Production method of soybeans rich in organic selenium, zinc and iron

Abstract

The invention relates to the technical field of agricultural production, and discloses a production method of soybeans rich in organic selenium, zinc and ferrum, which comprises the following steps: S1, reacting sodium lignin sulfonate with ferrous sulfate heptahydrate in a first reaction kettle to prepare an iron lignin sulfonate solution; s2, in a second reaction kettle, glycine and zinc sulfate heptahydrate are subjected to a reaction, and a zinc glycinate solution is prepared; s3, adding the iron lignosulfonate solution and the zinc glycinate solution into a main mixing kettle, further adding sodium selenate, L-methionine, L-ascorbic acid and mineral fulvic acid, and uniformly mixing to obtain a compound composition mother solution; and S4, diluting the prepared composite composition mother liquor, and spraying the diluted composite composition mother liquor to the leaf surfaces of soybean crops in the soybean growth period. According to the invention, an iron source and a zinc source are prepared step by step, that is, complexation and chelation are completed in an independent reactor, and then mixing is carried out to obtain a uniform and stable composite mother solution.

Description

Technical Field

[0001] This invention relates to the field of agricultural production technology, specifically to a method for producing soybeans rich in organic selenium, zinc, and iron. Background Technology

[0002] Soybeans are an important food and economic crop, and their growth and quality are influenced by a variety of micronutrients. Iron participates in chlorophyll synthesis, affecting photosynthetic efficiency; zinc is a component of many key enzymes, affecting growth; and selenium directly determines the nutritional value of soybeans as a functional agricultural product. Therefore, developing foliar nutrients that can simultaneously supplement iron, zinc, and selenium is of practical significance for improving soybean yield and added value.

[0003] To meet this need for compound supplementation, existing technologies offer several solutions. For example, inorganic salts of iron and zinc (such as sulfates) can be directly mixed and applied. This method uses readily available raw materials, has a simple preparation process, and lower costs. Other solutions employ organic chelating agents, such as using EDTA or citric acid to prepare chelated iron and chelated zinc, respectively. This method can improve the solubility of metal ions to some extent. Regarding selenium supplementation, the conventional approach is to apply inorganic selenium sources such as sodium selenate, which also allows crops to accumulate selenium.

[0004] However, the above-mentioned technical solutions have revealed significant shortcomings in practical applications. Firstly, there is the issue of formulation stability. The optimal stable pH ranges for iron and zinc ions are not the same. Iron ions are stable in weakly acidic conditions, while zinc ions require a near-neutral environment. Existing processes struggle to balance these factors when mixing and compounding them, leading to hydrolysis and precipitation during storage or dilution, thus reducing the effective components. Secondly, there is the problem of absorption antagonism. Iron and zinc exhibit highly similar absorption and transport pathways in plant leaves. Whether applying inorganic ions or similar chelates like EDTA, it's equivalent to the two ions competing for the same absorption channels simultaneously. This competitive antagonism results in unsatisfactory actual bioavailability for both elements. Finally, there is also a bottleneck in selenium supplementation efficiency. Existing technologies require sodium selenate (inorganic selenium) to be converted into high-value organic selenium through crop metabolism. This bioconversion process is limited by the content of specific substrates or activating substances within the plant, and the conversion efficiency is usually low. Therefore, the final accumulation of organic selenium in the grains is limited. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for producing soybeans rich in organic selenium, zinc, and iron, thereby solving the technical problems of poor stability of compound formulations, antagonistic absorption of iron and zinc elements, and low conversion efficiency of inorganic selenium in existing technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for producing soybeans rich in organic selenium, zinc, and iron, comprising the following steps: S1. In the first reaction vessel, sodium lignosulfonate is reacted with ferrous sulfate heptahydrate to prepare ferric lignosulfonate solution. S2. In the second reaction vessel, glycine is reacted with zinc sulfate heptahydrate to obtain a zinc glycine solution. S3. Add the lignin sulfonate iron solution and the glycine zinc solution to the main mixing vessel, and further add sodium selenate, L-methionine, L-ascorbic acid and mineral-derived fulvic acid, mix evenly to obtain the composite composition mother liquor; S4. After diluting the prepared composite composition mother liquor, apply it to the soybean crop as a foliar spray during the soybean growth cycle.

[0007] By adopting the above technical solution, the present invention achieves the synergistic effect of multiple components through the following technical design: 1. The separation and preparation process solves the problem of formulation stability: This invention employs steps S1 and S2 to separate the iron and zinc sources. Specifically, ferrous ions are first complexed with sodium lignosulfonate, and zinc ions are chelated with glycine to obtain two stable complex / chelated solutions, which are then combined in step S3. This process avoids the release of free Fe. 2+ With Zn 2+ Direct contact during the preparation or storage of the mother liquor effectively prevents hydrolysis, precipitation, or formation of insoluble double salts due to pH differences (ferrous ions are suitable for weakly acidic conditions, while zinc ions are suitable for neutral to slightly alkaline conditions), thus ensuring the storage stability of the composite composition mother liquor.

[0008] 2. The asymmetric complexing / chelation strategy solves the absorption antagonism problem: In this invention, different complexing / chelating agents are used in S1 and S2 to regulate the release rate of iron and zinc and avoid absorption antagonism.

[0009] S1 (Slow-release iron): High-molecular-weight sodium lignin sulfonate (weight-average molecular weight typically above 5,000 Da) is used as a complexing agent. The resulting iron lignin sulfonate complex is stable and, after being sprayed onto the leaves, slowly releases ferrous ions through the slow decomposition or ion exchange of the macromolecules.

[0010] S2 (Rapid Release of Zinc): Utilizing small-molecule glycine (approximately 75 Da) as a chelating agent, the resulting glycine-zinc chelate is readily recognized and absorbed by crop leaves, exhibiting rapid release and high mobility. This combination of slowly released iron and rapidly released zinc staggers the absorption peaks of iron and zinc ions, effectively avoiding the antagonistic effects that occur when they compete for the same transport pathway within the plant, thereby synergistically improving the overall bioavailability of iron and zinc.

[0011] 3. Synergistic effect of specific components in S3: L-Ascorbic acid, as a reducing agent, can effectively protect Fe2+ after storage of the mother liquor and foliar spraying. 2+ It is not oxidized into Fe, which has lower bioavailability. 3+ This maintains the availability of iron.

[0012] L-methionine and mineral-derived fulvic acid work together as activators for selenium conversion. Sodium selenate itself is inorganic selenium, while L-methionine and fulvic acid (rich in active groups) provide biochemical substrates (such as methyl groups) or carriers for the metabolic pathway by which crops convert inorganic selenium into organic selenium (such as selenomethionine), significantly increasing the accumulation of organic selenium in soybean seeds.

[0013] Therefore, the composition prepared by the method of the present invention has high stability and good absorption and utilization rate, and can effectively increase the content of selenium, zinc and iron in soybean crops, especially increasing the proportion of organic selenium.

[0014] Preferably, the mother liquor of the composite composition comprises, by weight, the following solid components: 10.0 to 20.0 parts by weight of ferric lignosulfonate; 5.0 to 10.0 parts by weight of zinc glycine; 0.1 to 0.5 parts by weight of sodium selenate; 0.5 to 2.0 parts by weight of L-methionine; 0.5 to 2.0 parts by weight of L-ascorbic acid; and 1.0 to 5.0 parts by weight of mineral-derived fulvic acid.

[0015] By adopting the above technical solution, the ratio range is an optimized ratio that achieves synergistic effects among the components. It ensures the effect of element supplementation while taking into account the safety of foliar spraying and avoids fertilizer damage to crop leaves caused by high concentrations of ions.

[0016] Preferably, in step S1, the molar ratio of the sodium lignosulfonate functional group to the ferrous ion is 1.5:1 to 3.0:1.

[0017] By adopting the above technical solution, this molar ratio range ensures that ferrous ions are fully complexed by sodium lignosulfonate, effectively avoiding the presence of free ferrous ions, which is beneficial to the stability of the S1 solution.

[0018] Preferably, the reaction in step S1 is carried out at a pH of 4.0 to 5.0 and a temperature of 40°C to 60°C.

[0019] By adopting the above technical solution, the pH and temperature conditions are the optimized process parameters for the complexation reaction between sodium lignosulfonate and ferrous ions, which helps to improve the reaction rate and complexation efficiency.

[0020] Preferably, in step S2, the molar ratio of glycine to zinc ions is 2.0:1 to 3.0:1.

[0021] By adopting the above technical solution, this molar ratio (especially higher than 2:1) helps to form more stable bicoordinated or tricoordinated glycine zinc chelates, ensuring the stability and bioavailability of zinc.

[0022] Preferably, the reaction in step S2 is carried out under conditions of pH 6.0 to 7.0.

[0023] By adopting the above technical solution, this pH range is the suitable pH range for glycine to form a stable chelate with zinc ions.

[0024] Preferably, the sodium lignosulfonate in step S1 has a weight-average molecular weight of 5,000 Da to 20,000 Da.

[0025] By adopting the above technical solution, sodium lignosulfonate in this molecular weight range has sufficient steric hindrance and functional group quantity to form a stable macromolecular complex, which is the technical basis for realizing the slow-release function of iron.

[0026] Preferably, in step S3, the pH value of the mother liquor of the composite composition is adjusted to 5.0 to 6.5.

[0027] By adopting the above technical solution, the pH range is weakly acidic, which on the one hand meets the suitable pH environment for crop leaf absorption, and on the other hand is also beneficial to the various components in the mother liquor (especially Fe). 2+ Stability of L-ascorbic acid.

[0028] Preferably, alkylphenol polyoxyethylene ether is further added in step S3.

[0029] By adopting the above technical solution and adding alkylphenol polyoxyethylene ether as a surfactant (wetting and spreading agent), the surface tension of the spray solution can be reduced, the adhesion area and retention time on crop leaves can be increased, and the penetration and absorption of various nutrients can be promoted.

[0030] Preferably, step S4 specifically includes: diluting the mother liquor of the composite composition with clean water at a volume ratio of 1:1000; and uniformly spraying the soybean crop on the leaves at the flowering and pod-setting stages and the grain-filling stage, respectively.

[0031] By adopting the above technical solution, a dilution ratio of 1:1000 is an application concentration that balances effectiveness and safety. The flowering and pod-setting stages of soybeans are critical periods for their nutritional needs for selenium, zinc, and iron, and are also the peak periods for grain filling and nutrient accumulation. Applying two foliar sprays during these stages can effectively improve nutrient conversion efficiency and the amount of elements accumulated in the final grains.

[0032] This invention provides a method for producing soybeans rich in organic selenium, zinc, and iron. It has the following beneficial effects: 1. This invention prepares iron and zinc sources in steps, that is, first completes complexation and chelation in independent reactors, and then mixes them to obtain a uniform and stable composite mother liquor. Existing technologies usually directly mix multiple inorganic salts, which leads to hydrolysis and precipitation between components due to pH incompatibility. This invention solves this technical defect and ensures the stability and effectiveness of the product.

[0033] 2. This invention employs differentiated treatment methods for iron and zinc. It uses macromolecular lignin sulfonate to chelate iron for slow release, while using small molecule glycine to chelate zinc for rapid release. Existing technologies often use similar chelating agents, which leads to iron and zinc competing for transport channels during crop absorption. The design of this invention avoids the absorption peaks of the two elements, thus circumventing antagonistic effects and synergistically improving bioavailability.

[0034] 3. The present invention incorporates L-methionine and mineral-derived fulvic acid into the composition, providing a biochemical substrate and carrier for crop conversion of inorganic selenium, significantly increasing the accumulation of organic selenium in soybean seeds. Existing technologies only apply inorganic selenium sources, but the conversion efficiency of the crop itself is limited. The design of the present invention overcomes this bottleneck and enhances the nutritional value of selenium. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0036] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0037] Ferrous sulfate heptahydrate, with the molecular formula FeSO4·7H2O and CAS number 7782-63-0, is used as an iron source.

[0038] Zinc sulfate heptahydrate, with the molecular formula ZnSO4·7H2O and CAS number 7446-20-0, is used as a zinc source.

[0039] Sodium selenate, with the molecular formula Na2SeO4 and CAS number 13410-01-0, is used as a selenium source.

[0040] Sodium lignosulfonate, CAS No.: 8061-51-6, is a lignosulfonate polymer with a weight-average molecular weight ranging from 5,000 Da to 20,000 Da, and is used as an iron chelating agent.

[0041] Glycine, with the molecular formula C2H5NO2 and CAS number 56-40-6, is used as a zinc chelating agent.

[0042] L-methionine, with the molecular formula C5H 11 NO2S, CAS No.: 63-68-3, is used as an activator of the selenium pathway.

[0043] L-Ascorbic acid, with the molecular formula C6H8O6 and CAS number 50-81-7, is used as an iron pathway stabilizer.

[0044] Mineral fulvic acid is a mixture of natural organic matter extracted from weathered coal or lignite. The fulvic acid content (on a dry basis) of mineral fulvic acid is not less than 50.0% (w / w), and it is used as an energy metabolism activator.

[0045] Alkylphenol polyoxyethylene ether, a commercially available nonionic surfactant, is used as an auxiliary agent G.

[0046] Disodium ethylenediaminetetraacetate, with the molecular formula C 10 H 14 N2Na2O8·2H2O, CAS No.: 6381-92-6, was used as a conventional chelating agent in the comparative example.

[0047] Preparation Example 1: This preparation example provides a component A (ferric lignosulfonate) solution, including the following steps: (1) Add 100 parts by mass of deionized water to the reactor and heat it to 40°C.

[0048] (2) Add 67.4 parts by weight of sodium lignosulfonate (weight average molecular weight of about 10,000 Da) and stir to dissolve.

[0049] (3) While stirring, slowly add 50.0 parts by weight of ferrous sulfate heptahydrate (FeSO4·7H2O). At this time, the functional groups of sodium lignosulfonate react with ferrous ions (Fe... 2+ The molar ratio of ( ) is approximately 1.5:1.

[0050] (4) Use citric acid to adjust the pH of the reaction solution to 4.0.

[0051] (5) The reaction was stirred continuously for 2.0 hours at 40℃ and pH 4.0.

[0052] (6) Cool to room temperature to obtain component A solution 1, for later use.

[0053] Preparation Example 2: This preparation example provides a component A (ferric lignosulfonate) solution, including the following steps: (1) Add 80 parts by mass of deionized water to the reactor and heat it to 50°C.

[0054] (2) Add 89.9 parts by weight of sodium lignosulfonate (weight average molecular weight of about 10,000 Da) and stir to dissolve.

[0055] (3) While stirring, slowly add 50.0 parts by weight of ferrous sulfate heptahydrate (FeSO4·7H2O). At this time, the functional groups of sodium lignosulfonate react with ferrous ions (Fe... 2+ The molar ratio of () is approximately 2.0:1.

[0056] (4) Use citric acid to adjust the pH of the reaction solution to 4.5.

[0057] (5) The reaction was stirred continuously for 1.5 hours at 50°C and pH 4.5.

[0058] (6) Cool to room temperature to obtain component A solution 2, for later use.

[0059] Preparation Example 3: This preparation example provides a component A (ferric lignosulfonate) solution, including the following steps: (1) Add 100 parts by mass of deionized water to the reactor and heat it to 60°C.

[0060] (2) Add 134.9 parts by weight of sodium lignosulfonate (weight average molecular weight of about 10,000 Da) and stir to dissolve.

[0061] (3) While stirring, slowly add 50.0 parts by weight of ferrous sulfate heptahydrate (FeSO4·7H2O). At this time, the functional groups of sodium lignosulfonate react with ferrous ions (Fe... 2+ The molar ratio of ( ) is approximately 3.0:1.

[0062] (4) Use citric acid to adjust the pH of the reaction solution to 5.0.

[0063] (5) The reaction was stirred continuously for 1.0 hour at 60℃ and pH 5.0.

[0064] (6) Cool to room temperature to obtain component A solution 3, for later use.

[0065] Preparation Example 4: This preparation example provides a component B (zinc glycine) solution, including the following steps: (1) Add 50 parts by mass of deionized water to the independent B reactor.

[0066] (2) Add 26.1 parts by weight of glycine and stir to dissolve.

[0067] (3) While stirring, add 50.0 parts by weight of zinc sulfate heptahydrate (ZnSO4·7H2O). At this time, glycine and zinc ions (Zn 2+ The molar ratio of () is approximately 2.0:1.

[0068] (4) Use 30% (w / v) sodium hydroxide solution to slowly add dropwise to adjust the pH of the reaction solution to 6.0.

[0069] (5) The reaction was stirred continuously for 1.0 hour at room temperature (25℃) and pH 6.0.

[0070] (6) Obtain component B solution 1 for later use.

[0071] Preparation Example 5: This preparation example provides a component B (zinc glycine) solution, including the following steps: (1) Add 40 parts by mass of deionized water to the independent B reactor.

[0072] (2) Add 32.6 parts by weight of glycine and stir to dissolve.

[0073] (3) While stirring, add 50.0 parts by weight of zinc sulfate heptahydrate (ZnSO4·7H2O). At this time, glycine and zinc ions (Zn 2+ The molar ratio of () is approximately 2.5:1.

[0074] (4) Use 30% (w / v) sodium hydroxide solution to slowly add dropwise and adjust the pH of the reaction solution to 6.5.

[0075] (5) The reaction was stirred continuously for 0.5 hours at room temperature (25℃) and pH 6.5.

[0076] (6) Obtain component B solution 2, and set aside.

[0077] Preparation Example 6: This preparation example provides a component B (zinc glycine) solution, including the following steps: (1) Add 50 parts by mass of deionized water to a separate reactor B.

[0078] (2) Add 39.1 parts by weight of glycine and stir to dissolve.

[0079] (3) While stirring, add 50.0 parts by weight of zinc sulfate heptahydrate (ZnSO4·7H2O). At this time, glycine and zinc ions (Zn 2+ The molar ratio of ( ) is approximately 3.0:1.

[0080] (4) Use 30% (w / v) sodium hydroxide solution to slowly add dropwise and adjust the pH of the reaction solution to 7.0.

[0081] (5) The reaction was stirred continuously for 0.5 hours at room temperature (25℃) and pH 7.0.

[0082] (6) Obtain component B solution 3, for later use.

[0083] Example 1: This embodiment provides a method for producing soybeans rich in organic selenium, zinc, and iron, including the following steps: (1) Add about 700 parts by weight of deionized water to the main mixing vessel.

[0084] (2) While stirring, add the A component (ferric lignosulfonate) solution 2 prepared in Preparation Example 2 (the amount added is equivalent to 15.0 parts by mass of ferric lignosulfonate solid content) and the B component (zinc glycinate) solution 2 prepared in Preparation Example 5 (the amount added is equivalent to 7.5 parts by mass of zinc glycinate solid content).

[0085] (3) While stirring, add 0.3 parts by mass of sodium selenate (component C), 1.2 parts by mass of L-methionine (component D), 1.2 parts by mass of L-ascorbic acid (component E) and 3.0 parts by mass of mineral fulvic acid (component F) in sequence, and stir until each component is completely dissolved.

[0086] (4) Add 2.0 parts by weight of alkylphenol polyoxyethylene ether (component G) and stir until homogeneous.

[0087] (5) Add deionized water to a final volume of 1000 parts by weight and stir until homogeneous.

[0088] (6) Adjust the pH of the final mother liquor to 5.5 using citric acid or sodium hydroxide solution to obtain the composite composition mother liquor of Example 1.

[0089] (7) Dilute the prepared composite composition mother liquor with clean water at a volume ratio of 1:1000 to obtain the spray solution.

[0090] (8) Spray soybeans evenly on the leaves during the flowering and pod-setting and grain-filling stages, ensuring that the leaves are evenly moistened each time.

[0091] Example 2: This embodiment provides a method for producing soybeans rich in organic selenium, zinc, and iron, including the following steps: (1) Add about 800 parts by weight of deionized water to the main mixing vessel.

[0092] (2) While stirring, add the A component (ferric lignosulfonate) solution 1 prepared in Preparation Example 1 (the amount added is equivalent to 10.0 parts by mass of ferric lignosulfonate solid content) and the B component (zinc glycinate) solution 1 prepared in Preparation Example 4 (the amount added is equivalent to 5.0 parts by mass of zinc glycinate solid content).

[0093] (3) While stirring, add 0.1 parts by weight of sodium selenate (component C), 0.5 parts by weight of L-methionine (component D), 0.5 parts by weight of L-ascorbic acid (component E) and 1.0 parts by weight of mineral fulvic acid (component F) in sequence, and stir until each component is completely dissolved.

[0094] (4) Add 1.0 part by weight of alkylphenol polyoxyethylene ether (component G) and stir until homogeneous.

[0095] (5) Add deionized water to a final volume of 1000 parts by weight and stir until homogeneous.

[0096] (6) The pH of the final mother liquor was adjusted to 5.0 using citric acid to obtain the composite composition mother liquor of Example 2.

[0097] (7) Dilute the prepared composite composition mother liquor with clean water at a volume ratio of 1:1000 to obtain the spray solution.

[0098] (8) Spray soybeans evenly on the leaves during the flowering and pod-setting and grain-filling stages, ensuring that the leaves are evenly moistened each time.

[0099] Example 3: This embodiment provides a method for producing soybeans rich in organic selenium, zinc, and iron, including the following steps: (1) Add about 600 parts by mass of deionized water to the main mixing vessel.

[0100] (2) While stirring, add the A component (ferric lignosulfonate) solution 3 prepared in Preparation Example 3 (the amount added is equivalent to 20.0 parts by mass of ferric lignosulfonate solid content) and the B component (zinc glycinate) solution 3 prepared in Preparation Example 6 (the amount added is equivalent to 10.0 parts by mass of zinc glycinate solid content).

[0101] (3) While stirring, add 0.5 parts by weight of sodium selenate (component C), 2.0 parts by weight of L-methionine (component D), 2.0 parts by weight of L-ascorbic acid (component E) and 5.0 parts by weight of mineral fulvic acid (component F) in sequence, and stir until each component is completely dissolved.

[0102] (4) Add 3.0 parts by weight of alkylphenol polyoxyethylene ether (component G) and stir until homogeneous.

[0103] (5) Add deionized water to a final volume of 1000 parts by weight and stir until homogeneous.

[0104] (6) Adjust the pH of the final mother liquor to 6.5 using citric acid or sodium hydroxide solution to obtain the composite composition mother liquor of Example 3.

[0105] (7) Dilute the prepared composite composition mother liquor with clean water at a volume ratio of 1:1000 to obtain the spray solution.

[0106] (8) Spray soybeans evenly on the leaves during the flowering and pod-setting and grain-filling stages, ensuring that the leaves are evenly moistened each time.

[0107] Example 4: This embodiment provides a method for producing soybeans rich in organic selenium, zinc, and iron, including the following steps: (1) Add about 700 parts by weight of deionized water to the main mixing vessel.

[0108] (2) While stirring, add the A component (ferric lignosulfonate) solution 3 prepared in Preparation Example 3 (the amount added is equivalent to 18.0 parts by mass of ferric lignosulfonate solid content) and the B component (zinc glycinate) solution 1 prepared in Preparation Example 4 (the amount added is equivalent to 6.0 parts by mass of zinc glycinate solid content).

[0109] (3) While stirring, add 0.4 parts by weight of sodium selenate (component C), 1.8 parts by weight of L-methionine (component D), 1.8 parts by weight of L-ascorbic acid (component E) and 4.0 parts by weight of mineral fulvic acid (component F) in sequence, and stir until each component is completely dissolved.

[0110] (4) Add 2.0 parts by weight of alkylphenol polyoxyethylene ether (component G) and stir until homogeneous.

[0111] (5) Add deionized water to a final volume of 1000 parts by weight and stir until homogeneous.

[0112] (6) Adjust the pH of the final mother liquor to 5.5 using citric acid or sodium hydroxide solution to obtain the composite composition mother liquor of Example 4.

[0113] (7) Dilute the prepared composite composition mother liquor with clean water at a volume ratio of 1:1000 to obtain the spray solution.

[0114] (8) Spray soybeans evenly on the leaves during the flowering and pod-setting and grain-filling stages, ensuring that the leaves are evenly moistened each time.

[0115] Example 5: This embodiment provides a method for producing soybeans rich in organic selenium, zinc, and iron, including the following steps: (1) Add about 700 parts by weight of deionized water to the main mixing vessel.

[0116] (2) While stirring, add the A component (ferric lignosulfonate) solution 1 prepared in Preparation Example 1 (the amount added is equivalent to 12.0 parts by mass of ferric lignosulfonate solid content) and the B component (zinc glycinate) solution 3 prepared in Preparation Example 6 (the amount added is equivalent to 9.0 parts by mass of zinc glycinate solid content).

[0117] (3) While stirring, add 0.4 parts by weight of sodium selenate (component C), 1.8 parts by weight of L-methionine (component D), 1.0 parts by weight of L-ascorbic acid (component E) and 4.0 parts by weight of mineral fulvic acid (component F) in sequence, and stir until each component is completely dissolved.

[0118] (4) Add 2.0 parts by weight of alkylphenol polyoxyethylene ether (component G) and stir until homogeneous.

[0119] (5) Add deionized water to a final volume of 1000 parts by weight and stir until homogeneous.

[0120] (6) Adjust the pH of the final mother liquor to 6.0 using citric acid or sodium hydroxide solution to obtain the composite composition mother liquor of Example 5.

[0121] (7) Dilute the prepared composite composition mother liquor with clean water at a volume ratio of 1:1000 to obtain the spray solution.

[0122] (8) Spray soybeans evenly on the leaves during the flowering and pod-setting and grain-filling stages, ensuring that the leaves are evenly moistened each time.

[0123] Comparative Example 1: Compared with Example 1, the difference lies in its preparation method: the precursor raw materials (ferrous sulfate heptahydrate, zinc sulfate heptahydrate, sodium lignosulfonate, glycine) required for the preparation of components A and B are mixed and stirred to dissolve in a single batch with components C, D, E, F, G and water in the main mixing vessel, and the pH is adjusted to 5.5. The rest are the same.

[0124] Comparative Example 2: Compared with Example 1, the difference is that sodium ferric ethylenediaminetetraacetate (EDTA-Fe) and sodium zinc ethylenediaminetetraacetate (EDTA-Zn) are used to replace component A (ferric lignin sulfonate) and component B (zinc glycine) respectively, and components D (L-methionine), E (L-ascorbic acid) and F (mineral-derived fulvic acid) are not added, while the rest are the same.

[0125] Comparative Example 3: Compared with Example 1, the difference is that component D (L-methionine) and component F (mineral-derived fulvic acid) are not added during the preparation process, while the rest are the same.

[0126] Comparative Example 4: The difference compared to Example 1 is that component E (L-ascorbic acid) is not added during the preparation process.

[0127] Comparative Example 5: Compared with Example 1, the difference is that component B (zinc glycinate) was replaced with an equal amount of zinc lignin sulfonate (the preparation method is the same as in Examples 1-3, except that ferrous sulfate heptahydrate was replaced with zinc sulfate heptahydrate), and all other aspects are the same.

[0128] Comparative Example 6: Compared with Example 1, the difference is that component A (ferric lignosulfonate) is replaced with an equal amount of iron glycine iron (the preparation method is the same as in Preparation Examples 4-6, except that zinc sulfate heptahydrate is replaced with ferrous sulfate heptahydrate).

[0129] Comparative Example 7: This comparative example provides a blank control treatment that uses an equal volume of water, does not contain any of the AG components from Example 1, and is otherwise identical.

[0130] Test Example 1: Formulation stability and mechanism simulation testing: Experimental description: 1. Formulation stability testing: Take 100 mL each of the preparation mother liquors from Examples 1-5, Comparative Examples 1 and 4, and place them in two clean, sealed glass bottles. One set of samples was placed in a constant-temperature oven at (54±2)℃ and stored continuously for 14 days for high-temperature storage testing. The other set of samples was placed in a constant-temperature refrigerator at (0±2)℃ and stored continuously for 7 days for low-temperature storage testing. After the storage period, all samples were brought back to room temperature (25℃), and their appearance was visually inspected under natural light. The presence of precipitation, crystallization, layering, or flocculation was recorded. For the samples stored at high temperatures, the o-phenanthroline colorimetric method was used to determine the water-soluble Fe in the samples before (0 days) and after (14 days) storage. 2+ Content, calculation of Fe 2+ Decomposition rate.

[0131] 2. Fe 2+ Oxidative stability simulation test: Take the stock solutions from Example 1 (containing component E: L-ascorbic acid) and Comparative Example 4 (without component E), and accurately dilute them 1000 times with deionized water to simulate field spraying concentrations. Accurately transfer 10 mL of the diluted solution and evenly spray (or coat) it onto a clean 15 cm x 15 cm glass plate, allowing the liquid to spread naturally to form a thin layer. Place the glass plate horizontally in a well-ventilated environment at room temperature (25°C) and relative humidity of 60% to simulate the oxidation conditions of the leaf surface liquid film exposed to air. At time points of 0 hours, 1 hour, 4 hours, and 8 hours, immediately spray 50 mL of deionized water (containing 0.1% hydrochloric acid to fix Fe) to the solution. 2+ Thoroughly wash away any residue from the glass plate surface and collect the eluent. Immediately determine the Fe content in the eluent using the o-phenanthroline colorimetric method. 2+ Concentration, and calculate Fe 2+ Retention rate, Fe 2+ Retention rate (%) = (current time point Fe) 2+ Concentration / 0 hours Fe 2+ (Concentration) × 100%.

[0132] 3. Simulation test of Fe / Zn transmembrane release rate: The mother liquors of Example 1 (component A + component B), Comparative Example 5 (component A + component A', both lignin sulfonate complexes), and Comparative Example 6 (component B + component B', both glycine chelates) were all diluted 100-fold with deionized water. A dialysis bag (regenerated cellulose membrane) with a molecular weight cutoff (MWCO) of 1000 Da was selected as the dialysis device. 10 mL of the diluted sample was precisely transferred into the dialysis bag and sealed tightly. The dialysis bag was completely immersed in a beaker containing 500 mL of deionized water. Under constant temperature of 25°C, the deionized water in the beaker was slowly stirred at 100 rpm using a magnetic stirrer. At time points of 0.5 hours, 1 hour, 2 hours, 4 hours, and 8 hours, 5 mL of water sample was taken from the deionized water (dialysis solution) outside the dialysis bag. After each sampling, 5 mL of isothermal deionized water was added to the beaker to maintain a constant total volume. The concentrations of Fe and Zn in the water samples were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES), and the cumulative release rate was calculated.

[0133] Experimental data: Table 1: Results of Formulation Stability Tests

[0134] Table 2: Fe 2+ Oxidation stability simulation test results

[0135] Table 3: Simulation results of Fe / Zn transmembrane release rate

[0136] From Tables 1-3, we can obtain: The data from Test Example 1 verified the physicochemical feasibility of the present invention and provided in vitro mechanistic support for subsequent biological effects.

[0137] Table 1 shows the formulation stability data, indicating that the formulations of Examples 1-5 remained homogeneous and stable under both high-temperature and low-temperature storage conditions, without precipitation or stratification. Comparative Example 1 (where all raw materials were mixed at once) showed trace amounts of flocculation, demonstrating that the process of separating and then compounding components A and B (i.e., an asymmetric complexation process) is essential for maintaining the physical stability of the compounded formulation.

[0138] Meanwhile, Fe in Table 1 2+ Decomposition rate data show that Example 1 (containing component E) showed Fe after high-temperature storage 2+ The decomposition rate (4.8%) was lower than that of Comparative Example 4 (without component E) (41.5%). This indicates that component E (L-ascorbic acid) played a crucial chemical stabilizing role in the composite mother liquor, effectively inhibiting Fe... 2+ Degradation during storage.

[0139] Table 2 Fe 2+ Oxidative stability simulation tests further validated the role of component E in the spraying application environment. This test simulated the oxidation conditions of the pesticide solution exposed to air after spreading on the leaf surface. Example 1 retained 80.2% Fe after 8 hours. 2+ In contrast, Comparative Example 4 retained only 19.5%. This data indicates that the presence of component E (L-ascorbic acid) ensures that Fe... 2+ In the leaf surface liquid film, in reduced state (Fe) 2+ The form is maintained for a relatively long time, which is why Fe... 2+ The basis for effective absorption and utilization by leaf cells.

[0140] Table 3 shows the transmembrane release rate simulation test, which validated the core mechanism of this protocol in vitro. This experiment used a 1000 Da dialysis membrane to simulate the size screening barrier of the cell membrane or transport channel.

[0141] The data from Example 1 (component A - Fe + component B - Zn) showed a clear release differentiation: the cumulative release rate of Zn (derived from component B zinc glycine, a small molecule chelate) reached 78.4% after 8 hours, exhibiting rapid release characteristics; while the cumulative release rate of Fe (derived from component A ferric lignosulfonate, a large molecule complex) was only 19.8%, exhibiting slow release characteristics.

[0142] Data from Comparative Example 5 (A+A', both macromolecular complexes) showed that the release rates of Fe and Zn were both low (approximately 20%), and their rates were similar.

[0143] Data from Comparative Example 6 (B+B', both small molecule chelates) showed that the release rates of Fe and Zn were both high (approximately 77-78%), and their rates were similar and rapid.

[0144] The comparison of three sets of data shows that Example 1 successfully achieved the kinetic separation of Fe (slow-release) and Zn (rapid-release). This difference in physicochemical release rates supports the Fe / Zn asymmetric differential track transport hypothesis proposed in this invention: that is, component B (zinc glycinate) can be absorbed through rapid channels (such as amino acid transporters), while component A (ferric lignosulfonate) is absorbed through a macromolecular slow-release permeation pathway. The two components achieve staggered absorption pathways and rates, thereby avoiding direct competition between Fe and Zn at absorption sites.

[0145] Test Example 2: Experimental description: 1. Experimental Design: The experiment was conducted at an agricultural research institute's experimental base (soil type: neutral brown soil). The test crop was soybean (variety: Zhonghuang 37). A total of 12 treatments were included: Examples 1-5 and Comparative Examples 1-7. A randomized block design was used, with each treatment replicated three times. The plot area was 20 m². 2 The application method involved diluting each sample prepared according to Examples 1-5 and Comparative Examples 1-7 with clean water at a volume ratio of 1:1000 before application. Foliar spraying was performed at the soybean flowering and pod-setting stage (R3) and the grain-filling stage (R5), with the same volume of diluted solution applied to each plot until the leaves were evenly moistened. Irrigation, fertilization (basal fertilizer), and pest and disease control practices remained consistent across all treatment plots.

[0146] 2. Measurement Indicators and Methods: Leaf physiological parameters were measured 7 days after the second spray. Thirty soybean plants were randomly selected from each plot, and the top 3rd-4 fully expanded compound leaves were taken, mixed thoroughly, and used for measurement. SPAD values ​​were determined using a SPAD-502 chlorophyll meter to measure the relative chlorophyll content of the leaves. Carbonic anhydrase (CA) activity was determined using conductivity or colorimetric methods. Glutathione peroxidase (GSH-Px) activity was determined using spectrophotometry.

[0147] 3. Nutrient content and speciation of seeds were determined at soybean maturity (R8). Each plot was harvested separately, threshed, and seed samples were dried and pulverized. Total Fe, Zn, and Se content: Samples were digested using HNO3-HClO4 (or HNO3-H2O2) microwave digestion. The total Fe, Zn, and Se content (mg / kg) in the digestion solution was determined using inductively coupled plasma mass spectrometry (ICP-MS). Determination of organic selenium speciation: Samples were extracted by combined proteinase K and lipase hydrolysis. The content of selenomethionine (SeMet) in the seeds was determined using high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Organic selenium conversion rate (%) = (SeMet content in seeds / Total Se content in seeds) × 100%.

[0148] 4. Yield traits were measured in each plot at maturity (R8). The yield was measured by actual harvesting, the weight of 100 grains was determined, and the yield per hectare (kg / ha) was calculated.

[0149] 5. Data Analysis: All data were analyzed using SPSS software for ANOVA and Duncan's multiple comparisons (P<0.05).

[0150] Experimental data: Table 4: Results of physiological index measurement of soybean leaves

[0151] Table 5: Analysis results of nutrient content and selenium speciation in soybean seeds

[0152] Table 6: Results of soybean yield traits determination

[0153] From Tables 4-6: The field trial data of Test Example 2 verified the effectiveness of the technical solution of the present invention from two aspects: crop physiology and final yield (grain).

[0154] First, leaf physiological parameters (Table 4) provided evidence of immediate physiological responses. The SPAD values, CA activity, and GSH-Px activity in the treatment groups of Examples 1-5 were all at high levels.

[0155] Compared to Comparative Example 4 (lacking component E), the SPAD value of Example 1 was significantly improved, which is consistent with the data in Table 2 of Test Example 1, indicating that component E (L-ascorbic acid) protects Fe 2+ It prevents oxidation on the leaf surface, thus ensuring the efficiency of chlorophyll synthesis.

[0156] Compared with Comparative Example 3 (deficient D and F components), the GSH-Px activity of Example 1 (115.3 U·mg) was significantly higher. -1 The prot content was much higher than that of comparative example 3 (79.5 U·mg). -1 The study confirmed that components D (L-methionine) and F (fulvic acid) have a direct effect on activating the plant selenium metabolism pathway (GSH-Px is a key selenium enzyme).

[0157] Secondly, the grain nutrient data (Table 5) is the core proof of the effectiveness of this scheme.

[0158] (1) Verification of the necessity of the preparation process: The Fe, Zn, and Se content in Comparative Example 1 (one-time mixing) (59.3, 41.5, 0.603) was significantly lower than that in Example 1 (75.1, 51.3, 0.812). This indicates that the process of separating and preparing components A and B and then compounding them is a prerequisite for preventing antagonism or precipitation between raw materials and ensuring the bioavailability of elements.

[0159] (2) Verification of the asymmetric split-track transport mechanism: The total Zn content of the grains in Comparative Example 5 (A+A', both macromolecule sustained-release) (44.2 mg / kg) was significantly lower than that in Example 1 (51.3 mg / kg); the total Fe content of the grains in Comparative Example 6 (B+B', both small molecule rapid-release) (63.8 mg / kg) was significantly lower than that in Example 1 (75.1 mg / kg). However, Example 1 (A-Fe sustained-release + B-Zn rapid-release) achieved high contents of both Fe and Zn.

[0160] This set of comparative data confirms the in vitro simulation results in Table 3 of Test Example 1. Using a uniform transport strategy (either fully sustained-release or fully rapid-release) will lead to an absorption bottleneck for either Fe or Zn. The asymmetric strategy of this invention (component A: sustained-release Fe, component B: rapid-release Zn) effectively avoids the competitive antagonism between Fe and Zn at absorption sites by matching the different absorption kinetics of Fe and Zn in the leaf epidermis and transport system, achieving highly efficient synergistic absorption of Fe / Zn.

[0161] (3) Verification of the activation effect of the selenium pathway: Although sodium selenate was also applied to Comparative Example 3 (without components D and F), its total Se content in the grains (0.648 mg / kg) was lower than that of Example 1 (0.812 mg / kg), and the organic selenium conversion rate (21.4%) was extremely low, close to that of the blank control (Comparative Example 7). In contrast, under the action of components D and F, Examples 1-5 not only increased the total Se content, but also achieved an organic selenium conversion rate of 68.1%. This indicates that components D and F are key to achieving efficient conversion of inorganic selenium to high-value organic selenium (SeMet).

[0162] Finally, the yield data (Table 6) show that the yields of the treatment groups in Examples 1-5 all exceeded 3000 kg / ha, significantly higher than all comparative examples. This indicates that the aforementioned improvements in physiological and nutrient absorption ultimately translated into actual yield benefits.

[0163] In summary, field trials have confirmed the effectiveness of the present invention. Its core lies in the following: through the separation and preparation of components A and B and the design of asymmetric complex / chelate structures, the Fe / Zn parallel transport was achieved, solving the absorption antagonism between divalent metal ions; at the same time, through the synergy of components D and F, the biotransformation pathway of Se was activated.

[0164] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for producing soybeans rich in organic selenium, zinc, and iron, characterized in that, Includes the following steps: S1. In the first reaction vessel, sodium lignosulfonate is reacted with ferrous sulfate heptahydrate to prepare ferric lignosulfonate solution. S2. In the second reaction vessel, glycine is reacted with zinc sulfate heptahydrate to obtain a zinc glycine solution. S3. Add the lignin sulfonate iron solution and the glycine zinc solution to the main mixing vessel, and further add sodium selenate, L-methionine, L-ascorbic acid and mineral-derived fulvic acid, mix evenly to obtain the composite composition mother liquor; S4. After diluting the prepared composite composition mother liquor, apply it to the soybean crop as a foliar spray during the soybean growth cycle.

2. The method for producing soybeans rich in organic selenium, zinc, and iron according to claim 1, characterized in that, The mother liquor of the composite composition contains the following components by weight: 10.0 to 20.0 parts by weight of ferric lignosulfonate; 5.0 to 10.0 parts by weight of zinc glycine; Sodium selenate, 0.1 to 0.5 parts by weight; 0.5 to 2.0 parts by weight of L-methionine; L-Ascorbic acid 0.5 to 2.0 parts by weight; 1.0 to 5.0 parts by weight of mineral-derived fulvic acid.

3. The method for producing soybeans rich in organic selenium, zinc, and iron according to claim 1, characterized in that, In step S1, the molar ratio of the sodium lignosulfonate functional group to the ferrous ion is 1.5:1 to 3.0:

1.

4. The method for producing soybeans rich in organic selenium, zinc, and iron according to claim 1, characterized in that, In step S1, the reaction between sodium lignosulfonate and ferrous sulfate heptahydrate is carried out at a pH of 4.0 to 5.0 and a temperature of 40°C to 60°C.

5. The method for producing soybeans rich in organic selenium, zinc, and iron according to claim 1, characterized in that, In step S2, the molar ratio of glycine to zinc ions is 2.0:1 to 3.0:

1.

6. The method for producing soybeans rich in organic selenium, zinc, and iron according to claim 1, characterized in that, In step S2, the reaction between the glycine and the zinc sulfate heptahydrate is carried out under conditions of pH 6.0 to 7.

0.

7. A method for producing soybeans rich in organic selenium, zinc, and iron according to claim 1, characterized in that, In step S1, the sodium lignosulfonate has a weight-average molecular weight of 5,000 Da to 20,000 Da.

8. A method for producing soybeans rich in organic selenium, zinc, and iron according to claim 2, characterized in that, In step S3, the pH value of the mother liquor of the composite composition is adjusted to 5.0 to 6.

5.

9. A method for producing soybeans rich in organic selenium, zinc, and iron according to claim 1, characterized in that, In step S3, alkylphenol polyoxyethylene ether is further added.

10. A method for producing soybeans rich in organic selenium, zinc, and iron according to claim 1, characterized in that, Step S4 specifically includes: The mother liquor of the composite composition was diluted with clean water at a volume ratio of 1:1000; The soybean crop was sprayed evenly on the leaves during the flowering and pod-setting stages and the grain-filling stage, respectively.

Images