Moisturizing high-adhesion starch-based slow-release foliar fertilizer and preparation method thereof
By using cross-linked carboxymethyl starch and polyvinyl alcohol acrylic acid graft polymer in foliar fertilizers, the problems of poor adhesion, lack of moisture retention and insufficient slow-release performance of foliar fertilizers are solved, and efficient foliar fertilizers are achieved. application to increase crop yields.
Patent Information
- Application Number
- CN202411602982.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-11
- Publication Date
- 2025-01-21
AI Technical Summary
During the application process, existing foliar fertilizers have problems such as poor adhesion, lack of moisturizing properties and no sustained release properties, resulting in low utilization, soil pollution and the need for multiple sprays to achieve the expected results.
Using purslane immersed liquid lipoly carboxymethyl starch and polyethylene acrylic polymer, through the crosslinage of hydroxymethyl starch and the cross -linking characteristics of polymers, it forms high adhesion, moisturizing and moisturizing, and Slow -release leaf fertilizer.
It realizes that foliar fertilizer can effectively adhere and retain moisture under different environmental conditions, prolongs the release time of nutrients, and improves utilization rate and crop yield.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of foliar fertilizers, and in particular to a moisture-retaining high-adhesion starch-based slow-release foliar fertilizer and a preparation method thereof. Background Art
[0002] Currently, foliar fertilizer has become an indispensable part of agricultural production. The main advantage of foliar fertilizer is that nutrient absorption occurs directly on the leaf surface, avoiding the adverse effects of soil fertilizers such as phytotoxicity, soil erosion, slow response and potential pollution.
[0003] However, there are three common problems in the application process of foliar fertilizer. First, it has poor adhesion. Foliar fertilizer is easy to slide off the leaf surface after application, resulting in low utilization rate and soil pollution. Second, it lacks moisturizing properties. Strong direct sunlight in summer causes crop leaf burns, affecting crop yields. Third, it has no sustained-release properties. Water-soluble nutrients are released quickly, and multiple sprayings are required during agricultural production to achieve the desired effect.
[0004] Some researchers have prepared liquid foliar fertilizer by mixing potassium dihydrogen phosphate, crosslinking agent, polyvinyl alcohol acrylic acid graft polymer and hydroxymethyl urea. When the external ambient temperature exceeds 40°C, the polyvinyl alcohol acrylic acid graft polymer can crosslink to produce a water-absorbing and water-retaining network, and then absorb water and swell to produce gel, thereby achieving the adhesion and moisture retention properties of the foliar fertilizer. The disadvantage of this prior art is that the adhesion and moisture retention properties depend on the ambient temperature reaching certain conditions and rain or appropriate water spraying. The foliar fertilizer cannot take effect immediately after spraying, and it is not convenient to use. Summary of the invention
[0005] In view of the problem that the existing moisturizing high-adhesion starch-based slow-release foliar fertilizer needs to rely on the ambient temperature to reach certain conditions and rain or appropriate water spraying to obtain adhesion and moisturizing properties, the present invention provides a moisturizing high-adhesion starch-based slow-release foliar fertilizer and a preparation method thereof.
[0006] In a first aspect, the present invention provides a method for preparing a moisture-retaining high-adhesion starch-based slow-release foliar fertilizer, comprising the following steps: (1) chopping purslane and adding it to an aqueous solution of ethylene glycol for extraction, filtering and collecting the filtrate to obtain a purslane extract; (2) adding carboxymethyl starch and N,N'-methylenebisacrylamide to the purslane extract to dissolve them, so as to cross-link the carboxymethyl starch and obtain solution A; (3) adding polyvinyl alcohol acrylic acid graft polymer and N,N'-methylenebisacrylamide into water and dissolving them to obtain solution B; (4) Mix solution A and solution B, and add potassium fertilizer to the mixture to obtain a moisture-retaining, highly adhesive starch-based slow-release foliar fertilizer.
[0007] Furthermore, in step (1), the mass ratio of purslane to ethylene glycol and water is 1:2~3:2~3.
[0008] Furthermore, in step (1), the extraction conditions of purslane are 25-30° C., 60-90 rpm stirring extraction for 48-72 hours.
[0009] Furthermore, in step (2), the mass ratio of carboxymethyl starch to N,N'-methylenebisacrylamide and purslane extract is 1:0.01-0.02:10-20.
[0010] Furthermore, in step (2), the cross-linking conditions of the carboxymethyl starch are 25-30° C. and 60-90 rpm stirring extraction for 2-4 hours.
[0011] Furthermore, in step (3), the mass ratio of the polyvinyl alcohol acrylic acid graft polymer to N,N'-methylenebisacrylamide and water is 1:0.01-0.02:5-10.
[0012] Furthermore, in step (4), the mass ratio of solution A to solution B and potassium fertilizer is 1:0.5~1:0.05~0.1.
[0013] Furthermore, the potash fertilizer in step (4) is dipotassium hydrogen phosphate or potassium dihydrogen phosphate.
[0014] In a second aspect, the present invention provides a moisture-retaining high-adhesion starch-based slow-release foliar fertilizer produced by the above-mentioned preparation method.
[0015] The beneficial effects of the present invention are: Based on the existing moisturizing high-adhesion slow-release foliar fertilizer, the present invention improves the foliar fertilizer components and adds cross-linked carboxymethyl starch in the purslane extract, which can act as a regular component of the foliar fertilizer. Specifically, after cross-linking, a network structure is formed between the starch molecules, which has a higher viscosity than ordinary hydroxymethyl starch, making the foliar fertilizer more adherent to the leaf surface. Purslane is an easily accessible and low-cost plant, and its extract is red. After spraying foliar fertilizer, a reddish light-transmitting film will form on the surface of the leaves. This light-transmitting film can appropriately reduce the entry of light and filter out part of the ultraviolet rays during the period of strong sunlight and high temperature in summer, providing red light illumination for the leaves, which is beneficial to photosynthesis of plants, thereby promoting the growth of leaves and plants; the polysaccharides, saponins and other components contained in the purslane extract are also beneficial to inhibiting the growth and reproduction of pathogens on plant leaves, increasing the hydration rate of the leaves, and reducing the water loss rate. In addition, the ethylene glycol used in the extraction of purslane has a certain moisturizing ability, which can absorb moisture in the air around the leaves and reduce the evaporation of moisture from the leaves.
[0016] The present invention also utilizes the property of polyvinyl alcohol acrylic acid graft polymer to undergo cross-linking when the external temperature exceeds 40°C, and uses the polyvinyl alcohol acrylic acid graft polymer as a slow-release component to play a role in hot summer weather. It can embed potash fertilizer into the formed water-absorbing and water-retaining network to achieve a slow-release effect. DETAILED DESCRIPTION
[0017] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.
[0018] The hydroxymethyl starch used in the present invention is prepared by the following method: Disperse 10g corn starch in 20mL isopropanol solution, continue mechanical stirring at room temperature, set the stirring speed to 1000rpm, heat the solution to 35℃, add 3.37g NaOH, react for 45min; add 0.08mol monochloroacetic acid and 3.16g NaOH, heat to 45℃, stir for 2h. The reacted solution is neutralized with 1mol / L glacial acetic acid, and then fully washed with 80% ethanol solution until the filtrate contains no chloride ions. Place the product in a vacuum drying oven at 60℃, dry to constant weight, and set aside.
[0019] The hydroxymethyl starch used in the present invention can also be replaced by commercially available products.
[0020] The polyvinyl alcohol acrylic acid graft polymer used in the present invention is prepared by the following method: 31.15 g of KOH solution (mass fraction 5%) was added dropwise to 20 g of acrylic acid to obtain neutralized acrylic acid; 10 g of polyvinyl alcohol powder was dissolved in 50 g of deionized water at 85° C. to obtain a polyvinyl alcohol solution; the neutralized acrylic acid was added to the polyvinyl alcohol solution, potassium persulfate was added under ice bath conditions, and then nitrogen was passed through for 5 minutes, and the reaction container was placed in a 55° C. water bath for reaction for 4 hours to obtain the product.
[0021] Example 1 A moisture-retaining high-adhesion starch-based slow-release foliar fertilizer is produced by the following preparation method: (1) 10 g of purslane was chopped and added to an aqueous solution of ethylene glycol, wherein the aqueous solution of ethylene glycol was prepared by mixing 20 g of ethylene glycol with 30 g of water. The solution was stirred for 48 h, and the stirring speed was controlled to be 90 rpm. During the stirring process, a thermometer was used to monitor the temperature of the solution, and the temperature of the solution was controlled to be maintained in the range of 25 to 30° C. The obtained extract was filtered, and the filtrate was taken to obtain a wine-red purslane extract; The polysaccharide content in the purslane extract was determined by the sulfuric acid-phenol method and was 35.48%. The saponin content in the purslane extract was determined by the liquid chromatography method and was 15.76%.
[0022] (2) Take 40 g of the purslane extract prepared in step (1), add 4 g of carboxymethyl starch and 0.08 g of N,N'-methylenebisacrylamide thereto, stir to crosslink the carboxymethyl starch, control the stirring speed to 90 rpm, use a thermometer to monitor the solution temperature during stirring, and control the solution temperature to maintain in the range of 25-30°C, stir for 2 h, and obtain solution A; (3) 4 g of polyvinyl alcohol acrylic acid graft polymer and 0.08 g of N,N'-methylenebisacrylamide were added to 40 g of water and dissolved to obtain solution B; (4) Mix 40 g of solution A and 40 g of solution B, and add 4 g of dipotassium hydrogen phosphate to the mixture to obtain a moisture-retaining, high-adhesion starch-based slow-release foliar fertilizer.
[0023] Example 2 A moisture-retaining high-adhesion starch-based slow-release foliar fertilizer is produced by the following preparation method: (1) 10 g of purslane was chopped and added to an aqueous solution of ethylene glycol, wherein the aqueous solution of ethylene glycol was prepared by mixing 30 g of ethylene glycol with 20 g of water. The solution was stirred for 72 h, and the stirring speed was controlled to be 60 rpm. During the stirring process, a thermometer was used to monitor the temperature of the solution and the temperature of the solution was controlled to be maintained in the range of 25 to 30° C. The obtained extract was filtered and the filtrate was collected to obtain a wine-red purslane extract; (2) Take 40 g of the purslane extract prepared in step (1), add 2 g of carboxymethyl starch and 0.02 g of N,N'-methylenebisacrylamide thereto, stir to crosslink the carboxymethyl starch, control the stirring speed to 60 rpm, use a thermometer to monitor the solution temperature during stirring, and control the solution temperature to maintain in the range of 25-30°C, stir for 4 h, and obtain solution A; (3) 4 g of polyvinyl alcohol acrylic acid graft polymer and 0.04 g of N,N'-methylenebisacrylamide were added to 20 g of water and dissolved to obtain solution B; (4) Mix 40 g of solution A with 20 g of solution B, and add 2 g of potassium dihydrogen phosphate to the mixture to obtain a moisture-retaining, high-adhesion starch-based slow-release foliar fertilizer.
[0024] Comparative Example 1 A foliar fertilizer is produced by the following preparation method: (1) Take 40 g of water, add 4 g of carboxymethyl starch and 0.08 g of N,N'-methylenebisacrylamide, stir to crosslink the carboxymethyl starch, control the stirring speed to 90 rpm, use a thermometer to monitor the solution temperature during stirring, and control the solution temperature to maintain in the range of 25-30 ° C, stir for 2 h, and obtain solution A; (2) 4 g of polyvinyl alcohol acrylic acid graft polymer and 0.08 g of N,N'-methylenebisacrylamide were added to 40 g of water and dissolved to obtain solution B; (3) Mix 40 g of solution A and 40 g of solution B, and add 4 g of dipotassium hydrogen phosphate to the mixture.
[0025] Comparative Example 2 A moisture-retaining high-adhesion starch-based slow-release foliar fertilizer is produced by the following preparation method: (1) 10 g of purslane was chopped and added to an aqueous solution of ethylene glycol, wherein the aqueous solution of ethylene glycol was prepared by mixing 20 g of ethylene glycol with 30 g of water. The solution was stirred for 48 h, and the stirring speed was controlled to be 90 rpm. During the stirring process, a thermometer was used to monitor the temperature of the solution, and the temperature of the solution was controlled to be maintained in the range of 25 to 30° C. The obtained extract was filtered, and the filtrate was taken to obtain a wine-red purslane extract; (2) adding 4 g of polyvinyl alcohol acrylic acid graft polymer and 0.08 g of N,N'-methylenebisacrylamide to 40 g of the purslane extract prepared in step (1) and dissolving them; (3) Take 40 g of the solution obtained in step (2), add 2 g of dipotassium hydrogen phosphate thereto, and obtain a moisture-retaining high-adhesion starch-based slow-release foliar fertilizer.
[0026] First, the contact angle test method was used to test the wettability of the foliar fertilizer. The foliar fertilizers of Examples 1 and 2 and Comparative Examples 1 and 2 were sprayed onto the surfaces of 10 fresh corn leaves (all washed and dried before use, and cut into 5 cm×5 cm sizes, the same below). Five droplets were taken on each corn leaf to test the contact angle between the foliar fertilizer droplets and the leaf, and the average value was calculated. The results are shown in Table 1 below.
[0027] Table 1 Average contact angles of various foliar fertilizer droplets on leaves
[0028] Then, the simulated rainwater flushing method was used to test the phosphorus retention rate on the leaf surface of each foliar fertilizer, and the adhesion of each foliar fertilizer was characterized and compared. The foliar fertilizers of Examples 1 and 2 and Comparative Examples 1 and 2 were sprayed on the surface of 10 fresh corn leaves, respectively, and the spraying amount of each leaf was controlled to be the same. The leaves were naturally air-dried at room temperature for 6 hours, and then 10 mL of water was used to spray the leaves to simulate rainwater. The phosphorus content was determined after the liquid washed down was collected and boiled, and the average value was taken to calculate the phosphorus retention rate according to the following formula: Phosphorus retention rate = (phosphorus content in the amount of fertilizer sprayed - phosphorus content in the flushing liquid) / phosphorus content in the amount of fertilizer sprayed × 100%.
[0029] The results are shown in Table 2 below.
[0030] Table 2 Phosphorus retention rate of various foliar fertilizers
[0031] As can be seen from Table 1 and Table 2, the foliar fertilizer of the present invention has good wettability and adhesion, can better wet and spread on the leaf surface when sprayed, and can adhere to the leaf surface for a longer time, and is not easily washed away by rain, thereby reducing the loss of nutrients in the environment and increasing the absorption opportunity of nutrients. In particular, compared with Comparative Example 2, the foliar fertilizer of the present invention adds cross-linked modified hydroxymethyl starch, which has good viscosity without a high temperature environment, and overcomes the deficiency of Comparative Example 2 that only uses polyvinyl alcohol acrylic acid graft polymer to improve adhesion and relies on a high temperature environment (>40°C).
[0032] Field tests were conducted in spring corn planting fields, and the foliar fertilizer effects of Examples 1 and 2 and Comparative Examples 1 and 2 were compared according to the corn leaf state and final yield. The test site is located in Zuoying Town, Juancheng County, Shandong Province, and the corn variety is Ludan 510. The test was divided into five groups, and the foliar fertilizer of Example 1, the foliar fertilizer of Example 2, the foliar fertilizer of Comparative Example 1, the foliar fertilizer of Comparative Example 2 and clear water were sprayed in the large trumpet mouth period, heading period and flowering period of corn, respectively. The size of each test field was 2 mu, and it was diluted 500 times for use, and sprayed according to 20 kg of diluent / mu. All other management measures were the same, and were carried out according to conventional planting methods.
[0033] The leaf status and yield of corn at different stages are shown in Table 3 below.
[0034] Table 3 Comparison of the effects of foliar fertilizer spraying
[0035] It can be seen that after spraying the foliar fertilizer of the present invention, at each growth stage, the leaf width of the corn leaves is wide, the leaves are thick, and the leaf color is dark green and shiny, which reflects the excellent adhesion performance, moisturizing performance and slow-release performance of the foliar fertilizer of the present invention; compared with the foliar fertilizer of the comparative example and the clear water control, the yield of corn per mu sprayed with the foliar fertilizer of the present invention is increased by 4.13%~15.64%. In the comparative example 1, the foliar fertilizer lacks the purslane extract, and the chloroplast photosynthesis of the corn leaves cannot be improved. At the same time, due to the lack of polysaccharides, saponins, ethylene glycol and other substances, the moisturizing effect of the leaf surface is weakened. In the comparative example 2, the foliar fertilizer lacks cross-linked hydroxymethyl starch. During the first two sprayings, due to the insufficient ambient temperature, the polyvinyl alcohol acrylic acid grafted polymer cannot be cross-linked or the degree of cross-linking is poor, and the water absorption and water retention network cannot be formed well. Therefore, the early leaves are in poor condition. In the later period, as the ambient temperature rises and precipitation occurs, the polyvinyl alcohol acrylic acid grafted polymer forms a gel, thereby achieving slow-release moisturizing of the leaves.
[0036] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily conceive of changes or substitutions within the technical scope disclosed by the present invention, and such changes or substitutions shall be within the scope of protection of the present invention.
Claims
1. A method for preparing a moisture-retaining high-adhesion starch-based slow-release foliar fertilizer, characterized in that: The steps include: (1) chopping purslane and adding it to an aqueous solution of ethylene glycol for extraction, filtering and collecting the filtrate to obtain a purslane extract; (2) adding carboxymethyl starch and N,N'-methylenebisacrylamide to the purslane extract to dissolve them, so as to cross-link the carboxymethyl starch and obtain solution A; (3) adding polyvinyl alcohol acrylic acid graft polymer and N,N'-methylenebisacrylamide into water and dissolving them to obtain solution B; (4) Mix solution A and solution B, and add potassium fertilizer to the mixture to obtain a moisture-retaining, highly adhesive starch-based slow-release foliar fertilizer.
2. The preparation method according to claim 1, characterized in that In step (1), the mass ratio of purslane to ethylene glycol to water is 1:2-3:2-3.
3. The preparation method according to claim 1, characterized in that: In step (1), the extraction conditions of purslane are 25-30° C., 60-90 rpm stirring and extraction for 48-72 hours.
4. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of carboxymethyl starch to N,N'-methylenebisacrylamide and purslane extract is 1:0.01-0.02:10-20.
5. The preparation method according to claim 1, characterized in that: In step (2), the cross-linking conditions of the carboxymethyl starch are 25-30° C. and 60-90 rpm stirring extraction for 2-4 hours.
6. The preparation method according to claim 1, characterized in that: In step (3), the mass ratio of polyvinyl alcohol acrylic acid graft polymer to N,N'-methylenebisacrylamide and water is 1:0.01-0.02:5-10.
7. The preparation method according to claim 1, characterized in that: In step (4), the mass ratio of solution A to solution B and potash fertilizer is 1:0.5~1:0.05~0.
1.
8. The preparation method according to claim 1, characterized in that: The potash fertilizer in step (4) is dipotassium hydrogen phosphate or potassium dihydrogen phosphate.
9. A moisture-retaining high-adhesion starch-based slow-release foliar fertilizer produced by the preparation method according to any one of claims 1 to 8.