Compound fertilizer for improving quality and yield of avocado fruits and preparation method thereof

Abstract

The invention belongs to the technical field of compound fertilizers, and particularly relates to a compound fertilizer for improving the quality and yield of avocado fruits and a preparation method of the compound fertilizer. The compound fertilizer for improving the fruit quality and yield of avocados is prepared from the following raw materials: urea, a calcium magnesium phosphate fertilizer, potassium sulfate, magnesium chloride, corn straw, livestock manure, plant ash, fulvic acid, bacillus subtilis and soybean meal and corn germ meal composite enzymatic hydrolysate, wherein the soybean meal and corn germ meal composite enzymatic hydrolysate is a papain directional enzymatic hydrolysate. When the fertilizer is used for planting avocados, the quality and yield of the avocados can be remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of compound fertilizer technology, and more specifically relates to a compound fertilizer for improving the quality and yield of avocados and its preparation method. Background Technology

[0002] Avocado (Persea americana Mill.) is a fruit with high economic value, rich in healthy fats, vitamins, and minerals, and is highly favored by consumers. With the continuous growth of global market demand for avocados, improving fruit quality and yield has become an important goal for the avocado industry. However, in actual cultivation, avocado growth and yield are often limited by factors such as insufficient soil nutrients and improper fertilization programs.

[0003] Currently, traditional fertilization methods mainly rely on single fertilizers or simple combinations of fertilizers, which makes it difficult to meet the diverse nutrient requirements of avocados at different growth stages. For example, excessive application of nitrogen fertilizer may lead to excessive plant growth, neglecting the improvement of fruit quality; insufficient phosphorus and potassium fertilizers may limit fruit development and yield. In addition, a lack of micronutrients in the soil (such as zinc, boron, and magnesium) will also directly affect the fruit quality and plant health of avocados.

[0004] In recent years, with the advancement of agricultural science and technology, compound fertilizers have been widely used in agricultural production due to their ability to provide balanced nutrients. However, existing compound fertilizer formulations are mostly designed for field crops or vegetables, and there is a lack of targeted research and application for the specific needs of avocados. Furthermore, traditional compound fertilizer preparation processes often fail to adequately consider the matching of nutrient release rates with the avocado growth cycle, resulting in low fertilizer utilization and potentially even environmental pollution.

[0005] Therefore, there is an urgent need to develop a compound fertilizer that can effectively improve the quality and yield of avocados and optimize its preparation process to meet the specific needs of avocado cultivation. Summary of the Invention

[0006] The purpose of this invention is to provide a compound fertilizer and its preparation method for improving the quality and yield of avocados. Based on the growth characteristics and nutrient requirements of avocados, a novel compound fertilizer formula was designed, and the nutrient release efficiency and utilization rate of the fertilizer were improved by optimizing the preparation method, thereby providing strong support for high-yield and high-quality avocado cultivation and solving the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] One of the technical solutions of this invention is to provide an application of a soybean meal and corn germ meal compound enzymatic hydrolysate in improving the quality of avocado fruit.

[0009] Furthermore, the soybean meal and corn germ meal compound enzymatic hydrolysate is a papain-directed enzymatic hydrolysis product obtained by mixing soybean meal and corn germ meal in a mass ratio of 5-7:3-5.

[0010] The second technical solution of this invention: provides a compound fertilizer to improve the quality and yield of avocados, comprising, by weight, the following raw materials:

[0011] 20-25 parts urea, 15-20 parts calcium magnesium phosphate fertilizer, 15-20 parts potassium sulfate, 2-3 parts magnesium chloride, 30-40 parts corn stalks, 20-25 parts poultry and livestock manure, 10-15 parts wood ash, 5-8 parts humic acid, 0.1-1 parts Bacillus subtilis, and 3-8 parts soybean meal and corn germ meal compound enzymatic hydrolysate.

[0012] Furthermore, the preparation steps of the soybean meal and corn germ meal compound enzymatic hydrolysate include:

[0013] Soybean meal and corn germ meal were mixed, microwaved, and then mixed with water for pre-soaking. Papain was then added for targeted enzymatic hydrolysis. After targeted enzymatic hydrolysis, the enzyme was inactivated by heating. The mixture was then filtered, ultrafiltered, and vacuum concentrated to obtain a soybean meal and corn germ meal compound enzymatic hydrolysate with an amino acid content of 15%.

[0014] Optionally, the dry weight ratio of the soybean meal to the corn germ meal is 5-7:3-5.

[0015] Optionally, the microwave processing frequency is 2300-2500MHz and the time is 2-3min.

[0016] Microwave treatment destroys anti-nutritional factors in raw materials, such as trypsin inhibitors.

[0017] Optionally, the material-to-water ratio is 1:15 (by mass), and the water temperature is 45-50℃.

[0018] Optionally, the pre-soaking treatment has a pH of 7.4-7.6 and a time of 120-150 min.

[0019] Optionally, in the directional enzymatic hydrolysis treatment, the amount of papain added is 0.05%-0.1% of the sum of the dry weights of soybean meal and corn germ meal, the reaction temperature is 55-60℃, the pH is maintained between 6.5 and 7.0 during the reaction, and the reaction time is 4-6 hours.

[0020] Papain enzyme activity ≥100000U / g.

[0021] Optionally, the filter screen has a pore size of 40-50 μm.

[0022] Optionally, the ultrafiltration uses an ultrafiltration membrane with a molecular weight cutoff of 5000-8000 Da.

[0023] Ultrafiltration removes large molecular impurities while retaining small molecule peptides (molecular weight < 3000 Da).

[0024] Optionally, the vacuum concentration temperature is 50-60℃ and the vacuum degree is -0.08MPa.

[0025] This invention destroys anti-nutritional factors in raw materials through microwave treatment, combined with targeted enzymatic hydrolysis by papain, to efficiently release small molecule active ingredients (molecular weight <3000Da). After ultrafiltration purification, the amino acid content reaches 15%, significantly improving the bioavailability of nutrients.

[0026] The third technical solution of this invention provides a method for preparing the above-mentioned compound fertilizer for improving the quality and yield of avocados, comprising the following steps:

[0027] After crushing the corn stalks, mix them evenly with wood ash, poultry and livestock manure, and humic acid to obtain dry material.

[0028] Bacillus subtilis is mixed with water to prepare a bacterial solution, which is then sprayed and mixed evenly with the dry material. The moisture content is adjusted to 45-50%, and the mixture is piled up for fermentation to obtain the fermentation product.

[0029] Urea, calcium magnesium phosphate, potassium sulfate, and magnesium chloride are added to the fermentation product, mixed evenly, and then a compound enzymatic hydrolysate of soybean meal and corn germ meal is sprayed evenly. After granulation and drying, the compound fertilizer that improves the quality and yield of avocado fruit is obtained.

[0030] The addition of corn stalks, poultry and livestock manure, and wood ash increases soil organic matter content, improves soil aggregate structure, enhances water and fertilizer retention capacity, and provides a good environment for avocado root growth.

[0031] During fermentation, Bacillus subtilis colonizes and secretes plant growth regulators (such as indoleacetic acid), while inhibiting soil pathogens, enhancing plant resistance (such as drought and disease resistance), and reducing reliance on chemical fertilizers.

[0032] Furthermore, the particle size of the crushed corn stalks is 20-30 mm.

[0033] Furthermore, the mass ratio of the Bacillus subtilis to water is 1:10-20.

[0034] Furthermore, the temperature for the composting fermentation is 35-45℃, the time is 15-20 days, and the compost is turned over every 3 days.

[0035] Furthermore, the particle size of the granulation is 2-4 mm.

[0036] Furthermore, the drying temperature is 40-45℃, and the drying is carried out until the moisture content is <10%.

[0037] Organic materials (corn stalks, livestock manure) are fermented by Bacillus subtilis to form a stable organic structure, which can delay the release of inorganic nutrients, match the growth cycle of avocados (such as the need for phosphorus during flowering and potassium during fruit enlargement), reduce nutrient loss, and lower the risk of environmental pollution.

[0038] The fourth technical solution of this invention provides an application of the above-mentioned compound fertilizer in improving the quality and yield of avocados.

[0039] The present invention discloses the following technical effects:

[0040] The compound fertilizer provided by this invention integrates nitrogen (urea), phosphorus (calcium magnesium phosphate), potassium (potassium sulfate), and trace elements (magnesium chloride), and supplements organic matter (corn stalks, poultry and livestock manure, wood ash) and humic acid, meeting the macro- and micronutrient needs of avocados at different growth stages, and avoiding nutrient imbalances caused by traditional single fertilizers or simple combinations (such as excessive nitrogen inhibiting quality, and insufficient phosphorus and potassium limiting yield). Meanwhile, the soybean meal and corn germ meal compound enzymatic hydrolysate is rich in small molecule peptides, amino acids, and reducing sugars, which can be directly absorbed and utilized by avocados, quickly replenishing key nutrients (such as nitrogen sources), optimizing fruit development by regulating metabolic pathways (such as promoting the activity of enzymes related to ethylene synthesis), and improving quality indicators such as fat content and vitamins.

[0041] The small-molecule peptides in the soybean meal and corn germ meal compound enzymatic hydrolysate can induce avocados to synthesize more healthy fats (monounsaturated fatty acids) and antioxidants (such as vitamin E and flavonoids), improving the fruit's taste and nutritional value. Humic acid promotes the absorption of trace elements (zinc and boron) and reduces physiological disorders (such as fruit deformities). Balanced nutrient supply and efficient absorption and utilization promote flower bud differentiation, fruit enlargement, and sugar accumulation, significantly increasing the yield per plant and the weight of each fruit.

[0042] This invention uses agricultural waste (corn stalks, soybean meal, corn germ meal) and livestock manure as raw materials to realize the resource utilization of waste, reduce pollution from incineration or stockpiling, and reduce nitrogen and phosphorus loss to water bodies through slow-release design (fermentation product loading) and high utilization rate, which meets the needs of green agricultural development. Detailed Implementation

[0043] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0044] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0045] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0046] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0047] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0048] Unless otherwise specified, room temperature and normal temperature in the specific embodiments of this invention refer to 20-30℃.

[0049] Unless otherwise specified, all raw materials and reagents involved in the specific embodiments of this invention are commercially available products.

[0050] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0051] In the specific embodiments of this invention, the papain used has an enzyme activity of 100,000 U / g, the alkaline protease used has an enzyme activity of 100,000 U / g, and the Bacillus subtilis used is a commercially available product with a bacterial count of 10. 9 cfu / g.

[0052] In some specific implementation schemes, the soybean meal and corn germ meal compound enzymatic hydrolysate involved is prepared through the following steps:

[0053] Defatted soybean meal (protein content ≥45%) was selected, pulverized through a 60-mesh sieve to remove fiber impurities, and set aside. Corn germ meal (protein ≥18%) was pulverized through an 80-mesh sieve and set aside. The defatted soybean meal and corn germ meal were mixed at a mass ratio of 7:3 and microwaved (2400MHz, 3min). Then, 50℃ warm water was added at a feed-to-water ratio of 1:15 to adjust the pH to 7.5 (using 0.1mol / L...). Pre-soak the mixture in NaOH for 2 hours to soften the cell structure. Then, add 0.1% papain by dry weight of defatted soybean meal and corn germ meal, adjust the pH to 6.5-7.0, and enzymatically hydrolyze the mixture at 55-60℃ for 5 hours with intermittent stirring (50 rpm). After enzymatic hydrolysis, raise the temperature to 85℃ and maintain it for 15 minutes to inactivate the enzyme. Remove the residue using a plate and frame filter press (50 μm filter mesh). Then, use an ultrafiltration membrane with a molecular weight cutoff of 5000-8000 Da to remove large molecular impurities and retain small molecular peptides (molecular weight <3000 Da). Finally, concentrate the mixture at 60℃ and -0.08 MPa until the amino acid content is about 15% (detected by refractometer) to obtain a soybean meal and corn germ meal compound enzymatic hydrolysate.

[0054] In some specific embodiments, the present invention provides a preparation step for a compound fertilizer that improves the quality and yield of avocado fruits, including:

[0055] S1. Prepare the following raw materials according to the mass fractions:

[0056] 20-25 parts urea, 15-20 parts calcium magnesium phosphate fertilizer, 15-20 parts potassium sulfate, 2-3 parts magnesium chloride, 30-40 parts corn stalks, 20-25 parts poultry and livestock manure, 10-15 parts wood ash, 5-8 parts humic acid, 0.1-1 parts Bacillus subtilis, and 3-8 parts soybean meal and corn germ meal compound enzymatic hydrolysate;

[0057] S2. Crush the corn stalks to a size of 20-30mm, mix them evenly with wood ash, poultry and livestock manure, and humic acid to obtain dry material;

[0058] S3. Mix Bacillus subtilis with water at a mass ratio of 1:10-20 to prepare a bacterial solution. Spray the solution evenly with the dry material, adjust the moisture content to 45-50%, and pile it up for fermentation. Maintain the fermentation temperature between 35-45℃ for 15-20 days, turning the pile every 3 days to obtain the fermentation product.

[0059] S4. Then, mix the fermentation product with urea, calcium magnesium phosphate fertilizer, potassium sulfate, and magnesium chloride evenly, and spray the mixture evenly with the soybean meal and corn germ meal compound enzymatic hydrolysate. Then, granulate the mixture (between 2-4 mm) and dry it (40-45℃) until the moisture content is <10% to obtain a compound fertilizer that improves the quality and yield of avocados.

[0060] The amino acids in the soybean meal and corn germ meal compound enzymatic hydrolysate can form stable chelates with trace elements such as zinc, boron, and magnesium in the soil and organic and inorganic fertilizers, protecting them from being fixed by the soil and significantly improving the absorption efficiency of trace elements by avocados.

[0061] The small molecule peptides and amino acids in the soybean meal and corn germ meal compound enzymatic hydrolysate serve as a fast-acting nitrogen source, which can quickly replenish the nitrogen needed for avocado growth, while inorganic nitrogen fertilizers such as urea provide a slow-release nitrogen source, forming a "fast-acting + slow-release" nutrient supply model that matches the needs of avocados at different growth stages.

[0062] The organic components (such as amino acids and reducing sugars) in the soybean meal and corn germ meal compound enzymatic hydrolysate can provide carbon sources and energy for beneficial microorganisms in the soil after application, promoting the reproduction and activity of beneficial microorganisms in the soil.

[0063] During fermentation, microorganisms decompose organic matter such as poultry and livestock manure and corn stalks, releasing more nutrients (such as phosphorus and potassium) and producing plant growth regulators such as indoleacetic acid. After application, these substances further promote the growth of avocado roots and nutrient absorption.

[0064] The combined enzymatic hydrolysate of soybean meal and corn germ meal, along with humic acid, works synergistically to promote soil aggregate formation and enhance water and fertilizer retention capacity. The addition of organic matter such as corn stalks and livestock manure increases soil organic matter content, providing a favorable growth environment for avocado roots, while simultaneously releasing nutrients through microbial decomposition.

[0065] The small-molecule peptides in the soybean meal and corn germ meal compound enzymatic hydrolysate can activate the antioxidant enzyme system of avocados (such as peroxidase and polyphenol oxidase), enhancing their resistance to adverse conditions such as drought and high temperatures. Simultaneously, amino acids and small-molecule peptides can induce avocados to synthesize more healthy fats (such as monounsaturated fatty acids) and antioxidants (such as vitamin E and flavonoids), improving the fruit's taste and nutritional value. Fulvic acid further ensures the marketability of the fruit by reducing physiological disorders (such as fruit deformities).

[0066] Example 1

[0067] The preparation steps of compound fertilizer to improve the quality and yield of avocados include:

[0068] S1. Prepare the following raw materials according to the mass fractions:

[0069] 25 parts urea, 20 parts calcium magnesium phosphate fertilizer, 20 parts potassium sulfate, 3 parts magnesium chloride, 40 parts corn stalks, 25 parts poultry and livestock manure, 15 parts wood ash, 8 parts humic acid, 1 part Bacillus subtilis and 8 parts soybean meal and corn germ meal compound enzymatic hydrolysate.

[0070] S2. Crush the corn stalks to a size of 20-30mm, mix them evenly with wood ash, poultry and livestock manure, and humic acid to obtain dry material;

[0071] S3. Mix Bacillus subtilis and water at a mass ratio of 1:20 to prepare a bacterial solution. Spray the solution evenly with the dry material and adjust the moisture content to between 45-50%. Pile the solution for fermentation, maintaining the fermentation temperature between 35-45℃ for 18 days. Turn the pile over every 3 days to obtain the fermentation product.

[0072] S4. Then, mix the fermentation product with urea, calcium magnesium phosphate fertilizer, potassium sulfate and magnesium chloride evenly, spray the soybean meal and corn germ meal compound enzymatic hydrolysate evenly, then granulate (between 2-4 mm), and dry (45℃) until the moisture content is <10% to obtain a compound fertilizer that improves the quality and yield of avocado fruit.

[0073] Example 2

[0074] The preparation steps of compound fertilizer to improve the quality and yield of avocados include:

[0075] S1. Prepare the following raw materials according to the mass fractions:

[0076] 20 parts urea, 15 parts calcium magnesium phosphate fertilizer, 15 parts potassium sulfate, 2 parts magnesium chloride, 30 parts corn stalks, 20 parts poultry and livestock manure, 10 parts wood ash, 5 parts humic acid, 0.1 parts Bacillus subtilis and 3 parts soybean meal and corn germ meal compound enzymatic hydrolysate.

[0077] S2. Crush the corn stalks to a size of 20-30mm, mix them evenly with wood ash, poultry and livestock manure, and humic acid to obtain dry material;

[0078] S3. Mix Bacillus subtilis and water at a mass ratio of 1:10 to prepare a bacterial solution. Spray the solution evenly with the dry material and adjust the moisture content to between 45-50%. Pile the solution for fermentation, keeping the fermentation temperature between 35-45℃ for 20 days. Turn the pile over every 3 days to obtain the fermentation product.

[0079] S4. Then, mix the fermentation product with urea, calcium magnesium phosphate fertilizer, potassium sulfate and magnesium chloride evenly, spray the soybean meal and corn germ meal compound enzymatic hydrolysate evenly, then granulate (between 2-4 mm), and dry (45℃) until the moisture content is <10% to obtain a compound fertilizer that improves the quality and yield of avocado fruit.

[0080] Example 3

[0081] The preparation steps of compound fertilizer to improve the quality and yield of avocados include:

[0082] S1. Prepare the following raw materials according to the mass fractions:

[0083] 25 parts urea, 15 parts calcium magnesium phosphate fertilizer, 20 parts potassium sulfate, 2 parts magnesium chloride, 40 parts corn stalks, 20 parts poultry and livestock manure, 15 parts wood ash, 5 parts humic acid, 1 part Bacillus subtilis and 8 parts soybean meal and corn germ meal compound enzymatic hydrolysate.

[0084] S2. Crush the corn stalks to a size of 20-30mm, mix them evenly with wood ash, poultry and livestock manure, and humic acid to obtain dry material;

[0085] S3. Mix Bacillus subtilis and water at a mass ratio of 1:10 to prepare a bacterial solution. Spray the solution evenly with the dry material and adjust the moisture content to 45-50%. Pile the material for fermentation, keeping the fermentation temperature between 35-45℃ for 15-20 days. Turn the pile over every 3 days to obtain the fermentation product.

[0086] S4. Then, mix the fermentation product with urea, calcium magnesium phosphate fertilizer, potassium sulfate and magnesium chloride evenly, spray the soybean meal and corn germ meal compound enzymatic hydrolysate evenly, then granulate (between 2-4 mm), and dry (45℃) until the moisture content is <10% to obtain a compound fertilizer that improves the quality and yield of avocado fruit.

[0087] Comparative Example 1

[0088] The preparation steps of compound fertilizer include:

[0089] S1. Prepare the following raw materials according to the mass fractions:

[0090] 25 parts urea, 20 parts calcium magnesium phosphate fertilizer, 20 parts potassium sulfate, 3 parts magnesium chloride, 40 parts corn stalks, 25 parts poultry and livestock manure, 15 parts wood ash, 8 parts humic acid and 1 part Bacillus subtilis.

[0091] S2. Crush the corn stalks to a size of 20-30mm, mix them evenly with wood ash, poultry and livestock manure, and humic acid to obtain dry material;

[0092] S3. Mix Bacillus subtilis and water at a mass ratio of 1:20 to prepare a bacterial solution. Spray the solution evenly with the dry material and adjust the moisture content to between 45-50%. Pile the solution for fermentation, maintaining the fermentation temperature between 35-45℃ for 18 days. Turn the pile over every 3 days to obtain the fermentation product.

[0093] S4. Then mix the fermentation product with urea, calcium magnesium phosphate fertilizer, potassium sulfate and magnesium chloride evenly, then granulate (between 2-4 mm), and dry (45℃) until the moisture content is <10% to obtain compound fertilizer.

[0094] Comparative Example 2

[0095] The preparation steps of compound fertilizer include:

[0096] S1. Prepare the following raw materials according to the mass fractions:

[0097] 25 parts urea, 20 parts calcium magnesium phosphate fertilizer, 20 parts potassium sulfate, 3 parts magnesium chloride, 40 parts corn stalks, 25 parts poultry and livestock manure, 15 parts wood ash, 8 parts humic acid, 1 part Bacillus subtilis, 5.6 parts soybean meal and 2.4 parts corn germ meal;

[0098] S2. Crush the corn stalks to a size of 20-30mm, and mix them evenly with soybean meal, corn germ meal, wood ash, poultry and livestock manure, and humic acid to obtain dry material;

[0099] S3. Mix Bacillus subtilis and water at a mass ratio of 1:20 to prepare a bacterial solution. Spray the solution evenly with the dry material and adjust the moisture content to between 45-50%. Pile the solution for fermentation, maintaining the fermentation temperature between 35-45℃ for 18 days. Turn the pile over every 3 days to obtain the fermentation product.

[0100] S4. Then, mix the fermentation product with urea, calcium magnesium phosphate fertilizer, potassium sulfate and magnesium chloride evenly, then granulate (between 2-4 mm), and dry (45℃) until the moisture content is <10% to obtain a compound fertilizer that improves the quality and yield of avocado fruit.

[0101] Comparative Example 3

[0102] The preparation steps of compound fertilizer include:

[0103] S1. Prepare the following raw materials according to the mass fractions:

[0104] 25 parts urea, 20 parts calcium magnesium phosphate fertilizer, 20 parts potassium sulfate, 3 parts magnesium chloride, 40 parts corn stalks, 25 parts poultry and livestock manure, 15 parts wood ash, 8 parts humic acid, 1 part Bacillus subtilis, 5.6 parts soybean meal and 2.4 parts corn germ meal;

[0105] S2. Crush the corn stalks to a size of 20-30mm, mix them evenly with wood ash, poultry and livestock manure, and humic acid to obtain dry material;

[0106] S3. Mix Bacillus subtilis and water at a mass ratio of 1:20 to prepare a bacterial solution. Spray the solution evenly with the dry material and adjust the moisture content to between 45-50%. Pile the solution for fermentation, maintaining the fermentation temperature between 35-45℃ for 18 days. Turn the pile over every 3 days to obtain the fermentation product.

[0107] S4. Then, mix the fermentation product with urea, calcium magnesium phosphate fertilizer, potassium sulfate, magnesium chloride, soybean meal, and corn germ meal evenly, then granulate (between 2-4 mm), and dry (45℃) until the moisture content is <10% to obtain a compound fertilizer that improves the quality and yield of avocados.

[0108] Comparative Example 4

[0109] Compared to Example 1, the only difference is that the soybean meal and corn germ meal complex enzymatic hydrolysate is obtained by enzymatic hydrolysis of soybean meal and corn germ meal using alkaline protease. Specifically, the papain in the preparation method of the soybean meal and corn germ meal complex enzymatic hydrolysate is replaced with an equal amount of alkaline protease.

[0110] Test case

[0111] Variety: Haas;

[0112] Fruit tree selection: trees in their peak fruiting period, with similar ages (5-7 years old) and similar growth conditions;

[0113] Eight treatment groups were set up, with three replicates in each group and five trees in each replicate, arranged in a randomized block arrangement.

[0114] The eight treatment groups were: Examples 1-3, Comparative Examples 1-4, and Blank Control Group (CK).

[0115] Apply the fertilizer in three applications each year: February (before flowering), June (fruit setting period), and September (fruit expansion period). The application rate is 3 kg per tree each time.

[0116] The same field management practices were adopted.

[0117] During the harvest period, the yield per plant and the weight of a single fruit were statistically analyzed (20 fruits were randomly selected and weighed to average the weight). The results are shown in Table 1.

[0118] Table 1

[0119] Processing group Yield per plant (kg) Single fruit weight (g) Fruit drop rate (%) CK 15.5±2.1 150±15 28.5±3.2 Comparative Example 1 18.3±3.5 180±18 15.7±2.1 Comparative Example 2 20.2±4.0 197±20 14.3±1.8 Comparative Example 3 19.6±3.8 190±22 12.8±1.5 Comparative Example 4 21.5±4.8 205±21 10.9±0.7 Example 1 24.4±5.2 215±25 8.2±0.9 Example 2 23.7±4.3 227±20 9.5±1.2 Example 3 25.8±5.0 223±23 9.1±1.0

[0120] The quality indicators are shown in Table 2.

[0121] Dry matter content (%): determined by drying at 105℃.

[0122] Fat content (%): determined by Soxhlet extraction.

[0123] Monounsaturated fatty acid percentage (%): Analysis of oil components by gas chromatography.

[0124] Table 2

[0125] Processing group Dry matter (%) Fat content (%) Percentage of monounsaturated fatty acids (%) CK 21.3±0.8 12.5±0.7 58.2±2.1 Comparative Example 1 24.5±1.0 15.8±0.9 63.5±2.5 Comparative Example 2 25.1±1.2 16.2±1.1 65.1±2.3 Comparative Example 3 26.3±1.1 17.0±1.0 67.8±2.7 Comparative Example 4 27.1±1.1 19.5±1.0 70.8±2.5 Example 1 29.8±1.5 22.5±1.3 75.4±3.0 Example 2 28.2±1.3 20.4±1.2 72.2±2.8 Example 3 28.9±1.4 21.0±1.4 73.6±3.1

[0126] Note: Different letters indicate significant differences.

[0127] A comparison of the data in Tables 1 and 2 shows that the soybean meal and corn germ meal compound enzymatic hydrolysate has an excellent synergistic effect on compound fertilizer. The yield and quality of the example group are significantly better than those of the comparative example, proving that the small molecule peptides / amino acids in the soybean meal and corn germ meal compound enzymatic hydrolysate can synergistically enhance the absorption efficiency of trace elements and activate the fat synthesis pathway. Although comparative examples 2-3 (direct addition or addition after fermentation of soybean meal / germ meal) are better than conventional organic fertilizer (comparative example 1), the effect is still lower than that of the enzymatic hydrolysis group, indicating that enzymatic hydrolysis pretreatment is the key to improving the quality and yield of avocados. The comparison of the data of comparative example 4 with that of comparative example 1 shows the superiority of papain in the enzymatic hydrolysis of this invention.

[0128] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0129] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. Application of a compound enzymatic hydrolysate of soybean meal and corn germ meal in improving the quality of avocado fruit.

2. The application as described in claim 1, characterized in that, The soybean meal and corn germ meal compound enzymatic hydrolysate is a papain-directed enzymatic hydrolysis product obtained by mixing soybean meal and corn germ meal in a mass ratio of 5-7:3-5.

3. A compound fertilizer for improving the quality and yield of avocados, characterized in that, By weight, the raw materials include: 20-25 parts urea, 15-20 parts calcium magnesium phosphate fertilizer, 15-20 parts potassium sulfate, 2-3 parts magnesium chloride, 30-40 parts corn stalks, 20-25 parts poultry and livestock manure, 10-15 parts wood ash, 5-8 parts humic acid, 0.1-1 parts Bacillus subtilis, and 3-8 parts soybean meal and corn germ meal compound enzymatic hydrolysate.

4. The compound fertilizer as described in claim 3, characterized in that, The preparation steps of the soybean meal and corn germ meal compound enzymatic hydrolysate include: Soybean meal and corn germ meal were mixed, microwaved, and then mixed with water for pre-soaking. Papain was then added for targeted enzymatic hydrolysis. After targeted enzymatic hydrolysis, the enzyme was inactivated by heating. The mixture was then filtered, ultrafiltered, and vacuum concentrated to obtain a soybean meal and corn germ meal compound enzymatic hydrolysate with an amino acid content of 15%.

5. The compound fertilizer as described in claim 4, characterized in that, The dry weight ratio of soybean meal to corn germ meal is 5-7:3-5; and / or, the microwave treatment frequency is 2300-2500MHz and the time is 2-3min; and / or, the material-to-water ratio of the mixture is 1:15 and the water temperature is 45-50℃; and / or, the pH value of the pre-soaking treatment is 7.4-7.6 and the time is 120-150min.

6. The compound fertilizer as described in claim 4, characterized in that, In the directional enzymatic hydrolysis treatment, the amount of papain added is 0.05%-0.1% of the sum of the dry weights of soybean meal and corn germ meal; the reaction temperature is 55-60℃; the pH is maintained between 6.5 and 7.0 during the reaction; and the reaction time is 4-6 hours. Alternatively, the filtration mesh has a pore size of 40-50 μm. Or, the ultrafiltration uses an ultrafiltration membrane with a molecular weight cutoff of 5000-8000 Da. Or, the vacuum concentration temperature is 50-60℃, and the vacuum degree is -0.08 MPa.

7. A method for preparing a compound fertilizer for improving the quality and yield of avocado fruit as described in any one of claims 3-6, characterized in that the step... include: After crushing the corn stalks, mix them evenly with wood ash, poultry and livestock manure, and humic acid to obtain dry material. Bacillus subtilis is mixed with water to prepare a bacterial solution, which is then sprayed and mixed evenly with the dry material. The moisture content is adjusted to 45-50%, and the mixture is piled up for fermentation to obtain the fermentation product. Urea, calcium magnesium phosphate, potassium sulfate, and magnesium chloride are added to the fermentation product, mixed evenly, and then a compound enzymatic hydrolysate of soybean meal and corn germ meal is sprayed evenly. After granulation and drying, the compound fertilizer that improves the quality and yield of avocado fruit is obtained.

8. The preparation method according to claim 7, characterized in that, The particle size of the crushed corn stalks is 20-30 mm; and / or the mass ratio of Bacillus subtilis to water is 1:10-20; and / or the temperature of the composting fermentation is 35-45℃, the time is 15-20 days, and the compost is turned over every 3 days.

9. The preparation method according to claim 7, characterized in that, The granulation particle size is 2-4 mm; and / or the drying temperature is 40-45℃, and the drying is carried out until the moisture content is <10%.

10. The application of the compound fertilizer according to any one of claims 3-6 in improving the quality and yield of avocado fruit.