Water-soluble slow-release fertilizer containing nutrient signal substance and preparation method of water-soluble slow-release fertilizer

Abstract

The invention discloses a water-soluble slow-release fertilizer containing nutrient signal substances and a preparation method of the water-soluble slow-release fertilizer, and belongs to the technical field of controlled-release fertilizer production. The terminator containing the crop nutrient demand signal substance is designed and prepared and then is grafted with hydroxymethyl urea, and a low-molecular-weight hydroxymethyl urea water-soluble slow-release nitrogen fertilizer and a medium / high-molecular-weight complete-element fertilizer are generated through reaction, so that the molecular weight control of the two fertilizers and the combination of the fertilizer and the crop demand fertilizer are realized. The water-soluble and slow-release fertilizer can be cooperated, the release of fertilizer nutrients can be matched with the fertilizer requirement rule of crops, meanwhile, a novel product scheme with higher adaptability is provided for large-scale popularization of a water and fertilizer integration technology, and the water-soluble and slow-release fertilizer has remarkable application value for promoting water and fertilizer saving in agricultural production and improving the utilization efficiency of crop nutrients.

Description

Technical Field

[0001] This invention relates to the field of controlled-release fertilizer production technology, specifically to a water-soluble slow-release fertilizer containing nutrient signaling substances and its preparation method. Background Technology

[0002] Fertilizer and water integration technology, due to its ability to achieve precise nutrient application and save water and fertilizer, will become one of the important directions for future agricultural development. However, traditional water-soluble fertilizers mostly use a "one-size-fits-all" formula, lacking targeted nutrient supply design, resulting in a mismatch between nutrient release and crop needs.

[0003] Slow-release fertilizers are an effective means of solving the above problems. However, it is difficult to simultaneously achieve both water solubility and slow release. Generally speaking, strong water solubility results in insufficient slow release, while good slow release leads to poor water solubility. Urea-formaldehyde slow-release fertilizers are chemical slow-release nitrogen fertilizers produced by the reaction of urea and formaldehyde under specific conditions. The main components of urea-formaldehyde slow-release fertilizers include condensates such as methylene diurea, dimethylene triurea, trimethylene tetraurea, tetramethylene pentaurea, and pentamethylene hexaurea. The length of the molecular chains of these condensates determines their solubility in water. For example, methylene diurea and dimethylene triurea, with shorter molecular chains, are soluble in cold water; trimethylene tetraurea and tetramethylene pentaurea, with longer molecular chains, are insoluble in cold water but soluble in boiling water; while pentamethylene hexaurea has an even longer molecular chain and is insoluble in boiling water. Liquid urea-formaldehyde slow-release fertilizers are an effective way to achieve both water solubility and slow release, but existing urea-formaldehyde fertilizers have problems such as difficulty in controlling molecular chain length, low nutrient utilization rate, and poor compatibility with total nutrients. Summary of the Invention

[0004] To address the problems existing in the prior art, the purpose of this invention is to provide a water-soluble slow-release fertilizer containing nutrient signaling substances and its preparation method. This invention designs and prepares a terminator containing crop nutrient requirement signaling substances, which is then grafted with hydroxymethylurea. Through this reaction, low-molecular-weight hydroxymethylurea water-soluble slow-release nitrogen fertilizer and medium / high-molecular-weight complete elemental fertilizer are generated, thereby achieving control over the molecular weight of both fertilizers and their integration with crop nutrient requirements. This achieves synergy between water solubility and slow-release fertilizer, matches fertilizer nutrient release with crop nutrient requirements, and provides a more adaptable new product solution for the large-scale promotion of fertigation technology. It has significant application value in promoting water and fertilizer conservation in agricultural production and improving crop nutrient utilization efficiency.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a terminator containing a nutrient signaling substance, which is obtained by reacting a hydroxyl-modified protected alcohol with an activated signaling substance; The hydroxyl-modified protected alcohol is prepared by the following method: Alcohols are dissolved in a solvent, and an acid catalyst and a hydroxyl modifier are added to carry out an acetalization reaction to prepare hydroxyl-modified alcohols. The activated signal substance is obtained by reacting a nutrient signal substance with an activating reagent.

[0006] Preferably, the alcohol is selected from one or more of monohydric alcohols, dihydric alcohols, and trihydric alcohols; more preferably, the alcohol is selected from one or more of methanol, ethylene glycol, propylene glycol, and glycerol.

[0007] Preferably, the acid catalyst is p-toluenesulfonic acid (TsOH). The acid catalyst is used to catalyze the acetalization reaction of the hydroxyl groups of alcohols with hydroxyl-modifying and protecting agents, ensuring sufficient hydroxyl protection and efficient reaction, ultimately generating a stable hydroxyl-protected alcohol prepolymer, which provides a guarantee for subsequent activation of signaling substances and precise molecular weight control.

[0008] Preferably, the hydroxyl-modifying protective agent is selected from one or more of tetrahydropyranyl (THP), benzyl (Bn), and tert-butyldimethylsilyl (TBDMS); more preferably, the hydroxyl-modifying protective agent is THP.

[0009] Preferably, the nutrient signaling substances include: nitrogen nutrient signaling substances, phosphorus nutrient signaling substances, and potassium nutrient signaling substances; The nitrogen nutrient signaling substance is selected from one or more of flavonoid derivatives, glutamine derivatives, γ-aminobutyric acid (GABA), benzoic acid, ferulic acid, and methyl jasmonic acid; The phosphorus nutrient signaling substance is selected from one or more of phytate phosphate, succinic acid, salicylic acid, and oxalic acid; The potassium nutrient signaling substance is selected from one or more of malic acid, betaine, zeatin nucleoside, and tartaric acid.

[0010] Preferably, the activating agent is selected from one or more of epichlorohydrin, phosphorous chloride, and thionyl chloride.

[0011] The addition of activating reagents helps to improve the reaction efficiency of the signal substance and the hydroxyl-protected protectant, and further promotes the grafting of the signal substance and the hydroxyl-protected protectant.

[0012] In some preferred embodiments of the present invention, the terminator containing the nutrient signaling substance is prepared by the following method: (1) Dissolve alcohols in solvent, add acid catalyst, add hydroxyl modifier dropwise at room temperature, and after the addition is complete, heat to 30℃ and react for 2-3 hours; adjust the pH of the system after reaction to 7.2, extract, remove solvent, and prepare hydroxyl-modified alcohols; (2) Mix the nutrient signaling substance with the activating reagent and perform an activation reaction to obtain the activated signaling substance; (3) Mix the hydroxyl-modified protected alcohol with the activated signaling substance, add the mixed catalyst, react at 55-65℃ and pH 7-8 for 1-2 hours, monitor the grafting rate by TLC to ≥88%, and then remove the water by vacuum distillation to a water content ≤12wt%.

[0013] In a second aspect, the present invention provides the use of the above-mentioned terminator in regulating the molecular weight of hydroxymethylurea water-soluble slow-release nitrogen fertilizer.

[0014] A third aspect of the present invention provides a water-soluble slow-release fertilizer containing nutrient signaling substances, comprising: a low molecular weight water-soluble slow-release nitrogen fertilizer and a medium / high molecular weight water-soluble slow-release complete elemental fertilizer; The low molecular weight water-soluble slow-release nitrogen fertilizer is obtained by reacting hydroxymethylurea solution, a first acidic suspension, and a terminator containing nutrient signaling substances. The medium / high molecular weight water-soluble slow-release all-element fertilizer is obtained by reacting hydroxymethyl urea solution, a second acidic suspension, a terminator containing nutrient signaling substances, all-element nutrients, and nutrient synergists.

[0015] Preferably, the water-soluble slow-release fertilizer is a compound of low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release total element fertilizer in a weight ratio of (1-2):(1-2).

[0016] In some preferred embodiments of the present invention, the hydroxymethylurea solution is prepared by the following method: Mix urea, aldehyde, catalyst and deionized water, stir evenly and heat to 60-70℃, keep the temperature for 1.5-2.5h.

[0017] In some preferred embodiments of the present invention, the first acidic suspension is obtained by mixing phosphoric acid, citric acid, xanthan gum and deionized water; The second acidic suspension is obtained by mixing phosphoric acid, malic acid, sodium carboxymethyl cellulose and deionized water.

[0018] In some preferred embodiments of the present invention, the total nutritional elements include: macronutrients, mesonutrients, and trace elements; The macroelements include nitrogen, phosphorus, and potassium sources; the phosphorus source is selected from one or more of citrate phosphoric anhydride, ammonium dihydrogen phosphate, potassium dihydrogen phosphate, diammonium hydrogen phosphate, and calcium dihydrogen phosphate. More preferably, the phosphorus source is citrate phosphoric anhydride, or a mixture of citrate phosphoric anhydride and potassium dihydrogen phosphate in a 3:2 ratio; Preferably, the potassium source is selected from one or more of potassium sulfate, potassium chloride, potassium dihydrogen phosphate, and potassium nitrate; More preferably, the potassium source is potassium sulfate.

[0019] In some preferred embodiments of the present invention, the nutrient synergist is selected from one or more of humic acid, amino acids, trehalose, and chitosan; More preferably, the nutrient enhancer is a mixture of humic acid and amino acids in a 1:1 ratio.

[0020] The beneficial effects of this invention are: (1) The terminating agent containing nutrient signaling substances of the present invention achieves dual-function integration: through hydroxyl protection and signal grafting process, the functions of "polymerization termination" and "nutrient guidance" are synergistically performed, the grafting rate of signaling substances is not less than 85%, and the activity retention period can exceed 60 days. It can accurately control the molecular weight of low molecular weight hydroxymethylurea water-soluble slow-release nitrogen fertilizer at 450-550 Da, and stabilize the molecular weight of medium / high molecular weight water-soluble slow-release all-element fertilizer at 800-1500 Da, effectively solving the problems of easy detachment of signaling substances and loss of control of molecular chain length.

[0021] (2) The water-soluble slow-release fertilizer of the present invention solves the contradiction of water solubility and slow release through a dual molecular weight system. Among them: the low molecular weight hydroxymethylurea water-soluble nitrogen fertilizer component has a small molecular weight and good water solubility, which is suitable for drip irrigation and solves the "water solubility" requirement. Medium / high molecular weight slow-release complete fertilizer components: Their molecular weight is appropriately increased, which also delays the release of nutrients and solves the "slow-release" requirement; When the two are mixed, the low molecular weight hydroxymethylurea water-soluble nitrogen fertilizer can quickly provide the nutrients needed by crops in a short period of time, while the medium / high molecular weight slow-release complete fertilizer can continuously provide the nutrients needed for crop growth. This achieves both soluble application and slow release tailored to the crop's growth stage. Therefore, this solution can effectively resolve the inherent contradiction of "strong water solubility but insufficient slow release, and good slow release but poor water solubility".

[0022] (3) Significantly enhanced efficiency of complete nutrients: The scientific and reasonable ratio of complete nutrients can effectively alleviate the antagonistic effect between elements. Field trials have verified that the comprehensive absorption efficiency of nitrogen, phosphorus and potassium by crops is significantly improved compared with traditional fertilizers, and the yields of crops such as corn, rice and vegetables have also increased significantly, truly achieving the effect of saving fertilizer and increasing yield.

[0023] (4) Strong adaptability to multiple crops: The core process of the product remains consistent. Only the signaling substance and nutrient ratio need to be adjusted to adapt to a variety of crops such as corn, rice, and vegetables, which reduces the cost of industrial production and the input in the planting and management process.

[0024] (5) It has both economic and ecological benefits: the raw materials used are low-cost, the reaction conditions are mild, and the feasibility of industrial production is high; the free formaldehyde content in the product does not exceed 0.1wt%, which effectively reduces the risk to the ecological environment. Attached Figure Description

[0025] Figure 1 Infrared spectral analysis results of the low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release total element fertilizer prepared in Example 1.

[0026] Figure 2 Electron microscopy analysis results of the low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release total element fertilizer prepared in Example 1; in the figure, a is the microstructure of the low molecular weight water-soluble slow-release nitrogen fertilizer; b is the microstructure of the medium / high molecular weight water-soluble slow-release total element fertilizer.

[0027] Figure 3 The 30-day stability test results of the low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release total element fertilizer prepared in Example 1, and the single molecular weight slow-release fertilizer prepared in Comparative Example 1. Detailed Implementation

[0028] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0029] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0030] The test materials used in the embodiments and comparative examples of this invention are all conventional test materials in the art and can be purchased through commercial channels. Experimental methods without specified detailed conditions were performed according to conventional test methods or the supplier's recommended operating instructions. Wherein: The "glutamine derivative" is selected from N-acetyl-L-glutamine, with CAS number 35305-74-9. Phytate phosphate has CAS number 83-86-3. The complex amino acid is a mixture of glutamic acid, aspartic acid, glycine, proline, and lysine in equal mass ratios.

[0031] Example 1: General preparation of water-soluble slow-release fertilizer containing nutrient signaling substances 1. Preparation of terminators containing nutrient signaling substances: (1) Hydroxyl modification protection: 100 mmol of glycerol and 100 mL of anhydrous dichloromethane were added to a round-bottom flask and stirred until dissolved. Then, 0.8 g of p-toluenesulfonic acid (TsOH) was added, and 220 mmol of tetrahydropyranyl (THP) was added dropwise at room temperature. After the addition was complete, the temperature was raised to 30 °C and the reaction was carried out for 2.5 hours. The mixture was neutralized to pH 7.2 with saturated sodium bicarbonate solution, extracted three times with dichloromethane, and the combined organic phases were dried over anhydrous sodium sulfate. The solvent was removed by vacuum distillation at -0.09 MPa and 55 °C to obtain hydroxyl-modified alcohols.

[0032] (2) Activation of signaling substances: Add 50 mL of epichlorohydrin to 110 g of nitrogen nutrient signaling substance (glutamine derivative) and react for 1 hour at 50 °C and pH 8.0 to obtain the activated nitrogen nutrient signaling substance.

[0033] Add 30 mL of phosphorous chloride to 90 g of phosphorus nutrient signaling substance (phytate phosphate), and react for 1 hour at 40 °C with 20 mL of acid-binding agent (triethylamine) to obtain activated phosphorus nutrient signaling substance.

[0034] Add 20 mL of thionyl chloride to 60 g of potassium nutrient signaling substance (malic acid) and react at 35 °C for 0.5 hours to obtain activated potassium nutrient signaling substance.

[0035] The activated nitrogen nutrient signaling substance, activated phosphorus nutrient signaling substance, and activated potassium nutrient signaling substance prepared above are mixed and stirred evenly to prepare the activated signaling substance.

[0036] (3) Covalent grafting reaction: Add the activated phosphorus nutrient signal substance prepared in step (2) to the hydroxyl-modified protected alcohol substance prepared in step (1), and then add 6g of mixed catalyst (3g potassium carbonate + 3g triethylamine). React at 60℃ and pH 7.8 for 1.5 hours. After the grafting rate is monitored by TLC to be ≥88%, remove the water by vacuum distillation at -0.1MPa and 58℃ until the water content is ≤12wt% to obtain the terminator containing the nutrient signal substance.

[0037] 2. Preparation of low molecular weight water-soluble slow-release nitrogen fertilizer: (1) Preparation of hydroxymethylurea solution: Add 200g of urea, 240g of 37wt% formaldehyde aqueous solution, 0.6g of potassium carbonate, and 100g of deionized water to a reactor. After stirring evenly, heat to 65℃ and keep the temperature for 2 hours to obtain a hydroxymethylurea solution with a number average molecular weight of 310 Da, which is then ready for use.

[0038] (2) Preparation of the first acidic suspension: Take 30 mL of phosphoric acid, 10 g of citric acid, 0.5 g of xanthan gum and 80 mL of deionized water, mix them evenly, adjust the pH to 5.0, and prepare the first acidic suspension.

[0039] (3) Preparation of low molecular weight water-soluble slow-release nitrogen fertilizer: Take 120 mL of the first acidic suspension prepared above, stir and heat to 50℃, slowly add 400 g of hydroxymethylurea solution, stir at a constant speed for 10 minutes, then add 6 g of a terminator containing nutrient signaling substances, and keep the reaction at this temperature for 45 minutes. When the system becomes slightly viscous, add 0.3 g of sodium bicarbonate to adjust the pH to 7.0, and continue the reaction for 15 minutes. Filter through a 0.22 μm filter membrane to obtain a low molecular weight water-soluble slow-release nitrogen fertilizer. Its molecular weight range was determined to be 450-550 Da.

[0040] 3. Preparation of medium / high molecular weight water-soluble slow-release complete elemental fertilizer: (1) Preparation of the second acidic suspension: Take 40 mL of phosphoric acid, 15 g of malic acid, 0.8 g of sodium carboxymethyl cellulose and 125 mL of deionized water, mix them evenly, adjust the pH to 5.5, and prepare the second acidic suspension.

[0041] (2) Preparation of complete nutritional elements: Mix 20g of nitrogen source, 35g of phosphorus source, 40g of potassium source, 8g of magnesium sulfate, 3g of calcium sulfate, 1.2g of zinc sulfate, 0.6g of boric acid, 0.5g of EDTA-Fe, 0.3g of manganese sulfate, 0.2g of copper sulfate, and 0.1g of ammonium molybdate evenly to obtain complete nutrient elements.

[0042] (3) Preparation of nutrient synergists: A nutrient enhancer was prepared by mixing 1.2g of mineral-derived humic acid and 1.2g of compound amino acids evenly.

[0043] (4) Preparation of medium / high molecular weight water-soluble slow-release complete elemental fertilizer: Take 180 mL of the second acidic suspension, 108 g of complete nutrient elements, and 2.4 g of nutrient synergist. Stir and heat to 60°C, mix thoroughly, then add 600 g of hydroxymethylurea solution and maintain the temperature for 50 minutes. Add 12 g of a terminator containing nutrient signaling substances and continue the reaction for 1 hour. When the system becomes viscous, add 0.4 g of potassium carbonate to adjust the pH to 7.5. After reacting for 20 minutes, filter to obtain a medium / high molecular weight water-soluble slow-release complete nutrient fertilizer. Its molecular weight range is determined to be 800-1500 Da.

[0044] 4. Preparation of water-soluble slow-release fertilizers containing nutrient signaling substances: The low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release total element fertilizer prepared above are mixed at a mass ratio of (1-2):(1-2) to prepare water-soluble slow-release fertilizer. In practical use, the ratio of low molecular weight water-soluble slow-release nitrogen fertilizer to medium / high molecular weight water-soluble slow-release complete fertilizer can be adjusted according to the type of crop.

[0045] Example 2: Preparation of a water-soluble slow-release fertilizer containing nutrient signaling substances suitable for corn 1. Preparation of terminators containing nutrient signaling substances: The difference from Example 1 is that 30g of benzoic acid, a corn-specific nitrogen signaling substance, was added to the nitrogen nutrient signaling substance, and 20g of zeatin, a corn-specific potassium signaling substance, was added to the potassium nutrient signaling substance; that is: 140g of nitrogen nutrient signaling substance (110g of glutamine derivative + 30g of benzoic acid), 90g of phosphorus nutrient signaling substance (phytate phosphate), and 80g of potassium nutrient signaling substance (60g of malic acid + 20g of zeatin nucleoside). The remaining preparation conditions are the same as in Example 1.

[0046] 2. Preparation of low molecular weight water-soluble slow-release nitrogen fertilizer: The preparation method is the same as in Example 1, except that the terminator containing nutrient signaling substances is the terminator prepared in this example.

[0047] 3. Preparation of medium / high molecular weight water-soluble slow-release complete elemental fertilizer: The preparation of the second acidic suspension and the nutrient enhancer is the same as in Example 1.

[0048] The preparation of complete nutritional elements has been adjusted as follows: Mix 20g of nitrogen source (urea), 35g of phosphorus source (citric acid phosphoric anhydride), 44g of potassium source (potassium sulfate), 1g of magnesium sulfate, 3g of calcium sulfate, 2.5g of zinc sulfate, 1.2g of boric acid, 0.5g of EDTA-Fe, 0.3g of manganese sulfate, 0.2g of copper sulfate, and 0.1g of ammonium molybdate evenly to obtain complete nutrient elements.

[0049] The preparation method of medium / high molecular weight water-soluble slow-release complete fertilizer is the same as in Example 1, except that the terminator containing nutrient signaling substances is the terminator prepared in this example.

[0050] 4. Suitable for the preparation of water-soluble slow-release fertilizers containing nutrient signaling substances for corn: The low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release total element fertilizer prepared above were mixed at a mass ratio of 1:2 to prepare a water-soluble slow-release fertilizer containing nutrient signaling substances suitable for corn.

[0051] The performance indicators of the low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release total element fertilizer prepared in this embodiment were measured, and the results are shown in Table 1. Among them: The method for determining the retention period of nutrient signaling substances is as follows: while determining the nutrient release period of fertilizer products, samples are collected and quantitatively detected using liquid chromatography to obtain the content of small molecule signaling substances. The retention period of nutrient signaling substance activity is represented by the change in the content of small molecule signaling substances.

[0052] The retention period is defined as the time when the retention rate of any one of the nitrogen, phosphorus, and potassium nutrient signaling substances is less than 75%.

[0053] Table 1: Performance Index Test Results of Water-Soluble Slow-Release Fertilizers Containing Nutrient Signaling Substances Suitable for Corn Example 3: Preparation of water-soluble slow-release fertilizer containing nutrient signaling substances suitable for rice 1. Preparation of terminators containing nutrient signaling substances: The difference from Example 1 is that 40g of γ-aminobutyric acid (GABA), a rice-specific nitrogen signaling substance, was supplemented into the nitrogen nutrient signaling substance, and 25g of salicylic acid, a rice-specific phosphorus signaling substance, was supplemented into the phosphorus nutrient signaling substance; that is: Nitrogen nutrient signaling substance (glutamine derivative 110g + γ-aminobutyric acid 40g) 150g, phosphorus nutrient signaling substance (phytate phosphate 90g + salicylic acid 25g) 115g, potassium nutrient signaling substance (malic acid) 60g. The remaining preparation conditions are the same as in Example 1.

[0054] 2. Preparation of low molecular weight water-soluble slow-release nitrogen fertilizer: The preparation method is the same as in Example 1, except that the terminator containing nutrient signaling substances is the terminator prepared in this example.

[0055] 3. Preparation of medium / high molecular weight water-soluble slow-release complete elemental fertilizer: The preparation of the second acidic suspension and the nutrient enhancer is the same as in Example 1.

[0056] The preparation of complete nutritional elements has been adjusted as follows: Mix 20g of nitrogen source (urea), 35g of phosphorus source (citric acid phosphoric anhydride), 40g of potassium source (potassium sulfate), 8g of magnesium sulfate, 3g of calcium sulfate, 1.2g of zinc sulfate, 0.6g of boric acid, 0.5g of EDTA-Fe, 0.3g of manganese sulfate, 0.2g of copper sulfate, 0.1g of ammonium molybdate, and 2g of potassium silicate (K2SiO3) evenly to obtain complete nutrient elements.

[0057] The preparation method of medium / high molecular weight water-soluble slow-release complete fertilizer is the same as in Example 1, except that the terminator containing nutrient signaling substances is the terminator prepared in this example.

[0058] 4. Preparation of water-soluble slow-release fertilizers containing nutrient signaling substances suitable for rice: The low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release total element fertilizer prepared above were mixed at a mass ratio of 1:1.8 to prepare a water-soluble slow-release fertilizer containing nutrient signaling substances suitable for rice.

[0059] The performance indicators of the low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release total element fertilizer prepared in this embodiment were measured, and the results are shown in Table 2.

[0060] Table 2: Performance index determination results of water-soluble slow-release fertilizer containing nutrient signaling substances suitable for rice Example 4: Preparation of a water-soluble slow-release fertilizer containing nutrient signaling substances suitable for wheat 1. Preparation of terminators containing nutrient signaling substances: The difference from Example 1 is that: 35g of ferulic acid, a wheat-specific nitrogen signaling substance, was supplemented into the nitrogen nutrient signaling substance, and 20g of oxalic acid, a wheat-specific phosphorus signaling substance, was supplemented into the phosphorus nutrient signaling substance; that is: 145g of nitrogen nutrient signaling substance (110g of glutamine derivative + 35g of ferulic acid), 110g of phosphorus nutrient signaling substance (90g of phytate phosphate + 20g of oxalic acid), and 60g of potassium nutrient signaling substance (malic acid). The remaining preparation conditions are the same as in Example 1.

[0061] 2. Preparation of low molecular weight water-soluble slow-release nitrogen fertilizer: The preparation method is the same as in Example 1, except that the terminator containing nutrient signaling substances is the terminator prepared in this example.

[0062] 3. Preparation of medium / high molecular weight water-soluble slow-release complete elemental fertilizer: The preparation of the second acidic suspension and the nutrient enhancer is the same as in Example 1.

[0063] The preparation of complete nutritional elements has been adjusted as follows: Mix 20g of nitrogen source (urea), 35g of phosphorus source (citric acid phosphoric anhydride), 40g of potassium source (potassium sulfate), 8g of magnesium sulfate, 3g of calcium sulfate, 1.2g of zinc sulfate, 0.6g of boric acid, 0.5g of EDTA-Fe, 0.3g of manganese sulfate, 0.2g of copper sulfate, 0.1g of ammonium molybdate, and 22g of calcium nitrate (Ca(NO3)) evenly to obtain complete nutrient elements.

[0064] The preparation method of medium / high molecular weight water-soluble slow-release complete fertilizer is the same as in Example 1, except that the terminator containing nutrient signaling substances is the terminator prepared in this example.

[0065] 4. Suitable for the preparation of water-soluble slow-release fertilizers containing nutrient signaling substances for wheat: The low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release total element fertilizer prepared above were mixed at a mass ratio of 1:1.5 to prepare a water-soluble slow-release fertilizer containing nutrient signaling substances suitable for wheat.

[0066] The performance indicators of the low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release total element fertilizer prepared in this embodiment were measured, and the results are shown in Table 3.

[0067] Table 3: Performance Index Test Results of Water-Soluble Slow-Release Fertilizers Containing Nutrient Signaling Substances Applicable to Wheat Example 5: Preparation of a water-soluble slow-release fertilizer containing nutrient signaling substances suitable for vegetables 1. Preparation of terminators containing nutrient signaling substances: The difference from Example 1 is that: 25g of methyl jasmonic acid, a vegetable-specific nitrogen signaling substance, was added to the nitrogen nutrient signaling substance, and 15g of tartaric acid, a vegetable-specific potassium signaling substance, was added to the potassium nutrient signaling substance; that is: Nitrogen nutrient signaling substance (glutamine derivative 110g + methyl jasmonate 25g) 135g, phosphorus nutrient signaling substance (phytate phosphate) 90g, potassium nutrient signaling substance (malic acid 60g + tartaric acid 15g) 75g. The remaining preparation conditions are the same as in Example 1.

[0068] 2. Preparation of low molecular weight water-soluble slow-release nitrogen fertilizer: The preparation method is the same as in Example 1, except that the terminator containing nutrient signaling substances is the terminator prepared in this example.

[0069] 3. Preparation of medium / high molecular weight water-soluble slow-release complete elemental fertilizer: The preparation of the second acidic suspension is the same as in Example 1.

[0070] The preparation of complete nutritional elements has been adjusted as follows: Mix 20g of nitrogen source (urea), 35g of phosphorus source (citric acid phosphoric anhydride), 40g of potassium source (potassium sulfate), 8g of magnesium sulfate, 3g of calcium sulfate, 1.2g of zinc sulfate, 1.0g of boric acid, 0.5g of EDTA-Fe, 0.3g of manganese sulfate, 0.2g of copper sulfate, and 0.1g of ammonium molybdate evenly to obtain complete nutrient elements.

[0071] The preparation of the nutrient enhancer has been adjusted as follows: A nutrient enhancer was prepared by mixing 1.2g of mineral humic acid, 1.2g of compound amino acids and 0.8g of seaweed extract evenly.

[0072] The preparation method of medium / high molecular weight water-soluble slow-release complete fertilizer is the same as in Example 1, except that the terminator containing nutrient signaling substances is the terminator prepared in this example.

[0073] 4. Suitable for the preparation of water-soluble slow-release fertilizers containing nutrient signaling substances for vegetables: The low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release total element fertilizer prepared above were mixed at a mass ratio of 1.5:1 to prepare a water-soluble slow-release fertilizer containing nutrient signaling substances suitable for wheat.

[0074] The performance indicators of the low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release total element fertilizer prepared in this embodiment were measured, and the results are shown in Table 4.

[0075] Table 4: Performance Index Test Results of Water-Soluble Slow-Release Fertilizers Containing Nutrient Signaling Substances Suitable for Vegetables Comparative Example 1: Following the conventional urea-formaldehyde fertilizer process, 200g of urea, 240g of 37wt% formaldehyde aqueous solution, 0.6g of reaction regulator (potassium carbonate), and 100g of deionized water are reacted at 65℃ for 2.5 hours. Then, 6g of common terminator (methanol) is added to prepare a single molecular weight slow-release fertilizer.

[0076] The performance indicators of the single molecular weight slow-release fertilizer prepared in this comparative example were measured, and the results are shown in Table 5.

[0077] Table 5: Performance Index Test Results of Single Molecular Weight Slow-Release Fertilizers Experimental Example 1: 1. Infrared spectral analysis of the product: Infrared spectroscopy analysis was performed on the low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release total element fertilizer prepared in Example 1.

[0078] The results are as follows Figure 1 As shown, the results indicate that both fertilizers are effective at a depth of 3500 cm. -1 The surrounding area exhibits characteristic absorption valleys, corresponding to the stretching vibrations of the OH / NH bonds, reflecting that both contain common structural units of hydroxyl and amino groups; 1500~1000 cm -1 The strong absorption peaks in the region correspond to the stretching vibrations of the PO and CO bonds, which are characteristic functional group responses of the nutrients in the product.

[0079] Medium / high molecular weight water-soluble slow-release complete fertilizer in the range of 1500~1000 cm -1 The region has a richer number of absorption peaks and a higher absorption intensity. This is because, compared to low molecular weight products, it is loaded with more diverse nutritional components and has a higher degree of polymerization, resulting in a more significant superposition effect of functional group vibrations.

[0080] 2. Electron microscopy analysis: Electron microscopy analysis was performed on the low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release total element fertilizer prepared in Example 1.

[0081] The results are as follows Figure 2 As shown, the results indicate that: Figure 2 a represents the microstructure of low molecular weight water-soluble slow-release nitrogen fertilizer, exhibiting a rough and dense aggregated structure with relatively tight interparticle bonding and only a few small pores. Figure 2 b corresponds to medium / high molecular weight water-soluble slow-release whole element fertilizer, whose microstructure is a loose porous network with obvious surface wrinkles and many cavities and pores of different sizes.

[0082] The aforementioned microstructural features correspond to the design characteristics of the two types of products in terms of molecular weight distribution and component loading, and also reflect the effect of the preparation process on the microstructure of the products.

[0083] 3. Product stability test over 30 days: The low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release total element fertilizer prepared in Example 1, as well as the single molecular weight slow-release fertilizer prepared in Comparative Example 1, were placed under the same conditions for 30 days to test the stability of the products.

[0084] The results are as follows Figure 3 As shown in the figure, the results indicate that: a is the single molecular weight slow-release fertilizer of Comparative Example 1, b is the low molecular weight water-soluble slow-release nitrogen fertilizer of Example 1, and c is the medium / high molecular weight water-soluble slow-release complete elemental fertilizer of Example 1. After 30 days, sample a showed obvious turbidity and poor system homogeneity; sample b showed a small amount of fine precipitate at the bottom and a slight decrease in transparency; sample c remained clear and transparent, without any precipitation, turbidity, or other unstable phenomena.

[0085] In summary, the medium / high molecular weight water-soluble slow-release all-element fertilizer of Example 1 exhibits the best stability, followed by the low molecular weight product, while the single molecular weight product in the comparative example shows poor stability, demonstrating the effect of the product structure design of this invention on improving stability.

[0086] Experimental Example 2: 1. Test method: A field experiment was conducted in a maize experimental field in Mazhuang Town, Daiyue District, Tai'an City, Shandong Province. The experiment was set up with five treatment groups, each with 1 mu (approximately 0.067 hectares) of land. The specific treatments are as follows: No fertilizer was applied; conventional urea-formaldehyde fertilizer (prepared in Comparative Example 1) was applied; low molecular weight water-soluble slow-release nitrogen fertilizer was applied alone (prepared in Example 2) was applied alone; medium / high molecular weight water-soluble slow-release complete fertilizer was applied alone (prepared in Example 2) was applied alone; and low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release complete fertilizer were mixed in a 1:2 ratio (Example 2). Except for the no-fertilizer treatment, all treatments were applied according to the nitrogen-phosphorus-potassium ratio of 225-90-60 kg / hm². 2 Nutrient application ratios were determined as follows: traditional urea-formaldehyde was applied once at sowing; low molecular weight water-soluble slow-release nitrogen fertilizer, medium / high molecular weight water-soluble slow-release complete fertilizer, and a mixture of low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release complete fertilizer in a 1:2 ratio were applied twice, once at the sowing stage and once at the large trumpet stage, along with drip irrigation. Other management practices followed standard farmer practices. The experiment lasted 120 days, and relevant indicators were measured at corn harvest.

[0087] After harvest, collect all corn cobs that have undergone the same treatment, dry them, thresh them, and weigh the total weight of the kernels as the corn yield.

[0088] The formula for calculating nitrogen use efficiency is as follows: Nitrogen use efficiency = [(nitrogen uptake by fertilized corn - nitrogen uptake by unfertilized corn) / nitrogen application rate] × 100%.

[0089] 2. Test Results: The results are shown in Table 6.

[0090] Table 6: Results of Field Trials The results showed that applying the low molecular weight water-soluble slow-release nitrogen fertilizer and the medium / high molecular weight water-soluble slow-release complete fertilizer of the present invention could promote the growth of maize. Moreover, compared with applying low molecular weight water-soluble slow-release nitrogen fertilizer alone or medium / high molecular weight water-soluble slow-release complete fertilizer alone, the combination of low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release complete fertilizer could synergistically improve crop yield and nitrogen use efficiency, achieving a synergistic effect of 1+1>2.

[0091] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A terminator containing a nutrient signaling substance, characterized in that, It is obtained by reacting hydroxyl-modified protected alcohols with activated signaling molecules; The hydroxyl-modified protected alcohol is prepared by the following method: Alcohols are dissolved in a solvent, and an acid catalyst and a hydroxyl modifier are added to carry out an acetalization reaction to prepare hydroxyl-modified alcohols. The activated signal substance is obtained by reacting a nutrient signal substance with an activating reagent.

2. The terminating agent according to claim 1, characterized in that, The alcohol is selected from one or more of monohydric alcohols, dihydric alcohols, and trihydric alcohols; preferably, the alcohol is selected from one or more of methanol, ethylene glycol, propylene glycol, and glycerol.

3. The terminating agent according to claim 1, characterized in that, The hydroxyl-modifying protective agent is selected from one or more of tetrahydropyranyl, benzyl, and tert-butyldimethylsilyl; preferably, the hydroxyl-modifying protective agent is THP.

4. The terminator according to claim 1, characterized in that, The nutrient signaling substances include: nitrogen nutrient signaling substances, phosphorus nutrient signaling substances, and potassium nutrient signaling substances; The nitrogen nutrient signaling substance is selected from one or more of flavonoid derivatives, glutamine derivatives, γ-aminobutyric acid, benzoic acid, ferulic acid, and methyl jasmonic acid; The phosphorus nutrient signaling substance is selected from one or more of phytate phosphate, succinic acid, salicylic acid, and oxalic acid; The potassium nutrient signaling substance is selected from one or more of malic acid, betaine, zeatin nucleoside, and tartaric acid; Preferably, the activating agent is selected from one or more of epichlorohydrin, phosphorous chloride, and thionyl chloride.

5. The terminating agent according to claim 1, characterized in that, The terminator containing the nutrient signaling substance is prepared by the following method: (1) Dissolve alcohols in solvent, add acid catalyst, add hydroxyl modifier dropwise at room temperature, and after the addition is complete, heat to 30℃ and react for 2-3 hours; adjust the pH of the system after reaction to 7.2, extract, remove solvent, and prepare hydroxyl-modified alcohols; (2) Mix the nutrient signaling substance with the activating reagent and perform an activation reaction to obtain the activated signaling substance; (3) Mix the hydroxyl-modified protected alcohol with the activated signaling substance, add the mixed catalyst, react at 55-65℃ and pH 7-8 for 1-2 hours, monitor the grafting rate by TLC to ≥88%, and then remove the water by vacuum distillation to a water content ≤12wt%.

6. Application of terminators in regulating the molecular weight of hydroxymethylurea water-soluble slow-release nitrogen fertilizer.

7. A water-soluble slow-release fertilizer containing nutrient signaling substances, characterized in that, include: Low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release complete elemental fertilizer; The low molecular weight water-soluble slow-release nitrogen fertilizer is obtained by reacting hydroxymethylurea solution, a first acidic suspension, and a terminator containing nutrient signaling substances. The medium / high molecular weight water-soluble slow-release all-element fertilizer is obtained by reacting hydroxymethyl urea solution, a second acidic suspension, a terminator containing nutrient signaling substances, all-element nutrients, and nutrient synergists.

8. The water-soluble slow-release fertilizer according to claim 7, characterized in that, The water-soluble slow-release fertilizer is a compound of low molecular weight water-soluble slow-release nitrogen fertilizer and medium / high molecular weight water-soluble slow-release total element fertilizer in a weight ratio of (1-2):(1-2).

9. The water-soluble slow-release fertilizer according to claim 7 or 8, characterized in that, The hydroxymethylurea solution is prepared by the following method: Mix urea, aldehyde, catalyst and deionized water, stir evenly and heat to 60-70℃, keep the temperature for 1.5-2.5h.

10. The water-soluble slow-release fertilizer according to claim 7 or 8, characterized in that, The first acidic suspension was obtained by mixing phosphoric acid, citric acid, xanthan gum, and deionized water; The second acidic suspension was obtained by mixing phosphoric acid, malic acid, sodium carboxymethyl cellulose and deionized water; Preferably, the nutrient enhancer is selected from one or more of humic acid, amino acids, trehalose, and chitosan; More preferably, the nutrient enhancer is a mixture of humic acid and amino acids in a 1:1 ratio.

Images