A composition for improving saline-alkali soil and preparation method thereof

Abstract

The present invention provides a composition for improving saline-alkali soil and a preparation method thereof, belonging to the technical field of soil improvement preparation technology. The composition comprises polyaspartic acid salt, a mycelial protein-derived biostimulant, and aminoadipic acid. The composition of the present invention uses polyaspartic acid (salt) as the main saline-alkali contaminated soil improver, while adding a mycelial protein-derived biostimulant and aminoadipic acid as improvement effect accelerators, thereby obtaining a composition with better saline-alkali soil improvement effect, thereby improving the saline-alkali soil improvement efficiency.

Description

Technical Field

[0001] The invention relates to a composition for improving saline-alkali soil, and belongs to the technical field of preparation of soil improving preparations. Background Art

[0002] Fertilizers, especially chemical fertilizers, are an essential component of agricultural production and have made significant contributions to ensuring human well-being. However, excessive use of chemical fertilizers has also had numerous negative impacts on the land, such as soil fertility degradation and soil compaction.

[0003] Polyaspartic acid is a representative synthetic water-soluble protein. Naturally present in the mucus of marine shellfish, such as oysters, it serves as one of the primary active substances used by these organisms to accumulate nutrients and build their shells. Since its discovery, this product has garnered significant attention from international research institutions and organizations, with applications underway in a variety of industries, including agriculture, water treatment, cosmetics, and oil fields. In agriculture, polyaspartic acid is primarily used as a water treatment agent and fertilizer enhancer; it also exhibits excellent saline-alkali soil amelioration properties. This is due to the fact that polyaspartic acid is a polymer with a near-normal molecular weight distribution, resulting in a low content of fast-acting, low-molecular-weight compounds. This results in a relatively short duration of action, but a relatively poor fast-acting effect. Preliminary research conducted by Hebei Collaborative Chemical Co., Ltd. revealed that using polyaspartic acid alone to improve saline-alkali soils was slow, typically requiring three to five years to show significant results. This limited its application and necessitated the use of other substances for functional supplementation.

[0004] Since the beginning of the 21st century, humans have gradually unleashed the power of living things. The rise of the fermentation industry has made the microbial industry increasingly efficient, green, and safe. However, it is undeniable that while obtaining effective ingredients, the fermentation industry also produces a large amount of waste, mainly mycelial protein from various microorganisms and a mixture of fermentation by-products containing mycelial protein. According to statistics, mycelial protein is currently processed mainly as feed protein or fertilizer. When mycelial protein is added to fertilizer, the extremely large molecular weight of the protein makes it difficult to release nutrients (mainly due to the large amount of secondary metabolites in the mycelium) and the effect is slow. These secondary metabolites are excellent biostimulants that have a good promoting effect on crop growth. Summary of the Invention

[0005] In view of the above problems, the present invention provides a composition for improving saline-alkali soil and a preparation method thereof, so as to increase the speed at which polyaspartic acid takes effect in improving saline-alkali soil.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] The composition of the present invention uses polyaspartic acid (salt) as a main soil improver, and simultaneously adds a biostimulant derived from waste mycelial protein of microbial fermentation with a wide molecular weight distribution and favorable for crop absorption, obtained by the joint action of cellulase, pectinase and neutral (or alkaline) protease, and further supplemented with an appropriate amount of aminoadipic acid to promote the effect of the biostimulant. The composition not only significantly improves the effect of polyaspartic acid on improving saline-alkali soil, but also greatly helps the comprehensive utilization of mycelial protein and by-product organic acids in the microbial fermentation industry, so that the composition can better serve agricultural production and income increase and circular economy.

[0008] The specific technical solution of the present invention is a composition for improving saline-alkali soil, comprising polyaspartate, a mycelial protein-derived biostimulant and aminoadipic acid.

[0009] Furthermore, the composition comprises, based on solid matter, 50-65 parts by weight of polyaspartate, 25-30 parts by weight of mycelial protein-derived biostimulant, and 10-20 parts by weight of aminoadipic acid.

[0010] Furthermore, the composition comprises, based on solid matter, 58 parts by weight of polyaspartate, 27 parts by weight of mycelial protein-derived biostimulant, and 15 parts by weight of aminoadipic acid.

[0011] Furthermore, the polyaspartate salt includes any one or a combination of solid products of industrial-grade potassium polyaspartate, ammonium polyaspartate and magnesium polyaspartate.

[0012] Furthermore, the pH value of the polyaspartate is 8-10, and the selection of this pH value can enhance the solubility of the mycelial protein-derived biostimulant and aminoadipic acid.

[0013] Furthermore, the raw material of the mycelial protein-derived biostimulant is a mixture of amino acid industry by-products and cephalosporin industry by-product mycelia, and the ratio of amino acid industry by-product mycelia to cephalosporin industry by-product mycelia is 1:9-2:8 based on dry matter mass.

[0014] Furthermore, the preparation method of the mycelial protein-derived biostimulant comprises the following steps:

[0015] Amino acid industrial by-product mycelium and cephalosporin industrial by-product mycelium are respectively decomposed by using pectinase (industrial grade enzyme activity ≥30,000 μ / g, dosage 0.20g / kg dry mycelial protein) and cellulase (industrial grade enzyme activity ≥50,000 μ / g, dosage 0.10g / kg dry mycelial protein) to enhance the efficiency of subsequent protein decomposition. The conditions are selected as pH 4.0-4.5, temperature 45-55°C, and time 6-8h; the above suspension selects a composite heavy metal chelating agent with a molar ratio of tetrasodium iminodisuccinate and tetrasodium glutamate diacetate of 4:6-6:4 for heavy metal removal. The removal process needs to control the pH>4.0 to enhance the removal of heavy metals. Add neutral (or alkaline) protease to the above material and adjust the pH (generally controlled at 7.0-8.0 for neutral and 8.5-9.5 for alkaline) and temperature (45-60° C. for neutral and 50-65° C. for alkaline) to hydrolyze until a clear solution is formed (12-24 hours), then raise the temperature (85-90° C.) to inactivate the protease; the above solution is the mycelial protein-derived biostimulant, and the solid content is measured before compounding; the molecular weight distribution is as follows: 20-30% for the portion <1000D, 20-40% for the portion 1000-3000D, 20-40% for the portion 3000-5000D, and <5% for the portion >5000D.

[0016] Furthermore, the aminoadipic acid is a-aminoadipic acid produced as a by-product of cephalosporin, and the content of a-aminoadipic acid is greater than 95% and the impurity content is less than 1.0%.

[0017] A method for preparing the above-mentioned composition for improving saline-alkali soil comprises adding appropriate amounts of water, solid polyaspartate, a mycelial protein-derived biostimulant, and aminoadipic acid to a reactor, stirring and dissolving them at 75-85°C until a clear liquid is obtained, and adjusting the solid content to a desired value to obtain a liquid composition product; and spray drying the liquid composition product to obtain a solid composition product.

[0018] Furthermore, based on solid matter, the polyaspartate is 50-65 parts by weight, the mycelial protein-derived biostimulant is 25-30 parts by weight, and the aminoadipic acid is 10-20 parts by weight.

[0019] The beneficial effects of the composition for improving saline-alkali soil and the preparation method thereof of the present invention are:

[0020] The composition of the present invention uses polyaspartic acid (salt) as the main saline-alkali contaminated soil improver, and simultaneously adds a biostimulant derived from mycelial protein and an organic complex acid such as aminoadipic acid as an improvement effect promoter, thereby obtaining a composition with better saline-alkali soil improvement effect and improving the saline-alkali soil improvement efficiency.

[0021] The composition of the present invention not only realizes the resource utilization of waste from the fermentation industry, but also provides a soil improvement composition that is of great help to agricultural production. The production and use of the composition helps to improve the utilization rate of fertilizers and reduce the overall application amount of fertilizers, thereby increasing the average agricultural output and total output, reducing carbon emissions related to agricultural production, and at the same time improving the quality of agricultural products, thereby achieving the comprehensive goals of energy conservation and environmental protection, water conservation and emission reduction, quality improvement and efficiency enhancement, and increased production and income.

[0022] When the composition of the present invention is used for soil improvement, the usage amount is 15kg / hm2 solid dosage. 2 The effects are mainly reflected in the increase of soil organic matter, the increase of soil colloid structure, the increase of seed germination rate, the increase of seedling growth rate and the increase of final yield.

[0023] Figures in the specification

[0024] Figure 1 This is a comparison chart of the growth status of corn seedlings in a saline-alkali soil pot experiment, where A1 represents the application of the composition of Example 1 at an addition rate of 15 kg / hm2. 2 , F is blank soil without salinity;

[0025] Figure 2 This is a comparison chart of the growth status of corn seedlings in saline-alkali soil potted experiments, where D3 represents the application of the composition of Comparative Example 1 at an addition rate of 15 kg / hm2. 2 , F is blank soil without salinity;

[0026] Figure 3 This is a comparison chart of the growth status of corn seedlings in saline-alkali soil potted experiments, where E1 represents the application of the composition of Comparative Example 3 at an addition rate of 15 kg / hm2. 2 , F is blank soil without salinity;

[0027] Figure 4 This is a comparison chart of the growth status of corn seedlings in saline-alkali soil potted experiments, where E2 represents the application of the composition of Comparative Example 5 at an addition rate of 15 kg / hm2. 2 , F is blank soil without salinity;

[0028] Figure 5 This is a comparison chart of the growth status of corn seedlings in saline-alkali soil potted experiments, where E3 represents the application of the composition of Comparative Example 7 at an addition rate of 15 kg / hm2. 2 , F is blank soil without salinity. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] A composition for improving saline-alkali soil, comprising polyaspartate, a mycelial protein-derived biostimulant, and aminoadipic acid. Preferably, the composition comprises, based on solids, 50-65 parts by weight of polyaspartate, 25-30 parts by weight of the mycelial protein-derived biostimulant, and 10-20 parts by weight of aminoadipic acid. Further preferably, the composition comprises, based on solids, 58 parts by weight of polyaspartate, 27 parts by weight of the mycelial protein-derived biostimulant, and 15 parts by weight of aminoadipic acid.

[0031] Preferably, the polyaspartate salt comprises any one or a combination of industrial-grade solid products of potassium polyaspartate, ammonium polyaspartate, and magnesium polyaspartate. The pH of the polyaspartate salt is 8-10. This solid product, which has a pH of 8-10, enhances the solubility of the mycelial protein-derived biostimulant and aminoadipic acid.

[0032] Preferably, the raw material of the mycelial protein-derived biostimulant is a mixture of amino acid industry by-products and cephalosporin industry by-product mycelia, and the ratio of amino acid industry by-product mycelia to cephalosporin industry by-product mycelia is 1:9-2:8 according to the dry matter mass. The preparation method of the mycelial protein-derived biostimulant includes the following steps: amino acid industry by-product mycelia and cephalosporin industry by-product mycelia are respectively decomposed by using pectinase (industrial-grade enzyme activity ≥30,000 μ / g, dosage 0.20g / kg dry mycelial protein) and cellulase (industrial-grade enzyme activity ≥50,000 μ / g, dosage 0.10g / kg dry mycelial protein) to enhance the efficiency of subsequent protein decomposition, and the conditions are selected to be pH 4.0-4.5, temperature 45-55°C, and time 6-8h; the above-mentioned suspension selects a composite heavy metal chelating agent with a molar ratio of tetrasodium iminodisuccinate and tetrasodium glutamate diacetate of 4:6-6:4 to remove heavy metals, and the removal process needs to control the pH >4.0 to enhance the removal efficiency of heavy metals; add neutral (or alkaline) protease to the above material to adjust the appropriate pH (generally controlled at 7.0-8.0 for neutral and 8.5-9.5 for alkaline) and temperature (45-60°C for neutral and 50-65°C for alkaline) for hydrolysis until a clear solution is formed (12-24 hours), and then increase the temperature (85-90°C) to inactivate the protease; the above solution is the mycelial protein-derived biostimulant, and the solid content is measured before compounding; its molecular weight distribution is 20-30% for the portion <1000D, 20-40% for the portion 1000-3000D, 20-40% for the portion 3000-5000D, and <5% for the portion >5000D.

[0033] Aminoadipic acid is a-aminoadipic acid produced as a by-product of cephalosporin, with a content of a-aminoadipic acid greater than 95% and an impurity content less than 1.0%.

[0034] A method for preparing a composition for improving saline-alkali soil comprises adding appropriate amounts of water, solid polyaspartate, a mycelial protein-derived biostimulant, and aminoadipic acid to a reactor, stirring and dissolving until a clear liquid is obtained, and adjusting the solids content to the desired amount to obtain a liquid composition product. The liquid composition product is then spray-dried to obtain a solid composition product. Based on solids, the polyaspartate comprises 50-65 parts by weight, the mycelial protein-derived biostimulant comprises 25-30 parts by weight, and the aminoadipic acid comprises 10-20 parts by weight. Spray drying can employ existing processes, as long as they do not affect the activity of the various substances in the product of the present invention or have other adverse effects on them. This is not a novel feature of the present invention and will not be further described here.

[0035] Example 1

[0036] The composition ratio (calculated on the basis of solid matter) is: 55 parts by weight of potassium polyaspartate (pH=8), 30 parts by weight of a mycelial protein-derived biostimulant, and 15 parts by weight of aminoadipic acid.

[0037] The mycelial protein-derived biostimulant is prepared according to the above method, and the ratio of amino acid industrial by-product mycelium and cephalosporin industrial by-product mycelium is 1:9 based on dry matter mass; the decomposition conditions are selected as pH 4.0-4.5, temperature 45°C, and time 8 hours; and the molar ratio of tetrasodium iminodisuccinate to tetrasodium glutamate diacetate is 4:6.

[0038] The preparation method comprises: adding appropriate amounts of water, solid polyaspartate, mycelial protein-derived biostimulant, and aminoadipic acid to a reaction kettle, stirring and dissolving until a clear liquid is obtained. The solid content is adjusted to the desired amount (generally 300 or 400 g / L) in accordance with the relevant provisions of NY / T3036-2016 Fertilizers and Soil Conditioners - Determination of Moisture Content, Particle Size, and Fineness) to obtain a liquid composition product. The liquid composition product is spray-dried to obtain a solid composition product. The preparation method is the same for the following examples.

[0039] The composition obtained according to the above operation process meets the following indicators: appearance is a brown uniform liquid, pH (1:250) is 6.57, solid content (detection method refers to NY / T3036-2016 Fertilizers and soil conditioners-Determination of moisture content, particle size and fineness, the same below) 40.75%, polyaspartic acid (detection method refers to NY T2878-2015 Water-soluble fertilizer Determination of polyaspartic acid content, the same below) content ≥240 g / L, other amino acids and their derivatives (detection method refers to GB / T 6432-2018 Determination of crude protein in feed Kjeldahl method, the same below) ≥120 g / L, aminoadipic acid (detection method refers to NYT3831-2021 General requirements for organic water-soluble fertilizers, the same below) content ≥60 g / L, storage stability and crop safety (detection methods and indicators refer to DB13 / T 2172-2015 Polyaspartate for agricultural use, the same below) meet relevant requirements.

[0040] Example 2

[0041] The composition ratio (calculated on the basis of solid matter) is: 65 parts by weight of magnesium polyaspartate (pH=10), 25 parts by weight of a mycelial protein-derived biostimulant, and 15 parts by weight of aminoadipic acid.

[0042] The mycelial protein-derived biostimulant is prepared according to the above method, and the ratio of amino acid industrial by-product mycelium to cephalosporin industrial by-product mycelium is 2:8 based on dry matter mass; the decomposition conditions are selected as pH 4.0-4.5, temperature 55°C, and time 6 hours; and the molar ratio of tetrasodium iminodisuccinate to tetrasodium glutamate diacetate is 6:4.

[0043] The composition obtained according to the above operation process meets the following indicators: appearance is a brown uniform liquid, pH (1:250) is 7.36, solid content is 40.80%, polyaspartic acid content is ≥300g / L, other amino acids and their derivatives are ≥100g / L, aminoadipic acid content is ≥60g / L, and storage stability and crop safety meet relevant requirements.

[0044] Example 3

[0045] The composition ratio (calculated on solid matter) is: 58 parts by weight of ammonium polyaspartate (pH=9), 27 parts by weight of mycelial protein-derived biostimulant, and 20 parts by weight of aminoadipic acid.

[0046] The mycelial protein-derived biostimulant is prepared according to the above method, and the ratio of amino acid industrial by-product mycelium to cephalosporin industrial by-product mycelium is 2:9 based on dry matter mass; the decomposition conditions are selected as pH 4.0-4.5, temperature 50°C, and time 7 hours; and the molar ratio of tetrasodium iminodisuccinate to tetrasodium glutamate diacetate is 1:1.

[0047] The composition obtained according to the above operation process meets the following indicators: appearance is a brown uniform liquid, pH (1:250) is 7.03, solid content is 40.07%, polyaspartic acid content is ≥270g / L, other amino acids and their derivatives are ≥120g / L, aminoadipic acid content is ≥80g / L, and storage stability and crop safety meet relevant requirements.

[0048] The application test results of the composition of the present invention are as follows:

[0049] The compositions produced in Examples 1-3 were used in agricultural experiments, including indoor potted plant experiments and field application tests. Comparative Examples 1-9 were used as control treatments (the preparation of the compositions of Comparative Examples 1-9 is described below). The indoor experiments were conducted in the bioassay laboratory of Hebei Collaborative Chemical Co., Ltd. The soil used was yellow loam (nutrient content: organic matter 1.76%, total nitrogen 1.14 g / kg, available phosphorus 30.52 mg / kg, available potassium 124.73 mg / kg) and horticultural vermiculite (particle size 2-3 mm) for cultivation at a mass ratio of 1:1 to prepare loose cultivation soil. Examples 1-3 and Comparative Examples 1-9 were used as control treatments, with the same treatment rate of 15 kg / hm2. 2; Sodium chloride with an analytically pure molecular weight of 58.44 and sodium carbonate with a molar mass ratio of 1:1 were mixed into 50 mmol / L solutions of different concentrations to simulate a moderate salinity environment, and a non-salt-alkali stress treatment was set as a background blank CK; Hoagland's modified nutrient solution was used as a nutritional supplement, and Zhengdan 958 coated varieties were used as test objects to conduct a seedling experiment on the effect of the composition on the salt-alkali resistance of crops; all treatments were repeated 3 times and arranged according to randomized blocks, and the indicators were soil organic matter content and soil ion exchange capacity (soil ion exchange capacity) specified in the 2000 edition of the soil agricultural chemical analysis method. Represents the exchange capacity of soil cations. The higher this value is, the less cations are accumulated, the less the total amount and rate of residual cations in the soil will be, which means the higher the degree of soil salinity improvement and the stronger the soil fertilizer retention capacity). The method described in the general botanical experiment was used to determine the emergence rate, growth (the total growth in the treatment) and growth inhibition rate (the total growth inhibition rate in the treatment). The statistical analysis method was then used to study the control effect. SPSS12.0 data analysis system was used for one-way analysis of variance and Dunckan method was used for difference significance test. The specific data are shown in the following table.

[0050] Table 1 Statistics of saline-alkali soil improvement indoor potted plant experiment data

[0051]

[0052] In the seedling experiment, the data of organic matter did not change significantly, mainly because the growth time was relatively short and no changes had occurred. However, the soil ion exchange capacity of the soil had a relatively obvious change. From the data, it can be seen that the data of Examples 1-3 were 29.32-30.09 cmol / kg, which was significantly different from the data of Comparative Examples 1-9, which were 22.09-26.54 cmol / kg. The salt-alkali effect on the emergence rate was also quite obvious. The emergence rate of Examples 1-3 was 94.68-95.67%, which was not significantly different from CK's 99.50%, but was significantly higher than Comparative Examples 1-9. In terms of growth and root growth in the seedling stage, the treatments shown in Examples 1-3 had a significant effect on improving the salt-alkali resistance of the test crop corn.

[0053] By the attached Figure 1-5 The comparison of the pictures further shows that the composition of the present invention has excellent salt-alkali resistance and growth-promoting effects. The salinity of the soil in the figure is the above-mentioned medium salinity. The figure shows the height or overall growth of corn seedlings under the soil conditions of different examples or comparative examples at the same time. Specifically: A1 in the figure represents the treatment amount of Example 1, 15 kg / hm 2 In the figure, D3 represents the treatment capacity of comparative example 1, 15 kg / hm 2 In the figure, E1 represents the comparative example 3 with a treatment capacity of 15 kg / hm2 In the figure, E2 represents the comparative example 5 with a treatment capacity of 15 kg / hm 2 In the figure, E3 represents the comparative example 7 with a treatment capacity of 15 kg / hm 2 , F represents the blank salt-free and alkali-free control, Figure 1-5 The comparison shows that the composition of the present invention has an excellent apparent effect on the salt-alkali resistance of corn seedling growth.

[0054] The field test was conducted in Haladaokou Town, Songshan District, Chifeng City, Inner Mongolia (N42°34′41.29″, E119°28′56.04″). Brown loam (nutrient content: organic matter 4.73%, alkaline nitrogen 0.98 g / kg, total phosphorus 0.38 g / kg, available potassium 64.73 mg / kg) was selected as the soil. Examples 1-3 and Comparative Examples 1-9 were used as control treatments, respectively. A blank control CK1 was used without applying any amendment. The treatment amount was the same as 15 kg / hm2. 2 ; Ordinary compound fertilizer (15-15-15) was directly applied as a nutrient source, and Zhengdan 958 coated variety was used as the test object to conduct an experiment on the effect of the composition on the salt and alkali resistance of crops during the growth period; all treatments were repeated 3 times and arranged according to random blocks; the data were determined by using the provisions of the 2000 version of the soil agricultural chemical analysis method for soil organic matter content and soil ion exchange capacity, and the method described in the general botanical experiment was used to determine the seedling rate, yield and yield increase rate (the total growth inhibition rate in the treatment), and then the statistical analysis method was used to study the control effect, and the SPSS12.0 data analysis system was used for one-way analysis of variance and the Dunckan method was used for significant difference test. The specific data are shown in the following table.

[0055] Table 2 Statistics of field experiments on saline-alkali soil improvement

[0056]

[0057] In the field experiment, the data on organic matter did not change significantly, mainly because the growing time of the season was relatively short and the straw was not returned to the field; however, the soil ion exchange capacity of the soil changed significantly. From the data, it can be seen that the data of Examples 1-3 were 34.20-35.12 cmol / kg, which was significantly different from the data of Comparative Examples 1-9, which were 28.09-30.48 cmol / kg. The effect of salt and alkali on the emergence rate was also quite obvious. The emergence rate of Examples 1-3 was 94.60-95.82%, which was significantly different from CK1's 70.88%, and was significantly higher than Comparative Examples 1-9. In terms of yield, the effect of the treatments shown in Examples 1-3 on improving the salt and alkali resistance of the test crop corn was significantly higher than that of Comparative Examples 1-9; at the same time, it was found that each comparative example had a certain effect compared with CK1.

[0058] Comparative Example 1

[0059] Comparative Example 1 is a comparative experiment of Example 1, except that the composition ratio in Comparative Example 1 (calculated on a solid basis) is: 55 parts by weight of potassium polyaspartate (pH = 8), 30 parts by weight of a mycelial protein-derived biostimulant, and the rest is the same as Example 1.

[0060] The composition obtained by the above-described operation process met the following specifications: appearance was a brown, uniform liquid, pH (1:250) was 8.05, solids content was 35.95%, polyaspartic acid content was ≥240 g / L, and other amino acids and their derivatives were ≥120 g / L. Storage stability did not meet relevant requirements (irreversible precipitation occurred after 7 days of storage, and the precipitate was soluble in dilute acid or ammonia but insoluble in dilute alkali). Crop safety met relevant requirements. (Reasoning: Without aminoadipic acid, the mycelial protein-derived biostimulant would undergo irreversible denaturation at the specified storage temperature, thereby affecting overall stability.)

[0061] Comparative Example 2

[0062] Comparative Example 2 is a comparative experiment of Example 1, except that the composition ratio in Comparative Example 2 (calculated on solid matter) is: 55 parts by weight of potassium polyaspartate (pH=8), 15 parts by weight of aminoadipic acid, and the rest is the same as Example 1.

[0063] The composition obtained according to the above operation process met the following indicators: appearance was a brown, uniform liquid, pH (1:250) was 5.45, solids content was 25.40%, polyaspartic acid content was ≥240 g / L, aminoadipic acid content was ≥60 g / L, storage stability at medium and high temperatures did not meet the relevant requirements (irreversible precipitation occurred after storage for 7 days, the precipitate was soluble in ammonia water, insoluble in dilute acid or dilute alkali), and crop safety did not meet the relevant requirements (the inhibition rate of plant height and root length of the tested corn exceeded 15%). (Reason: Without the mycelial protein-derived biostimulant, aminoadipic acid will have a certain negative impact on crop growth. The main reasons are the change in pH caused by organic acids and the inhibitory effect of organic acids on seed germination or seedling growth.)

[0064] Comparative Example 3

[0065] Comparative Example 3 is a comparative experiment of Example 1, except that the composition ratio (based on solid matter) in Comparative Example 3 is: 55 parts by weight of potassium polyaspartate (pH=8), and the rest is the same as Example 1.

[0066] The composition obtained according to the above operation process meets the following indicators: appearance is a brown uniform liquid, pH (1:250) is 8.50, solid content is 25.75%, polyaspartic acid content is ≥240g / L, and storage stability and crop safety meet relevant requirements.

[0067] Comparative Example 4

[0068] Comparative Example 4 is a comparative experiment of Example 1, except that the pH of potassium polyaspartate in Comparative Example 4 is 7, and the rest is the same as Example 1.

[0069] The composition obtained according to the above operation process meets the following indicators: appearance is a brown uniform liquid, pH (1:250) is 7.52, solid content is 24.98%, polyaspartic acid content is ≥240g / L, and storage stability and crop safety meet relevant requirements.

[0070] Comparative Example 5

[0071] Comparative Example 5 is a comparative experiment of Example 1, except that the pH of potassium polyaspartate in Comparative Example 5 is 11, and the rest is the same as Example 1.

[0072] The composition obtained according to the above operation process meets the following indicators: appearance is a brown uniform liquid, pH (1:250) is 11.72, solid content is 25.39%, polyaspartic acid content is ≥210 g / L (reason: the pH is too high, resulting in partial deamination reaction, causing loss of polyaspartic acid), storage stability and crop safety meet relevant requirements.

[0073] Comparative Example 6

[0074] Comparative Example 6 is a comparative experiment of Example 1, except that the composition ratio (based on solid matter) in Comparative Example 6 is: 55 parts by weight of potassium polyaspartate (pH=8), 20 parts by weight of mycelial protein-derived biostimulant, and 10 parts by weight of aminoadipic acid. The rest of the composition is the same as Example 1.

[0075] The composition obtained according to the above operation process meets the following indicators: appearance is a brown uniform liquid, pH (1:250) is 7.25, solid content is 38.35%, polyaspartic acid content is ≥240g / L, other amino acids and their derivatives are ≥100g / L, aminoadipic acid content is ≥40g / L, storage stability shows low-temperature stratification phenomenon (reason: the content of mycelial protein-derived biostimulant is low, resulting in poor system stability and easy low-temperature stratification, but it can be restored by increasing the temperature), and crop safety meets relevant requirements.

[0076] Comparative Example 7

[0077] Comparative Example 7 is a comparative experiment of Example 1, except that the composition ratio (based on solid matter) in Comparative Example 7 is: 55 parts by weight of potassium polyaspartate (pH=8), 35 parts by weight of mycelial protein-derived biostimulant, and 10 parts by weight of aminoadipic acid. The rest of the composition is the same as in Example 1.

[0078] The composition obtained according to the above operation process meets the following indicators: appearance is a brown uniform liquid, pH (1:250) is 6.89, solid content is 40.86%, polyaspartic acid content is ≥240g / L, other amino acids and their derivatives are ≥150g / L, aminoadipic acid content is ≥40g / L, storage stability has a large amount of high-temperature turbidity phenomenon (reason: the content of mycelial protein-derived biostimulant is relatively high, resulting in poor system stability and easy high-temperature denaturation, but it can be restored by lowering the temperature), and crop safety meets relevant requirements.

[0079] Comparative Example 8

[0080] Comparative Example 8 is a comparative experiment of Example 1, except that the composition ratio (based on solid matter) in Comparative Example 8 is: 55 parts by weight of potassium polyaspartate (pH=8), 30 parts by weight of mycelial protein-derived biostimulant, and 8 parts by weight of aminoadipic acid. The rest of the composition is the same as Example 1.

[0081] The composition obtained according to the above operation process meets the following indicators: appearance is a brown uniform liquid, pH (1:250) is 6.86, solid content is 39.58%, polyaspartic acid content is ≥240g / L, other amino acids and their derivatives are ≥120g / L, aminoadipic acid content is ≥40g / L, storage stability has a large amount of high-temperature turbidity phenomenon (reason: the content of mycelial protein-derived biostimulant is high while the content of aminoadipic acid is reduced, resulting in poor system stability, easy to deteriorate storage stability, resulting in precipitation of effective substances), and crop safety meets relevant requirements.

[0082] Comparative Example 9

[0083] Comparative Example 9 is a comparative experiment of Example 1, except that the composition ratio (based on solid matter) in Comparative Example 9 is: 55 parts by weight of potassium polyaspartate (pH=8), 30 parts by weight of mycelial protein-derived biostimulant, and 22 parts by weight of aminoadipic acid. The rest of the composition is the same as Example 1.

[0084] The composition obtained according to the above operation process meets the following indicators: appearance is a brown uniform liquid, pH (1:250) is 6.34, solid content is 41.25%, polyaspartic acid content ≥240g / L, other amino acids and their derivatives ≥120g / L, aminoadipic acid ≥120g / L, storage stability meets relevant requirements, and crop safety does not meet the requirements (the test corn plant height and root length inhibition rates are both greater than 25%) (Reason explanation: When aminoadipic acid is relatively high, aminoadipic acid will have a negative impact on crop growth. The main reason is the change in pH caused by organic acids and the inhibitory effect of organic acid substances on seed germination or seedlings.).

[0085] Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

Claims

1. A composition for improving saline-alkali soil, characterized in that: The composition comprises polyaspartate, a mycelial protein-derived biostimulant, and aminoadipic acid; the composition comprises, based on solid matter, 50-65 parts by weight of polyaspartate, 25-30 parts by weight of the mycelial protein-derived biostimulant, and 10-20 parts by weight of aminoadipic acid; The raw material of the mycelial protein-derived biostimulant is a mixture of amino acid industry by-products and cephalosporin industry by-product mycelia, with the ratio of amino acid industry by-product mycelia to cephalosporin industry by-product mycelia being 1:9-2:8 based on dry matter mass. The preparation method of the mycelial protein-derived biostimulant comprises the following steps: Amino acid industry by-product mycelia and cephalosporin industry by-product mycelia are structurally decomposed using pectinase and cellulase, respectively, to obtain suspensions, and the reaction conditions for the decomposition are pH 4.0-4.5, temperature 45-55°C, and time 6-8 hours. A composite heavy metal chelating agent with a molar ratio of tetrasodium iminodisuccinate to tetrasodium glutamate diacetate of 4:6-6:4 is selected from the suspension to remove heavy metals, and the pH is controlled to be greater than 4.0 during the removal process. Finally, a neutral or alkaline protease is added to adjust the pH and temperature for hydrolysis, and the solution is heated to inactivate the protease until a clear solution is formed.

2. A composition for improving saline-alkali soil according to claim 1, characterized in that The composition comprises, based on solid matter, 58 parts by weight of polyaspartate, 27 parts by weight of a mycelial protein-derived biostimulant, and 15 parts by weight of aminoadipic acid.

3. A composition for improving saline-alkali soil according to claim 1 or 2, characterized in that: The polyaspartate salt includes any one or a combination of solid products of industrial-grade potassium polyaspartate, ammonium polyaspartate and magnesium polyaspartate.

4. A composition for improving saline-alkali soil according to claim 3, characterized in that: The pH value of polyaspartate is 8-10.

5. A composition for improving saline-alkali soil according to claim 4, characterized in that: Aminoadipic acid is a-aminoadipic acid produced as a by-product of cephalosporins. The content of a-aminoadipic acid is >95% and the impurity content is <1.0%.

6. A method for preparing the composition for improving saline-alkali soil according to any one of claims 1 to 5, characterized in that: Appropriate amounts of water, solid polyaspartate, mycelial protein-derived biostimulant, and aminoadipic acid are added to a reactor respectively, stirred and dissolved until a clear liquid is obtained, and the solid content is adjusted to a desired amount to obtain a liquid composition product; the liquid composition product is spray-dried to obtain a solid composition product.

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