Saline-alkali soil modifier prepared from by-products generated in bone gelatin manufacturing process as well as preparation method and application of saline-alkali soil modifier

Abstract

The invention relates to the technical field of saline-alkali soil, and discloses a saline-alkali soil modifier prepared from by-products generated in the bone gelatin manufacturing process and a preparation method and application thereof.The method comprises the following steps that 1, bone gelatin production waste liquid is subjected to protein degradation and membrane separation, and bone-derived biological calcium is obtained; (2) carrying out enzymolysis on the gelatin production residues to obtain collagen oligopeptide; and (3) mixing the bone-derived biological calcium obtained in the step (1) with the collagen oligopeptide obtained in the step (2) to obtain the saline-alkali soil modifier, and the weight ratio of the bone-derived biological calcium to the collagen oligopeptide is 1: (0.002-0.05) on a dry basis. When the saline-alkali soil improver is used for sunflower planting, the soil bulk density can be increased, and the seedling protection rate, the chlorophyll content, the disc grain number, the hundred-grain weight, the disc full grain weight, the yield per mu and the like of sunflowers can be increased.

Description

Technical Field

[0001] The invention relates to the technical field of saline-alkali land, and in particular to a saline-alkali land improver prepared by using a byproduct generated in a bone gelatin manufacturing process, and a preparation method and application thereof. Background Art

[0002] Saline-alkali land is a type of soil that is widely distributed around the world, accounting for about 1 / 4 of the land area, and its range covers all five continents except Antarctica. Soil salinization seriously restricts agricultural production, especially irrigated farmland. In the history of irrigation in countries around the world, soil salinization has been one of the important reasons that affect agricultural development and even determine the rise and fall of a country. The improvement of saline-alkali land has always been called a world problem. Solving the problem of saline-alkali land improvement can greatly increase the country's grain output and land utilization rate, and has great economic, social and ecological benefits.

[0003] Saline-alkali land refers to land affected by natural or human factors, which causes salt substances to gradually penetrate into the soil, resulting in a high salt and alkali content in the soil, making this type of land unusable. The main reason for the formation of saline-alkali land is that under the action of evaporation, the water in the land in relatively arid areas is evaporated into water vapor and discharged into the air, but the salt in the water cannot be eliminated and remains in the soil. After a long period of accumulation, the salt content in the soil gradually increases, thus forming saline-alkali land. Saline-alkali soil has low organic matter content, low soil fertility, poor physical and chemical properties, and many anions and cations that are harmful to crops, making it difficult for crops to grow seedlings. Because the saline-alkali soil itself contains too much salt, according to the principle of plant cell osmosis, it is difficult for plant cells to absorb inorganic nutrients and water, resulting in the death of plants due to their own lack of inorganic nutrients and water, which in turn creates a vicious cycle of saline-alkali land ecology.

[0004] At present, the improvement of saline-alkali land has made certain progress in physical improvement, chemical improvement, and the cultivation and screening of salt-tolerant varieties, but there are certain limitations. Physical improvement includes leveling the land, deep plowing and drying, alkali reduction with imported soil, and the construction of water conservancy projects, which are costly and have limited improvement effects. Chemical improvement includes the application of gypsum, superphosphate, humic acid, silicon-calcium minerals, etc., but the cost of treating saline-alkali land is too high, difficult to promote, and cannot change the fertilizer efficiency of saline-alkali land, especially in severely saline-alkali land, where the environment is fragile and the improvement effect is poor. The breeding cycle of salt-tolerant varieties is long, the varieties are limited, and they cannot meet the needs of agricultural production. Therefore, it is urgent to find an effective method for improving saline-alkali land. Summary of the invention

[0005] The purpose of the present invention is to overcome the difficulty of improving saline-alkali land in the prior art and provide a saline-alkali land improver prepared by using byproducts produced in the bone gelatin manufacturing process and its preparation method and application. The byproducts refer to waste liquid from bone gelatin production and gelatin production residues.

[0006] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a saline-alkali land improving agent, the method comprising the following steps:

[0007] (1) subjecting the waste liquid from bone gelatin production to protein degradation and membrane separation to obtain bone-derived biological calcium;

[0008] (2) enzymatically hydrolyzing the gelatin production residue to obtain collagen oligopeptides;

[0009] (3) The bone-derived biocalcium obtained in step (1) and the collagen oligopeptide obtained in step (2) are mixed to obtain a saline-alkali land improver, wherein the weight ratio of the bone-derived biocalcium to the collagen oligopeptide, calculated on a dry basis, is 1:0.002-0.05.

[0010] The second aspect of the present invention provides a saline-alkali land improver prepared by the method described above;

[0011] Alternatively, a saline-alkali land improver comprises bone-derived biological calcium and collagen oligopeptide, wherein, on a dry basis, the weight ratio of the bone-derived biological calcium to the collagen oligopeptide is 1:0.002-0.05.

[0012] The third aspect of the present invention provides an improver prepared by the method described above or the use of the improver described above in improving saline-alkali land.

[0013] The fourth aspect of the present invention provides a method for improving saline-alkali land, the method comprising: applying the improver described in the third aspect to the saline-alkali land.

[0014] Through the above technical solution, the present invention has the following effects:

[0015] (1) The present invention makes full use of waste resources from gelatin production, treats waste to reduce environmental pollution, and turns waste into treasure, thereby achieving comprehensive utilization of waste generated during gelatin production.

[0016] (2) The saline-alkali land improver prepared by the present invention is harmless to the environment, safe and environmentally friendly; it is easy to use and meets the quality standards of organic, ecological and green agriculture.

[0017] (3) The saline-alkali land conditioner of the present invention can promote plant growth, increase the organic matter content in the soil, and improve the soil aggregate structure.

[0018] (4) The present invention treats waste liquid or solid waste from different stages of gelatin production in different ways, and then mixes them in a specific proportion to obtain an improver, which has a buffering effect on the pH value, improves the pH value of the crop root environment, and reduces the damage of pH to plant growth and development.

[0019] (5) The saline-alkali land conditioner of the present invention can reduce the sodium ion content in saline-alkali land, reduce salt damage, and promote the improvement of soil quality.

[0020] (6) When the saline-alkali land conditioner of the present invention is used for sunflower planting, it can increase soil bulk density, and improve the sunflower seedling survival rate, chlorophyll content, number of seeds per tray, 100-seed weight, full seed weight, per-acre yield, etc.

[0021] (7) The saline-alkali land improving agent of the present invention has a simple preparation method, low application cost, significant improvement effect on saline-alkali land, and plays a role in increasing production and harvest. DETAILED DESCRIPTION

[0022] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0023] The first aspect of the present invention provides a method for preparing a saline-alkali land improving agent, the method comprising the following steps:

[0024] (1) subjecting the waste liquid from bone gelatin production to protein degradation and membrane separation to obtain bone-derived biological calcium;

[0025] (2) enzymatically hydrolyzing the gelatin production residue to obtain collagen oligopeptides;

[0026] (3) The bone-derived biocalcium obtained in step (1) and the collagen oligopeptide obtained in step (2) are mixed to obtain a saline-alkali land improver, wherein the weight ratio of the bone-derived biocalcium to the collagen oligopeptide, calculated on a dry basis, is 1:0.002-0.05.

[0027] In the present invention, the raw materials for producing bone-derived bio-calcium and collagen oligopeptides are all wastes from gelatin (preferably bone gelatin) production. The wastes generated at different stages of gelatin production are treated separately and then mixed in a specific ratio to obtain a mixture. When used in saline-alkali land, the mixture can not only improve the alkalinity of the saline-alkali land and reduce the salt content in the saline-alkali land, but also increase the organic matter content in the saline-alkali land, and improve the growth of crops (such as the seedling survival rate in the seedling stage, the soil bulk density in the budding stage, the chlorophyll content of leaves in the flowering stage, the plant height, the stem thickness, the leaf area, etc.), and increase the yield of crops.

[0028] According to the present invention, preferably, the pH of the bone gelatin production wastewater is 3.5-7. The method for detecting the pH value of bone-derived biological calcium is as follows: dilute the bone-derived biological calcium with clean water at a mass ratio of 1:250 between the bone-derived biological calcium and water, and then detect the pH value in accordance with NY / T1973-2021.

[0029] According to the present invention, preferably, the content of Ca in the waste liquid from bone gelatin production is 10000-28000 mg / L. The detection method of the content of Ca in the waste liquid from bone gelatin production is in accordance with GB / T 6436-2018.

[0030] According to the present invention, preferably, the Cl content in the waste liquid from bone gelatin production is 18000-50000 mg / L. The detection method of the Cl content in the waste liquid from bone gelatin production is referred to GB 11896-1989.

[0031] According to the present invention, preferably, the content of CODcr (chemical oxygen demand) in the waste liquid from the production of bone gelatin is 2000-10000 mg / L. The detection method of the CODcr content in the waste liquid from the production of bone gelatin refers to HJ 828-2017.

[0032] According to the present invention, preferably, the crude protein content in the waste liquid from the production of bone gelatin is 500-7000 mg / L. In the present invention, the crude protein may be at least one of protein, polypeptide, and oligopeptide. The method for detecting the crude protein content in the waste liquid from the production of bone gelatin refers to GB / T 6432-2018.

[0033] According to the present invention, preferably, the content of fat in the waste liquid from bone gelatin production is 0-90 mg / L. The method for detecting the fat content in the waste liquid from bone gelatin production refers to HJ 637-2018.

[0034] In some embodiments of the present invention, the bone gelatin production waste liquid also contains macro- and trace elements other than Ca and Cl, and the content of the macro- and trace elements other than Ca and Cl in the bone gelatin production waste liquid is 0-3000 mg / L; wherein the macro- and trace elements other than Ca and Cl are at least one of phosphorus (P), potassium (K), magnesium (Mg), sulfur (S), copper (Cu), iron (Fe), manganese (Mn), zinc (Zn), boron (B), and molybdenum (Mo). Wherein, in the waste liquid produced by bone gelatin, the content of magnesium is calculated as Mg, the content of sulfur is calculated as S, and the detection method of magnesium and sulfur content is NY / T 1117-2010; the content of copper is calculated as Cu, the content of iron is calculated as Fe, the content of manganese is calculated as Mn, the content of zinc is calculated as Zn, the content of molybdenum is calculated as Mo, and the detection method of copper, iron, manganese, zinc and molybdenum content is NY / T 1974-2010; the content of phosphorus is calculated as P2O5, and the detection method of phosphorus content is NY / T1977-2010; the content of potassium is calculated as K2O, and the detection method of potassium content is GB / T 17767.3-2010. Preferably, the content of macro- and micro-elements (P, K, Mg, S, Cu, Fe, Mn, Zn, B, Mo) other than Ca and Cl in the waste liquid produced by bone gelatin is 400-1800 mg / L.

[0035] According to the present invention, preferably, in step (1), the protein degradation method is a sodium hypochlorite decomposition method.

[0036] According to the present invention, preferably, the protein degradation conditions include: mixing sodium hypochlorite with the material to be protein degraded for 10-60 minutes at 10-50°C; wherein the amount of sodium hypochlorite is 0.1-1g, preferably 0.25-1g relative to 1L of the material to be protein degraded. When the amount of sodium hypochlorite is within the preferred range, the content of chelated peptide calcium and small molecule peptide in the prepared bone-derived biological calcium can be further increased.

[0037] In the present invention, the sodium hypochlorite can be used in the form of a solution. In some embodiments of the present invention, the mass concentration of the sodium hypochlorite solution is 5-13%, and the volume ratio of the material to be protein degraded to the sodium hypochlorite solution is 1000:2-7. The inventors have found that when the mass concentration of the sodium hypochlorite solution is 10-13%, and the volume ratio of the material to be protein degraded to the sodium hypochlorite solution is 1000:5-7, the chelated peptide calcium content and the small molecule peptide content in the prepared bone-derived biological calcium can be further increased.

[0038] According to the present invention, preferably, in step (1), the membrane used in the membrane separation is a separation membrane, and the molecular weight cutoff of the separation membrane is greater than or equal to 10000 Da.

[0039] According to the present invention, preferably, the first implementation of step (1) comprises the following steps:

[0040] (1-1) Protein degradation: protein degradation of the waste liquid from the production of bone gelatin is performed to obtain a protein degradation liquid;

[0041] (1-2) Removal of insoluble matter: coagulating and precipitating the protein degradation liquid to obtain a first solid and a first liquid;

[0042] (1-3) filtering the first solid to obtain sludge and permeate, and optionally, returning the permeate to step (1-2) for further coagulation and sedimentation;

[0043] (1-4) membrane separation: subjecting the first liquid obtained by coagulation and precipitation to membrane separation to obtain a clear liquid and a concentrated liquid; optionally, the concentrated liquid is returned to step (1-1);

[0044] (1-5) concentrating the clear liquid to obtain liquid bone-derived biological calcium;

[0045] (1-6) The liquid bone-derived biocalcium is dried and granulated to obtain solid bone-derived biocalcium.

[0046] According to the present invention, preferably, the second implementation of step (1) comprises the following steps:

[0047] (1-1) Removal of insoluble matter: coagulating and precipitating the waste liquid from the production of bone gelatin to obtain a first solid and a first liquid;

[0048] (1-2) filtering the first solid to obtain sludge and permeate, and optionally, returning the permeate to step (1-1) for further coagulation and sedimentation;

[0049] (1-3) protein degradation: performing protein degradation on the first liquid to obtain a protein degradation liquid;

[0050] (1-4) Membrane separation: The protein degradation solution is subjected to membrane separation to obtain a clear solution and a concentrated solution; optionally, the concentrated solution is returned to step (1-3);

[0051] (1-5) concentrating the clear liquid to obtain liquid bone-derived biological calcium;

[0052] (1-6) The liquid bone-derived biocalcium is dried and granulated to obtain solid bone-derived biocalcium.

[0053] According to the present invention, preferably, the coagulation and precipitation includes: adjusting the pH value of the material to be coagulated and precipitated, mixing a coagulant and a flocculant with the material to be coagulated and precipitated, and obtaining the material and precipitate after coagulation and precipitation. Wherein, the first liquid is used for subsequent treatment. Preferably, the pH value is 6-11, preferably 7-10. In the present invention, since the waste liquid from the production of bone gelatin used contains colloidal impurities and inorganic salt ions, and the pH is low, the water quality is acidic, and the chloride ion concentration is high, it is not conducive to coagulation and sedimentation of insoluble matter. Therefore, the present invention adjusts the pH of the water quality before the coagulation process, thereby solving the problem that high-chloride and acidic waste liquid cannot be coagulated and precipitated.

[0054] In some embodiments of the present invention, the coagulant is an inorganic coagulant, and more preferably at least one of aluminum sulfate, polyaluminum chloride, polyferric sulfate, ferric chloride, and ferrous sulfate.

[0055] In some embodiments of the present invention, the flocculant is polyacrylamide, more preferably at least one of anionic polyacrylamide, cationic polyacrylamide and nonionic polyacrylamide. In the present invention, the molecular weight of the polyacrylamide can be conventional in the art, for example, 6-25 million.

[0056] In the present invention, the pH adjustment may be performed using conventional reagents in the art, such as at least one of calcium hydroxide and sodium hydroxide, preferably calcium hydroxide.

[0057] In some embodiments of the present invention, relative to 1 L of the material to be coagulated and coprecipitated, the amount of the coagulant is 0.15-0.6 g, and the amount of the flocculant is 0.5-4.5 mg.

[0058] In some embodiments of the present invention, the coagulant and flocculant are used in the form of a solution. In some embodiments of the present invention, the mass concentration of the coagulant solution is 10-20%, and the mass concentration of the flocculant solution is 0.5-1.5‰. Wherein, based on the total weight of the precipitated material to be coagulated, the amount of the coagulant solution added is 1.5-3wt‰. In some embodiments of the present invention, based on the total weight of the precipitated material to be coagulated, the amount of the flocculant solution added is 1-3wt‰.

[0059] In some embodiments of the present invention, the concentration condition makes the TDS in the liquid bone-derived biological calcium 8-80wt%, preferably 15-80wt%. The TDS refers to the total amount of dissolved solids.

[0060] In some embodiments of the present invention, the concentration is membrane concentration and / or evaporation. Preferably, the membrane used in the membrane concentration is a concentration membrane, preferably a reverse osmosis membrane, and more preferably a RO reverse osmosis membrane. In the present invention, the conditions and methods of the evaporation can be selected by conventional techniques in the art and will not be described in detail herein.

[0061] In some preferred embodiments of the present invention, the concentration is: firstly performing membrane concentration, and then evaporating the concentrated material.

[0062] In some embodiments of the present invention, the concentration is to concentrate the liquid containing bone-derived biological calcium to TDS=8-15wt% by membrane concentration.

[0063] In some embodiments of the present invention, the concentration is to concentrate the liquid containing bone-derived biological calcium to TDS=15-80wt% by evaporation.

[0064] According to the present invention, preferably, in step (2), the gelatin production residue contains protein, wherein the protein content of the gelatin production residue is 15-18.7% by weight on a dry basis.

[0065] According to the present invention, preferably, in step (2), the enzymes used for enzymolysis include: acidic protease and alkaline protease. In the present invention, the enzymatic activity of the acidic protease can be 450,000-550,000 U / g, and the alkaline protease can be 750,000-850,000 U / g.

[0066] According to the present invention, preferably, in step (2), the amount of acidic protease used is 20,000-50,000 U, and the amount of alkaline protease used is 240,000-400,000 U per 100 g of gelatin production residue.

[0067] In the present invention, the acidic protease can be refined by deep liquid fermentation of the selected Aspergillus niger strain. The acidic protease can efficiently catalyze the protein hydrolysis reaction under low pH conditions, act on the amide bonds in the protein molecules, and hydrolyze the protein into polypeptides and amino acids. The acidic protease belongs to the hydrolase class, which can cut the peptide bonds composed of various amino acids, preferentially cut the peptide bonds between the two ends of which are aromatic or hydrophobic amino acid residues, and the products are small peptides and amino acids.

[0068] In the present invention, the alkaline protease may be a serine-type endoprotease.

[0069] According to the present invention, preferably, in step (2), the amount of acidic protease used is 0.04-0.1g (for example, 0.04g, 0.05g, 0.06g, 0.07g, 0.09g, 0.1g, and the range formed by any two of the above points) per 100g of gelatin production residue, and the amount of alkaline protease used is 0.3-0.5g (for example, 0.3g, 0.35g, 0.4g, 0.45g, 0.5g, and the range formed by any two of the above points).

[0070] According to the present invention, preferably, the implementation of step (2) comprises the following steps:

[0071] (2-1) Grinding gelatin production residues to a particle size of 2-6 mm;

[0072] (2-2) The gelatin production residue and water are mixed in a weight ratio of 1:3-5 to obtain a solution, the pH of the solution is adjusted to 2.5-3.5, the temperature is raised to 50-70° C., acidic protease is added to react for 1-3 hours, the pH is adjusted to 8.5-9.5 using calcium oxide, alkaline protease is added to react for 1-3 hours, and an enzymatic hydrolysis product is obtained.

[0073] According to the present invention, preferably, step (2) further comprises: (2-3) flocculating the enzymatic hydrolysis product, filtering it through cardboard to remove impurities, and spray drying it to obtain collagen oligopeptide.

[0074] According to the present invention, preferably, the flocculants used in the flocculation process include diatomaceous earth and polyacrylamide, wherein the amount of diatomaceous earth is 1-3 g, and the amount of polyacrylamide is 0.025-0.05 g per 100 g of the enzymatic hydrolysate.

[0075] The second aspect of the present invention provides a saline-alkali land improver prepared by the method described above;

[0076] Alternatively, a saline-alkali land improver comprises bone-derived biological calcium and collagen oligopeptide, wherein the weight ratio of the bone-derived biological calcium to the collagen oligopeptide is 1:0.002-0.05.

[0077] According to the present invention, preferably, the bone-derived biological calcium contains a calcium source (Ca) and water-soluble organic matter; wherein, on a dry basis, the mass ratio of the calcium source and the water-soluble organic matter in the bone-derived biological calcium in terms of calcium element is 7-26:1-8 (such as 0.875, 1, 1.25, 1.75, 2, 2.25, 2.75, 3, 3.25, 3.75, 4, 4.25, 4.75, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 26 or any value between the above values); wherein the calcium source exists in the form of free calcium and chelated peptide calcium.

[0078] In some embodiments of the present invention, the bone-derived biological calcium contains 7-26wt% of calcium source on a dry basis, for example, it can be 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt%, 10wt%, 10.5wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, any one of the values ​​or a value within the range composed of any two of the above values.

[0079] In some embodiments of the present invention, the bone-derived biological calcium contains 1-8 wt% of water-soluble organic matter on a dry basis, for example, it can be any one of 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, or a value within the range of any two of the above values.

[0080] In the present invention, the bone-derived bio-calcium refers to a product of bone-derived bio-calcium containing specific small molecule peptides and a calcium source. The bone-derived bio-calcium is a liquid or solid (granular or powdered) product prepared by coagulation precipitation, membrane separation, and protein degradation to obtain a bone-derived bio-calcium solution from the high-calcium, high-chlorine, and high-organic waste liquid discharged during the production of bone gelatin. The product is then concentrated, granulated, and other processes. The main nutrients in the product are derived from animal bones, and contain small molecule peptides. It is a biogenic substance with biological activity and is easier for crops to absorb and utilize. It should be understood that the bone-derived bio-calcium described in the present invention is a mixture, which, in addition to containing a calcium source, also contains chlorine, water-soluble organic matter, and other components. Preferably, the bone-derived bio-calcium described in the present invention also contains a large amount and trace elements required by plants in addition to Ca and Cl.

[0081] In the present invention, unless otherwise specified, the content of the calcium source refers to the sum of the content of free calcium and chelated peptide calcium in terms of calcium element (Ca). The content of the calcium source (in terms of calcium element) is determined by the GB / T 6436-2018 ethylenediaminetetraacetic acid disodium complexometric titration method.

[0082] In the present invention, the water-soluble organic matter refers to the general term for organic substances in bone-derived biological calcium that can be completely dissolved in water, and the detection method for the content of the water-soluble organic matter is NY / T1976-2010.

[0083] In some embodiments of the present invention, in terms of calcium element and dry basis, the free calcium content in the bone-derived biological calcium is 7-25wt%, and the chelated peptide calcium content is 0.5-4wt%.

[0084] In some embodiments of the present invention, the chelation rate is 2-50%. The inventors have found that the chelation rate of the chelated peptide calcium in the bone-derived biological calcium of the present invention is significantly better than that of other products, and the chelated peptide calcium can promote the absorption of calcium by plants and increase the yield of crops.

[0085] In the present invention, the detection method of the free calcium content (calculated as elemental calcium) is as follows: after preparing the free calcium solution with reference to Chapter 4, 2.2, Determination of Chelation Rate of the Master's Thesis of Shanxi Agricultural University "Enzymatic Preparation of Sheep Collagen Peptide and Study on Peptide Calcium Chelation", the free calcium content is detected using the GB / T 6436-2018 disodium ethylenediaminetetraacetic acid complexometric titration method.

[0086] In the present invention, the calculation method of the chelation rate and the detection method of the chelated peptide calcium content (calculated as calcium element) are: chelated peptide calcium content (calculated as calcium element) = calcium source content (calculated as calcium element) - free calcium content (calculated as calcium element); chelation rate = chelated peptide calcium content (calculated as calcium element) / calcium source content (calculated as calcium element) × 100%.

[0087] In some embodiments of the present invention, the bone-derived biological calcium further contains Cl, and the content of Cl in the bone-derived biological calcium is 11-45 wt % on a dry basis.

[0088] In some embodiments of the present invention, the bone-derived biological calcium further contains macro- and micro-elements other than Ca and Cl, and on a dry basis, the bone-derived biological calcium contains 0-3wt% of macro- and micro-elements other than Ca and Cl; wherein the macro- and micro-elements other than Ca and Cl are at least one of phosphorus (P), potassium (K), magnesium (Mg), sulfur (S), copper (Cu), iron (Fe), manganese (Mn), zinc (Zn), boron (B), and molybdenum (Mo). The test method for the content of each substance in the bone-derived biological calcium is as described in the first aspect, and will not be repeated here.

[0089] In the present invention, the macro- and micro-elements other than Ca and Cl are also elements necessary for plant growth. Therefore, when the bone-derived biological calcium is used as a fertilizer or fertilizer raw material, it can further supplement the nutritional elements of crops and promote the growth of crops.

[0090] In some embodiments of the present invention, the water-soluble organic matter contains small molecule peptides, and the bone-derived biological calcium contains 0-4 wt% of small molecule peptides on a dry basis.

[0091] In some embodiments of the present invention, the molecular weight of the small molecule peptide is less than 10000Da, preferably 500-5000Da, more preferably 500-3000Da, more preferably 700-2000Da, and more preferably 700-1500Da. The inventors have found that when the bone-derived biological calcium contains a small molecule peptide with the above molecular weight, the chelation rate of Ca and peptide in the production process of the bone-derived biological calcium product is improved, and the content of chelated peptide calcium in the bone-derived biological calcium is increased, while maintaining the effect of the peptide on increasing plant production.

[0092] In the present invention, the method for detecting the content and molecular weight of the small molecule peptide is as follows: the molecular weight of the small molecule peptide is detected by Appendix A (high performance size exclusion chromatography) of GB 31645-2018, and the content of the small molecule peptide is detected by the method for measuring protein content in GB / T 6432-2018.

[0093] In the present invention, the bone-derived biological calcium also contains inevitable impurities and crystal water.

[0094] In the present invention, the bone-derived biological calcium may be in the form of liquid and / or solid, that is, it may be liquid bone-derived biological calcium and / or solid bone-derived biological calcium.

[0095] In the present invention, the dosage form of the solid bone-derived biological calcium can be selected conventionally in the art, for example, it can be at least one of granules, powders and flakes.

[0096] In the present invention, the dry basis of bone-derived biological calcium refers to bone-derived biological calcium at a temperature of 50°C and a vacuum degree of 7×10 4 Pa, the amount obtained by drying in a vacuum oven (vacuum drying oven purchased from Shanghai Heng Scientific Instrument Co., Ltd., DZF series) until the mass remains unchanged for 120 min.

[0097] In some embodiments of the present invention, when the bone-derived biocalcium is solid bone-derived biocalcium, the dry basis refers to solid bone-derived biocalcium at a temperature of 50°C and a vacuum degree of 7×10 4 Pa, the amount when the mass does not change after drying for 120 minutes by vacuum oven method. It should be understood that the solid bone-derived biocalcium before drying is not in an absolutely dry state, but also contains a small amount of free water. The water content of the solid bone-derived biocalcium before drying refers to the content of free water in the solid bone-derived biocalcium before drying. The water content of the solid bone-derived biocalcium before drying = (the mass of the solid bone-derived biocalcium before drying - the mass of the solid bone-derived biocalcium after drying) / the mass of the solid bone-derived biocalcium before drying. Among them, the water content of the solid bone-derived biocalcium before drying is preferably 1-10%, and the dry basis content of the solid bone-derived biocalcium before drying is preferably (1-water content) × 100%.

[0098] In some embodiments of the present invention, the proportion of the protein hydrolysate with a relative molecular mass of collagen oligopeptides less than 500D is ≥50%, preferably 50-80%.

[0099] The third aspect of the present invention provides an improver prepared by the method described above or the use of the improver described above in improving saline-alkali land.

[0100] The fourth aspect of the present invention provides a method for improving saline-alkali land, the method comprising: applying the improver described in the third aspect to the saline-alkali land.

[0101] Preferably, the application method includes: spraying into the soil before spring ploughing, followed by hoeing, harrowing, ridge-forming and sowing, wherein the application amount of the saline-alkali land improver is 40-60 kg / mu.

[0102] The present invention will be described in detail below by way of examples. In the following examples,

[0103] Normal temperature is about 25℃.

[0104] The test methods for the contents of various substances in the waste liquid from bone gelatin production, bone-derived biological calcium, gelatin production residues, and collagen oligopeptides refer to the test methods in the above-mentioned instructions.

[0105] The manufacturer of acidic protease is Ningxia Xiasheng Industrial Group Co., Ltd.;

[0106] The alkaline protease manufacturer is Nanning Pangbo Bioengineering Co., Ltd.

[0107] Example 1

[0108] This example is used to illustrate the method for preparing a saline-alkali land improver.

[0109] (1) Preparation of bone-derived biological calcium:

[0110] The indicators of the bone gelatin production waste liquid used in this example are shown in Table 1.

[0111] Table 1

[0112]

[0113] (1-1) Protein degradation: A chemical method is used to degrade proteins using sodium hypochlorite. A first-class industrial sodium hypochlorite solution with a mass concentration of 13% is added to the gelatin waste liquid to be treated at 25°C, and the gelatin waste liquid: sodium hypochlorite solution (volume ratio) is 1000:6. The mixture is stirred for 30 minutes to fully mix the gelatin waste liquid and sodium hypochlorite, and the macromolecular proteins in the waste liquid are converted into small molecular peptides to obtain a protein degradation solution a.

[0114] (1-2) Coagulation and precipitation (i.e., removal of insoluble matter): the protein degradation liquid a is placed in a coagulation reactor, and the pH value is adjusted to 9 using a calcium hydroxide solution; a 10% by mass PAC (polyaluminium chloride) solution and a 1% by mass PAM (anionic polyacrylamide, molecular weight of 15 million) solution are added for coagulation and precipitation (based on the total weight of the protein degradation liquid, the amounts of PCA solution and PAM solution added are 1.5 wt‰ and 1 wt‰, respectively), to obtain a first solid a and a first liquid a.

[0115] (1-3) The first solid a obtained by coagulation and precipitation is dehydrated by a plate and frame filter press to obtain sludge a and permeate a. The sludge a can be used to produce solid fertilizer, and the permeate a is returned to the coagulation reactor to continue coagulation and precipitation.

[0116] (1-4) Membrane separation: The first liquid a obtained by coagulation and precipitation enters the membrane separation system and is separated by a separation membrane with a molecular weight cutoff of 10,000 Da (purchased from Tianjin Motian Membrane Technology Co., Ltd., model TUIE4230) to obtain a clear liquid a and a concentrated liquid a. The concentrated liquid a is returned to the protein degradation process.

[0117] (1-5) Concentration: The clear liquid a obtained by membrane separation is concentrated by a RO reverse osmosis membrane (purchased from Tianjin Motian Membrane Technology Co., Ltd., brand name UOT), and the obtained concentrated liquid enters the evaporation system for evaporation and is concentrated to a TDS of 55 wt% to obtain liquid bone-derived bio-calcium. The permeate of the RO reverse osmosis membrane and the condensed water in the evaporation process can be reused as reclaimed water in other processes of gelatin production.

[0118] (1-6) The liquid bone-derived bio-calcium is cooled and flaked (i.e., flaked and dried) by a cooling and flaking machine, and then granulated by a granulator to obtain granular bone-derived bio-calcium (i.e., solid bone-derived bio-calcium). Every 1L of bone gelatin production waste liquid can produce 63g of solid bone-derived bio-calcium.

[0119] The solid bone-derived bio-calcium was dried at a temperature of 50°C and a vacuum degree of 7×104Pa for 120 minutes until its mass did not change, and the components and contents thereof were tested, and the results are shown in Table 2. The water content of the solid bone-derived bio-calcium before drying was 7%.

[0120] Table 2

[0121]

[0122]

[0123] (2) Preparation of collagen oligopeptides:

[0124] The gelatin production residue indicators used in this example are shown in Table 3.

[0125] Table 3

[0126] project index Crude protein (dry basis) / (g / 100g) 18.7

[0127] (2-1) Raw material crushing: The residue remaining at the end of gelatin extraction is further ground into a size of 2-6 mm.

[0128] (2-2) Enzyme hydrolysis: add water according to the weight ratio of gelatin residue: water = 1:4, adjust the pH to 3.0±0.1 with phosphoric acid, raise the temperature to 60°C, add acid protease (the activity of acid protease is 500,000 U / g) and react for 2 hours, adjust the pH to 9.0±0.1 with calcium oxide, add alkaline protease (alkaline protease is 800,000 U / g) and react for 2 hours to obtain enzymatic hydrolysis products. The amount of acid protease used is 0.1 g and the amount of alkaline protease used is 0.3 g for every 100 g of gelatin residue.

[0129] (2-3) Separating the enzymatic hydrolysis product: The enzymatic hydrolysis product is flocculated using diatomaceous earth and polyacrylamide, filtered through a paperboard filter to remove impurities, and spray-dried to obtain collagen oligopeptides. The amount of diatomaceous earth used is 2 g, and the amount of polyacrylamide used is 0.025 g per 100 g of the enzymatic hydrolysis product.

[0130] The components and content test results of collagen oligopeptides are shown in Table 4.

[0131] Table 4

[0132]

[0133] (3) The bone-derived biocalcium obtained in step (1) and the collagen oligopeptide obtained in step (2) are mixed and homogenized for 20 minutes to obtain a saline-alkali land improver; wherein, on a dry basis, the weight ratio of the bone-derived biocalcium to the collagen oligopeptide is 1:0.002.

[0134] Example 2

[0135] (1) Preparation of bone-derived biological calcium:

[0136] The indicators of the bone gelatin production waste liquid used in this example are shown in Table 5.

[0137] Table 5

[0138]

[0139] (1-1) Coagulation and precipitation (i.e., removal of insoluble matter): The waste liquid from the production of bone gelatin is placed in a coagulation reactor, and the pH value is adjusted to 8 using a calcium hydroxide solution; 15% by mass PAC (polyaluminium chloride) solution and 1‰ PAM (anionic polyacrylamide, molecular weight of 15 million) solution are added for coagulation and precipitation (based on the total weight of the waste liquid from the production of gelatin, the amounts of PCA solution and PAM solution added are 1.5wt‰ and 1wt‰, respectively), to obtain a first solid b and a first liquid b.

[0140] (1-2) The first solid b obtained by coagulation and precipitation is dehydrated by a plate and frame filter press to obtain sludge b and permeate b. The sludge b can be used to produce solid fertilizer, and the permeate b is returned to the coagulation reactor to continue coagulation and precipitation.

[0141] (1-3) Protein degradation: The first liquid b obtained by coagulation and precipitation is added with 13% primary industrial sodium hypochlorite at a mass concentration of 13% at 20° C. The gelatin waste liquid: sodium hypochlorite (volume ratio) is 1000:6, and stirred for 30 minutes to fully mix the gelatin waste liquid and sodium hypochlorite, thereby converting the large molecular proteins in the waste liquid into small molecular peptides to obtain protein degradation liquid b.

[0142] (1-4) Membrane separation: The protein degradation solution b enters the membrane separation system and is separated by a separation membrane with a molecular weight cutoff of 10,000 Da (purchased from Tianjin Membrane Technology Co., Ltd., model TUIE4230) to obtain a clear solution b and a concentrated solution b. The concentrated solution b is returned to the protein degradation process for protein degradation.

[0143] (1-5) Concentration: The clear liquid b obtained by membrane separation enters the RO reverse osmosis membrane, and the concentrated liquid of the RO reverse osmosis membrane enters the evaporation system for evaporation, and is concentrated to a TDS of 35wt%, thereby obtaining liquid bone-derived bio-calcium. The water quality index of the permeate of the RO reverse osmosis membrane and the condensed water in the evaporation process can meet the industrial reuse water standard, and can be reused as reclaimed water in other processes of gelatin production.

[0144] (1-6) The liquid bone-derived bio-calcium is cooled and flaked (i.e., flaked and dried) by a cooling flaking machine, and then granulated by a granulator to obtain granular bone-derived bio-calcium (i.e., solid bone-derived bio-calcium B). 70 g of solid bone-derived bio-calcium B can be produced for every 1 L of bone gelatin production waste liquid.

[0145] The solid bone-derived biological calcium B was dried at a temperature of 50°C and a vacuum degree of 7×104Pa until the mass remained unchanged for 120 minutes, and the components and contents thereof were tested. The results are shown in Table 6. The water content of the solid bone-derived biological calcium B before drying was 6%.

[0146] Table 6

[0147]

[0148] (2) Preparation of collagen oligopeptides:

[0149] The gelatin production waste indicators used in this example are shown in Table 7.

[0150] Table 7

[0151] project index Crude protein (dry basis) / (g / 100g) 15

[0152] (2-1) Raw material crushing: The residue remaining at the end of gelatin extraction is further ground into a size of 2-6 mm.

[0153] (2-2) Enzyme hydrolysis: add water according to the weight ratio of gelatin residue: water = 1:4, adjust the pH to 3.0±0.1 with phosphoric acid, raise the temperature to 60°C, add acid protease (the activity of acid protease is 500,000 U / g) and react for 2 hours, adjust the pH to 9.0±0.1 with calcium oxide, add alkaline protease (alkaline protease is 800,000 U / g) and react for 2 hours to obtain enzymatic hydrolysis products. The amount of acid protease used is 0.04 g and the amount of alkaline protease used is 0.5 g for every 100 g of gelatin residue.

[0154] (2-3) Separating the enzymatic hydrolysis product: The enzymatic hydrolysis product is flocculated using diatomaceous earth and polyacrylamide, filtered through a paperboard filter to remove impurities, and spray-dried to obtain collagen oligopeptides. The amount of diatomaceous earth used is 2 g, and the amount of polyacrylamide used is 0.05 g per 100 g of the enzymatic hydrolysis product.

[0155] The components and content test results of collagen oligopeptides are shown in Table 8.

[0156] Table 8

[0157]

[0158] (3) The bone-derived biocalcium obtained in step (1) and the collagen oligopeptide obtained in step (2) are mixed and homogenized for 20 minutes to obtain a saline-alkali land improver, wherein the weight ratio of the bone-derived biocalcium to the collagen oligopeptide on a dry basis is 1:0.05.

[0159] Example 3

[0160] The method of Example 1 was followed, except that the weight ratio of bone-derived biological calcium to collagen oligopeptide was 1:0.01 on a dry basis.

[0161] Example 4

[0162] The method of Example 1 is followed, except that: (1-2) coagulation and precipitation (i.e., removal of insoluble matter): the pH value is adjusted to 6 using calcium hydroxide solution.

[0163] Example 5

[0164] The method of Example 1 was followed, except that the enzymatic hydrolysis process in step (2-2) was as follows: water was added at a ratio of gelatin residue to water = 1:4, and neutral protease was added to react for 2 hours to obtain an enzymatic hydrolysis product. The amount of neutral protease used was 0.3 g for every 100 g of gelatin residue.

[0165] The components and content test results of collagen oligopeptides are shown in Table 9.

[0166] Table 9

[0167]

[0168] Comparative Example 1

[0169] The method of Example 1 was followed, except that the collagen oligopeptide in Example 1 was replaced by an equal weight of soy protein peptide (wherein the crude protein content (on a dry basis) was 92.1 g / 100 g, the moisture content was 5.77 wt %, and the peptide segments with a molecular weight of less than 2000 D accounted for 91.9%).

[0170] Test Example 1

[0171] This test example is used to illustrate the buffering effect of the saline-alkali land improver prepared in the above examples and comparative examples on pH value.

[0172] (1) Test method for buffering effect on acid: Weigh 5g of the saline-alkali land improver prepared in the above examples and comparative examples and place them in a beaker, then add 100mL of water to the beaker and stir evenly, measure the pH value of the initial solution, then add 1mol / L hydrochloric acid to the solution several times, each time adding 20μL, stir evenly after each addition, and then measure the pH value of the solution. The blank control group is 100mL of water. The pH value test results are shown in Table 10.

[0173] Table 10

[0174] Sample name initial 20μL 40μL 60μL 80μL 100μL 120μL 140μL 160μL Blank control 7.3 3.82 3.45 3.21 3.06 2.94 2.82 2.74 2.66 Example 1 7.16 6.66 5.91 5.48 5.2 5 4.84 4.71 4.6 Example 2 7.12 6.46 5.78 5.38 5.13 4.95 4.79 4.67 4.56 Example 3 7.13 6.48 5.84 5.42 5.17 5 4.84 4.69 4.58 Example 4 7.13 6.12 5.47 5.11 4.86 4.68 4.52 4.39 4.27 Example 5 7.15 6.01 5.38 5.04 4.81 4.63 4.48 4.35 4.25 Comparative Example 1 7.00 5.95 5.18 4.95 4.73 4.48 4.30 4.20 4.09

[0175] (2) Alkali buffering test method: Weigh 5g of the saline-alkali land improver prepared in the above examples and comparative examples and place them in a beaker, then add 100mL of water to the beaker and stir evenly, measure the pH value of the initial solution, then add 40wt% NaOH to the solution several times, each time adding 20μL, stir evenly after each addition, and then measure the pH value of the solution. The blank control group is 100mL of water. The pH value test results are shown in Table 11.

[0176] Table 11

[0177] initial 20μL 40μL 60μL 80μL 100μL 120μL 140μL 160μL Blank control 7.29 11.03 11.35 11.53 11.65 11.73 11.81 11.88 11.92 Example 1 7.16 8.72 9.52 10.06 10.34 10.4 10.42 10.43 10.4 Example 2 7.14 8.67 9.4 9.97 10.29 10.38 10.41 10.42 10.44 Example 3 7.1 8.93 9.62 10.13 10.37 10.42 10.44 10.45 10.45 Example 4 7.11 9.15 10.07 10.47 10.58 10.6 10.64 10.68 10.71 Example 5 7.17 9.21 10.1 10.49 10.59 10.61 10.64 10.67 10.7 Comparative Example 1 7.11 9.36 10.18 10.62 10.83 10.95 10.99 11.04 11.07

[0178] As can be seen from Tables 10-11, the saline-alkali land improver of the present invention has a good buffering effect on pH value and has a good buffering capacity for acid. The pH value of the blank control changes significantly after adding a small amount of hydrochloric acid, while the pH change of the sample with the saline-alkali land improver of the present invention is small, and the buffering capacity for acid is good. As the amount of hydrochloric acid added increases, the pH decreases slowly. Similarly, the solution after adding the saline-alkali land improver of the present invention has a buffering capacity for alkali. The pH value of the blank control changes significantly after adding a small amount of NaOH, while the pH change of the sample with the saline-alkali land improver of the present invention is small, and the buffering capacity for alkalinity is good. As the amount of NaOH added increases, the pH decreases slowly. When crops grow in saline-alkali land, this characteristic can balance the pH value of the saline-alkali soil and gradually tend to neutral, thereby reducing the impact of extreme environment on crop growth.

[0179] Compared with Comparative Example 1, Examples 1-5 of the present invention have better acid-base buffering properties; further preferably, compared with Examples 4-5, Examples 1-3 of the present invention have better acid-base buffering properties.

[0180] Test Example 2

[0181] Test crops and varieties: Sunflower, Guaner 316

[0182] Test location: This test demonstration was carried out in the project area of ​​Bainao Baogongchan Village, Linhe District, Bayannur City, Inner Mongolia, under the autonomous region's saline-alkali land improvement demonstration project.

[0183] Trial time: May 20, 2020 - October 25, 2020.

[0184] Experimental design: The experiment was conducted in a large area of ​​35 mu, with each treatment plot covering an area of ​​5 mu.

[0185] Application method: Use a large sprayer to evenly spray the soil before turning the soil in spring, apply 50 kg of the saline-alkali land improver prepared in the above embodiments and comparative examples per mu, then turn the land, harrow the land, make ridges, and sow. The cultivation management measures and water and fertilizer management measures of the demonstration field are synchronized and consistent with those of the local field. Sunflowers were sown on May 25, 2020, with a theoretical number of 1,800 plants per mu. Among them, the blank control group was not applied with the saline-alkali land improver of the present invention.

[0186] The test results are shown in Table 12.

[0187] The method for determining the seedling survival rate is as follows: when the average growth height of sunflowers reaches 13-15 cm, 5 test points are randomly selected for each treatment group, and the test area of ​​each point is 3m 2 , determine the existing number of plants, and calculate the existing number of plants per mu in each treatment group. Seedling survival rate calculation formula: Seedling survival rate (%) = existing number of plants per mu ÷ number of sown plants per mu.

[0188] The method for determining soil bulk density is as follows: randomly select 3 test points in each treatment group to measure the soil bulk density during the budding period. The test method is: NY / T 1121.4-2006.

[0189] The method for determining the chlorophyll content is as follows: randomly select 3 test points for each treatment group during the flowering period, select 5 plants at each test point, and select the top 3 functional leaves of each plant to determine the chlorophyll content (SPAD value). The instrument used is the TYS-4N chlorophyll meter.

[0190] Before sunflower harvest, the yield of each treatment was measured by random sampling at five points in a "Z" shape to determine the number of plants per mu (the determination method was the same as that for the seedling survival rate). Five plants were selected at each point, and the number of grains on the plate and the 100-grain weight were measured. The theoretical yield of each treatment was calculated based on the measurement results.

[0191] Calculation formula: Yield per mu = full grain weight*1800*0.8*seedling survival rate / 1000.

[0192] Table 12

[0193]

[0194] As can be seen from Table 12, from the perspective of several main measured indicators during the growth period of sunflower, compared with the blank control group, after applying the saline-alkali land improver, the seedling survival rate of sunflower in the seedling stage was improved, and the difference was significant; the soil bulk density during the budding stage decreased significantly, reaching a significant level, and the smaller the soil bulk density, the more conducive it is for the soil to absorb nutrients; the chlorophyll content of sunflower leaves during the flowering period increased significantly. Compared with Comparative Example 1, the seedling survival rate, leaf chlorophyll content, plate grain number, 100-grain weight, plate full grain weight, and per-acre yield of Examples 1-5 of the present invention were all improved, and the soil bulk density during the budding stage was reduced. Preferably, Examples 1-3 of the present invention can obtain higher seedling survival rate, leaf chlorophyll content, 100-grain weight, plate full grain weight, per-acre yield, and lower soil bulk density.

[0195] Test Example 3

[0196] In 2021, experiments were conducted on the lightly and moderately salinized soils in Bainao Baogongchan Village, Linhe District, Bayannur City, Inner Mongolia.

[0197] The effect of the soil conditioner prepared by the present invention on improving the plant height, stem thickness and leaf area of ​​sunflower was studied. The application method of the saline-alkali land conditioner was the same as that of Test Example 2. The plant height, stem thickness and leaf area of ​​sunflower were tested at the seedling stage, inflorescence formation stage and flowering stage. Test method: (1) Plant height (cm): During the measurement, in each sunflower planting area, the plants on the edge of the row were removed, and 10 plants were randomly selected. The height from the cotyledon node to the top was measured with a steel ruler, and the data was recorded. (2) Stem diameter (mm): During the measurement, in each sunflower planting area, the plants on the edge of the row were removed, and 10 plants were randomly selected. The stem diameter in the middle of the sunflower was measured with a vernier caliper, and the data was recorded. (3) Leaf area (cm 2 ): In each sunflower planting area, remove the plants on the edge of the row and randomly select 5 plants. Measure 3 leaves from each plant. The leaves are selected from the 4th to 6th leaves from the flower disk. Use a tape measure to measure the length and width of the leaves and record the data. The leaf area calculation formula is: leaf area = 0.75 × length × width.

[0198] The blank control group was not treated with saline-alkali soil improver. The test results of plant height, stem diameter and leaf area of ​​sunflowers planted in mild (soil salt content of 0.1 wt%-0.2 wt%) saline-alkali land are shown in Table 13. The test results of plant height, stem diameter and leaf area of ​​sunflowers planted in moderate (soil salt content of 0.2 wt%-0.4 wt%) saline-alkali land are shown in Table 14.

[0199] Table 13

[0200]

[0201]

[0202] Note: Test date #1 is July 6, 2021, test date #2 is July 19, 2021, test date #3 is July 29, 2021, and test date #4 is August 10, 2021.

[0203] Table 14

[0204]

[0205] Note: Test date #1 is July 6, 2021, test date #2 is July 19, 2021, test date #3 is July 29, 2021, and test date #4 is August 10, 2021.

[0206] It can be seen from Tables 13-14 that the application of the saline-alkali land modifier of the present invention in light and moderate saline-alkali land can effectively increase the plant height, stem thickness and leaf area of ​​sunflowers. Compared with the blank control group and comparative example 1, in the tests of the same period, the sunflowers to which the saline-alkali land modifier of the present invention was applied all had higher plant height, stem thickness and leaf area. Preferably, the saline-alkali land modifier of Examples 1-3 of the present invention can more effectively increase plant height, stem thickness and leaf area. And usually, the stem thickness of sunflowers largely determines the lodging resistance of sunflowers, so the stem thickness has a greater impact on the yield of sunflowers.

[0207] Test Example 4

[0208] Sunflowers were planted for two consecutive years (2020 and 2021) according to the application methods of Test Example 2 and Test Example 3, and the improved soil (soil after sunflower harvest) was tested in 2021 and 2022, respectively. The test results are shown in Table 15. Test method: Soil organic matter was determined according to the potassium dichromate oxidation-external heating method of LY / T 1237-1999; total nitrogen was determined using NYT53-1987; pH value was determined according to NYT1377-2007; exchangeable sodium ions in the soil were determined according to LY / T 1248-1999; alkalinity was calculated according to LY / T 1249-1999.

[0209] Determination of total salt content in soil: prepare an extract with a water-to-soil ratio of 5:1, oscillate on a constant temperature oscillator for 30 minutes, filter, and then draw 25 ml of the solution into an evaporating dish of known weight, place it in a water bath and evaporate until it is dried to a residue. Use 15% hydrogen peroxide aqueous solution to oxidize the organic matter (add small amounts and multiple times along the side wall of the evaporating dish to prevent salt from splashing), and constantly rotate the evaporating dish to allow hydrogen peroxide to fully contact the residue until the residue is white. Then put the white residue in an oven and bake for two hours, take it out and put it in a dryer to cool for 30 minutes, weigh it with an analytical balance, and put it in the oven to continue baking for one hour, weigh it after cooling, and then put it in the oven to continue baking for half an hour and weigh it until the weight remains unchanged (the difference between the two weights is within 1 mg as constant weight). The salt calculation formula is as follows: Soil water-soluble salt Where: m1 is the mass of the drying residue (g), m2 is the mass of the drying soil sample (g).

[0210] In Table 15, CK-light and CK-medium represent blank control groups (without application of saline-alkali land amendment) of light and moderate saline-alkali land, respectively; modified-light and modified-medium represent treatment groups to which the amendment of Example 1 is applied to light and moderate saline-alkali land, respectively.

[0211] Table 15

[0212]

[0213] Compared with the control group, after soil improvement, the total nitrogen content and organic matter content of the test treatment were increased, and the exchangeable sodium, alkalinity and total salt content were improved, indicating that the saline-alkali land improver of the present invention has obvious effect in improving light and moderate saline-alkali land.

[0214] Test Example 5

[0215] Test crops: corn.

[0216] Test location: Dongshizhou Village, Tabusai Township, Tumote Left Banner, Hohhot City, Inner Mongolia Autonomous Region. Soil salinization degree: mainly mild salinity and moderate salinity, with severe salinity in some areas. The specific physical and chemical properties of the soil samples (mixed soil samples) collected on April 20, 2022 are shown in Table 16.

[0217] Experimental design: The demonstration area and the traditional area each have an area of ​​5 mu. The demonstration area is treated with the saline-alkali land improver of Example 1 according to the method of Test Example 2. The traditional area is a blank control group, and no saline-alkali land improver is used.

[0218] Table 16

[0219]

[0220] Among them, NYT53-1987 was used for total nitrogen determination. Organic matter was determined according to NY / T 1121.6-2006 Soil Testing Part 6: Determination of Soil Organic Matter. pH value was determined according to NY / T 1121.2-2006 Soil Testing Part 2: Determination of Soil pH. Water-soluble total salt was determined according to NY / T 1121.16-2006 Soil Testing Part 16: Determination of Total Water-soluble Salt in Soil. Available phosphorus was determined according to NY / T 1121.7-2014 Soil Testing Part 7: Determination of Available Phosphorus in Soil. Available potassium was determined according to NY / T 889-2004 Determination of Available Potassium and Slow-release Potassium Content in Soil. EC value was determined according to LY / T 1251-1999 Analysis of Water-soluble Salt in Forest Soils.

[0221] (1) On July 7, 2022, the plant height and chlorophyll content of corn in the demonstration area and the traditional area were tested, and the test method was the same as that of Test Example 2 and Test Example 3. The test results are shown in Table 17.

[0222] Table 17

[0223] deal with Plant heightcm Chlorophyll (SPAD value) Experimental Demonstration Area 112 35.12 Conventional Fertilization Area (CK) 70 24.50

[0224] As shown in Table 17, compared with the traditional area, the plant height of the demonstration area increased by 42 cm and the chlorophyll content increased by 10.62. Therefore, compared with the blank control group, the saline-alkali land improver prepared by the present invention has obvious effects on promoting the growth of corn plant height and chlorophyll content.

[0225] (2) After corn harvest, soil samples were collected from the 0-20 cm, 20-40 cm, and 40-60 cm soil cultivation layers in the demonstration area and the traditional area on September 27, 2022, and the physical and chemical properties of the soil samples (mixed soil samples) were analyzed. The analysis results are shown in Table 18.

[0226] Table 18

[0227]

[0228]

[0229] It can be seen from Table 18 that compared with the traditional area, the organic matter in the soil tillage layer (0-20cm) of the demonstration area increased by an average of 0.7%, an increase of 32.6%; the soil pH decreased by an average of 0.59, a decrease of 6.2%; and the water-soluble total salt decreased by 0.84g / kg, a decrease of 34.1%.

[0230] (3) After corn harvest, soil samples were collected from the 0-20 cm, 20-40 cm, and 40-60 cm soil tillage layers of the heavily saline-alkali land in the demonstration area and the traditional area on September 27, 2022, and the physical and chemical properties of the soil samples were analyzed. The analysis results are shown in Table 19.

[0231] Table 19

[0232]

[0233] It can be seen from Table 19 that compared with the traditional area of ​​severe saline-alkali land, the organic matter in the soil tillage layer (0-20cm) of the severe saline-alkali land demonstration area increased by an average of 0.79%, an increase of 40.1%; the soil pH did not change; the water-soluble total salt decreased by 0.974g / kg, a decrease of 32.0%.

[0234] (4) Before corn matures and is harvested (September 27), the yield in the heavily saline-alkali area is measured using the “cutting method”, i.e., the corn cutting area is 6m 2 (10m*0.6m), three representative sample points were taken for each treatment, threshed and dried indoors (corn moisture content below 14%), weighed, and the yield per mu was calculated. The yield measurement results are shown in Table 20.

[0235] Table 20

[0236] Yield per mu (kg) Increased yield per mu (kg) Increase / decrease (%) Demonstration Area 528.9 156.3 41.9 Traditional District (CK) 372.6 －－ －－

[0237] It can be seen from Table 20 that under the same soil conditions (severe salinity), compared with the traditional area, the per mu yield in the demonstration area increased by 156.3 kg, and the increase in yield reached 41.9%.

[0238] The income is calculated based on the per-acre yield of severely saline-alkali land, and the results are shown in Table 21.

[0239] Table 21

[0240]

[0241] It can be seen from Table 21 that under the same soil conditions (severe salinity), the demonstration area can bring higher economic benefits than the traditional area, thereby promoting farmers' increased production and income.

[0242] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a saline-alkali land improving agent, characterized in that: The method comprises the following steps: (1) subjecting the waste liquid from bone gelatin production to protein degradation and membrane separation to obtain bone-derived biological calcium; (2) enzymatically hydrolyzing the gelatin production residue to obtain collagen oligopeptides; (3) The bone-derived biocalcium obtained in step (1) and the collagen oligopeptide obtained in step (2) are mixed to obtain a saline-alkali land improver, wherein the weight ratio of the bone-derived biocalcium to the collagen oligopeptide, calculated on a dry basis, is 1:0.002-0.

05.

2. The method according to claim 1, wherein The pH of the bone gelatin production wastewater is 3.5-7, And / or, the Ca content in the bone gelatin production wastewater is 10000-28000 mg / L; And / or, the Cl content in the bone gelatin production wastewater is 18000-50000 mg / L; And / or, the CODcr content in the bone gelatin production wastewater is 2000-10000 mg / L; And / or, the crude protein content in the bone gelatin production waste liquid is 500-7000 mg / L; And / or, the fat content in the bone gelatin production waste liquid is 0-90 mg / L.

3. The method according to claim 1, wherein In step (1), the protein degradation method is sodium hypochlorite decomposition method; Preferably, the protein degradation conditions include: mixing sodium hypochlorite with the material to be protein degraded at 10-50° C. for 10-60 min; wherein the amount of sodium hypochlorite used is 0.1-1 g, preferably 0.25-1 g, relative to 1 L of the material to be protein degraded.

4. The method according to claim 1, wherein In step (1), the membrane used in the membrane separation is a separation membrane, and the molecular weight cutoff of the separation membrane is greater than or equal to 10000Da.

5. The method according to claim 1, wherein: In step (2), the gelatin production residue contains protein, wherein the protein content of the gelatin production residue is 15-18.7% by weight on a dry basis.

6. The method according to claim 1, wherein: In step (2), the enzymes used for enzymolysis include: acidic protease and alkaline protease.

7. The method according to claim 1, wherein: In step (2), the amount of acidic protease used is 20,000-50,000 U, and the amount of alkaline protease used is 240,000-400,000 U per 100 g of gelatin production residue.

8. The saline-alkali land improver prepared by the method according to any one of claims 1 to 7; Alternatively, a saline-alkali land improver, characterized in that The improver comprises bone-derived biological calcium and collagen oligopeptide, wherein, on a dry basis, the weight ratio of the bone-derived biological calcium to the collagen oligopeptide is 1:0.002-0.

05.

9. Use of the improver prepared by the method described in claims 1 to 7 or the improver described in claim 8 in improving saline-alkali land.

10. A method for improving saline-alkali land, characterized in that: The method comprises: applying the ameliorator according to claim 8 to saline-alkali land; Preferably, the application method includes: spraying the improver into the soil before spring ploughing, and then plowing, harrowing, ridge-forming, and sowing; wherein the application amount of the saline-alkali land improver is 40-60 kg / mu.

Images