Application of phosphate blocking prevention additive in water and fertilizer integrated micro-irrigation system

Abstract

The invention discloses application of an anti-phosphate blocking additive in a water and fertilizer integrated micro-irrigation system, and belongs to the technical field of agricultural application. The anti-phosphate blocking additive is a binary or terpolymer containing acrylic acid; the binary polymer containing acrylic acid is a binary copolymer prepared from acrylic acid and methylallyl alcohol; the terpolymer containing acrylic acid is a terpolymer prepared from acrylic acid, methylallyl alcohol and a third monomer. The phosphate blocking prevention additive is applied to a high-phosphorus water-soluble fertilizer solution, has good calcium phosphate precipitation prevention capacity and can react with Ca < 2 + > in irrigation water, so that a large amount of calcium phosphate precipitates are prevented from being generated, the blocking problem is prevented, the irrigation efficiency is improved, meanwhile, the phosphate fertilizer utilization rate is increased, and the phosphate blocking prevention additive has the advantages of being small in dosage, low in cost and the like. Therefore, the water-fertilizer integrated irrigation system has a good prospect in actual water-fertilizer integrated irrigation application.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural applications, and in particular relates to application of an anti-phosphate blocking additive in a water-fertilizer integrated micro-irrigation system. Background Art

[0002] In recent years, in order to save irrigation water and improve fertilizer utilization, water-fertilizer integrated micro-irrigation technology has been widely used. Water-fertilizer integrated micro-irrigation technology can reduce fertilizer volatilization and leaching loss, improve water and fertilizer utilization and crop yields, promote uniform distribution of water and fertilizer in the root zone of crops, and improve the current status of water and fertilizer resource utilization in dryland agriculture. However, in practice, calcium and magnesium ions in high-hardness irrigation water will react chemically with phosphate-containing fertilizers to form phosphate precipitation, causing blockage of water pipelines or drippers, thereby affecting water output, reducing irrigation efficiency and phosphate fertilizer utilization efficiency, and even affecting the service life and economic benefits of the irrigation system. Therefore, solving the problem of chemical blockage caused by phosphate precipitation is of great significance to improving the life of micro-irrigation equipment and the utilization rate of phosphate fertilizer.

[0003] The current chemical blockage problem caused by phosphate precipitation is generally solved by pickling the pipeline with hydrochloric acid, sulfuric acid, etc. after the blockage occurs. However, long-term use of this method is prone to corroding the pipeline and causing soil acidification, which has an adverse effect on crop growth. European Patent 0375615A2 prevents irrigation components from being blocked by adding some common scale inhibitors such as acrylic acid or copolymers or homopolymers with methacrylic acid, maleic anhydride or organic phosphine polymers, etc. to irrigation water. However, the characteristics of this patent are not specific. The present invention is a series of polymers prepared by our independently developed synthetic acrylic acid and methyl allyl alcohol or supplemented with a third monomer. The production cost is low, and it has excellent phosphate scale inhibition effect in high hardness and high phosphorus content fertilizer solutions. In addition, Chinese patent CN107266205A prepares an anti-clogging water-soluble fertilizer by adding scale inhibitors, disinfectants, chelating agents, etc., and verifies the anti-clogging effect of the fertilizer by observing the change in clarity of the solution after mixing it with hard water. The patent's mixed scale inhibitors, disinfectants and chelating agents have low specificity and a large dosage, so the cost of use is high and it is easy to cause soil pollution. Summary of the invention

[0004] Aiming at the problem of chemical blockage caused by insoluble phosphate precipitates in the current water-fertilizer integrated micro-irrigation system, the present invention provides an anti-phosphate blockage additive for use in the water-fertilizer integrated micro-irrigation system. The additive is a series of polymers prepared from acrylic acid and methyl allyl alcohol or assisted by a third monomer, has good calcium phosphate precipitation resistance, can effectively solve the scaling blockage problem caused by calcium phosphate in the water-fertilizer integrated micro-irrigation system, and thus prolong the service life of the micro-irrigation equipment; and the additive used in the present invention is simple to synthesize, small in amount, and relatively low in cost.

[0005] The present invention is achieved through the following technical solutions: Application of an anti-phosphate blocking additive in a water-fertilizer integrated micro-irrigation system, wherein the anti-phosphate blocking additive is a binary or ternary copolymer containing acrylic acid; The acrylic acid-containing binary polymer is a binary copolymer prepared from acrylic acid and methyl allyl alcohol; The acrylic acid-containing terpolymer is a terpolymer prepared from acrylic acid, methyl allyl alcohol and a third monomer.

[0006] Furthermore, the third monomer is one of tert-butyl acrylate, vinyl acetate, acrylamide, and 2-acrylamide-2-methylpropanesulfonic acid.

[0007] Furthermore, the molar ratio of acrylic acid to methallyl alcohol in the binary polymer containing acrylic acid is 8:2.

[0008] Furthermore, the molar ratio of acrylic acid, methyl allyl alcohol and the third monomer in the acrylic acid-containing terpolymer is 70-90:5-10:5-20.

[0009] Furthermore, the viscosity average molecular weight of the binary polymer containing acrylic acid is 4,000.

[0010] Furthermore, the viscosity average molecular weight of the acrylic acid-containing terpolymer is 3800-4200.

[0011] Furthermore, the anti-phosphate blocking additive and the water-soluble fertilizer are mixed with the irrigation water and then the water-fertilizer integrated irrigation is carried out through the micro-irrigation system.

[0012] Furthermore, the amount of the anti-phosphate blocking additive added is 1-5 ppm.

[0013] Furthermore, the water-soluble fertilizer is a phosphorus-containing water-soluble fertilizer.

[0014] Beneficial effects achieved by the present invention: The anti-phosphate blocking additive of the present invention is applied to the water-fertilizer integrated micro-irrigation system, which solves the chemical blocking problem caused by calcium phosphate precipitation and avoids the problems of soil acidification, unfavorable crop growth, etc. caused by the use of acid-washing pipes and the like; The anti-phosphate blocking additive in the present invention is a binary copolymer prepared from acrylic acid and methyl allyl alcohol, or a ternary series copolymer prepared with the aid of a third monomer, which has good water solubility, can be quickly dissolved in a water-soluble fertilizer solution without leaving impurities, and can be directly added to fertilizer irrigation water according to the amount in practical applications. The method of use is simple, and the use of the additive in combination with the water-soluble fertilizer solution will not affect the effectiveness of the water-soluble fertilizer. The anti-phosphate blocking additive of the present invention has the advantages of simple synthesis process and low cost, and has good ability to prevent calcium phosphate precipitation when applied to high-phosphorus water-soluble fertilizer solution, and can react with Ca in irrigation water. 2+ The reaction prevents the massive formation of calcium phosphate precipitation, prevents the occurrence of blockage problems, and improves the utilization rate of phosphate fertilizer while improving irrigation efficiency; when the additive dosage is 5ppm, the scale inhibition rate of calcium phosphate is greater than 90%, which has the advantages of small dosage and obvious calcium phosphate scale inhibition effect, and has good prospects in actual water-fertilizer integrated irrigation applications. DETAILED DESCRIPTION

[0015] The above contents of the present invention are further described in detail below through examples, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples, and all technologies implemented based on the above contents of the present invention belong to the scope of the present invention. Example 1

[0016] (1) Preparation of acrylic acid / methallyl alcohol (AA / MAOH) binary copolymer: A mixture of acrylic acid and methallyl alcohol (the molar ratio of acrylic acid to methallyl alcohol is 8:2) is added dropwise to an 80°C aqueous solution containing a redox initiator system. After the addition is completed, the mixture is kept at 80°C for 30 minutes to obtain a binary copolymer with a viscosity average molecular weight of 4000.

[0017] (2) Hard water with a calcium content of about 200ppm prepared from tap water was mixed with Stanley water-soluble fertilizer N-P2O5-K2O 20-20-20 to form a fertilizer solution of 1g / L. After adding 1ppm, 2ppm, and 5ppm of acrylic acid / methyl allyl alcohol (AA / MAOH) binary copolymer, the solution was placed in a 30℃ water bath for 24h, and the precipitation was observed. The phosphate ion content in the water fertilizer solution was determined, and the scale inhibition rate was calculated by the reduction of phosphate ions. At the same time, a set of blanks was set up, and the calculated phosphate scale inhibition rates were 85.19%, 95.15%, and 96.97%, respectively. Example 2

[0018] (1) Preparation of acrylic acid / methallyl alcohol / tert-butyl acrylate (AA / MAOH / TBA) terpolymer: A mixture of acrylic acid, methallyl alcohol and tert-butyl acrylate (the molar ratio of acrylic acid, methallyl alcohol and tert-butyl acrylate is 8:1:1) is added dropwise to an 80°C aqueous solution containing a redox initiator system. After the addition is completed, the mixture is kept at 80°C for 30 minutes to obtain a terpolymer with a viscosity average molecular weight of 3800.

[0019] (2) Hard water with a calcium content of about 200ppm prepared from tap water was mixed with Stanley water-soluble fertilizer N-P2O5-K2O 20-20-20 to make a fertilizer solution of 1g / L. After adding 1ppm, 2ppm, and 5ppm of acrylic acid / methyl allyl alcohol polymer / tert-butyl acrylate (AA / MAOH / TBA) terpolymer, the solution was placed in a 30℃ water bath for 24h, and the precipitation was observed. The phosphate ion content in the fertilizer solution was determined, and the scale inhibition rate was calculated by the reduction of phosphate ions. At the same time, a blank group was set up, and the calculated phosphate scale inhibition rates were 89.7%, 90.3%, and 94.55%, respectively. Example 3

[0020] (1) Preparation of acrylic acid / methallyl alcohol / vinyl acetate (AA / MAOH / VA) terpolymer: A mixture of acrylic acid, methallyl alcohol and vinyl acetate (the molar ratio of acrylic acid, methallyl alcohol and vinyl acetate is 18:1:1) is added dropwise to an 80°C aqueous solution containing a redox initiator system. After the addition is completed, the mixture is kept at 80°C for 30 minutes to obtain a terpolymer with a viscosity-average molecular weight of 4100.

[0021] (2) Hard water with a calcium content of about 200ppm prepared from tap water was mixed with Stanley water-soluble fertilizer N-P2O5-K2O 20-20-20 to make a fertilizer solution of 1g / L. After adding 1ppm, 2ppm, and 5ppm of acrylic acid / methyl allyl alcohol / vinyl acetate (AA / MAOH / VA) terpolymer, the solution was placed in a 30℃ water bath for 24h, and the precipitation was observed. The phosphate ion content in the water fertilizer solution was determined, and the scale inhibition rate was calculated by the reduction of phosphate ions. At the same time, a set of blanks was set up, and the calculated phosphate scale inhibition rates were 89.7%, 90.3%, and 94.55%, respectively. Example 4

[0022] (1) Preparation of acrylic acid / methallyl alcohol / acrylamide (AA / MAOH / AM) terpolymer: A mixture of acrylic acid, methallyl alcohol and acrylamide (the molar ratio of acrylic acid, methallyl alcohol and acrylamide is 7:1:2) is added dropwise to an 80°C aqueous solution containing a redox initiator system. After the addition is completed, the mixture is kept at 80°C for 30 minutes to obtain a terpolymer with a viscosity-average molecular weight of 4200.

[0023] (2) Hard water with a calcium content of about 200ppm prepared from tap water was mixed with Stanley water-soluble fertilizer N-P2O5-K2O 20-20-20 to make a fertilizer solution of 1g / L. After adding 1ppm, 2ppm, and 5ppm of acrylic acid / methyl allyl alcohol / acrylamide (AA / MAOH / AM) terpolymer, the solution was placed in a 30℃ water bath for 24h, and the precipitation was observed. The phosphate ion content in the water fertilizer solution was determined, and the scale inhibition rate was calculated by the reduction of phosphate ions. At the same time, a set of blanks was set up, and the calculated phosphate scale inhibition rates were 89.7%, 90.3%, and 94.55%, respectively. Example 5

[0024] (1) Preparation of acrylic acid / methallyl alcohol / 2-acrylamide-2-methylpropane sulfonic acid (AA / MAOH / AMPS) terpolymer: A mixture of acrylic acid, methallyl alcohol and 2-acrylamide-2-methylpropane sulfonic acid (the molar ratio of acrylic acid, methallyl alcohol and 2-acrylamide-2-methylpropane sulfonic acid is 8:1:1) is added dropwise to an 80°C aqueous solution containing a redox initiator system. After the addition is completed, the mixture is kept at 80°C for 30 minutes to obtain a terpolymer with a viscosity-average molecular weight of 3900.

[0025] (2) Hard water with a calcium content of about 200ppm prepared from tap water was mixed with Stanley water-soluble fertilizer N-P2O5-K2O 20-20-201 to make a fertilizer solution of 1g / L. After adding 1ppm, 2ppm, and 5ppm of acrylic acid / methylallyl alcohol / 2-acrylamide-2-methylpropanesulfonic acid (AA / MAOH / AMPS) terpolymer, the solution was placed in a 30℃ water bath for 24h, and the precipitation was observed. The phosphate ion content in the fertilizer solution was determined, and the scale inhibition rate was calculated by the reduction of phosphate ions. At the same time, a set of blanks was set up, and the calculated phosphate scale inhibition rates were 89.7%, 90.3%, and 94.55%, respectively.

Claims

1. Application of an anti-phosphate blocking additive in a water-fertilizer integrated micro-irrigation system, characterized in that: The anti-phosphate blocking additive is a binary or ternary copolymer containing acrylic acid; The acrylic acid-containing binary polymer is a binary copolymer prepared from acrylic acid and methyl allyl alcohol; The acrylic acid-containing terpolymer is a terpolymer prepared from acrylic acid, methyl allyl alcohol and a third monomer.

2. The use of the anti-phosphate blocking additive according to claim 1 in a water-fertilizer integrated micro-irrigation system is characterized in that: The third monomer is one of tert-butyl acrylate, vinyl acetate, acrylamide, and 2-acrylamide-2-methylpropanesulfonic acid.

3. The use of the anti-phosphate blocking additive according to claim 1 in a water-fertilizer integrated micro-irrigation system is characterized in that: The molar ratio of acrylic acid to methallyl alcohol in the binary polymer containing acrylic acid is 8:

2.

4. The use of the anti-phosphate blocking additive according to claim 1 in a water-fertilizer integrated micro-irrigation system is characterized in that: The molar ratio of acrylic acid, methyl allyl alcohol and the third monomer in the acrylic acid-containing terpolymer is 70-90:5-10:5-20.

5. The use of the anti-phosphate blocking additive according to claim 1 in a water-fertilizer integrated micro-irrigation system, characterized in that: The viscosity average molecular weight of the binary polymer containing acrylic acid is 4000.

6. The use of the anti-phosphate blocking additive according to claim 1 in a water-fertilizer integrated micro-irrigation system, characterized in that: The viscosity average molecular weight of the acrylic acid-containing terpolymer is 3800-4200.

7. The use of the anti-phosphate blocking additive according to claim 1 in a water-fertilizer integrated micro-irrigation system, characterized in that: After the anti-phosphate blocking additives and water-soluble fertilizers are mixed with irrigation water, water-fertilizer integrated irrigation is carried out through the micro-irrigation system.

8. The use of the anti-phosphate blocking additive according to claim 7 in a water-fertilizer integrated micro-irrigation system, characterized in that: The amount of the anti-phosphate blocking additive added is 1-5 ppm.

9. The use of the anti-phosphate blocking additive according to claim 7 in a water-fertilizer integrated micro-irrigation system, characterized in that: The water-soluble fertilizer is a phosphorus-containing water-soluble fertilizer.