Slow-release organic compound fertilizer for dry land hulless oat and preparation method of slow-release organic compound fertilizer

Abstract

The invention discloses a slow-release organic compound fertilizer for dry land hulless oat and a preparation method of the slow-release organic compound fertilizer, and relates to the technical field of organic fertilizers. The slow-release organic compound fertilizer for the dry land hulless oat is prepared from icariin compound slow-release microspheres, wheat cellulose-based super absorbent resin and genipin, the wheat cellulose-based super absorbent resin and icariin composite sustained-release microspheres are cross-linked by genipin, and the microspheres are uniformly embedded into the resin to form an interpenetrating network structure, so that a micro reservoir can be formed in soil to slowly release water to be utilized by hulless oat root systems; the micro-water channel can absorb free nutrients released by the icariin composite sustained-release microspheres at the root system in a targeted mode, nutrient loss is reduced, water and nutrients are delivered into the hulless oat root system in a targeted mode through the micro-water channel, growth of hulless oat is effectively promoted, and the yield increasing effect is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of organic fertilizers, and in particular relates to a slow-release organic compound fertilizer for dryland naked oats and a preparation method thereof. Background Art

[0002] Naked oats have a well-developed root system, leaves with few stomata and covered with hairs on the surface, which can effectively reduce water evaporation. They can still grow normally in arid mountainous areas with an annual precipitation of 200-400 mm. Therefore, naked oats can form a stable production system in dry plateau areas without irrigation conditions and transform barren slopes into grain production areas. However, drought can also lead to reduced tillering of naked oats and a decrease in the number of grains per ear, which is not conducive to the growth and increase of naked oats.

[0003] In oat cultivation, nutrients in fertilizers can directly promote crop growth. Among them, phosphorus fertilizer promotes the development of oat root system, enhances the water absorption capacity of deep soil, and improves drought resistance. Potassium fertilizer makes oat stems thick, reduces the risk of lodging, and enhances resistance to drought and disease. Nitrogen fertilizer effectively promotes oat tillering and leaf growth, and increases the number of grains per ear.

[0004] The existing technology currently has the following problems:

[0005] The utilization rate of nitrogen, phosphorus and potassium in organic fertilizers is low, and they cannot improve the water retention capacity of naked oats roots under drought conditions, further limiting the absorption of nutrients, which is not conducive to the growth and yield increase of naked oats. Summary of the Invention

[0006] In view of the above situation, in order to overcome the defects of the prior art, the present invention proposes a slow-release organic compound fertilizer for dryland naked oats, comprising the following components in parts by weight: 20-30 parts of icariin composite slow-release microspheres, 50-60 parts of wheat cellulose-based super absorbent resin, and 2-5 parts of genipin.

[0007] The icariin composite sustained-release microspheres include the following components in parts by weight: 5-8 parts of icariin, 5-10 parts of bovine serum albumin, 80-100 parts of polylactic acid-glycolic acid copolymer, 20-50 parts of potassium dihydrogen phosphate, 30-60 parts of potassium nitrate, and 30-60 parts of cross-linking liquid.

[0008] The wheat cellulose-based super absorbent resin comprises the following components in parts by weight: 10-20 parts of wheat fiber, 0.5-1.5 parts of potassium persulfate, 100-120 parts of acrylic acid, 0.1-0.5 parts of N,N-methylenebisacrylamide, and 5-15 parts of KH550 modified expanded perlite.

[0009] The preparation method of the icariin composite sustained-release microspheres specifically comprises the following steps:

[0010] (1) Add 50-80 mg of icariin to 1 mL of dimethyl sulfoxide solution, dissolve it by ultrasonication, and obtain a mother liquor for use. Measure 100 μL of the mother liquor and bovine serum albumin and dissolve them in 200 μL of water. Dissolve them by ultrasonication for 1-2 minutes under ice bath conditions. Then add 20-50 mg of potassium dihydrogen phosphate and 30-60 mg of potassium nitrate as the aqueous phase. Dissolve 80-100 mg of polylactic acid-glycolic acid copolymer in 2 mL of dichloromethane solvent as the oil phase. Add the aqueous phase to the oil phase and ultrasonicate under ice bath conditions to obtain colostrum. As a natural amphiphilic protein, bovine serum albumin can reduce interfacial tension when colostrum is formed, making the microsphere particle size more uniform. Then add the colostrum to 10 mL of 2% polyvinyl alcohol aqueous solution by mass. The resulting emulsion is transferred to 400 mL of 10% sodium chloride aqueous solution by mass, magnetically stirred at 4°C for 2-4 hours, centrifuged for 10-20 minutes, and the supernatant is discarded. The precipitate is washed 3-5 times with ultrapure water, and the precipitate is collected. The process uses polylactic acid-glycolic acid copolymer as a carrier to synthesize uniform microspheres encapsulating nitrogen, phosphorus, potassium fertilizers and icariin, forming a nutrition-growth promotion-adversity resistance multifunctional system. Through the gradual hydrolysis of the carrier, icariin and nitrogen, phosphorus, potassium nutrients are slowly and continuously released to achieve the effect of promoting the growth of naked oats. Among them, icariin can optimize the soil microbial community, enhance the activity of nitrogen-fixing bacteria and phosphate-solubilizing bacteria, and is beneficial to the conversion of nitrogen, phosphorus, and potassium. Icariin has a similar effect to a plant growth regulator, can stimulate the growth of naked oats roots, and improve nutrient absorption efficiency. Icariin can also activate the plant's antioxidant system, enhance the activity of superoxide dismutase, reduce oxidative damage to naked oats in a drought environment, and improve the survival rate. At the same time, the degradation products of polylactic acid-glycolic acid copolymer, lactic acid and glycolic acid, also provide carbon sources for soil microorganisms, promote the proliferation of beneficial bacteria such as phosphate-solubilizing bacteria, and obtain icariin fertilizer microspheres;

[0011] (2) Soak the icariin fertilizer microspheres described in step (1) in a crosslinking solution, stir for 1-2 hours, centrifuge for 5-10 minutes, wash the precipitate with a pH 5.5 citric acid buffer solution for 3-5 times, and then freeze-dry in a vacuum. The crosslinking solution forms a coating protective layer on the icariin fertilizer microspheres, so that the microspheres absorb water and swell in the soil, forming a local reservoir at the root system of the naked oats, effectively improving the water retention capacity of the root system, thereby also benefiting the growth of the naked oats root system and the absorption of nutrients. At the same time, in the organic acid environment secreted by the naked oats root system, the targeted slow release The icariin and fertilizer nutrients contained in it are beneficial to the absorption and utilization of naked oats by the roots. The coating layer can enhance the mechanical properties of the microspheres and reduce the risk of breakage. The adhesion properties of the coating layer can also reduce losses caused by rainwater erosion. Among them, the amino groups of chitosan combine with the negative charge of soil clay particles to reduce water leakage losses. Under the induction of icariin, rhizosphere nitrogen-fixing bacteria secrete more mucus polysaccharides, forming a water-retaining biofilm and increasing the water content in the rhizosphere. The genipin cross-linking layer can reduce the photodegradation of icariin and enhance the stability of the active ingredient, thereby obtaining icariin composite slow-release microspheres.

[0012] Preferably, in step (1), the amount of bovine serum albumin added is 5-10 mg. Bovine serum albumin is rich in amino acids and can be gradually degraded in the soil as a nitrogen source. Its efficiency of conversion into ammonium nitrogen is slower than that of urea, thereby reducing leaching losses. Bovine serum albumin also binds to icariin through hydrophobic interactions and hydrogen bonds, thereby improving the encapsulation efficiency.

[0013] Preferably, in step (2), the cross-linking liquid is obtained by the following process: 0.1-0.3 g of chitosan is slowly added to 100 mL of a citric acid solution with a mass fraction of 1%, and magnetically stirred at 40-50 ° C and a speed of 400-500 rpm until completely dissolved, and then 0.1-0.3 g of genipin is added, the pH is controlled to 5.5, and stirred at 25 ° C for 0.5-1 h, forming a biocompatible, dual pH-triggered water-retaining, slow-release cross-linked gel network, which enhances water retention and fertilizer utilization. Among them, the citric acid maintenance system is close to the rhizosphere microenvironment of naked oats, and the cross-linked network preferentially swells in the root zone. Under the action of β-glucosidase secreted by the root system, the cross-linking bonds of genipin are selectively broken, realizing rhizosphere targeted release. In addition, the degradation products of genipin can stimulate the naked oats root system to secrete indoleacetic acid, accelerate the growth of primary root cells, and enhance the nutrient and water absorption capacity.

[0014] The present invention also provides a method for preparing a slow-release organic compound fertilizer for dryland naked oats, which specifically comprises the following steps:

[0015] S1. Soak 5.0-10.0g of expanded perlite in 5% hydrochloric acid solution for 0.5-1h to remove surface impurities, then wash with water until neutral, dry and set aside, then mix 0.5-1.0g of KH550 with 90.0g of anhydrous ethanol and 9.0-9.5g of deionized water, adjust the pH to 4.0-5.0 with acetic acid, and stir magnetically for 30-60min to obtain KH550 modified solution, then soak the dried expanded perlite in KH550 solution. The modified perlite is ultrasonically treated in a modification solution for 20-30 minutes, followed by magnetic stirring at 60-80°C for 2-4 hours, filtered, washed with deionized water 2-3 times, and finally dried. The silanol generated by the hydrolysis of KH550 reacts with the Si-OH group on the surface of the expanded perlite to enhance the chemical compatibility of the expanded perlite in the polymer matrix. At the same time, the amino group at the end of KH550 is exposed on the surface of the perlite, providing an active site, thereby obtaining KH550-modified expanded perlite.

[0016] S2. Wash and dry 10.0 g of wheat straw, crush it through a 100-200 mesh sieve, weigh 1.0-2.0 g of wheat straw powder and place it in 12-30 mL of 12% ammonia solution by mass for 48 hours, filter it, wash it with water until it is neutral, remove the hemicellulose in the wheat straw, and then add the alkali-treated wheat straw to 30 mL of 6% nitric acid solution, heat it in a water bath at 80-90°C for 30-50 minutes to remove lignin, then filter it, and wash the product with deionized water and ethanol 3-5 times, and finally dry it. This process extracts high-purity cellulose from wheat straw through alkali treatment and acid treatment. At the same time, the alkali-acid distribution treatment method avoids the decrease in cellulose crystallinity caused by strong alkali, maintains the high degree of polymerization and mechanical strength of the fiber, and after removing hemicellulose and lignin, micropores are formed on the fiber surface, the specific surface area is increased, the free hydroxyl groups are increased, and the chemical activity is high, which is conducive to subsequent modification treatment to obtain wheat fiber;

[0017] S3, the wheat fiber described in step S2 is placed in a 100mL beaker, 15mL distilled water is added, and the mixture is placed in a 70-80℃ water bath and stirred for activation for 5-10min, 0.05-0.15g potassium persulfate is added, and the KH550 modified expanded perlite described in step S1 is added, and the mixture is stirred at high speed for 10-15min, followed by adding 20mL monomer solution, wherein the monomer solution is prepared by neutralizing 10.0-12.0g acrylic acid with 4.0-4.4g sodium hydroxide, and finally 0.01-0.05g N,N-methylenebisacrylamide is added and stirred continuously until a gel appears. The gel is taken out, cooled to room temperature and washed with distilled water, and then soaked in 100mL anhydrous ethanol for 16h, and the anhydrous ethanol is replaced every 8h. The polymer prepared is vacuum dried, and the wheat fiber is used as a flexible skeleton, the KH550 modified expanded perlite is used as a rigid skeleton, and acrylic acid is used as a hydrophilic monomer. Under the action of a crosslinking agent and an initiator, the polymer is dissolved in water and the mixture is stirred for 10 min. A highly absorbent material with a resin-perlite synergistic water-retention network was prepared by liquid polymerization. The acrylic resin itself is highly absorbent, and the porous structure of the KH550-modified expanded perlite further absorbs and locks in water, reducing evaporation and deep seepage. Simultaneously, the KH550-modified expanded perlite absorbs fertilizer nutrients. The composite interface between the perlite and the resin forms a diffusion barrier, reducing the migration of nitrogen, phosphorus, and potassium nutrients. Through micro-water channels, these nutrients, along with water, enter the naked oats root system, thereby improving the root system's water retention and nutrient absorption capacity. The rigid skeleton of the KH550-modified expanded perlite reduces structural collapse of the resin after swelling, maintaining porosity and enhancing its repeated water absorption and release capacity. The amino groups on the surface of the KH550-modified expanded perlite form hydrogen bonds or covalent crosslinks with wheat cellulose and acrylic acid monomers, preventing sedimentation or phase separation of the perlite in the gel and allowing its uniform dispersion in the resin network. This enhances mechanical properties, resulting in a wheat cellulose-based highly absorbent resin.

[0018] S4, dissolving genipin in 100 mL of pH 7.4 phosphate buffer to obtain a genipin solution for standby use, and storing it in the dark, first immersing the icariin composite sustained-release microspheres in 50 mL of the genipin solution, and shaking the reaction at 25° C. for 8-12 h to form a preliminary cross-linked network between the microsphere surface and the genipin, then taking out the icariin composite sustained-release microspheres, mixing them with the wheat cellulose-based super absorbent resin described in step S3, adding the remaining 50 mL of the genipin solution, stirring the reaction at 40° C. for 12-24 h, and freeze-drying, and the genipin and the wheat cellulose-based super absorbent resin were separated. The hydroxyl groups and icariin composite slow-release microspheres form covalent bonds on their surfaces, building an interpenetrating network structure. This allows the microspheres to be evenly embedded in the porous resin structure, forming a micro-reservoir in the soil that slowly releases water for the oat root system to utilize. The microspheres can also adsorb free nutrients targeted for release at the root system, acting as a diffusion barrier to delay sudden release. At the same time, both water and nutrients can enter the oat root system through micro-water channels, improving the root system's water retention capacity and nutrient absorption capacity, thereby effectively promoting the oat's growth and significantly increasing yields, resulting in a slow-release organic compound fertilizer for dryland oat.

[0019] Preferably, in step S1, the bulk density of the expanded perlite is 80-180 kg / m 3 The particle size is 4-8mm, and it presents a honeycomb pore structure. It can not only absorb and store water, but also form micro-water channels to promote the migration of water to the root system and avoid deep leakage. At the same time, perlite fixes and absorbs nitrogen and potassium ions through the micropores on the surface, reducing the loss of nitrogen and potassium. The chemical inertness of perlite can also reduce the combination of phosphorus with Fe³⁺, Al³⁺ or Ca²⁺, thereby improving the effectiveness of phosphorus.

[0020] Preferably, in step S4, the amount of genipin added is 2.0-5.0 g. The suitable cross-linking environment of genipin is conducive to the survival of soil microorganisms such as nitrogen-fixing bacteria and phosphate-solubilizing bacteria, thereby also facilitating the conversion of nitrogen, phosphorus and potassium.

[0021] The beneficial effects achieved by the present invention are as follows:

[0022] The present invention cross-links wheat cellulose-based highly absorbent resin and icariin composite slow-release microspheres with genipin, uniformly embeds the microspheres in the resin, and forms an interpenetrating network structure. The microspheres can not only form a micro-reservoir in the soil and slowly release water for the naked oats root system to utilize, but also absorb the free nutrients targetedly released by the icariin composite slow-release microspheres at the root system, reducing nutrient loss, and delivering water and nutrients to the naked oats root system through micro-water channels, thereby improving the water retention of the root system, enhancing the nutrient absorption of the naked oats, effectively promoting the growth of the naked oats, and significantly improving the yield-increasing effect. In the icariin composite slow-release microspheres, polylactic acid-glycolic acid copolymer is first used as The carrier is synthesized into uniform microspheres encapsulating nitrogen, phosphorus and potassium fertilizers and icariin. Through the gradual hydrolysis of the carrier, icariin and nitrogen, phosphorus and potassium nutrients are slowly and continuously released. Then, the surface of the icariin fertilizer microspheres is coated with an adhesive and targeted cross-linking liquid. The microspheres absorb water and swell to form a local water reservoir at the root system of the oat, which improves the water retention capacity of the root system. At the same time, in the organic acid environment secreted by the oat root system, the icariin and fertilizer nutrients are slowly released in a targeted manner, which is beneficial to the absorption and utilization of the oat root system. Among them, icariin can stimulate the growth of the oat root system and improve the efficiency of nutrient absorption. Bovine serum albumin not only serves as a source of nitrogen fertilizer, but also interacts with icariin through hydrophobic interactions. The wheat cellulose-based super absorbent resin uses wheat fiber as a flexible skeleton, KH550 modified expanded perlite as a rigid skeleton, and acrylic acid as a hydrophilic monomer. With the participation of a cross-linking agent and an initiator, an aqueous solution polymerization method is used to prepare a super absorbent material with a resin-perlite synergistic water retention network. This material not only effectively reduces water evaporation and deep leakage, but also can absorb fertilizer nutrients through the KH550 modified expanded perlite. In addition, under the diffusion barrier effect of the composite interface of perlite and resin, the migration of nutrients such as nitrogen, phosphorus, and potassium is reduced. At the same time, with the micro-water channels formed by perlite, nitrogen, phosphorus, and potassium nutrients, epimedium, and chrysanthemum are absorbed by the resin. The icariin and water enter the naked oat root system together, thereby improving the water retention capacity of the root system and the absorption and utilization rate of nutrients, and promoting the growth of the naked oat; the cross-linked layer of genipin can reduce the photodegradation of icariin and enhance the stability of the effective ingredient, while the degradation product of genipin can stimulate the naked oat root system to secrete indoleacetic acid, accelerate the growth of primary root cells, and enhance the nutrient and water absorption capacity; the present invention uses icariin composite slow-release microspheres, wheat cellulose-based super absorbent resin, and genipin to prepare a slow-release organic compound fertilizer for dryland naked oat, which improves the water retention capacity of the root system, enhances the nutrient absorption of naked oat, effectively promotes the growth of naked oat, and significantly improves the yield-increasing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a scanning electron microscope image of the slow-release organic compound fertilizer for dryland naked oats prepared in Example 1 of the present invention;

[0024] Figure 2Result diagram of the relative water content of the roots of Examples 1-4 of the present invention and Comparative Examples 1-3;

[0025] Figure 3 The nitrogen, phosphorus and potassium content results of Examples 1-4 and Comparative Examples 1-3 of the present invention are shown in FIG.

[0026] Figure 4 The graph shows the results of the number of ears and the number of grains per ear for Examples 1-4 of the present invention and Comparative Examples 1-3. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0029] The experimental methods in the following examples are conventional methods unless otherwise specified; the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0030] Example 1

[0031] This embodiment provides a slow-release organic compound fertilizer for dryland naked oats, comprising the following components in parts by weight: 30 parts of icariin composite slow-release microspheres, 60 parts of wheat cellulose-based super absorbent resin, and 5 parts of genipin.

[0032] The icariin composite sustained-release microspheres include the following components in parts by weight: 8 parts of icariin, 10 parts of bovine serum albumin, 100 parts of polylactic acid-glycolic acid copolymer, 50 parts of potassium dihydrogen phosphate, 60 parts of potassium nitrate, and 60 parts of cross-linking liquid.

[0033] The wheat cellulose-based super absorbent resin comprises the following components in parts by weight: 20 parts of wheat fiber, 1.5 parts of potassium persulfate, 120 parts of acrylic acid, 0.5 parts of N,N-methylenebisacrylamide, and 15 parts of KH550 modified expanded perlite.

[0034] The preparation method of icariin composite sustained-release microspheres specifically comprises the following steps:

[0035] (1) Add 80 mg of icariin to 1 mL of dimethyl sulfoxide solution and dissolve it thoroughly by ultrasonication to obtain a mother solution for use. Measure 100 μL of the mother solution and bovine serum albumin and dissolve them in 200 μL of water. Ultrasonication is used to dissolve the solution for 2 minutes in an ice bath. The amount of bovine serum albumin added is 10 mg. Bovine serum albumin is rich in amino acids and can be gradually degraded in the soil as a nitrogen source. The efficiency of conversion to ammonium nitrogen is slower than that of urea, thereby reducing leaching losses. Bovine serum albumin also binds to icariin through hydrophobic interactions and hydrogen bonds. To improve the encapsulation efficiency, 50 mg of potassium dihydrogen phosphate and 60 mg of potassium nitrate were added as the aqueous phase. 100 mg of polylactic acid-glycolic acid copolymer was dissolved in 2 mL of dichloromethane solvent as the oil phase. The aqueous phase was added to the oil phase and ultrasonically treated under ice bath conditions to obtain colostrum. As a natural amphiphilic protein, bovine serum albumin can reduce the interfacial tension when colostrum is formed, making the microsphere particle size more uniform. Then, the colostrum was added to 10 mL of a 2% polyvinyl alcohol aqueous solution by mass fraction, and the resulting emulsion was transferred to 400 mL of a 2% polyvinyl alcohol aqueous solution by mass fraction. The mixture was added into a 10% sodium chloride aqueous solution, magnetically stirred for 4 hours at 4°C, centrifuged for 20 minutes, the supernatant was discarded, the precipitate was washed 5 times with ultrapure water, and the precipitate was collected. The process used polylactic acid-glycolic acid copolymer as a carrier to synthesize uniform microspheres encapsulating nitrogen, phosphorus, potassium fertilizers and icariin, forming a nutrition-growth-promoting-anti-stress multifunctional system. Through the gradual hydrolysis of the carrier, icariin, nitrogen, phosphorus, potassium nutrients were slowly and continuously released to achieve the effect of promoting naked oat growth. Among them, icariin can optimize the soil microbial community and increase The activity of strong nitrogen-fixing bacteria and phosphate-solubilizing bacteria is beneficial to the conversion of nitrogen, phosphorus and potassium. Icariin has a similar effect to a plant growth regulator, which can stimulate the growth of naked oats roots and improve nutrient absorption efficiency. Icariin can also activate the plant's antioxidant system, enhance the activity of superoxide dismutase, reduce the oxidative damage to naked oats caused by drought, and improve the survival rate. At the same time, the degradation products of polylactic acid-glycolic acid copolymer, lactic acid and glycolic acid, also provide carbon sources for soil microorganisms, promoting the proliferation of beneficial bacteria such as phosphate-solubilizing bacteria, and obtaining icariin fertilizer microspheres.

[0036] (2) The icariin fertilizer microspheres described in step (1) are immersed in a cross-linking solution. The cross-linking solution is obtained by the following process: 0.3 g of chitosan is slowly added to 100 mL of a 1% citric acid solution, and magnetically stirred at 50°C and 500 rpm until completely dissolved. Then, 0.3 g of genipin is added, the pH is controlled to 5.5, and stirred at 25°C for 1 hour to form a biocompatible, dual pH-triggered water-retaining, slow-release cross-linked gel network, which enhances water retention and fertilizer utilization. Among them, the citric acid maintenance system is close to the rhizosphere microenvironment of naked oats, and the cross-linked network swells preferentially in the root zone. Under the action of β-glucosidase secreted by the root system, the cross-linking bonds of genipin are selectively broken to achieve rhizosphere targeted release. In addition, the degradation products of genipin can stimulate the naked oats root system to secrete indoleacetic acid, accelerate the growth of primary root cells, and enhance the absorption capacity of nutrients and water. Stir for 2 hours, centrifuge for 10 minutes, and the precipitate is purified by pH 50. The microspheres were washed five times with 5.5% citric acid buffer solution and then vacuum freeze-dried. The cross-linking liquid formed a coating protective layer on the icariin fertilizer microspheres, which made the microspheres absorb water and swell in the soil, forming a local reservoir at the oat root system, effectively improving the root system's water retention capacity, which is also beneficial to the growth of the oat root system and the absorption of nutrients. At the same time, in the organic acid environment secreted by the oat root system, the icariin and fertilizer nutrients were slowly released in a targeted manner, which is beneficial to the absorption and utilization of the oat root system. The coating layer can enhance the mechanical properties of the microspheres and reduce the risk of breakage. The adhesion properties of the coating layer can also reduce losses caused by rainwater erosion. Among them, the amino groups of chitosan combine with the negative charge of soil clay particles to reduce water leakage losses. Rhizosphere nitrogen-fixing bacteria secrete more mucus polysaccharides under the induction of icariin, forming a water-retaining biofilm and increasing the water content in the rhizosphere. The genipin cross-linking layer can reduce the photodegradation of icariin and enhance the stability of the active ingredient to obtain icariin composite sustained-release microspheres.

[0037] This embodiment provides a method for preparing a slow-release organic compound fertilizer for dryland naked oats, which specifically comprises the following steps:

[0038] S1. Soak 10.0g of expanded perlite in 5% hydrochloric acid solution for 1 hour. The bulk density of the expanded perlite is 180kg / m 3, with a particle size of 8mm and a honeycomb pore structure, which can not only absorb and store water, but also form micro-water channels to promote the migration of water to the root system and avoid deep leakage. At the same time, perlite fixes and absorbs nitrogen and potassium ions through the micropores on the surface, reducing the loss of nitrogen and potassium. The chemical inertness of perlite can also reduce the combination of phosphorus with Fe³⁺, Al³⁺ or Ca²⁺, improve the effectiveness of phosphorus, remove surface impurities, then wash with water to neutrality, dry for use, and then mix 1.0g KH550 with 90.0g anhydrous ethanol and 9.0g deionized water, adjust the pH to 5.0 with acetic acid, and magnetic The mixture was stirred for 60 minutes to obtain a KH550 modified solution, and then the dried expanded perlite was immersed in the KH550 modified solution and ultrasonically treated for 30 minutes. Subsequently, the mixture was magnetically stirred at 80°C for 4 hours, filtered, and the modified expanded perlite was washed three times with deionized water. Finally, the mixture was dried. The silanol generated by the hydrolysis of KH550 condensed with the Si-OH group on the surface of the expanded perlite to enhance the chemical compatibility of the expanded perlite in the polymer matrix. At the same time, the amino group at the end of KH550 was exposed on the surface of the perlite, providing an active site, thereby obtaining the KH550-modified expanded perlite.

[0039] S2. Wash and dry 10.0 g of wheat straw, crush it through a 200-mesh sieve, weigh 2.0 g of wheat straw powder, place it in 30 mL of 12% ammonia solution by mass for 48 hours, filter it, wash it with water until it is neutral, remove the hemicellulose in the wheat straw, and then add the alkali-treated wheat straw to 30 mL of 6% nitric acid solution, heat it in a water bath at 90°C for 50 minutes to remove lignin, then filter it, and wash the product with deionized water and ethanol 5 times, and finally dry it. This process extracts high-purity cellulose from wheat straw through alkali treatment and acid treatment. At the same time, the alkali-acid distribution treatment method avoids the decrease in cellulose crystallinity caused by strong alkali, maintains the high degree of polymerization and mechanical strength of the fiber, and after removing the hemicellulose and lignin, micropores are formed on the fiber surface, the specific surface area is increased, the free hydroxyl groups are increased, and the chemical activity is high, which is conducive to subsequent modification treatment to obtain wheat fiber;

[0040] S3. The wheat fiber described in step S2 was placed in a 100 mL beaker, 15 mL of distilled water was added, and the mixture was placed in an 80 ° C water bath and stirred for activation for 10 min. 0.15 g of potassium persulfate was added, and the KH550 modified expanded perlite described in step S1 was added, and the mixture was stirred at high speed for 15 min. Then 20 mL of monomer solution was added, wherein the monomer solution was prepared by neutralizing 10.0 g of acrylic acid with 4.4 g of sodium hydroxide. Finally, 0.05 g of N, N-methylenebisacrylamide was added and stirred continuously until a gel appeared. The gel was taken out, cooled to room temperature, washed with distilled water, and then soaked in 100 mL of anhydrous ethanol for 16 h. The anhydrous ethanol was replaced every 8 h. The prepared polymer was vacuum dried. The resin-perlite synergistic polymer was prepared by aqueous solution polymerization using wheat fiber as a flexible skeleton, KH550 modified expanded perlite as a rigid skeleton, and acrylic acid as a hydrophilic monomer under the action of a crosslinking agent and an initiator. The highly absorbent material with the same water-retention network, acrylic resin itself is highly absorbent. The porous structure of KH550 modified expanded perlite further absorbs and locks in moisture, reducing water evaporation and deep seepage. Simultaneously, the KH550 modified expanded perlite absorbs fertilizer nutrients. The composite interface between perlite and resin forms a diffusion barrier, reducing the migration of nitrogen, phosphorus, and potassium nutrients. Through micro-water channels, nitrogen, phosphorus, and potassium nutrients enter the naked oats root system along with water, thereby improving the root system's water retention and nutrient absorption capacity. The rigid skeleton of the KH550 modified expanded perlite reduces structural collapse of the resin after swelling, maintaining porosity and improving repeated water absorption and release capacity. The amino groups on the surface of the KH550 modified expanded perlite hydrogen bond or covalently crosslink with wheat cellulose and acrylic acid monomers, preventing sedimentation or phase separation of the perlite in the gel and allowing it to be evenly dispersed in the resin network, enhancing mechanical properties, and resulting in a wheat cellulose-based highly absorbent resin.

[0041] S4, dissolving genipin in 100mL pH7.4 phosphate buffer, the amount of genipin added is 5.0g, the suitable cross-linking environment of genipin is conducive to the survival of soil nitrogen-fixing bacteria, phosphate-solubilizing bacteria and other microorganisms, which is also conducive to the conversion of nitrogen, phosphorus and potassium, and the genipin solution is obtained for standby use and stored in the dark. First, icariin composite sustained-release microspheres are immersed in 50mL genipin solution, and the reaction is shaken at 25°C for 12h to form a preliminary cross-linked network between the microsphere surface and genipin, and then the icariin composite sustained-release microspheres are taken out, mixed with the wheat cellulose-based super absorbent resin described in step S3, and the remaining 50mL genipin solution is added, and the reaction is stirred at 40°C for 24h. Freeze-drying forms covalent bonds between genipin and the hydroxyl groups and icariin groups on the surface of the slow-release microspheres in the wheat cellulose-based super absorbent resin, thereby constructing an interpenetrating network structure. The microspheres are evenly embedded in the porous structure of the resin, which not only forms a micro-reservoir in the soil to slowly release water for the use of the naked oats roots, but also adsorbs the free nutrients released by the microspheres at the root system, delaying the sudden release by acting as a diffusion barrier. At the same time, both water and nutrients can enter the naked oats root system through micro-water channels, improving the water retention capacity of the roots and the ability to absorb nutrients, thereby effectively promoting the growth of naked oats and significantly improving the yield-increasing effect, thereby obtaining a slow-release organic compound fertilizer for dryland naked oats.

[0042] In this example, the prepared slow-release organic compound fertilizer for dryland naked oats was subjected to scanning electron microscopy to observe its microscopic morphology. Figure 1 This is a 200-fold magnified SEM image of the slow-release organic compound fertilizer for dryland naked oats prepared in Example 1. Figure 1 The slow-release organic compound fertilizer for dryland naked oats prepared in this embodiment presents a uniform interpenetrating network structure.

[0043] Example 2

[0044] This embodiment provides a slow-release organic compound fertilizer for dryland naked oats, comprising the following components in parts by weight: 20 parts of icariin composite slow-release microspheres, 50 parts of wheat cellulose-based super absorbent resin, and 2 parts of genipin.

[0045] The icariin composite sustained-release microspheres include the following components in parts by weight: 5 parts of icariin, 5 parts of bovine serum albumin, 80 parts of polylactic acid-glycolic acid copolymer, 20 parts of potassium dihydrogen phosphate, 30 parts of potassium nitrate, and 30 parts of cross-linking liquid.

[0046] The wheat cellulose-based super absorbent resin comprises the following components in parts by weight: 10 parts of wheat fiber, 0.5 parts of potassium persulfate, 100 parts of acrylic acid, 0.1 parts of N,N-methylenebisacrylamide, and 5 parts of KH550 modified expanded perlite.

[0047] The preparation method of icariin composite sustained-release microspheres specifically comprises the following steps:

[0048] (1) Add 50 mg of icariin to 1 mL of dimethyl sulfoxide solution and dissolve it thoroughly by ultrasonication to obtain a mother liquor for use. Measure 100 μL of the mother liquor and bovine serum albumin and dissolve them in 200 μL of water. Dissolve them by ultrasonication in an ice bath for 1 minute. The amount of bovine serum albumin added is 5 mg. Bovine serum albumin is rich in amino acids and can be gradually degraded in the soil as a nitrogen source. The efficiency of converting it into ammonium nitrogen is slower than that of urea, thereby reducing leaching losses. Bovine serum albumin also binds to icariin through hydrophobic interactions and hydrogen bonds, which can improve the nitrogen content. High encapsulation efficiency, then add 20mg potassium dihydrogen phosphate and 30mg potassium nitrate as the aqueous phase, dissolve 80mg polylactic acid-glycolic acid copolymer in 2mL dichloromethane solvent as the oil phase, add the aqueous phase to the oil phase, and ultrasonically treat under ice bath conditions to obtain colostrum. As a natural amphiphilic protein, bovine serum albumin can reduce the interfacial tension when colostrum is formed, making the microsphere particle size more uniform. Then add the colostrum to 10mL of 2% polyvinyl alcohol aqueous solution by mass, and transfer the obtained emulsion to 400mL of 2% by mass. The mixture was added into a 10% sodium chloride aqueous solution, magnetically stirred for 2h at 4℃, centrifuged for 10min, the supernatant was discarded, the precipitate was washed 3 times with ultrapure water, and the precipitate was collected. The process used polylactic acid-glycolic acid copolymer as a carrier to synthesize uniform microspheres encapsulating nitrogen, phosphorus, potassium fertilizers and icariin, forming a nutrition-growth-promoting-anti-stress multifunctional system. Through the gradual hydrolysis of the carrier, icariin, nitrogen, phosphorus, potassium nutrients were slowly and continuously released to achieve the effect of promoting naked oat growth. Among them, icariin can optimize the soil microbial community and increase The activity of strong nitrogen-fixing bacteria and phosphate-solubilizing bacteria is beneficial to the conversion of nitrogen, phosphorus and potassium. Icariin has a similar effect to a plant growth regulator, which can stimulate the growth of naked oats roots and improve nutrient absorption efficiency. Icariin can also activate the plant's antioxidant system, enhance the activity of superoxide dismutase, reduce the oxidative damage to naked oats caused by drought, and improve the survival rate. At the same time, the degradation products of polylactic acid-glycolic acid copolymer, lactic acid and glycolic acid, also provide carbon sources for soil microorganisms, promoting the proliferation of beneficial bacteria such as phosphate-solubilizing bacteria, and obtaining icariin fertilizer microspheres.

[0049] (2) The icariin fertilizer microspheres described in step (1) are immersed in a cross-linking solution. The cross-linking solution is obtained by the following process: 0.1 g of chitosan is slowly added to 100 mL of a 1% citric acid solution, and magnetically stirred at 40°C and 400 rpm until completely dissolved. Then, 0.1 g of genipin is added, the pH is controlled to 5.5, and stirred at 25°C for 0.5 h to form a cross-linked gel network with good biocompatibility, dual pH-triggered water retention, and slow release, which enhances water retention and fertilizer utilization. Among them, the citric acid maintenance system is close to the rhizosphere microenvironment of naked oats, and the cross-linked network swells preferentially in the root zone. Under the action of β-glucosidase secreted by the root system, the cross-linking bonds of genipin are selectively broken to achieve rhizosphere targeted release. In addition, the degradation products of genipin can stimulate the naked oats root system to secrete indoleacetic acid, accelerate the growth of primary root cells, and enhance the absorption capacity of nutrients and water. Stir for 1 h, centrifuge for 5 min, and the precipitate is purified by pH 5. The microspheres were washed three times with 5.5% citric acid buffer solution and then vacuum freeze-dried. The cross-linking liquid formed a coating protective layer on the icariin fertilizer microspheres, which made the microspheres absorb water and swell in the soil, forming a local reservoir at the oat root system, effectively improving the root system's water retention capacity, which is also beneficial to the growth of the oat root system and the absorption of nutrients. At the same time, in the organic acid environment secreted by the oat root system, the icariin and fertilizer nutrients were slowly released in a targeted manner, which is beneficial to the absorption and utilization of the oat root system. The coating layer can enhance the mechanical properties of the microspheres and reduce the risk of breakage. The adhesion properties of the coating layer can also reduce losses caused by rainwater erosion. Among them, the amino groups of chitosan combine with the negative charge of soil clay particles to reduce water leakage losses. Rhizosphere nitrogen-fixing bacteria secrete more mucus polysaccharides under the induction of icariin, forming a water-retaining biofilm and increasing the water content in the rhizosphere. The genipin cross-linking layer can reduce the photodegradation of icariin and enhance the stability of the active ingredient to obtain icariin composite sustained-release microspheres.

[0050] This embodiment provides a method for preparing a slow-release organic compound fertilizer for dryland naked oats, which specifically comprises the following steps:

[0051] S1. Soak 5.0g of expanded perlite in 5% hydrochloric acid solution for 0.5h. The bulk density of the expanded perlite is 80kg / m 3, with a particle size of 4mm and a honeycomb pore structure, which can not only absorb and store water, but also form micro-water channels to promote the migration of water to the root system and avoid deep leakage. At the same time, perlite fixes and absorbs nitrogen and potassium ions through the micropores on the surface, reducing the loss of nitrogen and potassium. The chemical inertness of perlite can also reduce the combination of phosphorus with Fe³⁺, Al³⁺ or Ca²⁺, improve the effectiveness of phosphorus, remove surface impurities, then wash with water to neutrality, dry for use, and then mix 0.5g KH550 with 90.0g anhydrous ethanol and 9.5g deionized water, adjust the pH to 4.0 with acetic acid, and magnetic The mixture was stirred for 30 minutes to obtain a KH550 modified solution, and then the dried expanded perlite was immersed in the KH550 modified solution and ultrasonically treated for 20 minutes. The mixture was then magnetically stirred at 60°C for 2 hours, filtered, and the modified expanded perlite was washed twice with deionized water. Finally, the mixture was dried. The silanol generated by the hydrolysis of KH550 condensed with the Si-OH group on the surface of the expanded perlite to enhance the chemical compatibility of the expanded perlite in the polymer matrix. At the same time, the amino group at the end of KH550 was exposed on the surface of the perlite, providing an active site, thereby obtaining the KH550-modified expanded perlite.

[0052] S2. Wash and dry 10.0 g of wheat straw, crush it through a 100-mesh sieve, weigh 1.0 g of wheat straw powder and place it in 12 mL of 12% ammonia solution by mass for 48 h, filter it, wash it with water until it is neutral, remove the hemicellulose in the wheat straw, and then add the alkali-treated wheat straw to 30 mL of 6% nitric acid solution, heat it in a water bath at 80°C for 30 min to remove lignin, then filter it, and wash the product with deionized water and ethanol three times, and finally dry it. This process extracts high-purity cellulose from wheat straw through alkali treatment and acid treatment. At the same time, the alkali-acid distribution treatment method avoids the decrease in cellulose crystallinity caused by strong alkali, maintains the high degree of polymerization and mechanical strength of the fiber, and after removing the hemicellulose and lignin, micropores are formed on the fiber surface, the specific surface area is increased, the free hydroxyl groups are increased, and the chemical activity is high, which is conducive to subsequent modification treatment to obtain wheat fiber;

[0053] S3. The wheat fiber described in step S2 was placed in a 100 mL beaker, 15 mL of distilled water was added, and the mixture was stirred in a 70 ° C water bath for 5 min. 0.05 g of potassium persulfate was added, and the KH550 modified expanded perlite described in step S1 was added, and the mixture was stirred at high speed for 10 min. Then 20 mL of monomer solution was added, wherein the monomer solution was prepared by neutralizing 12.0 g of acrylic acid with 4.0 g of sodium hydroxide. Finally, 0.01 g of N, N-methylenebisacrylamide was added and stirred continuously until a gel appeared. The gel was taken out, cooled to room temperature, and washed with distilled water. It was then placed in 100 mL of anhydrous ethanol and soaked for 16 h. The anhydrous ethanol was replaced every 8 h. The prepared polymer was vacuum dried. The resin-perlite synergistic polymer was prepared by aqueous solution polymerization using wheat fiber as a flexible skeleton, KH550 modified expanded perlite as a rigid skeleton, and acrylic acid as a hydrophilic monomer under the action of a crosslinking agent and an initiator. The highly absorbent material with the same water-retention network, acrylic resin itself is highly absorbent. The porous structure of KH550 modified expanded perlite further absorbs and locks in moisture, reducing water evaporation and deep seepage. Simultaneously, the KH550 modified expanded perlite absorbs fertilizer nutrients. The composite interface between perlite and resin forms a diffusion barrier, reducing the migration of nitrogen, phosphorus, and potassium nutrients. Through micro-water channels, nitrogen, phosphorus, and potassium nutrients enter the naked oats root system along with water, thereby improving the root system's water retention and nutrient absorption capacity. The rigid skeleton of the KH550 modified expanded perlite reduces structural collapse of the resin after swelling, maintaining porosity and improving repeated water absorption and release capacity. The amino groups on the surface of the KH550 modified expanded perlite hydrogen bond or covalently crosslink with wheat cellulose and acrylic acid monomers, preventing sedimentation or phase separation of the perlite in the gel and allowing it to be evenly dispersed in the resin network, enhancing mechanical properties, and resulting in a wheat cellulose-based highly absorbent resin.

[0054] S4, dissolving genipin in 100mL pH7.4 phosphate buffer, the amount of genipin added is 2.0g, the suitable cross-linking environment of genipin is conducive to the survival of soil nitrogen-fixing bacteria, phosphate-solubilizing bacteria and other microorganisms, which is also conducive to the conversion of nitrogen, phosphorus and potassium, and the genipin solution is obtained for standby use and stored in the dark. First, icariin composite sustained-release microspheres are immersed in 50mL genipin solution, and oscillated at 25°C for 8h to form a preliminary cross-linked network on the surface of the microspheres and genipin, then take out the icariin composite sustained-release microspheres, mix them with the wheat cellulose-based super absorbent resin described in step S3, add the remaining 50mL genipin solution, and stir the reaction at 40°C for 12h, Freeze-drying forms covalent bonds between genipin and the hydroxyl groups and icariin groups on the surface of the slow-release microspheres in the wheat cellulose-based super absorbent resin, thereby constructing an interpenetrating network structure. The microspheres are evenly embedded in the porous structure of the resin, which not only forms a micro-reservoir in the soil to slowly release water for the use of the naked oats roots, but also adsorbs the free nutrients released by the microspheres at the root system, delaying the sudden release by acting as a diffusion barrier. At the same time, both water and nutrients can enter the naked oats root system through micro-water channels, improving the water retention capacity of the roots and the ability to absorb nutrients, thereby effectively promoting the growth of naked oats and significantly improving the yield-increasing effect, thereby obtaining a slow-release organic compound fertilizer for dryland naked oats.

[0055] Example 3

[0056] This embodiment provides a slow-release organic compound fertilizer for dryland naked oats, comprising the following components in parts by weight: 25 parts of icariin composite slow-release microspheres, 55 parts of wheat cellulose-based super absorbent resin, and 3.5 parts of genipin.

[0057] The icariin composite sustained-release microspheres include the following components in parts by weight: 6.5 parts of icariin, 7.5 parts of bovine serum albumin, 90 parts of polylactic acid-glycolic acid copolymer, 35 parts of potassium dihydrogen phosphate, 45 parts of potassium nitrate, and 45 parts of cross-linking liquid.

[0058] The wheat cellulose-based super absorbent resin comprises the following components in parts by weight: 15 parts of wheat fiber, 1.0 part of potassium persulfate, 110 parts of acrylic acid, 0.3 part of N,N-methylenebisacrylamide, and 10 parts of KH550 modified expanded perlite.

[0059] The preparation method of icariin composite sustained-release microspheres specifically comprises the following steps:

[0060] (1) Add 65 mg of icariin to 1 mL of dimethyl sulfoxide solution and dissolve it thoroughly by ultrasonication to obtain a mother solution for use. Measure 100 μL of the mother solution and bovine serum albumin and dissolve them in 200 μL of water. Dissolve them by ultrasonication in an ice bath for 1.5 min. The amount of bovine serum albumin added is 7.5 mg. Bovine serum albumin is rich in amino acids and can be gradually degraded in the soil as a nitrogen source. The efficiency of conversion to ammonium nitrogen is slower than that of urea, thereby reducing leaching losses. Bovine serum albumin also interacts with icariin through hydrophobic interactions and hydrogen bonds. Combined to improve the encapsulation efficiency, 35 mg of potassium dihydrogen phosphate and 45 mg of potassium nitrate were added as the aqueous phase, 90 mg of polylactic acid-glycolic acid copolymer was dissolved in 2 mL of dichloromethane solvent as the oil phase, the aqueous phase was added to the oil phase, and ultrasonic treatment was performed under ice bath conditions to obtain colostrum. As a natural amphiphilic protein, bovine serum albumin can reduce the interfacial tension when colostrum is formed, making the microsphere particle size more uniform. Then the colostrum was added to 10 mL of a 2% polyvinyl alcohol aqueous solution by mass, and the resulting emulsion was transferred to 400 mL of mass fraction. The mixture was stirred magnetically for 3 hours at 4°C in a 10% sodium chloride aqueous solution, centrifuged for 15 minutes, the supernatant was discarded, the precipitate was washed 4 times with ultrapure water, and the precipitate was collected. This process uses polylactic acid-glycolic acid copolymer as a carrier to synthesize uniform microspheres encapsulating nitrogen, phosphorus, potassium fertilizers and icariin, forming a nutrition-growth-promoting-anti-stress multifunctional system. Through the gradual hydrolysis of the carrier, icariin, nitrogen, phosphorus, potassium nutrients are slowly and continuously released to achieve the effect of promoting naked oats growth. Among them, icariin can optimize the soil microbial community. Enhance the activity of nitrogen-fixing bacteria and phosphate-solubilizing bacteria, which is beneficial to the conversion of nitrogen, phosphorus and potassium. Icariin has a similar effect to a plant growth regulator, which can stimulate the growth of naked oats roots and improve nutrient absorption efficiency. Icariin can also activate the plant's antioxidant system, increase the activity of superoxide dismutase, reduce the oxidative damage to naked oats caused by drought, and improve the survival rate. At the same time, the degradation products of polylactic acid-glycolic acid copolymer, lactic acid and glycolic acid, also provide carbon sources for soil microorganisms, promote the proliferation of beneficial bacteria such as phosphate-solubilizing bacteria, and obtain icariin fertilizer microspheres;

[0061] (2) The icariin fertilizer microspheres described in step (1) are immersed in a cross-linking solution. The cross-linking solution is obtained by the following process: 0.2 g of chitosan is slowly added to 100 mL of a 1% citric acid solution, and magnetically stirred at 45°C and 450 rpm until completely dissolved. Then, 0.2 g of genipin is added, the pH is controlled to 5.5, and stirred at 25°C for 0.75 h to form a cross-linked gel network with good biocompatibility, dual pH-triggered water retention, and slow release, which enhances water retention and fertilizer utilization. Among them, the citric acid maintenance system is close to the rhizosphere microenvironment of naked oats, and the cross-linked network swells preferentially in the root zone. Under the action of β-glucosidase secreted by the root system, the cross-linking bonds of genipin are selectively broken to achieve rhizosphere targeted release. In addition, the degradation products of genipin can stimulate the naked oats root system to secrete indoleacetic acid, accelerate the growth of primary root cells, and enhance the nutrient and water absorption capacity. Stir for 1.5 h, centrifuge for 7.5 min, and the precipitate is used. The microspheres were washed four times with a pH 5.5 citric acid buffer solution and then vacuum freeze-dried. The cross-linking liquid formed a protective coating on the icariin fertilizer microspheres, which allowed the microspheres to absorb water and swell in the soil, forming a local reservoir at the oat root system, effectively improving the root system's water retention capacity, thereby also benefiting the growth of the oat root system and the absorption of nutrients. At the same time, in the organic acid environment secreted by the oat root system, the icariin and fertilizer nutrients were slowly released in a targeted manner, which was beneficial to the absorption and utilization of the oat root system. The coating layer can enhance the mechanical properties of the microspheres and reduce the risk of breakage. The adhesion properties of the coating layer can also reduce the loss caused by rainwater erosion. Among them, the amino group of chitosan combines with the negative charge of soil clay particles to reduce water leakage loss. Rhizosphere nitrogen-fixing bacteria secrete more mucus polysaccharides under the induction of icariin, forming a water-retaining biofilm and increasing the rhizosphere water content. The cross-linking layer of genipin can reduce the photodegradation of icariin and enhance the stability of the active ingredient to obtain icariin composite sustained-release microspheres.

[0062] This embodiment provides a method for preparing a slow-release organic compound fertilizer for dryland naked oats, which specifically comprises the following steps:

[0063] S1. Soak 7.5g of expanded perlite in 5% hydrochloric acid solution for 0.75h. The bulk density of the expanded perlite is 130kg / m 3, with a particle size of 6mm and a honeycomb pore structure, which can not only absorb and store water, but also form micro-water channels to promote the migration of water to the root system and avoid deep leakage. At the same time, perlite fixes and absorbs nitrogen and potassium ions through the micropores on the surface, reducing the loss of nitrogen and potassium. The chemical inertness of perlite can also reduce the combination of phosphorus with Fe³⁺, Al³⁺ or Ca²⁺, improve the effectiveness of phosphorus, remove surface impurities, then wash with water to neutrality, dry for use, and then mix 0.75g KH550 with 90.0g anhydrous ethanol and 9.25g deionized water, adjust the pH to 4.5 with acetic acid, and magnetic The dried expanded perlite was then immersed in the KH550 modification solution and ultrasonically treated for 25 minutes. The solution was then magnetically stirred at 70°C for 3 hours, filtered, and the modified expanded perlite was washed twice with deionized water. The modified expanded perlite was finally dried. The silanol generated by the hydrolysis of KH550 condensed with the Si-OH group on the surface of the expanded perlite to enhance the chemical compatibility of the expanded perlite in the polymer matrix. At the same time, the amino group at the end of KH550 was exposed on the surface of the perlite, providing an active site, thereby obtaining the KH550-modified expanded perlite.

[0064] S2. Wash and dry 10.0 g of wheat straw, crush it through a 150-mesh sieve, weigh 1.5 g of wheat straw powder and place it in 21 mL of 12% ammonia solution for 48 hours, filter it, wash it with water until it is neutral, remove the hemicellulose in the wheat straw, and then add the alkali-treated wheat straw to 30 mL of 6% nitric acid solution, heat it in a water bath at 85°C for 40 minutes to remove lignin, then filter it, and wash the product with deionized water and ethanol four times, and finally dry it. This process extracts high-purity cellulose from wheat straw through alkali treatment and acid treatment. At the same time, the alkali-acid distribution treatment method avoids the decrease in cellulose crystallinity caused by strong alkali, maintains the high degree of polymerization and mechanical strength of the fiber, and after removing the hemicellulose and lignin, micropores are formed on the fiber surface, the specific surface area is increased, the free hydroxyl groups are increased, and the chemical activity is high, which is conducive to subsequent modification treatment to obtain wheat fiber;

[0065] S3. The wheat fiber described in step S2 was placed in a 100 mL beaker, 15 mL of distilled water was added, and the mixture was placed in a 75°C water bath and stirred for activation for 7.5 min. 0.10 g of potassium persulfate was added, and the KH550 modified expanded perlite described in step S1 was added and stirred at high speed for 12.5 min. Subsequently, 20 mL of monomer solution was added, wherein the monomer solution was prepared by neutralizing 11.0 g of acrylic acid with 4.2 g of sodium hydroxide. Finally, 0.03 g of N,N-methylenebisacrylamide was added and stirred continuously until a gel appeared. The gel was taken out, cooled to room temperature, and washed with distilled water. The gel was then placed in 100 mL of anhydrous ethanol and soaked for 16 h. The anhydrous ethanol was replaced every 8 h. The prepared polymer was vacuum dried. Resin-pearl was prepared by aqueous solution polymerization using wheat fiber as a flexible skeleton, KH550 modified expanded perlite as a rigid skeleton, and acrylic acid as a hydrophilic monomer under the action of a crosslinker and an initiator. The KH550 modified expanded perlite is a highly absorbent material that forms a synergistic water-retention network. The acrylic resin itself is highly absorbent. The porous structure of the KH550 modified expanded perlite further absorbs and locks in moisture, reducing water evaporation and deep seepage. At the same time, the KH550 modified expanded perlite absorbs fertilizer nutrients. The composite interface of the perlite and resin forms a diffusion barrier, reducing the migration of nitrogen, phosphorus, and potassium nutrients. Through the micro-water channels, nitrogen, phosphorus, and potassium nutrients enter the naked oats root system along with water, thereby improving the root system's water retention and nutrient absorption capacity. The rigid skeleton of the KH550 modified expanded perlite reduces structural collapse of the resin after swelling, maintains porosity, and improves repeated water absorption and release capacity. The amino groups on the surface of the KH550 modified expanded perlite can form hydrogen bonds or covalent crosslinks with wheat cellulose and acrylic acid monomers, preventing sedimentation or phase separation of the perlite in the gel, making it evenly dispersed in the resin network, enhancing mechanical properties, and obtaining a wheat cellulose-based highly absorbent resin.

[0066] S4, dissolving genipin in 100mL of pH7.4 phosphate buffer, the amount of genipin added is 3.5g, the suitable cross-linking environment of genipin is conducive to the survival of soil microorganisms such as nitrogen-fixing bacteria and phosphate-solubilizing bacteria, and thus is also conducive to the conversion of nitrogen, phosphorus and potassium, and the genipin solution is obtained for standby use and stored in the dark. First, icariin composite sustained-release microspheres are immersed in 50mL of genipin solution, and the reaction is shaken at 25°C for 10h to form a preliminary cross-linked network between the microsphere surface and genipin, and then the icariin composite sustained-release microspheres are taken out, mixed with the wheat cellulose-based super absorbent resin described in step S3, and the remaining 50mL of genipin solution is added, and the reaction is stirred at 40°C for 18h. Freeze-drying forms covalent bonds between genipin and the hydroxyl groups and icariin groups on the surface of the slow-release microspheres in the wheat cellulose-based super absorbent resin, thereby constructing an interpenetrating network structure. The microspheres are evenly embedded in the porous structure of the resin, which not only forms a micro-reservoir in the soil to slowly release water for the use of the naked oats roots, but also adsorbs the free nutrients released by the microspheres at the root system, delaying the sudden release by acting as a diffusion barrier. At the same time, both water and nutrients can enter the naked oats root system through micro-water channels, improving the water retention capacity of the roots and the ability to absorb nutrients, thereby effectively promoting the growth of naked oats and significantly improving the yield-increasing effect, thereby obtaining a slow-release organic compound fertilizer for dryland naked oats.

[0067] Example 4

[0068] This embodiment provides a slow-release organic compound fertilizer for dryland naked oats, comprising the following components in parts by weight: 20 parts of icariin composite slow-release microspheres, 60 parts of wheat cellulose-based super absorbent resin, and 2 parts of genipin.

[0069] The icariin composite sustained-release microspheres include the following components in parts by weight: 8 parts of icariin, 5 parts of bovine serum albumin, 80-100 parts of polylactic acid-glycolic acid copolymer, 50 parts of potassium dihydrogen phosphate, 60 parts of potassium nitrate, and 30 parts of cross-linking liquid.

[0070] The wheat cellulose-based super absorbent resin comprises the following components in parts by weight: 20 parts of wheat fiber, 1.5 parts of potassium persulfate, 120 parts of acrylic acid, 0.5 parts of N,N-methylenebisacrylamide, and 5 parts of KH550 modified expanded perlite.

[0071] The preparation method of icariin composite sustained-release microspheres specifically comprises the following steps:

[0072] (1) Add 80 mg of icariin to 1 mL of dimethyl sulfoxide solution and dissolve it thoroughly by ultrasonication to obtain a mother liquor for use. Measure 100 μL of the mother liquor and bovine serum albumin and dissolve them in 200 μL of water. Dissolve them by ultrasonication in an ice bath for 1 minute. The amount of bovine serum albumin added is 5 mg. Bovine serum albumin is rich in amino acids and can be gradually degraded in the soil as a nitrogen source. The efficiency of converting it into ammonium nitrogen is slower than that of urea, thereby reducing leaching losses. Bovine serum albumin also binds to icariin through hydrophobic interactions and hydrogen bonds, which can improve the nitrogen content. High encapsulation efficiency, then add 50mg potassium dihydrogen phosphate and 60mg potassium nitrate as the aqueous phase, dissolve 100mg polylactic acid-glycolic acid copolymer in 2mL dichloromethane solvent as the oil phase, add the aqueous phase to the oil phase, and ultrasonically treat under ice bath conditions to obtain colostrum. As a natural amphiphilic protein, bovine serum albumin can reduce the interfacial tension when colostrum is formed, making the microsphere particle size more uniform. Then add the colostrum to 10mL of 2% polyvinyl alcohol aqueous solution by mass, and transfer the obtained emulsion to 400mL of 2% by mass. The mixture was added into a 10% sodium chloride aqueous solution, magnetically stirred for 2h at 4℃, centrifuged for 10min, the supernatant was discarded, the precipitate was washed 5 times with ultrapure water, and the precipitate was collected. The process used polylactic acid-glycolic acid copolymer as a carrier to synthesize uniform microspheres encapsulating nitrogen, phosphorus, potassium fertilizers and icariin, forming a nutrition-growth-promoting-anti-stress multifunctional system. Through the gradual hydrolysis of the carrier, icariin, nitrogen, phosphorus, potassium nutrients were slowly and continuously released to achieve the effect of promoting naked oat growth. Among them, icariin can optimize the soil microbial community and increase The activity of strong nitrogen-fixing bacteria and phosphate-solubilizing bacteria is beneficial to the conversion of nitrogen, phosphorus and potassium. Icariin has a similar effect to a plant growth regulator, which can stimulate the growth of naked oats roots and improve nutrient absorption efficiency. Icariin can also activate the plant's antioxidant system, enhance the activity of superoxide dismutase, reduce the oxidative damage to naked oats caused by drought, and improve the survival rate. At the same time, the degradation products of polylactic acid-glycolic acid copolymer, lactic acid and glycolic acid, also provide carbon sources for soil microorganisms, promoting the proliferation of beneficial bacteria such as phosphate-solubilizing bacteria, and obtaining icariin fertilizer microspheres.

[0073] (2) The icariin fertilizer microspheres described in step (1) are immersed in a cross-linking solution. The cross-linking solution is obtained by the following process: 0.3 g of chitosan is slowly added to 100 mL of a 1% citric acid solution, and magnetically stirred at 50°C and 500 rpm until completely dissolved. Then, 0.1 g of genipin is added, the pH is controlled to 5.5, and stirred at 25°C for 0.5 h to form a cross-linked gel network with good biocompatibility, dual pH-triggered water retention, and slow release, which enhances water retention and fertilizer utilization. Among them, the citric acid maintenance system is close to the rhizosphere microenvironment of naked oats, and the cross-linked network swells preferentially in the root zone. Under the action of β-glucosidase secreted by the root system, the cross-linking bonds of genipin are selectively broken to achieve rhizosphere targeted release. In addition, the degradation products of genipin can stimulate the naked oats root system to secrete indoleacetic acid, accelerate the growth of primary root cells, and enhance the absorption capacity of nutrients and water. Stir for 1 h, centrifuge for 5 min, and the precipitate is purified by pH 50. The microspheres were washed five times with 5.5% citric acid buffer solution and then vacuum freeze-dried. The cross-linking liquid formed a coating protective layer on the icariin fertilizer microspheres, which made the microspheres absorb water and swell in the soil, forming a local reservoir at the oat root system, effectively improving the root system's water retention capacity, which is also beneficial to the growth of the oat root system and the absorption of nutrients. At the same time, in the organic acid environment secreted by the oat root system, the icariin and fertilizer nutrients were slowly released in a targeted manner, which is beneficial to the absorption and utilization of the oat root system. The coating layer can enhance the mechanical properties of the microspheres and reduce the risk of breakage. The adhesion properties of the coating layer can also reduce losses caused by rainwater erosion. Among them, the amino groups of chitosan combine with the negative charge of soil clay particles to reduce water leakage losses. Rhizosphere nitrogen-fixing bacteria secrete more mucus polysaccharides under the induction of icariin, forming a water-retaining biofilm and increasing the water content in the rhizosphere. The genipin cross-linking layer can reduce the photodegradation of icariin and enhance the stability of the active ingredient to obtain icariin composite sustained-release microspheres.

[0074] This embodiment provides a method for preparing a slow-release organic compound fertilizer for dryland naked oats, which specifically comprises the following steps:

[0075] S1. Soak 5.0g of expanded perlite in 5% hydrochloric acid solution for 0.5h. The bulk density of the expanded perlite is 180kg / m 3, with a particle size of 8mm and a honeycomb pore structure, which can not only absorb and store water, but also form micro-water channels to promote the migration of water to the root system and avoid deep leakage. At the same time, perlite fixes and absorbs nitrogen and potassium ions through the micropores on the surface, reducing the loss of nitrogen and potassium. The chemical inertness of perlite can also reduce the combination of phosphorus with Fe³⁺, Al³⁺ or Ca²⁺, improve the effectiveness of phosphorus, remove surface impurities, then wash with water to neutrality, dry for use, and then mix 1.0g KH550 with 90.0g anhydrous ethanol and 9.0g deionized water, adjust the pH to 5.0 with acetic acid, and magnetic Stirring for 30 minutes to obtain a KH550 modification solution, then immersing the dried expanded perlite in the KH550 modification solution, ultrasonically treating for 20 minutes, followed by magnetic stirring at 80°C for 2 hours, filtering, washing the modified expanded perlite three times with deionized water, and finally drying. The silanol generated by the hydrolysis of KH550 condenses with the Si-OH on the surface of the expanded perlite, thereby enhancing the chemical compatibility of the expanded perlite in the polymer matrix. At the same time, the amino group at the end of KH550 is exposed on the surface of the perlite, providing an active site, thereby obtaining the KH550-modified expanded perlite.

[0076] S2. Wash and dry 10.0 g of wheat straw, crush it through a 200-mesh sieve, weigh 2.0 g of wheat straw powder, place it in 30 mL of 12% ammonia solution by mass for 48 h, filter it, wash it with water until it is neutral, remove the hemicellulose in the wheat straw, and then add the alkali-treated wheat straw to 30 mL of 6% nitric acid solution, heat it in a water bath at 90°C for 30 min to remove lignin, then filter it, and wash the product with deionized water and ethanol 5 times, and finally dry it. This process extracts high-purity cellulose from wheat straw through alkali treatment and acid treatment. At the same time, the alkali-acid distribution treatment method avoids the decrease in cellulose crystallinity caused by strong alkali, maintains the high degree of polymerization and mechanical strength of the fiber, and after removing the hemicellulose and lignin, micropores are formed on the fiber surface, the specific surface area is increased, the free hydroxyl groups are increased, and the chemical activity is high, which is conducive to subsequent modification treatment to obtain wheat fiber;

[0077] S3. The wheat fiber described in step S2 was placed in a 100 mL beaker, 15 mL of distilled water was added, and the mixture was placed in an 80 ° C water bath and stirred for activation for 5 min. 0.15 g of potassium persulfate was added, and the KH550 modified expanded perlite described in step S1 was added, and the mixture was stirred at high speed for 10 min. Then 20 mL of monomer solution was added, wherein the monomer solution was prepared by neutralizing 10.0 g of acrylic acid with 4.4 g of sodium hydroxide. Finally, 0.05 g of N, N-methylenebisacrylamide was added and stirred continuously until a gel appeared. The gel was taken out, cooled to room temperature, and washed with distilled water. It was then placed in 100 mL of anhydrous ethanol and soaked for 16 h. The anhydrous ethanol was replaced every 8 h. The prepared polymer was vacuum dried. The resin-perlite synergistic polymer was prepared by aqueous solution polymerization using wheat fiber as a flexible skeleton, KH550 modified expanded perlite as a rigid skeleton, and acrylic acid as a hydrophilic monomer under the action of a crosslinking agent and an initiator. The highly absorbent material with the same water-retention network, acrylic resin itself is highly absorbent. The porous structure of KH550 modified expanded perlite further absorbs and locks in moisture, reducing water evaporation and deep seepage. Simultaneously, the KH550 modified expanded perlite absorbs fertilizer nutrients. The composite interface between perlite and resin forms a diffusion barrier, reducing the migration of nitrogen, phosphorus, and potassium nutrients. Through micro-water channels, nitrogen, phosphorus, and potassium nutrients enter the naked oats root system along with water, thereby improving the root system's water retention and nutrient absorption capacity. The rigid skeleton of the KH550 modified expanded perlite reduces structural collapse of the resin after swelling, maintaining porosity and improving repeated water absorption and release capacity. The amino groups on the surface of the KH550 modified expanded perlite hydrogen bond or covalently crosslink with wheat cellulose and acrylic acid monomers, preventing sedimentation or phase separation of the perlite in the gel and allowing it to be evenly dispersed in the resin network, enhancing mechanical properties, and resulting in a wheat cellulose-based highly absorbent resin.

[0078] S4, dissolving genipin in 100mL pH7.4 phosphate buffer, the amount of genipin added is 2.0g, the suitable cross-linking environment of genipin is conducive to the survival of soil nitrogen-fixing bacteria, phosphate-solubilizing bacteria and other microorganisms, which is also conducive to the conversion of nitrogen, phosphorus and potassium, and the genipin solution is obtained for standby use and stored in the dark. First, icariin composite sustained-release microspheres are immersed in 50mL genipin solution, and oscillated at 25°C for 8h to form a preliminary cross-linked network on the surface of the microspheres and genipin, then take out the icariin composite sustained-release microspheres, mix them with the wheat cellulose-based super absorbent resin described in step S3, add the remaining 50mL genipin solution, and stir the reaction at 40°C for 12h, Freeze-drying forms covalent bonds between genipin and the hydroxyl groups and icariin groups on the surface of the slow-release microspheres in the wheat cellulose-based super absorbent resin, thereby constructing an interpenetrating network structure. The microspheres are evenly embedded in the porous structure of the resin, which not only forms a micro-reservoir in the soil to slowly release water for the use of the naked oats roots, but also adsorbs the free nutrients released by the microspheres at the root system, delaying the sudden release by acting as a diffusion barrier. At the same time, both water and nutrients can enter the naked oats root system through micro-water channels, improving the water retention capacity of the roots and the ability to absorb nutrients, thereby effectively promoting the growth of naked oats and significantly improving the yield-increasing effect, thereby obtaining a slow-release organic compound fertilizer for dryland naked oats.

[0079] Comparative Example 1

[0080] This comparative example provides a slow-release organic compound fertilizer for dryland naked oats, which differs from Example 1 in that the icariin composite slow-release microspheres do not contain a cross-linking liquid; in the preparation method of the icariin composite slow-release microspheres, the icariin fertilizer microspheres described in step (1) are not immersed in a cross-linking liquid in step (2), but are directly vacuum freeze-dried; the preparation method of the slow-release organic compound fertilizer for dryland naked oats is the same as that in Example 1.

[0081] Comparative Example 2

[0082] This comparative example provides a slow-release organic compound fertilizer for dryland naked oats, which differs from Example 1 in that the wheat cellulose-based super absorbent resin does not contain KH550 modified expanded perlite; the preparation method of icariin composite slow-release microspheres is the same as that of Example 1; the preparation method of the slow-release organic compound fertilizer for dryland naked oats does not include step S1, and KH550 modified expanded perlite is not added in step S3.

[0083] Comparative Example 3

[0084] This comparative example provides a slow-release organic compound fertilizer for dryland naked oats, which differs from Example 1 in that the slow-release organic compound fertilizer for dryland naked oats does not contain genipin; the preparation method of icariin composite slow-release microspheres is the same as that of Example 1; in the preparation method of the slow-release organic compound fertilizer for dryland naked oats, genipin is not added in step S4, and only the icariin composite slow-release microspheres are mixed with the wheat cellulose-based super absorbent resin.

[0085] Experimental Example 1

[0086] Water retention test

[0087] Test sample: the slow-release organic compound fertilizer for dryland naked oats prepared in Examples 1-4 and Comparative Examples 1-3.

[0088] Test method: Prepare 7 PVC tubes filled with homogeneous soil, sow 10 naked oat seeds in each pot, and thin out to 6 plants after emergence. All naked oat seeds are of the same variety. Then use 10g of the test sample for fertilization treatment to ensure that the soil moisture content is 40% to simulate drought conditions. After 30 days, weigh the weight of 3 fresh roots and take the average as the fresh root weight (FW). Water and control the soil moisture content at 55%. After 1 day, weigh the remaining 3 roots, wipe them dry and weigh the saturated weight. The average value is the saturated weight (TW). Finally, dry them at 80℃ to constant weight. The average value is the constant weight (DW). Calculate the relative water content (%) of the root system according to the following formula:

[0089] Root relative water content (%) = (FW-DW) / (TW-DE) × 100%

[0090] Figure 2 The results of the relative water content of the roots of Examples 1-4 and Comparative Examples 1-3 are shown in the figure; as shown in the figure, the relative water content of the roots of Examples 1-4 is 82-89%, indicating that the water retention of the naked oats is good; the relative water content of the roots of Comparative Examples 1-3 is 60-73%, indicating that the water retention of the naked oats is average; the icariin composite sustained-release microspheres of Comparative Example 1 do not contain a cross-linking liquid, do not have a rhizosphere targeted release effect, and cannot form a local water reservoir at the naked oats root system, resulting in average water retention of the naked oats root system; the wheat cellulose-based super absorbent resin in Comparative Example 2 Without KH550 modified expanded perlite, micro-water channels cannot be formed, which is not conducive to promoting the migration of water to the root system, and a rigid skeleton cannot be introduced, which increases the risk of structural collapse of the resin after swelling, which is not conducive to the water absorption and release properties of the resin, resulting in average water retention of the naked oats roots; the slow-release organic compound fertilizer for dryland naked oats in Comparative Example 3 does not contain genipin, and the icariin composite slow-release microspheres cannot be evenly embedded in the wheat cellulose-based super absorbent resin, which is not conducive to the stability and effectiveness of the interpenetrating network, resulting in average water retention of the naked oats roots.

[0091] Experimental Example 2

[0092] Absorption test

[0093] Test sample: the slow-release organic compound fertilizer for dryland naked oats prepared in Examples 1-4 and Comparative Examples 1-3.

[0094] Test method: Use 10g of the test sample to fertilize naked oats, and control the soil moisture content at 40%±5%. After 30 days, take the stems and leaves of the naked oats for drying, crushing, grinding, and boiling. Then, determine the nitrogen, phosphorus, and potassium contents (g / 100g) according to GB / T6432-2018, GB / T6437-2018, and GB / T6434-2022 standards.

[0095] Figure 3 The results of nitrogen, phosphorus and potassium content of Examples 1-4 and Comparative Examples 1-3 are shown in the figure; as shown in the figure, the nitrogen, phosphorus and potassium contents of Examples 1-4 are 3.0-3.3g / 100g, 0.43-0.51g / 100g and 2.5-2.8g / 100g, respectively, indicating that naked oats have a strong absorption of nitrogen, phosphorus and potassium; the nitrogen, phosphorus and potassium contents of Comparative Examples 1-3 are 1.5-2.5g / 100g, 0.18-0.33g / 100g and 1.1-2.0g / 100g, respectively, indicating that naked oats have a general absorption of nitrogen, phosphorus and potassium; the icariin composite sustained-release microspheres of Comparative Example 1 do not contain a cross-linking liquid, and cannot target the release of icariin and fertilizer nutrients, which is not conducive to the absorption of naked oats by the roots, resulting in the naked oats having a poor absorption of nitrogen, phosphorus and potassium. The absorbency is average; the wheat cellulose-based super absorbent resin of Comparative Example 2 does not contain KH550 modified expanded perlite, and cannot form micro-water channels, which is not conducive to the passage of nutrients into the naked oats root system, and cannot effectively adsorb nutrients such as nitrogen, phosphorus and potassium. At the same time, it weakens the diffusion barrier effect of the resin and increases the migration of nutrients, resulting in the average absorption of nitrogen, phosphorus and potassium by naked oats; the slow-release organic compound fertilizer for dryland naked oats in Comparative Example 3 does not contain genipin, and cannot form a protective layer at the junction of the icariin composite slow-release microspheres and the wheat cellulose-based super absorbent resin through cross-linking, which increases the degradation of icariin and is not conducive to enhancing the absorption capacity by stimulating the naked oats root system, resulting in the average absorption of nitrogen, phosphorus and potassium by naked oats.

[0096] Experimental Example 3

[0097] Yield increase effect experiment

[0098] Test sample: the slow-release organic compound fertilizer for dryland naked oats prepared in Examples 1-4 and Comparative Examples 1-3.

[0099] Test method: Seven areas of the same size in the Gansu naked oat demonstration field in the arid area were selected for the experiment. The soil moisture content was 40%±5%. The test samples were used as base fertilizer for fertilization at a rate of 20 kg / mu, once every 15 days. After entering the maturity stage, the number of ears and grains per ear of 20 naked oat plants at maturity were measured, and the average value was calculated.

[0100] Figure 4 The result diagram of the number of ears and the number of grains per ear of Examples 1-4 and Comparative Examples 1-3 is as follows; as shown in the figure, the number of ears and the number of grains per ear of Examples 1-4 are 2.4-2.8 ears / plant and 50-55 grains / ear, respectively, indicating that the yield-increasing effect is better; the number of ears and the number of grains per ear of Comparative Examples 1-3 are 1.2-2.0 ears / plant and 28-42 grains / ear, respectively, indicating that the yield-increasing effect is average; the icariin composite slow-release microspheres of Comparative Example 1 do not contain a cross-linking liquid, which can neither form a local water reservoir at the root system of naked oats, reducing the water retention of the root system, nor can they release fertilizer nutrients in a targeted manner, which is not conducive to the growth of naked oats. growth, resulting in a general yield-increasing effect; the wheat cellulose-based super absorbent resin of Comparative Example 2 does not contain KH550 modified expanded perlite, and nutrients and water cannot enter the naked oat root system through the micro-water channel formed by the perlite, which is not conducive to the water retention of the root system and the absorption and utilization rate of nutrients, and thus cannot effectively promote the growth of naked oat, resulting in a general yield-increasing effect; the slow-release organic compound fertilizer for dryland naked oat of Comparative Example 3 does not contain genipin, and cannot stimulate the growth of primary root cells of naked oat through degradation products, which is not conducive to the absorption of water and nutrients, resulting in a general yield-increasing effect.

[0101] The above experimental results show that the root water retention, nitrogen, phosphorus and potassium absorption and oat yield increase effect of Examples 1-4 of the present invention are significantly better than those of the samples of Comparative Examples 1-3. Among them, the root water retention, nitrogen, phosphorus and potassium absorption of Example 1 using icariin composite slow-release microspheres, wheat cellulose-based super absorbent resin and genipin are better, the yield increase effect is better, and the wheat cellulose-based super absorbent resin and icariin composite slow-release microspheres are cross-linked with genipin, and the microspheres are evenly embedded in the resin to form an interpenetrating network structure, which can not only form a micro-reservoir in the soil and slowly release water for the oat root system to utilize, but also absorb the free nutrients targeted by the icariin composite slow-release microspheres at the root system, reduce nutrient loss, and deliver water and nutrients to the oat root system through micro-water channels, thereby improving the water retention of the root system, enhancing the nutrient absorption of oat, effectively promoting the growth of oat, and significantly improving the yield increase effect.

[0102] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

[0103] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. A slow-release organic compound fertilizer for dryland naked oats, characterized by: The slow-release organic compound fertilizer for dryland naked oats comprises the following components in parts by weight: 20-30 parts of icariin composite slow-release microspheres, 50-60 parts of wheat cellulose-based super absorbent resin, and 2-5 parts of genipin; the icariin composite slow-release microspheres comprise the following components in parts by weight: 5-8 parts of icariin, 5-10 parts of bovine serum albumin, 80-100 parts of polylactic acid-glycolic acid copolymer, 20-50 parts of potassium dihydrogen phosphate, 30-60 parts of potassium nitrate, and 30-60 parts of cross-linking liquid; the wheat cellulose-based super absorbent resin comprises the following components in parts by weight: 10-20 parts of wheat fiber, 0.5-1.5 parts of potassium persulfate, 100-120 parts of acrylic acid, 0.1-0.5 parts of N,N-methylenebisacrylamide, and 5-15 parts of KH550 modified expanded perlite; The preparation method of the icariin composite sustained-release microspheres specifically comprises the following steps: (1) Add 50-80 mg of icariin to 1 mL of dimethyl sulfoxide solution, dissolve it by ultrasonication, and obtain a mother liquor for use. Measure 100 μL of the mother liquor and bovine serum albumin and dissolve them in 200 μL of water. Dissolve them by ultrasonication in an ice bath for 1-2 minutes. Then add 20-50 mg of potassium dihydrogen phosphate and 30-60 mg of potassium nitrate as the aqueous phase. Dissolve 80-100 mg of polylactic acid-glycolic acid copolymer in 2 mL of dichloromethane solvent as the oil phase. Add the aqueous phase to the oil phase and ultrasonicate in an ice bath to obtain colostrum. Then add the colostrum to 10 mL of a 2% by mass polyvinyl alcohol aqueous solution. Transfer the obtained emulsion to 400 mL of a 10% by mass sodium chloride aqueous solution, stir magnetically at 4°C for 2-4 hours, centrifuge for 10-20 minutes, discard the supernatant, wash the precipitate with ultrapure water 3-5 times, collect the precipitate, and obtain icariin fertilizer microspheres. (2) Soaking the icariin fertilizer microspheres described in step (1) in a cross-linking solution, stirring for 1-2 hours, centrifuging for 5-10 minutes, washing the precipitate 3-5 times with a pH 5.5 citric acid buffer solution, and then vacuum freeze-drying to obtain icariin composite slow-release microspheres.

2. A method for preparing the slow-release organic compound fertilizer for dryland naked oats according to claim 1, characterized in that: The specific steps include: S1. Soak 5.0-10.0 g of expanded perlite in a 5% hydrochloric acid solution for 0.5-1 h to remove surface impurities, then wash with water until neutral, and dry for use. Then, mix 0.5-1.0 g of KH550 with 90.0 g of anhydrous ethanol and 9.0-9.5 g of deionized water, adjust the pH to 4.0-5.0 with acetic acid, and magnetically stir for 30-60 min to obtain a KH550 modified solution. Then, soak the dried expanded perlite in the KH550 modified solution, ultrasonically treat for 20-30 min, and then magnetically stir at 60-80 ° C for 2-4 h, filter, wash the modified expanded perlite with deionized water 2-3 times, and finally dry to obtain KH550 modified expanded perlite; S2. Wash and dry 10.0 g of wheat straw, grind it through a 100-200 mesh sieve, weigh 1.0-2.0 g of wheat straw powder, place it in 12-30 mL of 12% ammonia solution by mass for 48 hours, filter it, wash it with water until it is neutral, then add the alkali-treated wheat straw to 30 mL of 6% nitric acid solution by mass, heat it in a water bath at 80-90°C for 30-50 minutes, then filter it, wash the product with deionized water and ethanol 3-5 times, and finally dry it to obtain wheat fiber; S3. Place the wheat fiber described in step S2 in a 100 mL beaker, add 15 mL of distilled water, place in a 70-80 ° C water bath and stir to activate for 5-10 minutes, add 0.05-0.15 g of potassium persulfate, and then add the KH550 modified expanded perlite described in step S1, stir at high speed for 10-15 minutes, then add 20 mL of monomer solution, wherein the monomer solution is prepared by neutralizing 10.0-12.0 g of acrylic acid with 4.0-4.4 g of sodium hydroxide, finally add 0.01-0.05 g of N, N-methylenebisacrylamide, and stir continuously until a gel appears. Remove the gel, cool to room temperature and wash with distilled water, then soak in 100 mL of anhydrous ethanol for 16 hours, replacing the anhydrous ethanol every 8 hours, and finally vacuum dry the prepared polymer to obtain a wheat cellulose-based super absorbent resin; S4. Dissolve genipin in 100 mL of pH 7.4 phosphate buffer to obtain a genipin solution for standby use and store in the dark. First, immerse the icariin composite sustained-release microspheres in 50 mL of the genipin solution, and shake and react at 25° C. for 8-12 hours. Then, take out the icariin composite sustained-release microspheres, mix them with the wheat cellulose-based super absorbent resin described in step S3, add the remaining 50 mL of the genipin solution, stir and react at 40° C. for 12-24 hours, and freeze-dry to obtain a slow-release organic compound fertilizer for dryland naked oats.

3. The method for preparing the slow-release organic compound fertilizer for dryland naked oats according to claim 2, wherein: In step S1, the bulk density of the expanded perlite is 80-180 kg / m 3 , particle size is 4-8mm.

4. The method for preparing the slow-release organic compound fertilizer for dryland naked oats according to claim 3, wherein: In step S4, the amount of genipin added is 2.0-5.0 g.

5. The method for preparing the slow-release organic compound fertilizer for dryland naked oats according to claim 4, wherein: In step (1), the amount of bovine serum albumin added is 5-10 mg.

6. The method for preparing the slow-release organic compound fertilizer for dryland naked oats according to claim 5, characterized in that: In step (2), the cross-linking solution is obtained by slowly adding 0.1-0.3 g of chitosan to 100 mL of a 1% citric acid solution, stirring the solution with a magnetic stirrer at 40-50° C. and 400-500 rpm until the solution is completely dissolved, and then adding 0.1-0.3 g of genipin, controlling the pH to 5.5, and stirring the solution at 25° C. for 0.5-1 h.

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