A slow-release composite organic liquid water-soluble fertilizer based on natural extract and a preparation method thereof

Abstract

The application discloses a slow-release type composite organic liquid water-soluble fertilizer based on natural extractives and a preparation method thereof, and belongs to the technical field of agricultural fertilizers. The preparation method comprises the following steps: mixing a cross-linked mussel myoglobin mixed solution, a diamine cross-linking agent and an oxidized cyclodextrin-plant oil-urea inclusion body mixed solution according to a weight ratio of 1:0.01-0.02:3-5, then stirring and reacting for 2-3 hours under the condition of temperature control of 30-35 DEG C to obtain the slow-release type composite organic liquid water-soluble fertilizer. The application firstly constructs the cross-linked mussel myoglobin mixed solution with high-temperature resistance through condensation cross-linking, then utilizes the characteristics that the outside of cyclodextrin is hydrophilic and the inside is hydrophobic to obtain the oxidized cyclodextrin-plant oil-urea inclusion body mixed solution by wrapping urea, and finally forms the slow-release type composite organic liquid water-soluble fertilizer by cross-linking the oxidized cyclodextrin-plant oil-urea inclusion body mixed solution and the cross-linked mussel myoglobin mixed solution through amino groups and aldehyde groups with the help of the diamine cross-linking agent.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of agricultural fertilizers, and particularly relates to a slow-release composite organic liquid water-soluble fertilizer based on natural extracts and a preparation method thereof. BACKGROUND

[0002] The growth of the world population has increased the demand for food. In order to meet the current supply of food, a large area of fertile land is needed to grow more food. However, factors such as industrialization, soil degradation and urbanization have reduced agricultural land, and at the same time, a large amount of fertilizer is needed to grow food on infertile farmland due to insufficient nutrient supply. Although the effect of fertilizer on crop yield is undeniable, excessive input of fertilizer will have a great negative impact on the environment such as groundwater and atmosphere. Due to the failure of fertilizer to be absorbed and utilized in the soil in time, a large amount of nutrient elements in the fertilizer can easily flow into groundwater and surface water through surface runoff and farmland drainage, causing eutrophication of water bodies such as lakes and rivers. The main reason for the low efficiency of fertilizer is the unreasonable fertilizer structure. Blind application of fertilizer will only increase the production cost and environmental pollution. With the increase of food production, fertilizer is still an indispensable production factor in crop production. Therefore, in the process of increasing food production, how to improve the utilization rate of fertilizer in agricultural production and reduce the pollution of fertilizer to soil and environment, and realize the green and ecological sustainable development of agriculture, is an important guarantee to realize the sustainable development of agriculture. Under this background, slow-release fertilizer emerges as the times require. Slow-release fertilizer is based on chemical fertilizer as the base body, and the release of nutrients is adjusted and controlled through various methods to improve the absorption rate of plants to nutrients. Due to the sustainability of nutrient release, slow-release water-soluble fertilizer can reduce the frequency of fertilization, thereby effectively reducing the loss of nutrients, reducing the risk of water eutrophication, and reducing the occurrence of environmental problems such as soil salinization. And the composition of slow-release fertilizer can improve the soil structure, promote the activity of soil microorganisms, and enhance the water retention capacity and aeration of the soil, thereby improving the soil health level. From the current situation of slow-release fertilizer, the slow-release fertilizers currently put on the market include urea-formaldehyde coated, sulfur-coated urea and polystyrene coated urea. Although these slow-release fertilizers achieve slow-release performance to some extent, the use of polymer materials has a certain pollution to the environment, which makes it difficult for slow-release fertilizer to be popularized. Therefore, it is of great significance to develop environmentally friendly slow-release fertilizer to reduce pollution to the environment.

[0003] Patent CN116730771A discloses a slow-release nitrogen fertilizer and a preparation method thereof, the invention introduces MOF-COF composite material, which has high stability in aqueous solution, and the MOF-COF composite material contains high-density nitrogen-containing groups and oxygen-containing groups, and the lone pair of electrons on nitrogen is conducive to improving the adsorption performance, and sodium carboxymethyl cellulose and sodium alginate are also introduced to form a slow-release nitrogen fertilizer with a porous structure with the MOF-COF composite material, which improves the slow-release performance and has good water and fertilizer retention capacity, effectively improves crop productivity, and does not pollute the environment.

[0004] Patent CN116283420A discloses a preparation method of a composite slow-release nitrogen fertilizer for improving the bait supply of shellfish culture, the invention immerses the block prepared from ammonium chloride, gelatinized starch, sodium alginate and water in a calcium chloride solution, utilizes the gelation reaction between sodium alginate and calcium chloride, and dries the easily soluble nitrogen fertilizer through pressing and immersion process, and then obtains the composite slow-release nitrogen fertilizer.

[0005] Biologically derived materials have the natural environmental protection advantage, and mussels are a kind of marine organisms, and the mussel adhesive protein contained therein is a kind of biologically derived material with good application prospect and excellent adhesion performance. However, the content of mussel adhesive protein contained in mussels is low, and the adhesion of the mussel adhesive protein directly extracted is poor, so most of the existing mussel adhesive proteins are prepared by genetic recombination. However, the genetic recombination technology for preparing mussel adhesive protein has high cost and is difficult to popularize and apply. Moreover, the mussel adhesive protein has high waterproof performance after adhesion and poor hydrophilicity, and direct application to the fertilizer has a great influence on the water retention performance of the fertilizer, which is not conducive to the function of the fertilizer.

[0006] Therefore, it is of great significance to modify the mussel adhesive protein directly extracted from mussels to have good adhesion and water retention performance, so as to improve the utilization efficiency of the fertilizer and reduce the use of polymeric macromolecular materials in slow-release fertilizers. SUMMARY

[0007] According to the deficiencies of the prior art, the cross-linked mussel adhesive protein mixture with high temperature resistance is first constructed by condensation cross-linking, then the urea is wrapped to obtain the oxidized cyclodextrin-plant oil-urea inclusion body mixture by utilizing the characteristics that the outside of cyclodextrin is hydrophilic and the inside is hydrophobic, and finally the slow-release composite organic liquid water-soluble fertilizer is formed by cross-linking the oxidized cyclodextrin-plant oil-urea inclusion body mixture and the cross-linked mussel adhesive protein mixture through amino and aldehyde groups with the help of diamine cross-linking agent, thereby solving the technical problems in the background art. Specifically, the technical scheme of the present application includes the following contents:

[0008] One of the purposes of the present application is to provide a preparation method of a slow-release composite organic liquid water-soluble fertilizer based on natural extracts, which comprises the following steps:

[0009] The cross-linked mussel myoglobin mixture, diamine cross-linking agent and oxidized cyclodextrin-plant oil-urea inclusion mixture are mixed in a weight ratio of 1:0.01-0.02:3-5, and then the temperature is controlled at 30-35°C for stirring reaction for 2-3h to obtain the slow-release type composite organic liquid water-soluble fertilizer.

[0010] Further, the preparation method of the cross-linked mussel myoglobin mixture comprises the following steps:

[0011] The mussel meat and distilled water are mixed in a solid-liquid ratio of 1:1-2, and then high-speed homogenization treatment is performed to obtain a mussel meat slurry;

[0012] After the mussel meat slurry is adjusted to a pH of 7-7.5, neutral protease is added, and enzymatic hydrolysis is performed at a temperature of 45-50°C for 3-5h to obtain an enzymatic hydrolysate;

[0013] The enzymatic hydrolysate and a dialdehyde cross-linking agent are mixed and reacted at 20-25°C for 10-12h, and then high-temperature inactivation treatment is performed at 80-90°C for 10-15min to obtain the cross-linked mussel myoglobin mixture.

[0014] Further, the high-speed homogenization conditions include a rotation speed of 8000-10000r / min and a treatment time of 90-150s.

[0015] Further, the neutral protease is added in an amount of 0.6-0.7% of the weight of the mussel meat slurry.

[0016] Further, the dialdehyde cross-linking agent comprises glyoxal.

[0017] Further, the weight ratio of the enzymatic hydrolysate to the dialdehyde cross-linking agent is 1:0.005-0.007.

[0018] Further, the diamine cross-linking agent comprises ethylenediamine or 1,3-propanediamine.

[0019] Further, the preparation method of the oxidized cyclodextrin-plant oil-urea inclusion mixture comprises the following steps:

[0020] Urea and plant oil are mixed in a weight ratio of 1:2-4, and then high-speed shearing is performed to obtain a dispersion, and the dispersion and an emulsifier are mixed in a weight ratio of 1:0.01-0.02 to obtain a plant oil-encapsulated urea mixture by stirring;

[0021] The oxidized cyclodextrin solution and the plant oil-encapsulated urea mixture are mixed in a weight ratio of 1-5:1, and then stirring is performed at a temperature of 25-30°C for 2-4h to obtain the oxidized cyclodextrin-plant oil-urea inclusion mixture.

[0022] Further, the vegetable oil includes soybean oil or peanut oil.

[0023] Further, the condition of the high-speed shearing includes rotation speed 5000r / min~6000r / min and shearing time 3min~4min.

[0024] Further, the emulsifier includes Span 60 or Span 80.

[0025] Further, the preparation method of the oxidized cyclodextrin solution includes the following steps:

[0026] After cyclodextrin is dissolved and dispersed in water, sodium periodate is mixed with the dissolved cyclodextrin according to the weight ratio of cyclodextrin:sodium periodate 1:1 to obtain a reaction solution, the pH of the reaction solution is adjusted to 5.0~6.0, and then the reaction is carried out at 20℃~25℃ for 1h~1.5h to obtain the oxidized cyclodextrin solution.

[0027] Further, the cyclodextrin includes beta-cyclodextrin or gamma-cyclodextrin.

[0028] The second object of the application provides a slow-release type composite organic liquid water-soluble fertilizer based on a natural extract prepared by the preparation method.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] The application obtains the enzymatic hydrolysate containing mussel mucin by enzymatic hydrolysis of mussel, and then according to the characteristics that the mussel mucin contains amino groups in structure, the enzymatic hydrolysate is mixed with a dialdehyde cross-linking agent containing dialdehyde functional groups to form a dynamic imine bond with heat resistance through condensation and cross-linking between the amino groups and aldehyde groups. Since the enzymatic hydrolysate contains neutral protease required for enzymatic hydrolysis, high-temperature inactivation treatment is required to remove the neutral protease to prevent further enzymatic hydrolysis from damaging the adhesion of the mussel mucin. The mussel mucin contained in natural mussels is relatively low, and if it is not protected, the mussel mucin is easy to denature and lose adhesion activity during high-temperature inactivation. Therefore, the dialdehyde cross-linking agent containing dialdehyde functional groups can protect the mussel mucin from high temperature through the dynamic imine bond with heat resistance, reduce the loss of activity of the mussel mucin, and then obtain a cross-linked mussel mucin mixture. Then, the plant oil is wrapped with urea through high-speed shearing to form a plant oil-urea mixture with hydrophobic properties. By using the characteristics that the outside of cyclodextrin is hydrophilic and the inside is hydrophobic, the adjacent diol structure on the surface of cyclodextrin is first oxidized to obtain an oxidized cyclodextrin aqueous solution containing aldehyde functional groups, and then the plant oil-urea mixture and the oxidized cyclodextrin solution are mixed and stirred to encapsulate the plant oil-urea mixture with hydrophobic properties into the hydrophobic cavity inside the oxidized cyclodextrin, thereby obtaining an oxidized cyclodextrin-plant oil-urea inclusion body mixture. Finally, by means of a diamine cross-linking agent, the oxidized cyclodextrin-plant oil-urea inclusion body mixture and the cross-linked mussel mucin mixture are cross-linked through amino and aldehyde groups to form a slow-release type composite organic liquid water-soluble fertilizer. This cross-linking process has the following advantages: on the one hand, during the preparation of the cross-linked mussel mucin mixture, in order to reduce the adhesion activity of the mussel mucin in the enzymatic hydrolysate due to high-temperature inactivation, a dialdehyde cross-linking agent is used to construct a heat-resistant system. However, due to the cross-linking of the amino groups and aldehyde groups of the mussel mucin, the adhesion of the mussel mucin, which is already weak due to its low content, is further reduced. At this time, the use of a diamine cross-linking agent can improve the overall adhesion performance, so that the fertilizer can be better adhered to the soil when applied to the soil, and is not prone to rapid loss. On the other hand, the outer surface of the oxidized cyclodextrin contains a large number of hydrophilic groups, and after cross-linking, the hydrophilic performance of the mussel mucin is improved, thereby improving the water retention performance of the slow-release type composite organic liquid water-soluble fertilizer prepared finally after the fertilizer is applied to the soil, and improving the utilization efficiency of the fertilizer. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described clearly and completely through the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0032] Unless otherwise indicated, the starting materials and reagents used in the following examples of the application are commercially available or can be prepared by known methods.

[0033] Preparation Example 1

[0034] The preparation method of the cross-linked mussel myoglobin mixture specifically includes the following processes:

[0035] The commercially available fresh mussels are washed with tap water to remove surface impurities, then shelled to obtain mussel meat, and the mussel meat is cut into pieces with scissors to obtain mussel pieces. According to the solid-liquid ratio, 1 part by weight of the mussel pieces and 1 part by weight of distilled water are mixed, then placed in a homogenizer, and the rotation speed is adjusted to 8000 r / min for 90 s of homogenization treatment to obtain a mussel meat slurry. The pH value of the mussel meat slurry is adjusted to 7 with ammonia water, then 0.6% of neutral protease by weight of the mussel meat slurry is sucked into it with a pipette gun for mixing, then placed in an environment with a temperature of 45°C for timed enzymolysis for 3 h. After the enzymolysis is completed, the obtained enzymolysis liquid is taken out, then 0.005 times the weight of the enzymolysis liquid of glyoxal cross-linking agent is added to the enzymolysis liquid for mixing, and the mixing temperature is controlled at 20°C, the mixing rotation speed is set at 200 r / min, and the stirring mixing reaction is carried out for 10 h. After the mixing reaction is completed, it is immediately placed in a temperature environment of 80°C for high-temperature inactivation treatment, and the treatment time is maintained for 10 min. After inactivation is completed, it is naturally cooled to room temperature to obtain a cross-linked mussel myoglobin mixture, which is then placed in a temperature environment of 5°C for low-temperature preservation before use.

[0036] Preparation Example 2

[0037] The preparation method of the cross-linked mussel myoglobin mixture specifically includes the following processes:

[0038] The commercially available fresh mussels are washed with tap water to remove surface impurities, then shelled to obtain mussel meat, and the mussel meat is cut into pieces with scissors to obtain mussel pieces. According to the solid-liquid ratio, 1 part by weight of the mussel pieces and 1 part by weight of distilled water are mixed, then placed in a homogenizer, and the rotation speed is adjusted to 8000 r / min for 90 s of homogenization treatment to obtain a mussel meat slurry. The pH value of the mussel meat slurry is adjusted to 7 with ammonia water, then 0.6% of neutral protease by weight of the mussel meat slurry is sucked into it with a pipette gun for mixing, then placed in an environment with a temperature of 45°C for timed enzymolysis for 3 h. After the enzymolysis is completed, the obtained enzymolysis liquid is taken out, then 0.005 times the weight of the enzymolysis liquid of glyoxal cross-linking agent is added to the enzymolysis liquid for mixing, and the mixing temperature is controlled at 20°C, the mixing rotation speed is set at 200 r / min, and the stirring mixing reaction is carried out for 10 h. After the mixing reaction is completed, it is immediately placed in a temperature environment of 80°C for high-temperature inactivation treatment, and the treatment time is maintained for 10 min. After inactivation is completed, it is naturally cooled to room temperature to obtain a cross-linked mussel myoglobin mixture, which is then placed in a temperature environment of 5°C for low-temperature preservation before use.

[0039] Preparation Example 3

[0040] The preparation method of the cross-linked mussel myoglobin mixture specifically includes the following processes:

[0041] The commercially available fresh mussels are washed with tap water to remove surface impurities, then shelled to obtain mussel meat, and the mussel meat is cut into pieces with scissors to obtain mussel meat pieces. According to the solid-liquid ratio, 1 part by weight of the mussel meat pieces and 2 parts by weight of distilled water are mixed, then placed in a homogenizer, and the rotation speed is adjusted to 10,000 r / min for homogenization treatment for 150 s to obtain a mussel meat slurry. The pH value of the mussel meat slurry is adjusted to 7.5 with ammonia water, then 0.7% of neutral protease by weight of the mussel meat slurry is sucked into it with a pipette for mixing, then placed in an environment with a temperature of 50°C for timed enzymolysis for 5 h. After the enzymolysis is completed, the obtained enzymolysis liquid is taken out, then 0.007 times the weight of the enzymolysis liquid of glyoxal cross-linking agent is added to the enzymolysis liquid for mixing, and the mixing temperature is controlled at 25°C, the mixing rotation speed is set to 200 r / min, and the mixing reaction is stirred for 12 h. After the mixing reaction is completed, it is immediately placed in a temperature environment of 90°C for high-temperature inactivation treatment, and the treatment time is maintained for 15 min. After inactivation is completed, it is naturally cooled to room temperature to obtain a cross-linked mussel myoglobin mixture, which is then placed in a temperature environment of 5°C for low-temperature preservation for use.

[0042] Preparation Example 4

[0043] The preparation method of the cross-linked mussel myoglobin mixture specifically includes the following processes:

[0044] The commercially available fresh mussels are washed with tap water to remove surface impurities, then shelled to obtain mussel meat, and the mussel meat is cut into pieces with scissors to obtain mussel meat pieces. According to the solid-liquid ratio, 1 part by weight of the mussel meat pieces and 2 parts by weight of distilled water are mixed, then placed in a homogenizer, and the rotation speed is adjusted to 10,000 r / min for homogenization treatment for 150 s to obtain a mussel meat slurry. The pH value of the mussel meat slurry is adjusted to 7.5 with ammonia water, then 0.7% of neutral protease by weight of the mussel meat slurry is sucked into it with a pipette for mixing, then placed in an environment with a temperature of 50°C for timed enzymolysis for 5 h. After the enzymolysis is completed, the obtained enzymolysis liquid is taken out, then 0.007 times the weight of the enzymolysis liquid of glyoxal cross-linking agent is added to the enzymolysis liquid for mixing, and the mixing temperature is controlled at 25°C, the mixing rotation speed is set to 200 r / min, and the mixing reaction is stirred for 12 h. After the mixing reaction is completed, it is immediately placed in a temperature environment of 90°C for high-temperature inactivation treatment, and the treatment time is maintained for 15 min. After inactivation is completed, it is naturally cooled to room temperature to obtain a cross-linked mussel myoglobin mixture, which is then placed in a temperature environment of 5°C for low-temperature preservation for use.

[0045] Preparation Example 5

[0046] The preparation method of the cross-linked mussel myoglobin mixture specifically includes the following processes:

[0047] The glyoxal crosslinking agent in Preparation Example 3 is replaced with glutaraldehyde crosslinking agent, and the rest of the conditions remain the same as in Preparation Example 3.

[0048] Preparation Example 6

[0049] The preparation method of the oxidized cyclodextrin solution specifically includes the following processes:

[0050] β-cyclodextrin is added to water and stirred to dissolve and disperse uniformly (heating can be appropriately performed to promote dissolution), and then sodium periodate is added in an equal weight portion to the β-cyclodextrin to perform mixing reaction, dilute hydrochloric acid is used to adjust the pH of the reaction solution to 5.0, and then light shielding is performed in a temperature environment of 20°C, and then timed reaction is performed for 1 h, after the reaction is completed, dialysis treatment is performed using a 500 Da dialysis bag to obtain the oxidized cyclodextrin solution.

[0051] Preparation Example 7

[0052] The preparation method of the oxidized cyclodextrin solution specifically includes the following processes:

[0053] β-cyclodextrin is added to water and stirred to dissolve and disperse uniformly (heating can be appropriately performed to promote dissolution), and then sodium periodate is added in an equal weight portion to the β-cyclodextrin to perform mixing reaction, dilute hydrochloric acid is used to adjust the pH of the reaction solution to 5.5, and then light shielding is performed in a temperature environment of 20°C, and then timed reaction is performed for 70 min, after the reaction is completed, dialysis treatment is performed using a 500 Da dialysis bag to obtain the oxidized cyclodextrin solution.

[0054] Preparation Example 8

[0055] The preparation method of the oxidized cyclodextrin solution specifically includes the following processes:

[0056] γ-cyclodextrin is added to water and stirred to dissolve and disperse uniformly (heating can be appropriately performed to promote dissolution), and then sodium periodate is added in an equal weight portion to the γ-cyclodextrin to perform mixing reaction, dilute hydrochloric acid is used to adjust the pH of the reaction solution to 6.0, and then light shielding is performed in a temperature environment of 25°C, and then timed reaction is performed for 1.5 h, after the reaction is completed, dialysis treatment is performed using a 500 Da dialysis bag to obtain the oxidized cyclodextrin solution.

[0057] Preparation Example 9

[0058] The preparation method of the oxidized cyclodextrin solution specifically includes the following processes:

[0059] The α-cyclodextrin is added into water and stirred to dissolve and disperse uniformly (heating can be appropriately performed to promote dissolution), and then sodium periodate equal in weight to the α-cyclodextrin is added to mix the reaction solution. The pH of the reaction solution is adjusted to 6.0 with dilute hydrochloric acid, and then the solution is subjected to light-shielding treatment at a temperature environment of 25°C, and then timed reaction is performed for 1.5 h. After the reaction is completed, the solution is subjected to dialysis treatment with a 500 Da dialysis bag to obtain an oxidized cyclodextrin solution.

[0060] Preparation Example 10

[0061] The preparation method of the oxidized cyclodextrin solution specifically includes the following processes:

[0062] The γ-cyclodextrin is added into water and stirred to dissolve and disperse uniformly (heating can be appropriately performed to promote dissolution), and then sodium periodate equal in weight to the γ-cyclodextrin is added to mix the reaction solution. The pH of the reaction solution is adjusted to 4.0 with dilute hydrochloric acid, and then the solution is subjected to light-shielding treatment at a temperature environment of 30°C, and then timed reaction is performed for 2 h. After the reaction is completed, the solution is subjected to dialysis treatment with a 500 Da dialysis bag to obtain an oxidized cyclodextrin solution.

[0063] Preparation Example 11

[0064] The preparation method of the oxidized cyclodextrin-plant oil-urea inclusion body mixed solution specifically includes the following processes:

[0065] 1 part by weight of urea and 2 parts by weight of soybean oil are weighed and mixed together, and then put into a high-speed shearing machine, and the shearing rotation speed is controlled to be 5000 r / min, and shearing treatment is performed for 3 min. After the shearing treatment is completed, the obtained dispersion is taken out, and Span 60 is added to the dispersion in an amount of 0.01 times the weight of the dispersion, and mixed, and stirred at a speed of 300 r / min for 20 min to obtain a plant oil-encapsulated urea mixture. 1 part by weight of the oxidized cyclodextrin solution prepared in Preparation Example 6 and 1 part by weight of the plant oil-encapsulated urea mixture are weighed and mixed, and then mixed and stirred in a temperature environment of 25°C for 2 h to obtain an oxidized cyclodextrin-plant oil-urea inclusion body mixed solution.

[0066] Preparation Example 12

[0067] The preparation method of the oxidized cyclodextrin-plant oil-urea inclusion body mixed solution specifically includes the following processes:

[0068] Take 1 part by weight of urea and 3 parts by weight of soybean oil mixed together, and then put into a high-speed shearing machine, control the shearing speed of 5500r / min, shearing treatment 3 min. After shearing treatment, the dispersion obtained is taken out, according to 0.015 times of the weight of the dispersion, Span 60 is added to the dispersion for mixing, stirring at a speed of 300r / min for 20 min to obtain a plant oil-encapsulated urea mixture. Take 3 parts by weight of the oxidized cyclodextrin solution prepared in Preparation Example 7 and 1 part by weight of the plant oil-encapsulated urea mixture, and then mix and stir in a temperature environment of 30℃ for 3h to obtain an oxidized cyclodextrin-plant oil-urea inclusion body mixture.

[0069] Preparation Example 13

[0070] The preparation method of the oxidized cyclodextrin-plant oil-urea inclusion body mixture specifically includes the following processes:

[0071] Take 1 part by weight of urea and 4 parts by weight of peanut oil mixed together, and then put into a high-speed shearing machine, control the shearing speed of 6000r / min, shearing treatment 4 min. After shearing treatment, the dispersion obtained is taken out, according to 0.02 times of the weight of the dispersion, Span 80 is added to the dispersion for mixing, stirring at a speed of 300r / min for 20 min to obtain a plant oil-encapsulated urea mixture. Take 5 parts by weight of the oxidized cyclodextrin solution prepared in Preparation Example 8 and 1 part by weight of the plant oil-encapsulated urea mixture, and then mix and stir in a temperature environment of 30℃ for 4h to obtain an oxidized cyclodextrin-plant oil-urea inclusion body mixture.

[0072] Preparation Example 14

[0073] The preparation method of the oxidized cyclodextrin-plant oil-urea inclusion body mixture specifically includes the following processes:

[0074] The oxidized cyclodextrin solution in Preparation Example 13 is replaced with the oxidized cyclodextrin solution obtained in Preparation Example 9, and the rest of the conditions remain the same as in Preparation Example 13.

[0075] Preparation Example 15

[0076] The preparation method of the oxidized cyclodextrin-plant oil-urea inclusion body mixture specifically includes the following processes:

[0077] The oxidized cyclodextrin solution in Preparation Example 13 is replaced with the oxidized cyclodextrin solution obtained in Preparation Example 10, and the rest of the conditions remain the same as in Preparation Example 13.

[0078] Preparation Example 16

[0079] The preparation method of the oxidized cyclodextrin-plant oil-urea inclusion body mixture specifically includes the following processes:

[0080] Take 1 part by weight of urea and 4 parts by weight of peanut oil mixed together, and then put into a high-speed shearing machine, control the shearing speed of 7000r / min, shearing treatment 5min. After shearing treatment, the obtained dispersion is taken out, according to 0.02 times of the weight of the dispersion, Span 80 is added to the dispersion for mixing, stirring at a speed of 300r / min for 20min to obtain a plant oil-coated urea mixture. Take 5 parts by weight of the oxidized cyclodextrin solution prepared in Preparation Example 8 and 1 part by weight of the plant oil-coated urea mixture, and then mix them in a temperature environment controlled at 30℃ for 4h to obtain an oxidized cyclodextrin-plant oil-urea inclusion body mixture.

[0081] Example 1

[0082] A preparation method of a slow-release type composite organic liquid water-soluble fertilizer based on natural extracts, specifically including the following processes:

[0083] Mix 1 part by weight of the cross-linked mussel mucin mixture obtained in Preparation Example 1, 0.01 parts by weight of ethylenediamine cross-linking agent, and 3 parts by weight of the oxidized cyclodextrin-plant oil-urea inclusion body mixture obtained in Preparation Example 11, and then control the mixing temperature to be 30℃, stir at a speed of 200r / min for 2h to obtain a slow-release type composite organic liquid water-soluble fertilizer.

[0084] Example 2

[0085] A preparation method of a slow-release type composite organic liquid water-soluble fertilizer based on natural extracts, specifically including the following processes:

[0086] Mix 1 part by weight of the cross-linked mussel mucin mixture obtained in Preparation Example 2, 0.015 parts by weight of ethylenediamine cross-linking agent, and 4 parts by weight of the oxidized cyclodextrin-plant oil-urea inclusion body mixture obtained in Preparation Example 12, and then control the mixing temperature to be 30℃, stir at a speed of 200r / min for 2.5h to obtain a slow-release type composite organic liquid water-soluble fertilizer.

[0087] Example 3

[0088] A preparation method of a slow-release type composite organic liquid water-soluble fertilizer based on natural extracts, specifically including the following processes:

[0089] Mix 1 part by weight of the cross-linked mussel mucin mixture obtained in Preparation Example 3, 0.02 parts by weight of 1,3-propanediamine cross-linking agent, and 5 parts by weight of the oxidized cyclodextrin-plant oil-urea inclusion body mixture obtained in Preparation Example 13, and then control the mixing temperature to be 35℃, stir at a speed of 200r / min for 3h to obtain a slow-release type composite organic liquid water-soluble fertilizer.

[0090] Comparative Example 1

[0091] A preparation method of a slow-release composite organic liquid water-soluble fertilizer based on natural extracts, specifically including the following processes:

[0092] The cross-linked mussel myoglobin mixture solution in Example 3 was replaced with the cross-linked mussel myoglobin mixture solution obtained in Preparation Example 4, and the remaining conditions were kept consistent with Example 3.

[0093] Comparative Example 2

[0094] A preparation method of a slow-release composite organic liquid water-soluble fertilizer based on natural extracts, specifically including the following processes:

[0095] The cross-linked mussel myoglobin mixture solution in Example 3 was replaced with the cross-linked mussel myoglobin mixture solution obtained in Preparation Example 5, and the remaining conditions were kept consistent with Example 3.

[0096] Comparative Example 3

[0097] A preparation method of a slow-release composite organic liquid water-soluble fertilizer based on natural extracts, specifically including the following processes:

[0098] The oxidized cyclodextrin-plant oil-urea inclusion body mixture solution in Example 3 was replaced with the oxidized cyclodextrin-plant oil-urea inclusion body mixture solution obtained in Preparation Example 14, and the remaining conditions were kept consistent with Example 3.

[0099] Comparative Example 4

[0100] A preparation method of a slow-release composite organic liquid water-soluble fertilizer based on natural extracts, specifically including the following processes:

[0101] The oxidized cyclodextrin-plant oil-urea inclusion body mixture solution in Example 3 was replaced with the oxidized cyclodextrin-plant oil-urea inclusion body mixture solution obtained in Preparation Example 15, and the remaining conditions were kept consistent with Example 3.

[0102] Comparative Example 5

[0103] A preparation method of a slow-release composite organic liquid water-soluble fertilizer based on natural extracts, specifically including the following processes:

[0104] The oxidized cyclodextrin-plant oil-urea inclusion body mixture solution in Example 3 was replaced with the oxidized cyclodextrin-plant oil-urea inclusion body mixture solution obtained in Preparation Example 16, and the remaining conditions were kept consistent with Example 3.

[0105] Comparative Example 6

[0106] A preparation method of a slow-release composite organic liquid water-soluble fertilizer based on natural extracts, specifically including the following processes:

[0107] The cross-linked mussel adhesive protein mixture solution obtained in Preparation Example 3, 0.02 parts by weight of 1,3-propanediamine cross-linking agent, and 5 parts by weight of the oxidized cyclodextrin-plant oil-urea inclusion complex mixture obtained in Preparation Example 13 were mixed, and then the temperature of the mixture was controlled at 35°C, and the mixture was stirred at a rotation speed of 200 r / min for 10 h, and it was found that the fertilizer gel was solidified.

[0108] According to the standard of GB / T 23348-2009 Slow-Release Fertilizer, the slow-release type composite organic liquid water-soluble fertilizers prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were mixed with tap water at 500 times the weight of the slow-release type composite organic liquid water-soluble fertilizers, and were placed in an environment at 25±2°C, and the cumulative release rate of urea was detected on the 28th day, and the results are shown in Table 1 below.

[0109] Table 1 Cumulative release rate of urea

[0110]

[0111]

[0112] The slow-release type composite organic liquid water-soluble fertilizers prepared in Examples 1 to 3 and Comparative Examples 1 to 6 were mixed with tap water at 500 times the weight of the slow-release type composite organic liquid water-soluble fertilizers, 9 plastic boxes each containing 500 g of dry soil were weighed, 20 small holes were punched in the bottom of each plastic box, and the above water-soluble fertilizers were poured into the plastic boxes containing dry soil, respectively, and then the plastic boxes were sealed with plastic film, and only the bottom needle holes were exposed, and a plastic cup was placed below the bottom needle holes to prevent water from leaking, and then the plastic boxes were placed in an incubator at 25±2°C, and the amount of water leaking from the bottom needle holes was observed, and the weight of the water in the plastic cup was measured on the 3rd day, and the results are shown in Table 2 below.

[0113] Table 2 Water retention test

[0114]

[0115]

[0116] From the above Tables 1 and 2, the following conclusions can be drawn:

[0117] (1) It can be found from Examples 1 to 3 that, first, the cross-linked mussel adhesive protein mixture solution with high temperature resistance is constructed by condensation cross-linking, then the oxidized cyclodextrin-plant oil-urea inclusion complex mixture is obtained by wrapping urea with cyclodextrin, and finally, the slow-release type composite organic liquid water-soluble fertilizer is formed by cross-linking the oxidized cyclodextrin-plant oil-urea inclusion complex mixture and the cross-linked mussel adhesive protein mixture solution through amino and aldehyde groups with the aid of diamine cross-linking agent, and has good slow-release and water-retention properties.

[0118] (2) From Comparative Example 1, it can be found that, due to the low mussel mucin contained in mussels, if no cross-linking protection treatment is performed, the activity of mussel mucin in the enzymatic hydrolysate may be weakened during high-temperature inactivation, and without cross-linking protection, when mixed with the oxidized cyclodextrin-plant oil-urea inclusion mixture in the later stage, although the amino groups contained in the mussel mucin can be cross-linked with the oxidized cyclodextrin-plant oil-urea inclusion mixture through a diamine cross-linking agent, the adhesion is poor, resulting in poor water retention performance of the slow-release type composite organic liquid water-soluble fertilizer prepared finally.

[0119] (3) From Comparative Example 2, it can be found that, although glutaraldehyde also contains two aldehyde groups and can be cross-linked, due to the long carbon chain of glutaraldehyde, when it is introduced into the cross-linked mussel mucin mixture, the long carbon chain will increase the hydrophobicity to some extent, resulting in poor water retention performance of the slow-release type composite organic liquid water-soluble fertilizer prepared finally.

[0120] (4) From Comparative Example 3, it can be found that, although α-cyclodextrin has the same hydrophilic outer and hydrophobic inner cavity structure, the particle size of the plant oil-urea mixture obtained by wrapping urea with plant oil is large, resulting in poor encapsulation effect of α-cyclodextrin on the plant oil-urea mixture, so that the slow-release type composite organic liquid water-soluble fertilizer prepared finally is released quickly.

[0121] (5) From Comparative Example 4, it can be found that, further increasing the acidic environment, reaction temperature and reaction time is beneficial to the further oxidation of sodium periodate to generate aldehyde groups from vicinal diol structures, but in this system, due to excessive oxidation, the cavity structure of γ-cyclodextrin is destroyed, which cannot achieve the wrapping of urea, and thus the slow-release type composite organic liquid water-soluble fertilizer prepared loses the slow-release effect.

[0122] (6) From Comparative Example 5, it can be found that, due to the high-speed shearing treatment, the wrapping of urea by peanut oil is destroyed, and urea is water-soluble, so that the slow-release type composite organic liquid water-soluble fertilizer prepared loses the slow-release effect.

[0123] (7) From Comparative Example 6, it can be found that, due to over-cross-linking, gel solidification occurs, which is difficult to dissolve in the room temperature test environment (25±2℃) after adding water, and the amount of urea dissolved is extremely low, resulting in failure of preparation.

[0124] The above examples have described the technical solutions and beneficial effects of the present application in detail, and it should be understood that the above description is only a specific embodiment of the present application and is not used to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application.

Claims

1. A method for preparing a slow-release composite organic liquid water-soluble fertilizer based on natural extracts, characterized in that, The preparation method comprises the following steps: The cross-linked mussel myoglobin mixture, the diamine cross-linking agent and the oxidized cyclodextrin-plant oil-urea inclusion mixture are mixed in a weight ratio of 1:0.01-0.02:3-5, and then stirring reaction is carried out at a temperature of 30-35 DEG C for 2-3 hours to obtain the slow-release type composite organic liquid water-soluble fertilizer. The preparation method of the oxidized cyclodextrin-plant oil-urea inclusion mixture comprises the following steps: The urea and the plant oil are mixed in a weight ratio of 1:2-4, and then a dispersion is obtained through high-speed shearing; the dispersion and the emulsifier are mixed in a weight ratio of 1:0.01-0.02, and then stirring is carried out to obtain a plant oil-encapsulated urea mixture; The oxidized cyclodextrin solution and the plant oil-encapsulated urea mixture are mixed in a weight ratio of 1-5:1, and then stirring is carried out in a temperature environment of 25-30 DEG C for 2-4 hours to obtain the oxidized cyclodextrin-plant oil-urea inclusion mixture.

2. The method for preparing the slow-release composite organic liquid water-soluble fertilizer based on natural extracts according to claim 1, characterized in that, The preparation method of the cross-linked mussel myoglobin mixture comprises the following steps: The mussel minced meat and distilled water are mixed in a material-liquid ratio of 1:1-2, and then high-speed homogenization treatment is carried out to obtain a mussel meat slurry; The pH of the mussel meat slurry is adjusted to 7-7.5, and then neutral protease is added, and enzymolysis is carried out at a temperature of 45-50 DEG C for 3-5 hours to obtain an enzymolysis liquid; The enzymolysis liquid and the dialdehyde cross-linking agent are mixed, and then reaction is carried out at 20-25 DEG C for 10-12 hours, and then high-temperature inactivation treatment is carried out at 80-90 DEG C for 10-15 minutes to obtain the cross-linked mussel myoglobin mixture.

3. The method for preparing a slow-release compound organic liquid water-soluble fertilizer based on natural extracts according to claim 2, characterized in that, The dialdehyde cross-linking agent comprises glyoxal.

4. The method for preparing the slow-release composite organic liquid water-soluble fertilizer based on natural extracts according to claim 2, characterized in that, The weight ratio of the enzymolysis liquid to the dialdehyde cross-linking agent is 1:0.005-0.

007.

5. The method for preparing the slow-release composite organic liquid water-soluble fertilizer based on natural extracts according to claim 1, characterized in that, The diamine cross-linking agent comprises ethylenediamine or 1,3-propanediamine.

6. The method for preparing the slow-release composite organic liquid water-soluble fertilizer based on natural extracts according to claim 1, characterized in that, The plant oil comprises soybean oil or peanut oil.

7. The method for preparing a slow-release compound organic liquid water-soluble fertilizer based on natural extracts according to claim 1, characterized in that, The preparation method of the oxidized cyclodextrin solution comprises the following steps: After cyclodextrin is dissolved and dispersed in water, sodium periodate is mixed with the dissolved cyclodextrin to obtain a reaction liquid in a weight ratio of 1:1 of cyclodextrin to sodium periodate, the pH of the reaction liquid is adjusted to 5.0-6.0, and then reaction is carried out at 20-25 DEG C in the dark for 1-1.5 hours to obtain the oxidized cyclodextrin solution. 8.A slow-release type composite organic liquid water-soluble fertilizer prepared by the preparation method of the slow-release type composite organic liquid water-soluble fertilizer based on natural extracts according to any one of claims 1-7.

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