Polypeptide fertilizer beneficial to cold resistance of crops and preparation method thereof

Abstract

The invention discloses a polypeptide fertilizer beneficial to cold resistance of crops and a preparation method thereof, and belongs to the technical field of agricultural fertilizers, the fertilizer is prepared by taking livestock and poultry blood (preferably pig blood) as a raw material, preparing high iron protein peptide through a compound protease hydrolysis process, and matching with a trace element compound, humic acid and a carrier. The preparation process comprises the steps of enzymolysis preparation of the ferritin peptide, fertilizer mixing, granulation, drying and the like. The polypeptide fertilizer disclosed by the invention takes the high-iron protein peptide as a core, the contained small-molecular amino acid polypeptide can enhance the antioxidant enzyme activity of crops at low temperature and reduce malonaldehyde accumulation, the porphyrin iron can promote chlorophyll synthesis and energy metabolism, and the high-iron protein peptide and the porphyrin iron cooperate to remarkably improve the cold resistance of the crops. Meanwhile, by cooperating with trace elements and humic acid, the cold resistance is enhanced, nutrient absorption of crops is promoted, the yield and quality are improved, multiple effects of resisting cold, improving quality, increasing yield and the like are achieved, the raw materials are wide in source, the cost is low, the preparation process is simple, and large-scale production and application are facilitated.

Description

Technical Field

[0001] This invention belongs to the field of agricultural fertilizer technology, specifically relating to a polypeptide fertilizer that is beneficial to crop cold resistance and its preparation method. Background Technology

[0002] In agricultural production, low temperature damage is one of the important environmental stress factors affecting crop growth, development, and yield. Low temperatures can damage crop cell membrane structure, reduce enzyme activity, inhibit photosynthesis and metabolism, leading to slow crop growth, reduced yield, or even death.

[0003] Currently, measures to improve crop cold resistance mainly include breeding cold-resistant varieties, adopting physical cold protection measures (such as mulching and fumigation), and applying chemical regulators. However, breeding cold-resistant varieties has a long cycle and high cost; physical cold protection measures are cumbersome to operate and are greatly limited by environmental conditions; traditional chemical regulators may have residue problems and their cold resistance effect is singular.

[0004] Polypeptide fertilizers, as a new type of environmentally friendly fertilizer, are rich in active substances such as amino acids and polypeptides, which can promote crop growth and improve nutrient utilization. However, existing polypeptide fertilizers are not effective enough in specifically enhancing the cold resistance of crops. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing fertilizers in terms of cold resistance and to provide a polypeptide fertilizer that is beneficial to crop cold resistance and its preparation method. This fertilizer uses high-ferritin peptide as the core and enhances the physiological activity and cold resistance of crops under low temperature stress through the synergistic effect of amino acid polypeptides and porphyrin iron, while improving yield and quality.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is to provide a polypeptide fertilizer that is beneficial to crop cold resistance, comprising the following components in parts by weight: 30-50 parts of high-ferritin peptide, 5-10 parts of trace element complex, 10-20 parts of humic acid and 30-50 parts of carrier.

[0007] The high-ferritin peptides include amino acid polypeptides and porphyrin iron, with a crude protein content ≥80%, polypeptide content ≥60%, and porphyrin iron content ≥3%.

[0008] High-ferritin peptides are rich in polypeptides (≥60%) and porphyrin iron (≥3%). They can reduce malondialdehyde content in crops under low-temperature stress, increase the activity of antioxidant enzymes (such as superoxide dismutase) and chlorophyll content (SPAD value), alleviate cell damage, and enhance crop frost resistance. Simultaneously, they promote nutrient absorption, maintain metabolic function under low temperatures, and enhance growth vitality during the cold-resistant period. The micronutrient complex synergistically participates in the regulation of crop enzyme activity (such as zinc maintaining the function of stress-related enzymes), cell wall stability (boron enhancing cell structural integrity), and energy metabolism (molybdenum promoting nitrogen utilization), ensuring orderly physiological activities under low temperatures and enhancing cold tolerance. Humic acid helps improve the soil environment, promotes nutrient absorption and utilization by crops under low temperatures, and synergistically enhances cell water retention capacity and the synthesis of stress-related substances with polypeptides, enhancing crop adaptability in cold environments. The carrier ensures fertilizer formation and uniform nutrient dispersion, slowly releasing nutrients in low-temperature environments, continuously providing energy and nutritional support to crops, and maintaining their growth needs during the cold-resistant period.

[0009] As a further description of the above technical solution, the high-ferritin peptide is prepared from livestock and poultry blood through enzymatic hydrolysis. Livestock and poultry blood (such as pig blood) is a major by-product of the slaughtering industry, with abundant sources and low costs. Pig blood is rich in high-quality proteins such as hemoglobin, which can be converted into small molecule peptides through enzymatic hydrolysis. This process retains the natural activity of the peptides and porphyrin iron, effectively stimulating crop growth and development, enhancing stress resistance (such as cold and drought resistance), and improving yield and quality.

[0010] As a further description of the above technical solution, the trace element complex includes water-soluble salts of zinc, boron, and molybdenum, with an effective element mass ratio of 3:2:1. Zinc participates in the regulation of the activity of crop stress-resistance-related enzymes, enhancing the efficiency of enzymatic reactions at low temperatures; boron can strengthen the integrity of cell wall structure and improve the cell's resistance to frost damage; molybdenum promotes nitrogen metabolism, ensuring the energy supply of crops in cold environments. The three components, combined in a specific ratio, form a complementary function, synergistically enhancing the crop's cold-resistance physiological function. The proportion of the three components closely matches the absorption and utilization patterns of trace elements in the complex, avoiding excess or deficiency of any single element, and can efficiently assist components such as ferritin peptides in exerting their effects, promoting nutrient absorption by crops while enhancing cold resistance, thereby improving growth vitality and quality.

[0011] As a further description of the above technical solution, the carrier is zeolite powder or bentonite.

[0012] The present invention also provides a method for preparing the above-mentioned polypeptide fertilizer that is beneficial to crop cold resistance, comprising the following steps:

[0013] S1. Raw material pretreatment: Take fresh animal blood, add anticoagulant to prevent coagulation, and then preserve and transport it under low temperature (around 4℃) conditions to ensure the freshness of the raw materials;

[0014] S2. Centrifugation: Pretreated blood is separated into plasma protein solution and hemoglobin solution using centrifugation technology. Hemoglobin solution is used as the core raw material for preparing ferritin peptides, while plasma protein can be used for processing other products (such as plasma protein powder).

[0015] S3. Enzymatic hydrolysis: Take hemoglobin solution, adjust the pH to 7.5-8.0, add 1%-3% of the protein content of the hemoglobin solution with complex protease, and enzymatically hydrolyze at 50-55℃ for 4-6 hours to obtain the enzymatic hydrolysate; the role of the complex protease is to directionally cleave large molecular hemoglobin into small molecular amino acid peptides, while releasing porphyrin iron.

[0016] S4. Separation and purification: After enzymatic hydrolysis, the enzymatic hydrolysate is separated by centrifugation to obtain a supernatant (containing water-soluble amino acid peptides and porphyrin iron) and a precipitate (impurities); the supernatant is further purified by ultrafiltration membrane to retain small molecule active peptides and porphyrin iron, and remove large molecule impurities to obtain a peptide solution containing porphyrin iron.

[0017] S5. Concentration and Drying: The purified peptide solution is concentrated by triple-effect falling film evaporation to avoid high temperature damage to the active ingredients, and then dried by low-temperature spray drying technology to obtain high-ferritin peptides.

[0018] S6. Mixed granulation: After mixing the high-ferritin peptide with other components in the specified weight proportions, spray-dry the mixture at 60-70℃ to form granules, thus obtaining a polypeptide fertilizer that is beneficial for crop cold resistance.

[0019] This preparation method utilizes animal blood as raw material to achieve resource utilization. The process is mild and can retain the activity of small molecule peptides and porphyrin iron. The high-ferritin peptides in the resulting fertilizer work synergistically with other components to enhance the cold resistance of crops (such as increasing the activity of antifreeze-related enzymes and reducing low-temperature damage), and has the advantages of being both environmentally friendly and enhancing cold resistance.

[0020] As a further description of the above technical solution, the complex protease mentioned in step S3 is trypsin and papain in a mass ratio of 1:1. The synergistic effect of trypsin and papain can cover more cleavage sites in hemoglobin, hydrolyzing large hemoglobin molecules into small active polypeptides (mainly 500-1000 Daltons) through targeted cleavage, while simultaneously releasing porphyrin iron. The sulfhydryl groups (-SH) of papain also have antioxidant effects, preserving the bioactivity of the polypeptides and porphyrin iron under mild conditions (preventing Fe...). 2+ Oxidized to Fe 3+ This provides high-quality functional ingredients for fertilizers containing high-ferritin peptides to enhance crop cold resistance (such as increasing antioxidant enzyme activity and reducing low-temperature damage).

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This invention's polypeptide fertilizer uses high-ferritin peptides as its core. The small-molecule polypeptides it contains can enhance the activity of antioxidant enzymes in crops at low temperatures and reduce malondialdehyde accumulation (alleviating cell damage). Porphyrin iron can promote chlorophyll synthesis and energy metabolism; the two work synergistically to significantly improve crop cold resistance. High-ferritin peptides, in conjunction with trace elements (zinc, boron, molybdenum) and humic acid, enhance cold resistance while promoting nutrient absorption and improving yield and quality (such as increasing vitamin C and protein content), achieving multiple benefits including cold resistance, quality improvement, and increased yield. Its preparation method uses livestock and poultry blood as raw material, employing an enzymatic hydrolysis process to directionally retain the activity of polypeptides and porphyrin iron. This achieves both the resource utilization of waste (compliant with the circular economy) and avoids the destruction of effective components by high temperatures. The product is highly safe and environmentally friendly, superior to traditional chemically synthesized cold-resistant agents or low-activity polypeptide fertilizers. Attached Figure Description

[0023] Figure 1 This is a comparison chart of the growth of strawberries in the experimental group and the control group. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. 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 skilled in the art without creative effort should fall within the scope of protection of this application. Furthermore, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0025] Example 1

[0026] A polypeptide fertilizer that is beneficial for crop cold resistance includes the following components: 40 kg of high-ferritin peptide, 15 kg of water-soluble humic acid with a purity ≥90%, 8 kg of trace element complex (including 5.3 kg of zinc sulfate heptahydrate, 1.8 kg of boric acid, and 0.9 kg of ammonium molybdate tetrahydrate), and 37 kg of zeolite powder (particle size 200 mesh, water-soluble impurities ≤0.5%).

[0027] Its preparation method includes the following steps:

[0028] S1. Raw material pretreatment: Take fresh pig blood, add 1% sodium citrate by mass to prevent coagulation, and then preserve and transport it under low temperature (around 4℃) conditions to ensure the freshness of the raw materials.

[0029] S2. Centrifugal separation: Through centrifugal separation technology, the pretreated blood is separated into plasma protein solution and hemoglobin solution. Hemoglobin solution is used as the core raw material for preparing ferritin peptides, while plasma protein can be used for processing other products (such as plasma protein powder).

[0030] S3. Enzymatic hydrolysis: Take hemoglobin solution, adjust pH to 8.0, add 3% of hemoglobin solution protein with complex protease (trypsin and papain in a 1:1 mass ratio), and hydrolyze at 50℃ for 5 hours to obtain enzymatic hydrolysate.

[0031] S4. Separation and purification: After enzymatic hydrolysis, centrifuge (about 3000 r / min, 15 minutes) to separate the enzymatic hydrolysate, and obtain the supernatant and impurity precipitate; the supernatant is further purified by ultrafiltration membrane (molecular weight cutoff of 500-1000 Da) to retain small molecule active peptides and porphyrin iron, and remove large molecule impurities to obtain a peptide solution containing porphyrin iron.

[0032] S5. Concentration and Drying: The purified polypeptide solution is concentrated by triple-effect falling film evaporation to avoid high temperature damage to active ingredients. Then, low-temperature spray drying technology is used to obtain high-ferritin peptides with the following physicochemical indicators: crude protein ≥80%, polypeptide ≥60%, porphyrin iron ≥3%, and heavy metals such as lead, cadmium, arsenic, mercury, and chromium are not detected, which meets the fertilizer safety standards.

[0033] S6. Mixing and granulation: After mixing the high-ferritin peptide with other components according to the weight ratio, put it into a mixer and stir for 15 minutes until uniform. Then, send the mixture into a spray drying tower and spray dry and granulate at 65°C. Control the particle size to 2-3 mm to obtain the target polypeptide fertilizer.

[0034] Example 2

[0035] A polypeptide fertilizer for promoting plant growth comprises the following components: 50 kg of high-ferritin peptide, 10 kg of water-soluble humic acid with a purity ≥90%, 10 kg of trace element complex (including 6.6 kg of zinc sulfate heptahydrate, 2.3 kg of boric acid, and 1.1 kg of ammonium molybdate tetrahydrate), and 30 kg of bentonite (particle size 200 mesh, water-soluble impurities ≤0.5%).

[0036] Example 3

[0037] A polypeptide fertilizer for promoting plant growth comprises the following components: 30 kg of high-ferritin peptide, 20 kg of water-soluble humic acid with a purity ≥90%, 10 kg of trace element complex (including 6.6 kg of zinc sulfate heptahydrate, 2.3 kg of boric acid, and 1.1 kg of ammonium molybdate tetrahydrate), and 40 kg of bentonite (particle size 200 mesh, water-soluble impurities ≤0.5%).

[0038] Field Trial 1:

[0039] At the Jiaozhou base of Qingdao Agricultural University, the winter wheat variety used in the experiment was Jimai 44. Five treatments were established: a control group (CK), a control group (CG), experimental group 1 (EG1), experimental group 2 (EG2), and experimental group 3 (EG3). The control group was sprayed with water; the control group was foliar-sprayed with a common water-soluble fertilizer without ferritin peptides (formula same as in Example 1, but ferritin peptides were replaced with an equal amount of urea, 100 g / mu, diluted 500 times); experimental group 1 was foliar-sprayed with the polypeptide fertilizer of Example 1 (100 g / mu, diluted 500 times); experimental group 2 was foliar-sprayed with the polypeptide fertilizer of Example 2 (100 g / mu, diluted 500 times); and experimental group 3 was foliar-sprayed with the polypeptide fertilizer of Example 3 (100 g / mu, diluted 500 times). Each treatment was replicated three times, with a plot area of ​​20 m². 2 Foliar spraying was applied 7 days before winter. After low-temperature stress (-5℃ for 3 days), the malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, chlorophyll content (SPAD value), and final yield of wheat were measured. MDA content was determined using the thiobarbituric acid (TBA) method, SOD activity using the nitroblue tetrazolium (NBT) photoreduction method, and chlorophyll content (SPAD value) was directly measured using a SPAD-502 chlorophyll meter. Yield was calculated based on the actual harvest from each plot. After wheat maturity, all plants in each plot were harvested, threshed, and dried to constant weight. The fresh weight of the grains in each plot was recorded, and yields were calculated based on plot area (20 m²). 2 The conversion was performed, and the results are shown in Table 1.

[0040] Table 1. Test results of indicators for winter wheat in the experimental and control groups.

[0041]

[0042] Results analysis:

[0043] Malondialdehyde (MDA) is a marker product of membrane lipid peroxidation; lower MDA levels indicate less damage to cells from low-temperature stress. The experimental group (containing ferritin peptide) showed a 39.0%–40.1% reduction in MDA content compared to the control group (CK) and a 33.8%–35.1% reduction compared to the control group (CG), indicating that ferritin peptide significantly reduced the damage to wheat cells at -5°C by inhibiting membrane lipid peroxidation, and different carriers (zeolite powder, bentonite) had no significant effect on the effect. Superoxide dismutase (SOD) is an important antioxidant enzyme that can scavenge reactive oxygen species induced by low temperature. The SOD activity in the experimental group was 36.7%–38.4% higher than the control group (CK) and 20.9%–22.4% higher than the control group (CG), indicating that ferritin peptide enhanced the wheat's ability to scavenge low-temperature stress by increasing antioxidant enzyme activity, and the type of carrier did not affect this effect.

[0044] Chlorophyll content directly reflects photosynthetic capacity, and maintaining a high chlorophyll content at low temperatures helps sustain energy supply. The SPAD value of the experimental group was 19.3%–21.0% higher than the control group (CK) and 12.2%–13.8% higher than the control group (CG), indicating that ferritin peptides (especially porphyrin iron components) promoted or stabilized chlorophyll synthesis, alleviating the inhibition of photosynthesis by low temperatures. In terms of yield, the experimental group yielded 15.8%–16.8% more than the control group (CK), significantly higher than the 9.8%–10.1% increase in the control group (CG), and the differences among the three experimental groups were not significant. This suggests that ferritin peptides significantly increased winter wheat yield by mitigating low-temperature damage and maintaining photosynthetic efficiency; furthermore, the effects were consistent when zeolite powder and bentonite were used as carriers, verifying the stability of the formulation.

[0045] The polypeptide fertilizer (containing ferritin peptide) of this invention significantly enhances the cold resistance of winter wheat by synergistically enhancing antioxidant capacity (increasing SOD activity), reducing membrane damage (reducing MDA content), and maintaining photosynthetic function (increasing chlorophyll content), ultimately increasing yield. Different carriers (zeolite powder, bentonite) have no significant impact on the effect, further verifying the scientific nature and applicability of the formula.

[0046] Field Trial 2:

[0047] The experimental site was selected at the Biaojiatai strawberry planting base (soil was sandy loam, pH 6.5–7.0); the experimental variety was Hongyan strawberry; two treatments were set up: a control group (CG) and an experimental group (EG), with a plot area of ​​20 m². 2 Seven days before the onset of low temperatures, the experimental group was foliar-sprayed with the polypeptide fertilizer of Example 1 (100 g / mu, diluted 800 times), while the control group (CG) was foliar-sprayed with conventional compound fertilizer (NPK 15-15-15, 200 g / mu). The growth of strawberries in the experimental and control groups is as follows: Figure 1 As shown, in the control group, approximately 35% of the plants exhibited leaf edge scorching and flower drop, with a frost damage level of 2-3. In the experimental group, 90% of the plants had dark green leaves and abundant flowers, with a frost damage level ≤1, demonstrating a significant difference in cold resistance phenotype. It can be concluded that the polypeptide fertilizer containing high-ferritin peptides (experimental group) significantly enhanced the cold resistance phenotype of strawberries, achieving reduced frost damage and increased yield (the experimental group yielded approximately 1600 kg per mu, an increase of over 18% compared to the control group), effectively meeting the winter cold resistance requirements of strawberries.

[0048] In summary, the polypeptide fertilizer of the present invention can significantly enhance the cold resistance of winter wheat, strawberries and other crops and increase yield through the synergistic effect of high ferritin peptides, trace elements and humic acid, and the effect can be guaranteed to be stable with different carriers (zeolite powder, bentonite).

[0049] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. A polypeptide fertilizer that promotes crop cold resistance, characterized in that, It includes the following components in parts by weight: 30-50 parts of high-ferritin peptide, 5-10 parts of trace element complex, 10-20 parts of humic acid and 30-50 parts of carrier. The high-ferritin peptide comprises amino acid polypeptides and porphyrin iron, with a crude protein content ≥80%, polypeptide content ≥60%, and porphyrin iron content ≥3%.

2. The polypeptide fertilizer beneficial for crop cold resistance according to claim 1, characterized in that: The ferritin peptides mentioned above are prepared from animal blood via enzymatic hydrolysis.

3. The polypeptide fertilizer beneficial for crop cold resistance according to claim 2, characterized in that: The trace element complex includes water-soluble salts of zinc, boron, and molybdenum, with an effective element mass ratio of 3:2:

1.

4. The polypeptide fertilizer beneficial for crop cold resistance according to claim 3, characterized in that: The carrier is zeolite powder or bentonite.

5. A method for preparing a polypeptide fertilizer beneficial to crop cold resistance as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Raw material pretreatment: Take fresh animal blood and add anticoagulant to prevent coagulation; S2. Centrifugation: Using centrifugation technology, pretreated blood is separated into plasma protein solution and hemoglobin solution; S3. Enzymatic hydrolysis: Take hemoglobin solution, adjust the pH to 7.5-8.0, add 1%-3% of complex protease, and hydrolyze at 50-55℃ for 4-6 hours to obtain the hydrolysate. S4. Separation and purification: After the enzymatic hydrolysis is completed, the enzymatic hydrolysate is separated by centrifugation, and the supernatant is further purified by ultrafiltration to obtain a polypeptide solution containing porphyrin iron. S5. Concentration and Drying: The polypeptide solution is concentrated by triple-effect falling film evaporation and dried by low-temperature spray drying technology to obtain high-ferritin peptides. S6. Mixed granulation: After mixing the high-ferritin peptide with other components in the specified weight proportions, spray-dry the mixture at 60-70℃ to form granules, thus obtaining a polypeptide fertilizer that is beneficial for crop cold resistance.

6. The method for preparing the polypeptide fertilizer beneficial to crop cold resistance according to claim 5, characterized in that: The complex protease mentioned in step S3 is trypsin and papain in a mass ratio of 1:

1.

7. The method for preparing the polypeptide fertilizer beneficial to crop cold resistance according to claim 6, characterized in that: The anticoagulant mentioned in step S1 is a sodium citrate solution with a mass fraction of 0.5-1%.

8. The method for preparing the polypeptide fertilizer beneficial to crop cold resistance according to claim 6, characterized in that: The ultrafiltration membrane described in step S4 has a molecular weight cutoff of 500 to 1000 Da.

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