A phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil, its preparation method and application

Abstract

This invention provides a phosphorus-solubilizing agent for use as a substitute for phosphate fertilizers in soil, its preparation method, and its application. The phosphorus-solubilizing agent of this invention is prepared from the following raw materials in parts by weight: 1-15 parts of a composite initiator, 1-10 parts of an organic acid containing carbon-carbon double bonds, 1-10 parts of an unsaturated organic salt containing sulfonic acid, 0.5-5 parts of an organic ester containing carbon-carbon double bonds, and 1-80 parts of water as a solvent. The preparation method of this phosphorus-solubilizing agent is simple, efficient, and low-cost. Furthermore, it eliminates the need for additional inert protective gas injection during industrial production, reducing potential hazards and further lowering costs. This phosphorus-solubilizing agent is green, safe, and environmentally friendly. Its carboxyl and sulfonic acid groups can degrade and prevent the accumulation of insoluble phosphate salts naturally present in the soil, thereby increasing the available phosphorus content in the soil and improving crop yields. This provides a new direction for the future development of phosphorus additives and fertilizer substitutes in agriculture.

Description

Technical Field

[0001] This invention relates to a phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, its preparation method and application, belonging to the field of agricultural application technology. Background Technology

[0002] China, as a traditional agricultural powerhouse, possesses abundant soil resources. However, data from the Third National Soil Census shows that the phosphorus content in Chinese soils is only 0.44-0.85 g / kg. -1 Within the specified range, the available phosphorus content in the soil (referring to the total amount of phosphorus in the soil that can be absorbed and utilized by plants) is insufficient. Even in soils with high phosphorus content, there is not enough available phosphorus to meet the needs of normal crop growth in the current season. Due to the presence of a large amount of free calcium carbonate in the soil, most of the phosphorus becomes insoluble calcium phosphate salts, and the amount of available phosphorus that can be absorbed and utilized by crops is very low. However, phosphorus is an essential element for the formation of cell nucleoproteins and lecithin in crops. It can accelerate cell division, promote root growth, increase crop branching, shorten the time for flower bud differentiation, advance maturity, and improve fruit quality.

[0003] To promote vigorous growth and increase crop yield, phosphate fertilizers are often applied during the crop growth stage. Commonly used phosphate fertilizers include potassium dihydrogen phosphate and calcium magnesium phosphate. Crops are grown and harvested quarterly, requiring large amounts of phosphate fertilizer that are applied multiple times. Prolonged use of phosphate fertilizers has two main negative effects: First, phosphate fertilizers easily antagonize micronutrients in the soil, such as zinc, molybdenum, silicon, and iron, causing physiological diseases in crops due to micronutrient deficiencies. Second, excessive phosphate fertilizers are not easily lost from the soil, and crop absorption and utilization are limited, leading to soil acidification and compaction. Furthermore, the current phosphate fertilizer production process in my country mainly uses sulfuric acid to treat phosphate rock, generating large amounts of phosphogypsum. The amount of phosphogypsum that can be utilized is limited, and its accumulation and storage cause serious environmental pollution.

[0004] To address the issues of insufficient available phosphorus content in soil and excessive application of phosphate fertilizers, phosphorus-solubilizing agents can be used to degrade insoluble phosphate salts naturally present in the soil through chelation and distortion. However, phosphorus-solubilizing agents such as molybdates and tungstates are generally used in the chemical industry; applying them directly to soil may cause problems such as residues and environmental pollution.

[0005] In summary, from the perspective of crop nutrition and fertilization, it is of great significance to explore a green, low-cost, and stable phosphorus solubilizing agent that can degrade insoluble phosphate salts in soil. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a phosphorus-solubilizing agent for use as a substitute for phosphate fertilizers in soil, along with its preparation method and application. The preparation method of this phosphorus-solubilizing agent is simple, efficient, and low-cost. Furthermore, it eliminates the need for additional inert protective gas injection during industrial production, reducing potential hazards and further lowering costs. This phosphorus-solubilizing agent is green, safe, and environmentally friendly. Its carboxyl and sulfonic acid groups can degrade and prevent the accumulation of insoluble phosphate salts naturally present in the soil, thereby increasing the available phosphorus content in the soil and improving crop yields. This provides a new direction for the future development of phosphorus additives and fertilizer substitutes in agriculture.

[0007] The technical solution of the present invention is as follows:

[0008] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer is prepared from the following raw materials in parts by weight:

[0009] 1-15 parts of a complex initiator, 1-10 parts of an organic acid containing carbon-carbon double bonds, 1-10 parts of an unsaturated organic salt containing sulfonic acid, 0.5-5 parts of an organic ester containing carbon-carbon double bonds, and 1-80 parts of water as a solvent.

[0010] According to a preferred embodiment of the present invention, the phosphorus-solubilizing agent applied to soil as a substitute for phosphate fertilizer is prepared from the following raw materials in parts by weight:

[0011] 10-11 parts of a complex initiator, 3-7 parts of an organic acid containing carbon-carbon double bonds, 5-7 parts of an unsaturated organic salt containing sulfonic acid, 1-2 parts of an organic ester containing carbon-carbon double bonds, and 5-60 parts of water as solvent.

[0012] Preferably, the phosphorus-solubilizing agent applied to soil as a substitute for phosphate fertilizer is prepared from the following raw materials in parts by weight:

[0013] 10-11 parts of a complex initiator, 5-6 parts of an organic acid containing carbon-carbon double bonds, 6-7 parts of an unsaturated organic salt containing sulfonic acid, 1-2 parts of an organic ester containing carbon-carbon double bonds, and 5-15 parts of water as a solvent.

[0014] More preferably, the phosphorus-solubilizing agent applied to soil as a substitute for phosphate fertilizer is prepared from the following raw materials in parts by weight:

[0015] The composition includes 10.032 parts of a composite initiator, 5.8642 parts of an organic acid containing carbon-carbon double bonds, 6.045 parts of an unsaturated organic salt containing sulfonic acid, 1.0738 parts of an organic ester containing carbon-carbon double bonds, and 10 parts of water as a solvent.

[0016] According to a preferred embodiment of the present invention, the composite initiator is a combination of two or more selected from oxysulfate, a 20-30% hydrogen peroxide aqueous solution, sodium persulfate, ammonium persulfate, or ammonium bicarbonate. Preferably, the composite initiator is a combination of oxysulfate and a 20-30% hydrogen peroxide aqueous solution; the mass ratio of oxysulfate to the 20-30% hydrogen peroxide aqueous solution is 0.01-0.05:10, preferably 0.032:10.

[0017] According to a preferred embodiment of the present invention, the organic acid containing a carbon-carbon double bond is one or a combination of two or more of maleic anhydride, itaconic acid, acrylic acid, methacrylic acid, ethylacrylic acid, fumaric acid, or cis-methylbutenic acid. Preferably, the organic acid containing a carbon-carbon double bond is a combination of maleic anhydride and itaconic acid; the mass ratio of maleic anhydride to itaconic acid is 1:0.9-3, preferably 1:2.

[0018] According to a preferred embodiment of the present invention, the sulfonic acid-containing unsaturated organic salt is one or a combination of sodium methpropylene sulfonate or sodium allyl sulfonate. Preferably, the sulfonic acid-containing unsaturated organic salt is a combination of sodium methpropylene sulfonate and sodium allyl sulfonate; the mass ratio of sodium methpropylene sulfonate to sodium allyl sulfonate is 1-2:1, preferably 1.1:1.

[0019] According to a preferred embodiment of the present invention, the organic ester containing a carbon-carbon double bond is one of hydroxyethyl methacrylate, vinyl acetate, or 2-hydroxyethyl acrylate.

[0020] According to a preferred embodiment of the present invention, the relative molecular mass of the phosphorus-solubilizing agent is 2000-4000.

[0021] The above-mentioned method for preparing a phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil includes the following steps:

[0022] In water as a solvent, under the action of a composite initiator, organic acids containing carbon-carbon double bonds, unsaturated organic salts containing sulfonic acids, and organic esters containing carbon-carbon double bonds are polymerized to prepare a phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil.

[0023] According to a preferred embodiment of the present invention, the polymerization reaction temperature is 80-100℃, the polymerization reaction time is 3-5h, and the heating rate is 4-6℃ / min; preferably, the polymerization reaction temperature is 90℃.

[0024] According to a preferred embodiment of the present invention, the preparation method of a phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil includes the following steps:

[0025] Water is heated at a rate of 4-6℃ / min. Under stirring conditions, organic acids containing carbon-carbon double bonds, unsaturated organic salts containing sulfonic acids, and organic esters containing carbon-carbon double bonds are added to the water and stirred until completely dispersed. When the temperature reaches 85℃, a composite initiator is added, and then the mixture is stirred to obtain a phosphorus solubilizing agent that can be used to replace phosphate fertilizer in soil.

[0026] The aforementioned phosphorus-solubilizing agents, used in soil as a substitute for phosphate fertilizers, are applied to the soil to degrade phosphates and increase the available phosphorus content, thereby improving crop yield and quality.

[0027] The technical features and beneficial effects of this invention are as follows:

[0028] 1. The preparation method of this invention is simple, efficient, and low in cost. This invention adds an initiator to the synthesis system of organic acids containing carbon-carbon double bonds, unsaturated organic salts containing sulfonic acids, and organic esters containing carbon-carbon double bonds to improve the reaction polymerization efficiency. At the same time, the initiator generates a protective gas to isolate the oxygen environment during the polymerization reaction, thereby eliminating the need to introduce an additional inert protective gas, avoiding the risks caused by using a large amount of inert protective gas in large-scale industrial production, and further reducing production costs.

[0029] 2. This invention chemically synthesizes a polymeric phosphorus-solubilizing agent, broadening the types of phosphorus-solubilizing agents and the varieties that can be used in agricultural production, thereby improving the quality and yield of crops and reducing the disadvantages of existing phosphorus-solubilizing agents, such as high volatility, residues in agricultural products, and environmental pollution. The phosphorus-solubilizing agent prepared by this invention is phosphorus-free yet can degrade phosphate salts in the soil; it has good stability, low volatility, and long storage time; it has good water solubility and requires a small dosage; it leaves little residue in agricultural products, has low toxicity, and causes minimal environmental pollution.

[0030] 3. Traditional phosphate fertilizers, after being applied to the soil, hydrolyze to form a saturated solution or undergo microbial acid hydrolysis to provide available phosphorus. This invention provides a phosphorus-solubilizing agent that can be applied to soil as a substitute for phosphate fertilizers. This invention's phosphorus-solubilizing agent for soil application introduces a high proportion of carboxyl groups into the copolymer chemical structure by selecting specific types of organic acids containing carbon-carbon double bonds, thereby enhancing the chelating performance of the phosphorus-solubilizing agent. Furthermore, the unsaturated organic salts containing sulfonic acid in the raw materials prevent the aggregation of calcium phosphate crystal nuclei in the soil, thus improving its effect on degrading phosphate salts in the soil. The carboxyl groups and sulfonic acid groups in this invention's phosphorus-solubilizing agent can degrade and prevent the aggregation of insoluble phosphate salts already present in the soil, thereby increasing the available phosphorus content in the soil and improving crop yields. This provides a new direction for the future development of phosphorus additives and fertilizer substitutes in the agricultural field.

[0031] 4. The superior phosphorus-releasing effect of this invention can only be achieved by combining specific types of composite initiators, organic acids containing carbon-carbon double bonds, unsaturated organic salts containing sulfonic acids, and organic esters containing carbon-carbon double bonds in specific ratios. If the types and ratios of raw materials are not suitable, or if one or more components are omitted, the phosphorus-releasing effect will be reduced. Attached Figure Description

[0032] Figure 1 This is a picture of an actual sample of the phosphorus-solubilizing agent prepared in Example 1 of the present invention, which can be used to replace phosphate fertilizer in soil.

[0033] Figure 2 Comparison of the phosphorus-solubilizing agent prepared in Example 1 of the present invention before and after phosphorus-solubilizing (left) and before phosphorus-solubilizing (right). Detailed Implementation

[0034] The present invention will be further described below with reference to specific embodiments, but is not limited thereto.

[0035] In addition, the experimental methods described in the following embodiments are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0036] Example 1

[0037] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer is prepared from the following raw materials in parts by weight:

[0038] The complex initiator is 0.032g of sulfuric acid oxyvanadium, 10g of 30% hydrogen peroxide aqueous solution, 1.9612g of maleic anhydride and 3.903g of itaconic acid (organic acids containing carbon-carbon double bonds), 3.163g of sodium methpropylene sulfonate and 2.882g of sodium allyl sulfonate (unsaturated organic salts containing sulfonic acids), 1.0738g of hydroxyethyl methacrylate (organic ester containing carbon-carbon double bonds), and 10g of deionized water as solvent.

[0039] The preparation method of the above-mentioned phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil includes the following steps:

[0040] Step 1: Add deionized water to the three-necked flask and adjust the heating rate to 5℃ / min to heat the water.

[0041] Step 2: Under stirring conditions, maleic anhydride, itaconic acid, sodium methacrylate, sodium allyl sulfonate, and hydroxyethyl methacrylate are added sequentially to the system from Step 1, and stirred until the monomers are completely dispersed.

[0042] Step 3: When the temperature reaches 85℃, add sulfuric acid oxyvanadium, stir for 60 seconds, and then add a 30% (w / w) aqueous solution of hydrogen peroxide dropwise over 30 minutes. Then, stir the reaction at 90℃ for 4 hours, and finally cool and collect the product. No additional inert gas is required for this reaction.

[0043] The phosphorus-solubilizing agent obtained in this embodiment, which is used to replace phosphate fertilizer in soil, has a relative molecular mass of 3068 as determined by the viscosity method.

[0044] The appearance of the product prepared in this embodiment is as follows: Figure 1 As shown, the resulting product is a viscous liquid.

[0045] Example 2

[0046] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that itaconic acid is 2.602g; the composition of other raw materials is the same as in Example 1.

[0047] The preparation method of the above-mentioned phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil is as described in Example 1.

[0048] Example 3

[0049] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that itaconic acid is 1.952g; the composition of other raw materials is the same as in Example 1.

[0050] The preparation method of the above-mentioned phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil is as described in Example 1.

[0051] Example 4

[0052] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that the maleic anhydride content is 2.942 g; the composition of other raw materials is the same as in Example 1.

[0053] The preparation method of the above-mentioned phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil is as described in Example 1.

[0054] Example 5

[0055] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that the maleic anhydride content is 1.471 g; the composition of other raw materials is the same as in Example 1.

[0056] The preparation method of the above-mentioned phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil is as described in Example 1.

[0057] Example 6

[0058] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that the initiator contains 0.016g of oxysulfate; the composition of other raw materials is the same as in Example 1.

[0059] The preparation method of the above-mentioned phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil is as described in Example 1.

[0060] Example 7

[0061] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that the initiator contains 0.048g of oxysulfate; the composition of other raw materials is the same as in Example 1.

[0062] The preparation method of the above-mentioned phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil is as described in Example 1.

[0063] Example 8

[0064] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that the amount of deionized water is 60g; the composition of other raw materials is the same as in Example 1.

[0065] The preparation method of the above-mentioned phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil is as described in Example 1.

[0066] Example 9

[0067] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that hydroxyethyl methacrylate is replaced with vinyl acetate; the composition of other raw materials is the same as in Example 1.

[0068] The preparation method of the phosphorus-solubilizing agent used as a substitute for phosphate fertilizer in soil is as described in Example 1, with the same differences.

[0069] Example 10

[0070] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that hydroxyethyl methacrylate is replaced with 2-hydroxyethyl acrylate; the other raw material composition is the same as in Example 1.

[0071] The preparation method of the phosphorus-solubilizing agent used as a substitute for phosphate fertilizer in soil is as described in Example 1, with the same differences.

[0072] Example 11

[0073] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that itaconic acid is replaced with acrylic acid; the other raw material composition is the same as in Example 1.

[0074] The preparation method of the phosphorus-solubilizing agent used as a substitute for phosphate fertilizer in soil is as described in Example 1, with the same differences.

[0075] Example 12

[0076] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that sodium persulfate is replaced with oxysulfate; the composition of other raw materials is the same as in Example 1.

[0077] The preparation method of the phosphorus-solubilizing agent used as a substitute for phosphate fertilizer in soil is as described in Example 1, with the same differences.

[0078] Example 13

[0079] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that sodium methyl propylene sulfonate is not added; the composition of other raw materials is the same as in Example 1.

[0080] The preparation method of the phosphorus-solubilizing agent used as a substitute for phosphate fertilizer in soil is as described in Example 1, with the same differences.

[0081] Example 14

[0082] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that sodium allyl sulfonate is not added; the other raw material composition is the same as in Example 1.

[0083] The preparation method of the phosphorus-solubilizing agent used as a substitute for phosphate fertilizer in soil is as described in Example 1, with the same differences.

[0084] Example 15

[0085] A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, as described in Example 1, except that maleic anhydride is not added; the composition of other raw materials is the same as in Example 1.

[0086] The preparation method of the phosphorus-solubilizing agent used as a substitute for phosphate fertilizer in soil is as described in Example 1, with the same differences.

[0087] Comparative Example 1

[0088] A phosphorus solubilizing agent, as described in Example 1, except that hydroxyethyl methacrylate is not added; the other raw material composition is the same as in Example 1.

[0089] The preparation method of the above-mentioned phosphorus solubilizing agent is the same as that described in Example 1, except that it is the same as above.

[0090] In this comparative example, because hydroxyethyl methacrylate was not present, the reaction product showed stratification.

[0091] Comparative Example 2

[0092] A phosphorus solubilizing agent, as described in Example 1, except that the composite initiator is replaced with 6g of ammonium persulfate; the composition of other raw materials is the same as in Example 1.

[0093] The preparation method of the above-mentioned phosphorus solubilizing agent is the same as that described in Example 1, except that it is the same as above.

[0094] In this comparative example, due to the lack of protective gas, the initiator used failed to initiate the reaction, and the target product was ultimately not obtained.

[0095] Comparative Example 3

[0096] A phosphorus solubilizing agent, as described in Example 1, except that the composite initiator is replaced with 6g of sodium persulfate; the other raw material composition is the same as in Example 1.

[0097] The preparation method of the above-mentioned phosphorus solubilizing agent is the same as that described in Example 1, except that it is the same as above.

[0098] In this comparative example, due to the lack of protective gas, the initiator used failed to initiate the reaction, and the target product was ultimately not obtained.

[0099] Experimental Example 1

[0100] Phosphorus solubilization experiment

[0101] Preparation of solutions: Dissolve 25g of calcium nitrate in 100mL of water to prepare calcium nitrate solution; dissolve 6.8g of potassium dihydrogen phosphate and 1.9g of sodium hydroxide in 100mL of water to prepare orthophosphate solution.

[0102] Step 1: Add 200mL of water to a beaker, then add 5mL of calcium nitrate solution and 5mL of orthophosphate solution to the beaker in sequence, and stir with a glass rod to form a cloudy phosphate solution.

[0103] Step 2: Add the phosphate solubilizing agent drop by drop to the beaker, stirring continuously with a glass rod until the solution becomes clear and start timing.

[0104] Table 1. Phosphorus dissolution effect

[0105]

[0106]

[0107] Note: Under stirring conditions, the phosphate-solubilizing agent was titrated into the phosphate solution at a constant rate using a pipette until the phosphate solution became clear. The amount of phosphate-solubilizing agent used was recorded. The time from the start of titration to the time when the phosphate solution became clear is the phosphate-solubilizing time. Stability is the state of the phosphate-solubilizing agent after standing at room temperature for 72 hours.

[0108] As can be seen from the test results in Table 1, the phosphorus-solubilizing agent obtained by the method of the present invention, which can be applied to soil as a substitute for phosphate fertilizer, has advantages such as excellent phosphorus-solubilizing effect, low dosage, and good stability. The phosphorus-solubilizing agent obtained in Example 1 of the present invention has the best dosage and phosphorus-solubilizing time, and compared with the phosphorus-solubilizing agent prepared without the introduction of organic esters into the raw materials, it has excellent stability. Figure 2The image shows a comparison of the phosphorus-solubilizing agent prepared in Example 1 of this invention before (left) and after (right) phosphorus-solubilizing. It can be seen that the phosphorus-solubilizing agent of this invention successfully achieves phosphorus-solubilizing.

Claims

1. A phosphorus-solubilizing agent for use in soil as a substitute for phosphate fertilizer, characterized in that, It is prepared from the following parts by mass of raw materials: 1-15 parts of a complex initiator, 1-10 parts of an organic acid containing carbon-carbon double bonds, 1-10 parts of an unsaturated organic salt containing sulfonic acid, 0.5-5 parts of an organic ester containing carbon-carbon double bonds, and 5-15 parts of water as a solvent. The composite initiator is a combination of sulfuric acid sulfoxide and a 20-30% (w / w) aqueous solution of hydrogen peroxide; the organic acid containing carbon-carbon double bonds is a combination of maleic anhydride and itaconic acid; the organic ester containing carbon-carbon double bonds is hydroxyethyl methacrylate; and the unsaturated organic salt containing sulfonic acid is one or a combination of sodium methacrylate or sodium allyl sulfonate.

2. The phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil according to claim 1, characterized in that, The phosphorus-solubilizing agent applied to soil as a substitute for phosphate fertilizer is prepared from the following raw materials in parts by weight: 10-11 parts of a complex initiator, 3-7 parts of an organic acid containing carbon-carbon double bonds, 5-7 parts of an unsaturated organic salt containing sulfonic acid, 1-2 parts of an organic ester containing carbon-carbon double bonds, and 5-15 parts of water as a solvent.

3. The phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil according to claim 2, characterized in that, The phosphorus-solubilizing agent applied to soil as a substitute for phosphate fertilizer is prepared from the following raw materials in parts by weight: 10-11 parts of a complex initiator, 5-6 parts of an organic acid containing carbon-carbon double bonds, 6-7 parts of an unsaturated organic salt containing sulfonic acid, 1-2 parts of an organic ester containing carbon-carbon double bonds, and 5-15 parts of water as a solvent.

4. The phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil according to claim 1, characterized in that, The mass ratio of sulfuric acid oxyvanadium and hydrogen peroxide aqueous solution with a mass concentration of 20-30% is 0.01-0.05:

10.

5. The phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil according to claim 1, characterized in that, The mass ratio of maleic anhydride to itaconic acid is 1:0.9-3.

6. The phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil according to claim 1, characterized in that, The unsaturated organic salt containing sulfonic acid is a combination of sodium methpropylene sulfonate and sodium allyl sulfonate; the mass ratio of sodium methpropylene sulfonate to sodium allyl sulfonate is 1-2:

1.

7. The phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil according to claim 1, characterized in that, The relative molecular mass of the phosphorus-solubilizing agent is 2000-4000.

8. A method for preparing a phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil, as described in any one of claims 1-7, comprising the steps of: In water, under the action of a composite initiator, organic acids containing carbon-carbon double bonds, unsaturated organic salts containing sulfonic acids, and organic esters containing carbon-carbon double bonds are polymerized to prepare a phosphorus-solubilizing agent for use as a substitute for phosphate fertilizer in soil. The polymerization reaction temperature is 80-100°C, the polymerization reaction time is 3-5 hours, and the heating rate is 4-6°C / min.

9. The application of the phosphorus-solubilizing agent as described in any one of claims 1-7 in soil as a substitute for phosphate fertilizer, characterized in that, It is applied to soil to degrade phosphates and increase the available phosphorus content in the soil, thereby improving crop yield and quality.

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