Synergist for promoting nitrogen and phosphorus absorption and preparation method and application thereof

Abstract

The invention relates to the technical field of agricultural planting industry, in particular to a synergist for promoting nitrogen and phosphorus absorption and a preparation method and application thereof. Polymeric amino acid is synthesized to serve as a bottom layer, then the synergist is obtained by inlaying microbial source oligosaccharide and organic chelated zinc, the polymeric amino acid on the bottom layer belongs to macromolecular substances and has a gap structure, coating and release of nutrients are facilitated, and the functions of transporting, activating and stimulating crops to absorb the nutrients can be achieved through biological chain scission. The crop utilization period of nitrogen and phosphorus nutrients is prolonged; the organic chelated zinc can provide active nutrients, and can be absorbed and utilized in the form of a composite mosaic, so as to determine the advantages and effects of radicles in the competition of radicles and germs when crops germinate; and the microbial oligosaccharide can realize the functions of permeation, disease resistance and biological stimulation, so that nutrient absorption channels of crops can be quickly opened.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural planting, and particularly relates to a synergist for promoting nitrogen and phosphorus absorption, a preparation method thereof, and an application thereof. Background Art

[0002] There are three destinations for nutrients applied artificially: firstly, absorption, which is utilized by crops to promote crop growth, thereby carrying out the cycle of mineral nutrients; secondly, fixation, which changes from the mobile state to the immobile state and becomes a component of the soil; finally, loss, which conducts material circulation in the air or water body. Among the above destinations, only being absorbed by crops is what people expect.

[0003] Taking nitrogen as an example, its various forms lead to low comprehensive utilization rate. According to statistics, the current nitrogen utilization rate in China is only 30%, and about 45% of the rest is lost into the air, causing air pollution, and the rest is lost into the water body, causing water eutrophication. Similar to nitrogen is phosphorus. Compared with nitrogen, the form of phosphorus nutrient is single, and it is mostly applied in the form of phosphate or polyphosphate. However, phosphorus is extremely easy to react with metal ions in the soil and is thus fixed, resulting in the current-season production utilization rate of phosphorus in China being only about 20%, seriously hindering the grain yield; at the same time, it is also found that the fixation of phosphorus is usually accompanied by the simultaneous fixation of medium and trace elements, thereby leading to the overall nutrient deficiency of crops and the decline of crop quality.

[0004] Among the macronutrients, the loss of potassium is basically through loss with water, and there are few other loss ways, so it is relatively easy to control; while nitrogen and phosphorus are more difficult, so people generally conduct relevant research and development in the control of nitrogen and phosphorus. For nitrogen, the most commonly used methods are coating controlled release, physical loss control, inhibiting biological bacteria, and using multi-form nitrogen. Among them, the main means of coating controlled release is coated urea, physical loss control is loss-controlled urea, inhibiting biological bacteria is nitrification inhibitor or urease inhibitor, and multi-form nitrogen is urea ammonium nitrate solution, etc. Although these methods all have good effects, they also have certain defects, such as causing pollution of the coating material, uneven electro-negativity of soil colloids, and harm to dominant flora. The biggest defect is that the above methods have no obvious effect on improving the utilization rate of phosphorus. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a synergist for promoting nitrogen and phosphorus absorption, a preparation method thereof, and an application thereof. The synergist provided by the present invention can simultaneously promote the absorption of nitrogen and phosphorus and improve the production utilization rate of nitrogen and phosphorus.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a preparation method of a synergist for promoting nitrogen and phosphorus absorption, comprising the following steps:

[0008] Mix structural amino acids, non-structural amino acids, water and aldehyde substances, and carry out a modification reaction to obtain a modified amino acid solution;

[0009] Add hydrochloric acid to the modified amino acid solution to precipitate the modified amino acid. After solid-liquid separation, carry out a polymerization reaction on the obtained modified amino acid under a protective atmosphere to obtain a polymerization intermediate;

[0010] Mix the polymerization intermediate, alkali and water, and carry out a hydrolysis reaction to obtain a polymerized amino acid solution;

[0011] Mix the polymerized amino acid solution with organic chelated zinc for a chelation reaction, and then mix it with microbial-derived oligosaccharides for a complexation reaction to obtain a solution of the synergist;

[0012] Alternatively, mix the polymerized amino acid solution with microbial-derived oligosaccharides for a complexation reaction, and then mix it with organic chelated zinc for a chelation reaction to obtain a solution of the synergist.

[0013] Preferably, the structural amino acids include one or more of L-aspartic acid, L-glutamic acid and glycine;

[0014] The non-structural amino acids include one or more of γ-aminobutyric acid, β-aminobutyric acid, D-aspartic acid and D-glutamic acid;

[0015] The molar ratio of the structural amino acids to the non-structural amino acids is (5-9):1.

[0016] Preferably, the aldehyde substances include one or more of paraformaldehyde, formaldehyde, acetaldehyde and propionaldehyde; the molar amount of the aldehyde substances is 10-20% of the total molar amount of the structural amino acids and the non-structural amino acids.

[0017] Preferably, the temperature of the modification reaction is 80-95°C.

[0018] Preferably, the temperature of the polymerization reaction is 180-200°C; the protective atmosphere means that the reaction atmosphere only contains gas components that do not oxidize and reduce under specified conditions;

[0019] The alkali includes one or more of sodium hydroxide, potassium hydroxide and ammonium hydroxide; the molar ratio of the polymer intermediate to the hydroxide ions in the alkali is 1:(0.78-0.90).

[0020] Preferably, the organic chelated zinc is a chelate of an organic chelating agent and an inorganic zinc salt; the organic chelating agent includes at least one of iminodisuccinic acid, tetrasodium glutamate diacetate and trisodium methylglycine diacetate.

[0021] Preferably, the mass ratio of the polyamino acid to the organic chelated zinc in the polyamino acid solution is (4-6.5):1;

[0022] The temperature of the chelation reaction is 65-85 °C, and the time is 30-90 min.

[0023] Preferably, the microbial oligosaccharides include one or more of mannan oligosaccharides, chitosan oligosaccharides, and algal oligosaccharides obtained by microbial fermentation;

[0024] The mass ratio of the polyamino acid to the microbial oligosaccharides in the polyamino acid solution is (4-6.5):0.6;

[0025] The temperature of the complexation reaction is 65-85 °C, and the time is 30-90 min.

[0026] The present invention provides a synergist for promoting nitrogen and phosphorus absorption prepared by the preparation method described in the above solution, including polyamino acids and organic chelated zinc and microbial oligosaccharides bound to the polyamino acids.

[0027] The present invention provides the application of the synergist for promoting nitrogen and phosphorus absorption described in the above solution in the fertilizer production process, and the fertilizer includes at least one basal fertilizer containing nitrogen and phosphorus nutrients.

[0028] The present invention provides a preparation method of a synergist for promoting nitrogen and phosphorus absorption, including the following steps: mixing structural amino acids, non-structural amino acids, water, and aldehyde substances, and performing a modification reaction to obtain a modified amino acid solution; adding hydrochloric acid to the modified amino acid solution to precipitate the modified amino acid, and after solid-liquid separation, performing a polymerization reaction on the obtained modified amino acid under a protective atmosphere to obtain a polymerization intermediate; mixing the polymerization intermediate, alkali, and water, and performing a hydrolysis reaction to obtain a polyamino acid solution; mixing the polyamino acid solution with organic chelated zinc for a chelation reaction and then mixing with microbial oligosaccharides for a complexation reaction to obtain a solution of the synergist; or, mixing the polyamino acid solution with microbial oligosaccharides for a complexation reaction and then mixing with organic chelated zinc for a chelation reaction to obtain a solution of the synergist.

[0029] The present invention first synthesizes polyamino acids as the bottom layer, and then obtains a synergist by embedding microbial-derived oligosaccharides and organic chelated zinc. The polyamino acids in the bottom layer are macromolecular substances with a void structure, which is conducive to the encapsulation and release of nutrients. It can also achieve the functions of transporting, activating, and stimulating crop nutrient absorption through biological chain breaking, extending the utilization period of nitrogen and phosphorus nutrients by crops. To exert the functions of activating nutrients, maintaining nutrient forms, and stimulating absorption, a key is needed to promote its effect; one of the embedded keys is organic chelated zinc, which can provide active nutrients and can be absorbed and utilized in the form of a composite inlay, determining the radicle dominance effect in the competition between radicle and plumule during crop germination; the other key, microbial-derived oligosaccharides, can achieve the functions of penetration, disease resistance, and biological stimulation, thus quickly opening the nutrient absorption channel of crops.

[0030] The synergist prepared by the present invention is a polymer biodegradable material with a curved void structure. After embedding nutrients and applying them, a net-like structure can be formed in the soil tillage layer, which combines with soil colloid particles to form a more complex electronegativity to adsorb nutrients. As the nutrients and water in the soil are lost, the electronegativity gradually changes, reducing the release of nutrients into the environment.

[0031] The polyamino acids, organic chelated zinc, and microbial-derived oligosaccharides used in the present invention all have certain biological stimulation functions and can play roles in disease resistance, promoting nutrient absorption, and promoting root development; the polyamino acids are in the form of composite amino acids, and the process of combining structural amino acids and non-structural amino acids is used to enhance their biological stimulation function while delaying the degradation rate of polyamino acids; the synergist of the present invention has a multi-level degradation and release. Specifically, microbial-derived oligosaccharides and organic chelated zinc are first released through the tiny internal circulation system formed by the roots and microbial breakage, and then the polyamino acids slowly degrade, having the effect of multi-level nutrient release, which is more conducive to the supply of crop nutrients.

[0032] In summary, the present invention achieves a targeted effect by controlling the release rate of nitrogen and phosphorus nutrients, promoting crop nutrient absorption, and reducing the non-active absorption of low-concentration nutrients by crops. It can also catalyze and promote the appropriate, timely, and moderate release of nutrients in the soil for crop absorption and utilization, and at the same time has a certain improvement effect on the soil. The synergist prepared by the present invention should have the characteristics of scientific release, high crop absorption rate, and low crop active absorption of low-concentration nutrients. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is the preparation flow chart of the synergist of the present invention;

[0034] Figure 2 is the structural schematic diagram of the synergist. DETAILED DESCRIPTION OF THE INVENTION

[0035] As Figure 1 shown, the present invention provides a method for preparing a synergist for promoting nitrogen and phosphorus absorption, comprising the following steps:

[0036] Mix structural amino acids, non-structural amino acids, water and aldehyde substances, and carry out a modification reaction to obtain a modified amino acid solution;

[0037] Add hydrochloric acid to the modified amino acid solution to precipitate the modified amino acid. After solid-liquid separation, carry out a polymerization reaction on the obtained modified amino acid under a protective atmosphere to obtain a polymerization intermediate;

[0038] Mix the polymerization intermediate, alkali and water, and carry out a hydrolysis reaction to obtain a polymerized amino acid solution;

[0039] Mix the polymerized amino acid solution with organic chelated zinc for a chelation reaction and then with microbial-derived oligosaccharides for a complexation reaction to obtain the solution of the synergist;

[0040] Alternatively, mix the polymerized amino acid solution with microbial-derived oligosaccharides for a complexation reaction and then with organic chelated zinc for a chelation reaction to obtain the solution of the synergist.

[0041] In the present invention, unless otherwise specified, the raw materials used are all commercially available products well-known in the art.

[0042] The present invention mixes structural amino acids, non-structural amino acids, water and aldehyde substances, and carries out a modification reaction to obtain a modified amino acid solution.

[0043] In the present invention, the structural amino acids preferably include one or more of L-aspartic acid, L-glutamic acid and glycine. When the structural amino acids include glycine, the molar amount of glycine in the structural amino acids is preferably not more than 20%. Glycine is the amino acid with the smallest molecular weight and the lowest melting point among all amino acids, and it is very easy to be carbonized or sublimated at high temperature; even after modification, it is very easy to occur; the present invention controls the molar amount of glycine in the structural amino acids not to exceed 20%, which can avoid the loss of materials and the imbalance of proportions during the solid polymerization process. In the present invention, the non-structural amino acids preferably include one or more of γ-aminobutyric acid, β-aminobutyric acid, D-aspartic acid and D-glutamic acid. In the present invention, the molar ratio of the structural amino acids to the non-structural amino acids is preferably (5-9):1, and in specific embodiments, it can be 5:1, 6:1, 7:1, 8:1 or 9:1. The present invention uses structural amino acids and non-structural amino acids to better endow the synergist with the ability to stimulate crop growth and embed other synergistic substances; at the same time, when the two are used in combination, it can also slow down the degradation rate of the polymerized amino acids.

[0044] In the present invention, the structural amino acids refer to amino acids that can directly participate in the formation of plant proteins and have biological activities, mainly the L-configured amino acids among the 20 standard amino acids in the human body. In the present invention, the non-structural amino acids refer to amino acids that cannot directly participate in the formation of plant proteins or participate in the formation of the structure but do not have biological activities themselves, such as D-amino acids or modified substances of standard amino acids. Different from structural amino acids, although non-structural amino acids do not participate in protein formation, the functions of these amino acids cannot be ignored.

[0045] In the present invention, the ratio of the mass of water to the total mass of structural amino acids and non-structural amino acids is preferably (2 - 3):1, and in specific embodiments, it can be 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1 or 3:1.

[0046] In the present invention, the role of water is to provide reaction conditions for the modification of aldehydes.

[0047] In the present invention, the aldehyde substances preferably include one or more of paraformaldehyde, formaldehyde, acetaldehyde and propionaldehyde; the molar amount of the aldehyde substances is preferably 10 - 20% of the total molar amount of structural amino acids and non-structural amino acids, and in specific embodiments, it can be 10%, 12%, 15%, 17% or 20%.

[0048] In the present invention, the temperature of the modification reaction is preferably 80 - 95°C, and in specific embodiments, it can be 80°C, 85°C, 90°C or 95°C; the time of the modification reaction is preferably more than 1 h, and more preferably 1 - 4 h. In the modification process of the present invention, amino acids react with aldehydes under the action of water to carry out graft modification on the amino groups of amino acids. Through aldehyde modification, the disease resistance of the polymerized amino acids is improved in the present invention, and it helps to construct the three-dimensional structure of the polymerized amino acid molecules. The polymerized amino acids with a three-dimensional structure will show a higher molecular weight, and thus can accommodate more nutrients and obtain better long-term effectiveness; in addition, another advantage of using aldehyde modification is the sterilization effect of the aldehyde structure, which further protects the main structure and extends its long-term effectiveness period.

[0049] After obtaining the modified amino acid solution, the present invention adds hydrochloric acid to the modified amino acid solution to precipitate the modified amino acids. After solid-liquid separation, the obtained modified amino acids are subjected to a polymerization reaction under a protective atmosphere to obtain a polymerization intermediate.

[0050] In the present invention, the mass fraction of the hydrochloric acid is preferably 37%. The present invention has no special requirements for the addition amount of the hydrochloric acid. Adjusting the pH value of the modified amino acid solution to below the lowest isoelectric point of the amino acid can precipitate the modified amino acid. The present invention selects hydrochloric acid for pH adjustment, and the residual co-crystallized hydrochloric acid therein can promote the extension of the amino acid molecular chain. After adding hydrochloric acid in the present invention, it is preferably left standing for 12 h to fully precipitate the modified amino acid.

[0051] The present invention has no special requirements for the solid-liquid separation method, and the well-known solid-liquid separation methods in the art can be adopted, such as filtration and centrifugation.

[0052] After obtaining the modified amino acid, the present invention conducts a polymerization reaction on the modified amino acid under a protective atmosphere to obtain a polymerization intermediate.

[0053] In the present invention, the protective atmosphere means that the reaction atmosphere only contains gas components that do not undergo oxidation-reduction under specified conditions, such as nitrogen, argon, and helium. In the embodiments of the present invention, the protective atmosphere is specifically a nitrogen atmosphere; the temperature of the polymerization reaction is preferably 180-200 °C, and can be 180 °C, 185 °C, 190 °C, 195 °C, or 200 °C in specific embodiments; the time of the polymerization reaction is preferably 3-5 h, and more preferably 4 h.

[0054] After obtaining the polymerization intermediate, the present invention mixes the polymerization intermediate, an alkali, and water to conduct a hydrolysis reaction to obtain a polyamino acid solution.

[0055] In the present invention, the alkali preferably includes one or more of sodium hydroxide, potassium hydroxide, and ammonium hydroxide; the molar ratio of the polymer intermediate to the hydroxide ion in the alkali is preferably 1:(0.78-0.90), and more preferably 1:0.84.

[0056] In the present invention, the dosage of the water is preferably 1.4-1.5 times the mass of all dry substances, and preferably 1.5 times.

[0057] In the present invention, the temperature of the hydrolysis reaction is preferably 55-70 °C, and the time is preferably 2-3 h. In specific embodiments, the temperature of the hydrolysis reaction can be 55 °C, 60 °C, 65 °C, or 70 °C, and the time of the hydrolysis reaction can be 2 h or 3 h. During the hydrolysis reaction in the present invention, the non-water-soluble cyclic imine structure formed after the polymerization of the modified amino acid undergoes hydrolysis ring-opening under alkaline conditions to generate free carboxyl and amino groups, and these two groups are also one of the effective groups. After the hydrolysis reaction, the formed polyamino acid is in a liquid state and is dissolved in the polyamino acid solution.

[0058] In the present invention, the viscosity-average molecular weight of the polyamino acid in the polyamino acid solution is preferably > 15 KD. In the present invention, the polyamino acid is affected by soil microbial flora and chemical substances and thus undergoes a degradation reaction. Only by maintaining a certain molecular weight can its presence time in the soil be maintained and its effect be better exerted. The polyamino acid with a molecular weight > 15 KD has a more prominent effect.

[0059] After obtaining the polyamino acid solution, in the present invention, the polyamino acid solution is mixed with organic chelated zinc for a chelation reaction and then mixed with microbial-derived oligosaccharides for a complexation reaction to obtain the solution of the synergist.

[0060] Alternatively, the polyamino acid solution is mixed with microbial-derived oligosaccharides for a complexation reaction and then mixed with organic chelated zinc for a chelation reaction to obtain the solution of the synergist.

[0061] In the present invention, the organic chelated zinc is preferably a chelate of an organic chelating agent and an inorganic zinc salt; the organic chelating agent includes at least one of iminodisuccinic acid (IDHA), tetrasodium glutamate diacetate (GLDA), and trisodium methylglycine diacetate (MGDA); the inorganic zinc salt preferably includes zinc nitrate hexahydrate and / or zinc sulfate heptahydrate, and the purity of zinc nitrate hexahydrate and zinc sulfate heptahydrate is preferably 98%. In the present invention, the molar ratio of the organic chelating agent to the inorganic zinc salt is preferably 1:1. The organic chelated zinc of the present invention is obtained by a compound chelation form. In addition to containing the target zinc element, it also contains some medium and large elements (S or N), making it easier to form a composite synergist by subsequent embedding.

[0062] In the present invention, the preparation of the organic chelated zinc preferably includes: adding an inorganic zinc salt to an organic chelating agent (in liquid form), mixing evenly, starting stirring, dissolving the inorganic zinc salt, and then keeping it at 65 - 85 °C for 1 h, and drying for standby to obtain the organic chelated zinc (in solid form).

[0063] In the present invention, the mass ratio of the polyamino acid to the organic chelated zinc in the polyamino acid solution is preferably (4 - 6.5):1, and in specific embodiments, it can be 4:1, 4.5:1, 5:1, 5.5:1, 6:1, or 6.5:1.

[0064] In the present invention, the temperature of the chelation reaction is preferably 65 - 85 °C, and the time is preferably 30 - 90 min. In specific embodiments, the temperature of the chelation reaction can be 65 °C, 70 °C, 75 °C, 80 °C, or 85 °C, and the time of the chelation reaction can be 30 min, 45 min, 60 min, 75 min, or 90 min. During the chelation reaction, the organic chelated zinc can combine with the free carboxyl groups on the polyamino acid to form a composite polyamino acid - zinc - chelating agent structure with zinc ions as the central particles.

[0065] In the present invention, the microbial-derived oligosaccharides preferably include one or more of mannan oligosaccharides, chitosan oligosaccharides, and algal oligosaccharides obtained by biological methods. In the examples of the present invention, the microbial-derived oligosaccharides are obtained by purchase. In the present invention, the mass ratio of the polymeric amino acids to the microbial-derived oligosaccharides in the polymeric amino acid solution is preferably (4 - 6.5):0.6, and in specific embodiments, it can be 4:0.6, 4.5:0.6, 5:0.6, 5.5:0.6, 6:0.6, or 6.5:0.6.

[0066] In the present invention, the temperature of the complexation reaction is preferably 65 - 85°C, and the time is preferably 30 - 90 min. In specific embodiments, the temperature of the complexation reaction can be 65°C, 70°C, 75°C, 80°C, or 85°C, and the time of the complexation reaction can be 30 min, 45 min, 60 min, 75 min, or 90 min. During the complexation reaction, the microbial-derived oligosaccharides combine with the free amino groups on the polymeric amino acids, thereby embedding the microbial-derived oligosaccharides on the polymeric amino acids.

[0067] In the present invention, by embedding organic chelated zinc, the organic chelated zinc can provide active nutrients and can be absorbed and utilized in the form of a composite mosaic, determining the radicle dominance effect in the competition between the radicle and plumule during crop germination; the embedded microbial-derived oligosaccharides can achieve the functions of penetration, disease resistance, and biological stimulation, thereby quickly opening the nutrient absorption channels of the crops.

[0068] In the present invention, the synergist obtained after the chelation reaction and the complexation reaction is a liquid, dissolved in the reaction solution, and can be directly used for fertilizer production, or can be made into a solid by means such as low-temperature freeze-drying or negative-pressure protection drying for use.

[0069] The present invention provides a synergist for promoting nitrogen and phosphorus absorption prepared by the preparation method described in the above solution, including polymeric amino acids and organic chelated zinc and microbial-derived oligosaccharides bound to the polymeric amino acids.

[0070] Figure 2 is a schematic structural diagram of the synergist, wherein PASP represents polymeric amino acids, OS represents microbial-derived oligosaccharides, IDS represents organic chelated zinc, and X 2+ represents Zn 2+ .

[0071] The synergist provided by the present invention has the following effects: first, there is a curved void structure, which is beneficial to the encapsulation and release of nutrients; second, the materials used all have a certain biological stimulation function and can play a role in disease resistance, promoting nutrient absorption, and promoting root development; third, the polymerized amino acids at the bottom layer are the most critical. In the form of compound amino acids, the process of combining structural amino acids and non-structural amino acids is adopted to enhance its biological stimulation function; finally, the multi-level degradation and release of the synergistic complex is more conducive to the supply of crop nutrients.

[0072] The present invention provides an application of the synergist for promoting nitrogen and phosphorus absorption described in the above solution in the fertilizer production process. The application target of the present invention is a base fertilizer containing at least one of nitrogen and phosphorus nutrients, specifically such as urea, compound (mixed) fertilizer, monoammonium phosphate, diammonium phosphate, etc.

[0073] In the present invention, the synergist is preferably added additionally outside the nutrients during the fertilizer production process, and specifically can be added in a drum granulation, tower granulation or extrusion granulation system; the addition amount of the synergist is preferably 0.5-2.0% of the fertilizer quality, and can be 0.5%, 1%, 1.5% or 2% in specific embodiments.

[0074] The following combines examples to detail the synergist for promoting nitrogen and phosphorus absorption provided by the present invention, its preparation method and application, but they cannot be understood as limiting the protection scope of the present invention.

[0075] Example 1

[0076] Put 0.8 mol of aspartic acid and 0.1 mol of γ-aminobutyric acid into a four-necked flask, add 1.0 mol of pure water, stir evenly, then add paraformaldehyde accounting for 15% of the total molar amount of the above amino acids, and keep warm at 90 °C for 2 h for the modification reaction. After the reaction is completed, add 1.5 mol of hydrochloric acid solution (mass fraction 37%), stir evenly, and then stand still at room temperature (20-25 °C) for 12 h to obtain the crystals of modified amino acids; polymerize the crystals in a nitrogen atmosphere at 190 °C for 4 h to obtain a polymerization intermediate; mix 100 g of the polymerization intermediate with 33.36 g of 98% sodium hydroxide and 191.91 g of water (wherein, the molar ratio of the polymerization intermediate to sodium hydroxide is 1:0.84, and the amount of substance of the polymerization intermediate is 102.78 g / mol), and carry out a hydrolysis reaction at 70 °C for 2 h to obtain the required polymerized amino acids; the molecular weight of the polymerized amino acids is 15.5 KD and the effective substance content is 36.13%, meeting the usage requirements;

[0077] After uniformly mixing 100 g of 42% IDHA with 84.44 g of 40% MGDA (the molar mass of IDHA is 337.1 g / mol; the molar mass of MGDA is 271.1 g / mol; the molar ratio of the two is 1:1), 75.52 g of 98% zinc nitrate hexahydrate solid is added. After starting stirring to dissolve it and then keeping it warm at 85 °C for 1 h, it is dried for standby to obtain the required chelated zinc solid;

[0078] Mix 100 g of the obtained polyamino acid liquid with 8.75 g of chelated zinc, and keep it warm at 85 °C for 30 min for chelation reaction; after the reaction is completed, add 57.94 g of mannan oligosaccharide with a purity of 9.06% and continue to keep it warm for 30 min for complexation reaction to obtain the synergist liquid; it contains 21.67% of polyamino acid, 5.25% of chelated zinc and 3.15% of mannan oligosaccharide.

[0079] Add the synergist to the compound fertilizer (15-15-15) at a ratio of 7.5 kg / ton, and apply it to the corn planting in North China.

[0080] Example 2

[0081] The difference in the preparation of polyamino acid compared with Example 1 is: mix 100 g of the polymerization intermediate with 30.97 g of 98% sodium hydroxide and 188.47 g of water (wherein, the molar ratio of the polymerization intermediate to sodium hydroxide is 1:0.78, and the amount of substance of the polymerization intermediate is 102.78 g / mol), and carry out hydrolysis reaction at 75 °C for 1.5 h to obtain the required polyamino acid; the molecular weight of this polyamino acid is 16.5 KD and the effective substance content is 36.78%, meeting the usage requirements;

[0082] After uniformly stirring 200 g of 42% IDHA, add 72.98 g of 98% zinc sulfate heptahydrate solid. After starting stirring to dissolve it and then keeping it warm at 65 °C for 1 h, it is dried for standby to obtain the required chelated zinc solid;

[0083] Mix 125 g of the obtained polyamino acid liquid with 8.75 g of chelated zinc, and keep it warm at 65 °C for 60 min for chelation reaction; after the reaction is completed, add 57.94 g of mannan oligosaccharide with a purity of 9.06% and continue to keep it warm for 60 min for complexation reaction to obtain the synergist liquid; it contains 23.98% of polyamino acid, 4.56% of chelated zinc and 2.74% of mannan oligosaccharide.

[0084] Add the synergist to the compound fertilizer (15-15-15) at a ratio of 7.5 kg / ton, and apply it to the corn planting in North China.

[0085] Example 3

[0086] The preparation of the polymeric amino acid is different from that in Example 1 in that: 100 g of the polymeric intermediate is mixed with 35.03 g of 98% sodium hydroxide and 194.31 g of water (wherein the molar ratio of the polymeric intermediate to sodium hydroxide is 1:0.90, and the amount of substance of the polymeric intermediate is 102.78 g / mol); hydrolysis reaction is carried out at 65 °C for 1 h to obtain the required polymeric amino acid; the molecular weight of the polymeric amino acid is 15.2 KD and the content of the active substance is 35.68%, meeting the usage requirements;

[0087] 100 g of 42% IDHA and 84.44 g of 40% MGDA (the molar mass of IDHA is 337.1 g / mol; the molar mass of MGDA is 271.1 g / mol; the molar ratio of the two is 1:1) are mixed evenly, then 72.98 g of 98% zinc sulfate heptahydrate solid is added, stirring is started to dissolve it, and then it is kept warm at 75 °C for 1 h, and then dried for standby to obtain the required chelated zinc solid;

[0088] 150 g of the obtained polymeric amino acid liquid and 8.75 g of chelated zinc are mixed and kept warm at 65 °C for 60 min for chelation reaction; after the reaction is completed, 57.94 g of mannan oligosaccharide with a purity of 9.06% is added and kept warm for another 60 min for complexation reaction to obtain the synergist liquid; it contains 24.70% of polymeric amino acid, 4.04% of chelated zinc and 2.42% of mannan oligosaccharide.

[0089] This synergist is added to compound fertilizer (15-15-15) at a ratio of 7.5 kg / ton and applied to corn planting in North China.

[0090] Example 4

[0091] The preparation and indexes of the polymeric amino acid are the same as those in Example 1;

[0092] 100 g of 42% IDHA and 93.08 g of 57% GLDA (the molar mass of IDHA is 337.1 g / mol; the molar mass of GLDA is 351.14 g / mol; the molar ratio of the two is 1:1) are mixed evenly, then 75.52 g of 98% zinc nitrate hexahydrate solid is added, stirring is started to dissolve it, and then it is kept warm at 75 °C for 1 h, and then dried for standby to obtain the required chelated zinc solid;

[0093] 100 g of the obtained polymeric amino acid liquid and 8.75 g of chelated zinc are mixed and kept warm at 85 °C for 30 min for chelation reaction; after the reaction is completed, 57.94 g of mannan oligosaccharide with a purity of 9.06% is added and kept warm for another 30 min for complexation reaction to obtain the synergist liquid; it contains 21.67% of polymeric amino acid, 5.25% of chelated zinc and 3.15% of mannan oligosaccharide.

[0094] The synergist is added to the compound fertilizer (15-15-15) at a ratio of 7.5 kg / ton to obtain the synergistic compound fertilizer.

[0095] Example 5

[0096] The preparation and indexes of the polymeric amino acid are the same as those in Example 1;

[0097] 100 g of 42% IDHA, 42.22 g of 40% MGDA and 46.54 g of 57% GLDA (the molar mass of IDHA is 337.1 g / mol; the molar mass of MGDA is 271.1 g / mol; the molar mass of GLDA is 351.14 g / mol; the molar ratio of the three is 1:0.5:0.5) are mixed evenly, then 51.96 g of 98% zinc chloride tetrahydrate solid is added. After starting stirring to dissolve it, it is kept warm at 75 °C for 1 h, and then dried for standby to obtain the required chelated zinc solid;

[0098] 100 g of the obtained polymeric amino acid liquid and 8.75 g of chelated zinc are mixed and kept warm at 85 °C for 30 min for chelation reaction; after the reaction is completed, 57.94 g of mannan oligosaccharide with a purity of 9.06% is added and kept warm for another 30 min for complexation reaction to obtain the synergist liquid; it contains 21.67% of polymeric amino acid, 5.25% of chelated zinc and 3.15% of mannan oligosaccharide.

[0099] The synergist is added to the compound fertilizer (15-15-15) at a ratio of 7.5 kg / ton to obtain the synergistic compound fertilizer.

[0100] Comparative Example 1

[0101] The difference from Example 1 is only that the non-structural amino acid γ-aminobutyric acid is omitted, and the obtained synergist does not contain non-structural amino acids. It is added to the compound fertilizer (15-15-15) at a ratio of 7.5 kg / ton and applied to corn planting in North China.

[0102] Comparative Example 2

[0103] Only polymeric amino acid is used as the synergist, without combining with organic chelated zinc and mannan oligosaccharide. It is added to the compound fertilizer (15-15-15) at a ratio of 7.5 kg / ton and applied to corn planting in North China.

[0104] Comparative Example 3

[0105] The difference from Example 1 is only that the chelation reaction with organic chelated zinc is omitted, and the obtained synergist does not contain organic chelated zinc. It is added to the compound fertilizer (15-15-15) at a ratio of 7.5 kg / ton and applied to corn planting in North China.

[0106] Comparative Example 4

[0107] The difference from Example 1 is only that the complexation reaction with mannan oligosaccharide is omitted, and the obtained synergist does not contain mannan oligosaccharide. It is added to compound fertilizer (15-15-15) at a ratio of 7.5 kg / ton and applied to corn planting in North China.

[0108] Application Example

[0109] Field trials were conducted on the compound fertilizers prepared in Example 1 and Comparative Examples 1-4. When sowing, 750 kg / hm of each of the above compound fertilizers was applied 2 and was applied as basal dressing at sowing in the production of summer maize in different test areas, denoted as T1-T5; at the same time, 750 kg / hm of ordinary compound fertilizer 2 was also used for field trials, denoted as CK; all the above treatments were respectively recorded as separate test areas, and the area of each test area was 300 m 2 , and each treatment was repeated 5 times. All test areas were arranged in a randomized block design (a randomized block design means random arrangement to exclude experimental errors).

[0110] This experiment was conducted in Gaocheng District, Shijiazhuang City, Hebei Province (114°52′49E, 38°01′27N) in 2024. The test area has a typical cinnamon soil texture. The soil organic matter content is 1.95%, total nitrogen is 1.22 g / kg, available phosphorus is 31.83 mg / kg, and available potassium is 117.59 mg / kg, which is a plot with low organic matter and medium levels of nitrogen, phosphorus, and potassium. The experimental period was from the sowing period to the harvest of summer maize. The yield data was obtained by separately harvesting and threshing each plot, drying, and then converting to the hectare quantity. The total N, P 2 O 5 and K 2 O in the plants and grains were compared with the applied amounts to obtain the nutrient recovery rates, which were used to characterize the fertilizer utilization rate. For the measured items of N, P 2 O 5 and K 2 O, the determination was carried out according to the relevant regulations in the textbook "Physical and Chemical Analysis of Soil, Water, and Plants". The remaining indicators were all carried out according to the relevant requirements of general agronomy. The obtained data was sorted and statistically analyzed through an EXCEL spreadsheet, and then the method of comprehensive statistical analysis was used to verify the effect of the synergist on promoting nitrogen and phosphorus absorption. The SPSS 20.0 data analysis system was continued to be used for one-way analysis of variance and the Dunckan method was used for significance test of differences. The comprehensive data results are shown in Table 1.

[0111] Table 1 Comparison of the effects of the synergist on the yield and nutrients of summer maize

[0112]

[0113] As can be seen from the data in Table 1, in terms of the nutrient recovery rates of each treatment, for the T1 treatment in N and P 2 O5 were significantly higher than the other treatments in all aspects, indicating that treatment T1 could significantly improve the utilization rates of N and P 2 O 5 of fertilizers. Of course, more importantly, after using the synergist of the present invention, the accumulation of crop dry matter was promoted, thus making the nutrients in the crops more balanced, rather than simply increasing nutrient absorption. In terms of K 2 O, there was no significant difference between treatment T1 and treatments T2 - T5, but compared with the CK treatment, the effect was significant, indicating that the use of the synergist was also helpful for the absorption of K 2 O, but not as significant as that for N and P 2 O 5 . Considering comprehensively, in terms of nutrient recovery rate, treatment T1 was still the optimal solution among all treatments.

[0114] In addition to the nutrient recovery rate, in terms of the yield in Table 1, treatment T1 was significantly higher than other treatments (except T2. However, it should be noted that although treatment T2 did not reach a significant yield increase level, it still had a yield increase of 2.91%). In terms of 1000-grain weight, there was no significant difference between treatment T1 and treatments T2 - T4, but the difference was extremely significant compared with other treatments, indicating that although the 1000-grain weight was not the primary reason for the yield increase, it was also an important factor (the increase range of T1 compared with T2 - T4 was 1.64 - 3.84%). In terms of the number of grains per ear, there was a significant difference between treatment T1 and other treatments. Considering the fertilizer recovery rate data comprehensively, it can be judged that in the experiments involved in the application examples, T1 had significant advantages both in terms of yield and nutrient recovery rate. The main reasons for this result were as follows: the synergist for promoting nitrogen and phosphorus absorption applied in the present invention had an obvious effect. After being added to compound fertilizers and applied to corn planting, it could effectively improve the utilization efficiency of nutrients (the reason for the increase in 1000-grain weight), and it could stimulate crop growth to make it absorb more nutrients; at the same time, it promoted the pollination of corn in the later growth stage, resulting in a significant increase in the number of grains per ear. The above reasons combined led to the increase in corn yield.

[0115] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a synergist for promoting nitrogen and phosphorus absorption, characterized in that: The following steps are involved: Mixing structural amino acids, non-structural amino acids, water and aldehyde substances to carry out modification reaction to obtain a modified amino acid solution; adding hydrochloric acid to the modified amino acid solution to precipitate the modified amino acid, and after solid-liquid separation, polymerizing the obtained modified amino acid under a protective atmosphere to obtain a polymer intermediate; The polymerized intermediate, a base and water are mixed to perform a hydrolysis reaction to obtain a polymerized amino acid solution; The polymerized amino acid solution is mixed with organic chelated zinc for chelation reaction and then mixed with oligosaccharides from microorganisms for complexation reaction to obtain the synergist solution; Alternatively, the polymerized amino acid solution is mixed with oligosaccharides of microbial origin for complexation reaction and then mixed with organic chelated zinc for chelation reaction to obtain the synergist solution.

2. The preparation method according to claim 1, characterized in that: The structural amino acids include one or more of L-aspartic acid, L-glutamic acid and glycine; The non-structural amino acids include one or more of γ-aminobutyric acid, β-aminobutyric acid, D-aspartic acid and D-glutamic acid; The molar ratio of the structural amino acids to the non-structural amino acids is (5-9):

1.

3. The preparation method according to claim 1, characterized in that: The aldehyde substance comprises one or more of paraformaldehyde, formaldehyde, acetaldehyde and propionaldehyde; the molar amount of the aldehyde substance is 10-20% of the total molar amount of structural amino acids and non-structural amino acids.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The temperature of the modification reaction is 80-95°C.

5. The preparation method according to claim 1, characterized in that: The polymerization reaction temperature is 180-200°C; the protective atmosphere refers to the reaction atmosphere containing only gas components that are not oxidized and reduced under the specified conditions; The alkali includes one or more of sodium hydroxide, potassium hydroxide and ammonium hydroxide; the molar ratio of the polymer intermediate to the hydroxide ion in the alkali is 1:(0.78-0.90).

6. The preparation method according to claim 1, characterized in that: The organic chelated zinc is a chelate of an organic chelating agent and an inorganic zinc salt; the organic chelating agent comprises at least one of iminodisuccinic acid, tetrasodium glutamate diacetate and trisodium methylglycine diacetate.

7. The preparation method according to claim 1, characterized in that: The mass ratio of the polymerized amino acid to the organic chelated zinc in the polymerized amino acid solution is (4-6.5):1; The temperature of the chelating reaction is 65-85° C., and the time is 30-90 minutes.

8. The preparation method according to claim 1, characterized in that: The microbial oligosaccharide includes one or more of manno-oligosaccharide, chito-oligosaccharide and seaweed-oligosaccharide obtained by microbial fermentation; The mass ratio of the polymerized amino acid to the oligosaccharide from microorganism in the polymerized amino acid solution is (4-6.5):0.6; The temperature of the complexation reaction is 65-85° C. and the time is 30-90 minutes.

9. The synergist for promoting nitrogen and phosphorus absorption prepared by the preparation method according to any one of claims 1 to 8, comprising a polymeric amino acid and organic chelated zinc and microbial oligosaccharides bound to the polymeric amino acid.

10. Use of the synergist for promoting nitrogen and phosphorus absorption according to claim 9 in a fertilizer production process, wherein the fertilizer comprises at least one base fertilizer containing nitrogen and phosphorus nutrients.

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