonic acid content in the system is ≤0.5%. After natural cooling, the enhanced humic acid is obtained.

2. The vitamin C-rich, synergistic humic acid fertilizer for stress resistance, quality improvement, and root promotion according to claim 1, characterized in that: The specific preparation method of the enhanced humic acid is as follows: (1) Add deionized water to the corrosion-resistant reaction vessel, heat to 45-60℃, stir at 400-500r / min, slowly add humic acid while stirring, and form a uniform mixture. (2) Maintain the temperature and stirring speed, add polyglutamic acid, and continue stirring until the pH of the system is 5.0-5.5; (3) Maintain the temperature, adjust the stirring speed to 500-600 r / min, add gulonic acid, stir until completely dissolved, slowly add 98% sulfuric acid, stir after the addition is complete, the pH of the system is 2.5-3.0, and when the residual amount of gulonic acid in the system is ≤0.5%, let it cool down naturally.

3. The vitamin C-rich, synergistic humic acid fertilizer for stress resistance, quality improvement, and root promotion according to claim 2, characterized in that: In step (1), the humic acid is either fulvic acid or potassium fulvicate, and the humic acid is added in 3-4 portions, with an interval of 5 minutes between each addition; in step (2), the molecular weight of the polyglutamic acid is 100-300 kDa.

4. The application of the VC-rich humic acid-enhanced fertilizer for stress resistance, quality improvement and root promotion as described in any one of claims 1-3 in improving the cold resistance and disease resistance of crops.

5. A method for preparing a vitamin C-rich, synergistic humic acid fertilizer for stress resistance, quality improvement, and root promotion, as described in any one of claims 1-3, characterized in that: The nitrogen, phosphorus, and potassium base fertilizer is a water-soluble base fertilizer. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth and then mixed with the nitrogen, phosphorus, and potassium base fertilizer.

6. A method for preparing a vitamin C-rich, synergistic humic acid fertilizer for stress resistance, quality improvement, and root promotion, as described in any one of claims 1-3, characterized in that: The nitrogen, phosphorus, and potassium base fertilizer is a long-acting solid base fertilizer. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth, and the filtrate is spray-dried, pulverized, sieved, and mixed with the nitrogen, phosphorus, and potassium base fertilizer.

7. A method for preparing a vitamin C-rich, synergistic humic acid fertilizer for stress resistance, quality improvement, and root promotion, as described in any one of claims 1-3, characterized in that: The nitrogen, phosphorus, and potassium base fertilizer is a long-acting solid base fertilizer. The enhanced humic acid obtained after natural cooling is filtered through a 100-mesh filter cloth, and a portion of it is fully mixed with biochar. It is then mixed with snail pulverized material under heating conditions of 70-90℃, dried and pulverized, and then another portion of enhanced humic acid is added. It is then mixed with snail pulverized material, dried, pulverized and sieved, and then mixed with the nitrogen, phosphorus, and potassium base fertilizer.

8. The preparation method of the VC-rich, synergistic humic acid-based stress-resistant, quality-improving, and root-promoting fertilizer according to claim 7, characterized in that: The mass ratio of the biochar to the total synergistic humic acid is 1:2.0-2.2; the snail powder is obtained by grinding farmed snails after they have been crushed, steamed at 100°C, frozen, and then ground; the mass ratio of the snail powder to the total synergistic humic acid is 1:4.0-5.

0.

9. The application of the fertilizer prepared by the method for preparing the VC-rich, synergistic humic acid-based fertilizer for stress resistance, quality improvement, and root promotion as described in claim 7 in saline-alkali land, characterized in that: The fertilizer increases the available nitrogen, available phosphorus, and organic matter in saline-alkali land, while reducing the pH and soluble salt content of the land.

10. The application of the fertilizer prepared by the method of preparing the VC-rich, synergistic humic acid fertilizer for stress resistance, quality improvement, and root promotion according to claim 7 in improving the cold resistance, disease resistance, and survival rate of crops, characterized in that: The crops mentioned include, but are not limited to, wheat, corn, rice, fruit vegetables, and leafy greens.

Images