Special controlled-release nitrogen fertilizer containing nitrogen signal substance for rice and application of special controlled-release nitrogen fertilizer

Abstract

The invention discloses a special controlled-release nitrogen fertilizer for rice containing a nitrogen signal substance and application of the special controlled-release nitrogen fertilizer. The special controlled-release nitrogen fertilizer containing the nitrogen signal substance for the rice sequentially comprises nitrogen fertilizer particles, a signal substance layer and a coating layer from inside to outside, the nitrogen fertilizer particles are quick-acting nitrogen fertilizer; the signal substance layer is a phenolic acid-beta-cyclodextrin inclusion compound; the preparation method comprises the following steps: completely dissolving beta-cyclodextrin in distilled water, heating, slowly dropwise adding an ethanol solution containing phenolic acid, a chelating agent and an antioxidant while stirring, and reacting to obtain the phenolic acid-beta-cyclodextrin inclusion compound. And the coating layer is prepared from bio-based polyol and isocyanate. According to the invention, phenolic acid is used as a signal substance, beta-cyclodextrin is added to include phenolic acid, and an antioxidant and a chelating agent are added to coat the surface of urea to prepare nitrogen fertilizer particles; and coating a coating material to obtain the special controlled-release nitrogen fertilizer containing the nitrogen signal substance for the rice. The controlled-release fertilizer not only can accurately release the nitrogen fertilizer and reduce the waste of the nitrogen fertilizer, but also can improve the yield and quality of the rice and reduce common diseases of the rice.

Description

Technical Field

[0001] The present invention relates to the technical field of novel fertilizers, and in particular to a controlled-release nitrogen fertilizer specifically for rice containing a nitrogen signal substance and application thereof. Background Art

[0002] Nitrogen, as one of the essential macronutrients for rice, affects nutrient transport, the activity of related enzymes, and leaf photosynthesis. It plays a key role in all stages of rice growth and development, determining rice yield and quality. However, in rice production, ammonia volatilization, denitrification, and nitrate leaching account for 30%-70% of the total applied nitrogen, and nitrogen utilization efficiency is less than 30%. This low nitrogen utilization rate of rice significantly limits its yield and quality. To increase rice yield, farmers often apply excessive amounts of nitrogen fertilizer, which not only increases agricultural production costs and reduces rice grain quality, but also leads to a series of serious environmental problems such as eutrophication of water bodies and soil acidification and compaction.

[0003] Coated controlled-release nitrogen fertilizers can control the continuous and slow release of nitrogen, effectively avoid the problems caused by excessive nitrogen application, reduce nitrogen loss and waste, and improve the nitrogen utilization efficiency of rice. However, the coated controlled-release nitrogen fertilizers on the market are often suitable for a variety of crops, and their nitrogen release rate fails to fully match the different nitrogen requirements of rice in different growth and development stages, and has not yet achieved dedicated and precise controlled release.

[0004] Phenolic acids, as a secondary metabolite of plants, can affect rice nitrogen transformation by influencing the synthesis and activity of nitrogen-transforming enzymes in rice. They can also influence rice nitrogen uptake by influencing the colonization of soil microorganisms involved in nitrogen fixation and transformation, effectively improving rice nitrogen use efficiency. Furthermore, they can promote the growth of beneficial soil microorganisms, increase the species and abundance of rhizosphere microorganisms, inhibit the growth and reproduction of pathogens, and effectively enhance rice disease resistance. However, phenolic acids are volatile and easily degraded in soil, requiring frequent additions of small amounts, hindering their widespread application. Consequently, reports on their use in controlled-release fertilizers are limited. Therefore, there is a need for a rice-specific controlled-release nitrogen fertilizer containing phenolic acids that can prevent phenolic acid oxidation and hydrolysis while aligning nitrogen release with the nitrogen requirements of rice at various stages of growth and development. Summary of the Invention

[0005] In response to the above-mentioned prior art, the present invention aims to provide a controlled-release nitrogen fertilizer specifically for rice that contains a nitrogen signal substance, and its application. This invention uses phenolic acid as the signal substance. The phenolic acid is encapsulated by adding β-cyclodextrin, and then coated on the surface of urea with an antioxidant and a chelating agent to produce nitrogen fertilizer granules. This granules are then coated with a coating material to produce a controlled-release nitrogen fertilizer specifically for rice that contains a nitrogen signal substance. This controlled-release fertilizer not only enables precise release of nitrogen fertilizer, reducing nitrogen fertilizer waste, but also improves rice yield and quality, and reduces common rice diseases.

[0006] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a controlled-release nitrogen fertilizer for rice containing a nitrogen signal substance, wherein the controlled-release nitrogen fertilizer for rice containing a nitrogen signal substance comprises, from the inside to the outside, nitrogen fertilizer particles, a signal substance layer, and a coating layer; The nitrogen fertilizer particles are fast-acting nitrogen fertilizers; the signal substance layer is a phenolic acid-β-cyclodextrin inclusion complex; The phenolic acid-β-cyclodextrin inclusion compound is prepared by the following method: β-cyclodextrin is completely dissolved in distilled water, and an ethanol solution containing phenolic acid, a chelating agent, and an antioxidant is slowly added dropwise under heating and stirring. After the addition is completed, the reaction is continued under heating and stirring. After the reaction is completed, the product is frozen overnight and then placed at room temperature. Finally, the phenolic acid-β-cyclodextrin inclusion complex is obtained by vacuum filtration.

[0007] Preferably, the quick-acting nitrogen fertilizer is urea; the phenolic acid is selected from at least one of protocatechuic acid, salicylic acid, p-hydroxybenzoic acid, komaric acid, and vanillin; the antioxidant is tert-butylhydroquinone; and the chelating agent is zinc chloride.

[0008] Preferably, the amount of phenolic acid added accounts for 1.0-3.0% of the weight of the fast-acting nitrogen fertilizer; the molar ratio of the phenolic acid to β-cyclodextrin is 1:1; the mass ratio of the phenolic acid to the antioxidant is 1000:1; the mass ratio of the chelating agent to the fast-acting nitrogen fertilizer is 1:1000; and the volume ratio of the distilled water to the ethanol solution is 2:1.

[0009] Preferably, the heating temperature is 60°C; the dropping rate is 1 mL / min; the reaction time is 48 h; the freezing temperature is -20°C; and the storage time at room temperature is at least 10 min.

[0010] Preferably, the coating layer is obtained by spraying a coating material; the coating material is obtained by adding bio-based polyol to isocyanate, introducing nitrogen at room temperature and continuously stirring.

[0011] Preferably, the bio-based polyol is selected from vegetable oil; the vegetable oil is castor oil, soybean oil or palm oil; the isocyanate is selected from pentamethylene diisocyanate, isophorone diisocyanate or hexamethylene diisocyanate; and the added amount of the coating material accounts for 4% of the mass of the quick-acting nitrogen fertilizer.

[0012] Preferably, the nitrogen-containing signal substance-specific controlled-release nitrogen fertilizer for rice is prepared by the following method: (1) Add nitrogen fertilizer particles into the coating machine and preheat them, control the hot air flow rate, and evenly spray the phenolic acid-β-cyclodextrin inclusion complex onto the surface of the quick-acting nitrogen fertilizer. After the reaction solidifies, a signal substance layer is formed on the surface of the nitrogen fertilizer particles. (2) Spraying the coating material onto the signal substance layer prepared in step (1) in multiple times, and obtaining a controlled-release nitrogen fertilizer for rice containing nitrogen signal substances after solidification.

[0013] Preferably, in step (1), the preheating temperature is 70°C and the time is 10 min; the spraying speed is 25 g / min; the hot air flow rate is 300 m 3 / min.

[0014] Preferably, in step (2), the spraying speed is 25 g / min; the coating material is sprayed in 6 to 10 times; and the curing time is 10 minutes.

[0015] A second aspect of the present invention provides a use of a controlled-release nitrogen fertilizer for rice containing a nitrogen signal substance in at least one of the following 1) to 3): 1) Improve rice's nitrogen utilization: The controlled-release period is greater than 100 days, with no less than 25% of nitrogen released during the rice tillering stage, no less than 40% of nitrogen released during the rice booting stage, and no less than 15% of nitrogen released during the rice heading stage; 2) Increase the number of rice grains; 3) Reduce the occurrence of common rice diseases.

[0016] Beneficial effects of the present invention: (1) The controlled-release nitrogen fertilizer for rice containing nitrogen signal substances produced by the present invention has a controlled-release period of more than 100 days, releases no less than 25% of nitrogen nutrients in the rice tillering period, releases no less than 40% of nitrogen nutrients in the rice heading period, and releases no less than 15% of nitrogen nutrients in the rice heading period. Its nitrogen release is well matched with the nitrogen demand of rice during the growth and development period, can meet the nitrogen demand of rice during the tillering period, and significantly increase the number of effective panicles of rice; its longer controlled-release period can especially meet the nitrogen demand of rice in the later growth and development stages such as the heading period and the heading period, effectively increase the number of solid grains of rice, and has a strong special precise controlled-release ability, effectively reduces nitrogen waste while providing sufficient nitrogen nutrient supply to rice, greatly improves the nitrogen utilization efficiency of rice, and has a significant effect on improving rice yield and quality.

[0017] (2) The nitrogen signal substance-containing controlled-release nitrogen fertilizer for rice produced by the present invention is a controlled-release nitrogen fertilizer containing phenolic acid. As mentioned above, phenolic acid can effectively improve the nitrogen utilization efficiency and disease resistance of rice, but it is easily degraded in the soil environment and needs to be added in small amounts multiple times. The controlled-release nitrogen fertilizer and phenolic acid are slowly released by utilizing the controlled release characteristics of β-cyclodextrin and the coating material, which solves this problem well. The controlled-release nitrogen fertilizer containing phenolic acid can release 80% of the phenolic acid before the end of the rice heading period, continuously supplying and stimulating nutrients to the rice root system and the soil in which it is located. While supplementing nitrogen to rice, it can effectively enhance the rice's ability to absorb, transform and utilize nitrogen, reduce nitrogen waste and losses such as volatilization and leaching, and greatly improve the nitrogen utilization efficiency in the early stage of rice growth and development. The controlled-release nitrogen fertilizer containing phenolic acid can also significantly enhance the disease resistance of rice, create a good soil microbial ecological environment, and effectively reduce the occurrence of common diseases such as rice sheath blight. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 : Comparison of the effects of different coated controlled-release nitrogen fertilizers; Figure 2 : Determination results of nitrogen release rate of coated controlled-release nitrogen fertilizers with different treatments; Figure 3 : Determination results of phenolic acid release rate of coated controlled-release nitrogen fertilizers with different treatments; Figure 4 : Rice pot yields under different treatments; Figure 5 : Nitrogen fertilizer utilization efficiency of rice under different treatments; Figure 6 : Nitrogen absorption curve of rice at different stages; Figure 7 : Disease index of rice sheath blight under different treatments; Figure 8 : Field yield of rice under different treatments. DETAILED DESCRIPTION

[0019] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0020] As introduced in the background technology section, the following problems exist in rice production: ammonia volatilization, denitrification and nitrate leaching account for 30%-70% of the total nitrogen applied, and the nitrogen utilization efficiency is less than 30%. The low nitrogen utilization rate of rice greatly limits its yield and quality; the coated controlled-release nitrogen fertilizers on the market are often suitable for a variety of crops, and their nitrogen release amount fails to fully match the different nitrogen requirements of rice in different growth and development stages, and dedicated precise controlled release has not yet been achieved; although the addition of phenolic acid can effectively improve the nitrogen utilization efficiency of rice, phenolic acid is volatile and easily degraded in the soil, requiring small amounts of multiple additions, and has not been widely used.

[0021] Based on this, the present invention aims to provide a controlled-release nitrogen fertilizer specifically for rice containing a nitrogen signal substance and its application. The phenolic acids in this invention continuously supply and stimulate nutrients to the rice root system and the soil in which it resides. The nitrogen released by the controlled-release nitrogen fertilizer closely matches the nitrogen requirements of rice during its growth and development, particularly during the tillering, booting, and heading stages. While supplementing nitrogen to the rice plant, it also effectively enhances the ability of rice and its rhizosphere microorganisms to absorb, transform, and utilize nitrogen, reducing nitrogen waste and losses through volatilization and leaching, significantly improving nitrogen utilization efficiency in rice. β-Cyclodextrin (β-CD) is a cyclic oligosaccharide composed of seven glucose units linked by α-1,4-glycosidic bonds. Its cavity has a volume of 262 Å and a diameter of 6.0-6.5 Å. Due to its unique cyclic structure and hydrophobic cavity, β-CD can incorporate various hydrophobic molecules to form inclusion complexes.

[0022] This controlled-release nitrogen fertilizer uses phenolic acid as a signaling substance and incorporates it into β-cyclodextrin, increasing its solubility and bioavailability. It also stabilizes easily degradable or volatile phenolic acid. Furthermore, antioxidants and chelating agents are added to block the oxidative chain reaction of phenolic acid. During fertilizer processing, the adhesive properties of the phenolic acid-β-cyclodextrin inclusion complex allow for better coating on the urea surface. The controlled-release nitrogen fertilizer prepared by this invention also recruits beneficial microorganisms for colonization, creating a favorable soil microbial environment and significantly enhancing rice disease resistance, thereby improving rice yield and quality. This achieves multiple goals at once and offers significant potential economic benefits.

[0023] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below with reference to specific embodiments.

[0024] The test materials used in the examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels.

[0025] Example 1: Preparation of controlled-release nitrogen fertilizer for rice containing nitrogen signal substances (1) Preparation method of phenolic acid-β-cyclodextrin inclusion complex: 140.97 g of β-cyclodextrin was completely dissolved in 1300 ml of distilled water. Then, 650 ml of an ethanol solution containing 19.14 g of protocatechuic acid, 1 g of zinc chloride, and 0.01914 g of tert-butylhydroquinone was slowly added dropwise at a rate of 1 mL / min at 60°C with magnetic stirring. The resulting solution was stirred continuously at 60°C for 48 hours and then frozen overnight at -20°C. The solution was then removed and allowed to stand at room temperature for at least 10 minutes before being recovered by vacuum filtration to obtain the protocatechuic acid-β-cyclodextrin inclusion complex. Vacuum filtration recovered the solution as a powdery solid, while the ethanol solution containing phenolic acid and β-cyclodextrin, which may not have been included, was removed by filtration.

[0026] (2) Preparation method of urea granules containing nitrogen signal substances: 1000 g of urea granules were added to a coating machine at 30 rpm and preheated at 70°C for 10 minutes. 160.11 g of protocatechuic acid-β-cyclodextrin inclusion complex was mixed with water in a mass ratio of 1:2 to form a uniform slurry. The mixture was then sprayed onto the surface of the rotating urea granules in the coating machine at a speed of 25 g / min for reaction and solidification. The hot air flow rate was controlled at 300 m 3 / min or so, and urea particles containing nitrogen signal substances were obtained.

[0027] (3) Preparation of outer coating material 3 g of castor oil was added to 2 g of pentamethylene diisocyanate, and the mixture was stirred for 7 min at room temperature under nitrogen flow to obtain a coating material for a controlled-release nitrogen fertilizer for rice.

[0028] (4) Preparation of controlled-release nitrogen fertilizer for rice containing nitrogen signal substances The uniformly mixed coating material is sprayed onto 1 kg of urea particles containing nitrogenous signal substances prepared in step (2) at a rate of 25 g / min. The coating material undergoes a solidification reaction within 10 minutes. The amount sprayed each time is 0.5% of the weight of urea. After repeating the spraying 8 times, a controlled-release nitrogen fertilizer for rice containing nitrogenous signal substances is obtained.

[0029] Example 2: Preparation of controlled-release nitrogen fertilizer for rice containing nitrogen signal substances The difference from Example 1 is that: Step (1) Preparation method of phenolic acid-β-cyclodextrin inclusion compound: Dissolve 140.97 g of β-cyclodextrin completely in 1300 ml of distilled water. Add 650 ml of an ethanol solution containing 17.15 g of salicylic acid, 1 g of zinc chloride, and 0.01715 g of tert-butylhydroquinone dropwise at a rate of 1 mL / min at 60°C with magnetic stirring. Stir the resulting solution continuously at 60°C for 48 hours, then freeze it in a -20°C refrigerator overnight. The solution was then allowed to stand at room temperature for at least 10 minutes before being recovered by vacuum filtration to obtain a salicylic acid-β-cyclodextrin inclusion complex.

[0030] Finally, a controlled-release nitrogen fertilizer specifically for rice containing nitrogen signal substances was prepared.

[0031] Example 3: Preparation of controlled-release nitrogen fertilizer for rice containing nitrogen signal substances The difference from Example 1 is that: Step (1) Preparation method of phenolic acid-β-cyclodextrin inclusion compound: 140.97 g of β-cyclodextrin was completely dissolved in 1300 ml of distilled water. Then, 650 ml of an ethanol solution containing 8.56 g of p-hydroxybenzoic acid, 8.70 g of komaric acid, 1 g of zinc chloride, and 0.01726 g of tert-butylhydroquinone was added dropwise at a rate of 1 mL / min at 60°C with magnetic stirring. The resulting solution was stirred continuously at 60°C for 48 hours and then frozen at -20°C overnight. The solution was then allowed to stand at room temperature for at least 10 minutes before being recovered by vacuum filtration to obtain a p-hydroxybenzoic acid-komaric acid-β-cyclodextrin inclusion complex.

[0032] Finally, a controlled-release nitrogen fertilizer specifically for rice containing nitrogen signal substances was prepared.

[0033] Example 4: Preparation of a controlled-release nitrogen fertilizer for rice containing nitrogen signal substances The difference from Example 1 is that: Step (1) Preparation method of phenolic acid-β-cyclodextrin inclusion compound: 140.97 g of β-cyclodextrin was completely dissolved in 1300 ml of distilled water. Then, 650 ml of an ethanol solution containing 5.72 g of salicylic acid, 6.38 g of protocatechuic acid, 6.30 g of vanillin, 1 g of zinc chloride, and 0.0184 g of tert-butylhydroquinone was added dropwise at a rate of 1 mL / min at 60°C with magnetic stirring. The resulting solution was stirred continuously at 60°C for 48 hours and then frozen at -20°C overnight. The solution was then allowed to stand at room temperature for at least 10 minutes before being recovered by vacuum filtration to obtain a salicylic acid-protocatechuic acid-vanillin-β-cyclodextrin inclusion complex.

[0034] Finally, a controlled-release nitrogen fertilizer specifically for rice containing nitrogen signal substances was prepared.

[0035] Comparative Example 1: Preparation of controlled-release nitrogen fertilizer without nitrogen signal substance The coating material prepared in step (3) of Example 1 was directly sprayed on the surface of urea in an amount of 4% of the weight of the urea to prepare a controlled-release nitrogen fertilizer that did not contain nitrogen signal substances.

[0036] The controlled-release urea containing protocatechuic acid prepared in Example 1 and the controlled-release urea without nitrogen signal substance prepared in Comparative Example 1 were photographed and compared. Figure 1 Compared with the urea in comparative example 1 without spraying the inclusion complex, the urea in example 1 sprayed with the phenolic acid-β-cyclodextrin inclusion complex had no adverse effect on the later coating.

[0037] Comparative Example 2 (1) Preparation method of urea granules containing nitrogen signal substances: 1000 g of urea granules were added to a coating machine at 30 rpm and preheated at 70°C for 10 minutes. 650 ml of ethanol solution containing 19.14 g of protocatechuic acid was evenly sprayed onto the surface of the rotating urea granules in the coating machine at a speed of 25 g / min to react and solidify. The hot air flow was controlled at 300 m 3 / min or so, and urea particles containing nitrogen signal substances were obtained.

[0038] (2) The preparation of the outer coating material and the preparation of the controlled-release nitrogen fertilizer for rice containing nitrogen signal substances are the same as steps (3) and (4) of Example 1.

[0039] Comparative Example 3 The difference from Example 1 is that in step (1), zinc chloride and tert-butylhydroquinone are not added.

[0040] Finally, a controlled-release nitrogen fertilizer specifically for rice containing nitrogen signal substances was prepared.

[0041] Comparative Example 4 The difference from Example 1 is that in step (1), tert-butylhydroquinone is not added.

[0042] Finally, a controlled-release nitrogen fertilizer specifically for rice containing nitrogen signal substances was prepared.

[0043] Comparative Example 5 The difference from Example 1 is that in step (1), zinc chloride is not added.

[0044] Finally, a controlled-release nitrogen fertilizer specifically for rice containing nitrogen signal substances was prepared.

[0045] Test Example 1 The nitrogen release rate of the controlled-release nitrogen fertilizers prepared in Example 1 and Comparative Examples 1 to 5 was determined by the 25°C static water extraction method. The results are as follows: Figure 2After obtaining an extract containing phenolic acid substances by using a 25°C hydrostatic extraction method, the phenolic acid release rate of the controlled-release nitrogen fertilizers prepared in Examples 1 to 4 and Comparative Examples 2 to 5 was determined by ultra-performance liquid chromatography-tandem mass spectrometry using precise targeted metabolomics technology.

[0046] according to Figure 2 It can be seen that the controlled-release nitrogen fertilizer prepared in Example 1, with its phenolic acid compounds and early release of nitrogen, can meet the nitrogen demand of rice during the tillering stage, contributing to an increase in the number of effective rice panicles. The nitrogen release period is relatively long, allowing a certain amount of nitrogen to be released during the booting and heading stages, contributing to an increase in the number of set rice grains and effectively improving rice yield. Furthermore, spraying the controlled-release nitrogen fertilizer in Example 1 with the phenolic acid-β-cyclodextrin inclusion complex not only does not affect nitrogen release, but also further enhances its controlled-release effect.

[0047] according to Figure 3 It can be seen that different types of phenolic acids have different molecular weights and solubilities, so the release rates are different, but the prepared controlled-release urea can release 80% of phenolic acid compounds before the end of the rice heading period, effectively improving the utilization of nitrogen in the early stage of rice growth.

[0048] Test Example 2 1. Test method: To test the effect of the nitrogen-signaling substance-containing controlled-release nitrogen fertilizer for rice prepared by the present invention on rice yield in brown soil, a potted experiment was conducted at Shandong Agricultural University using the rice variety "Xudao No. 3". The experimental treatments were as follows: Treatment PK: no nitrogen fertilizer was applied, but 1.7 g of potassium dihydrogen phosphate and 15.6 g of potassium sulfate were applied; Treatment of NPK: 19.3 g of urea, 1.7 g of potassium dihydrogen phosphate, and 15.6 g of potassium sulfate were applied; Treatment PA1: 23.3 g of the controlled-release nitrogen fertilizer prepared in Example 1, 1.7 g of potassium dihydrogen phosphate, and 15.6 g of potassium sulfate were applied; Treatment PA2: 20.1 g of the controlled-release nitrogen fertilizer prepared in Comparative Example 1, 1.7 g of potassium dihydrogen phosphate, and 15.6 g of potassium sulfate were applied; Treatment PA3: 20.5 g of the controlled-release nitrogen fertilizer prepared in Comparative Example 2, 1.7 g of potassium dihydrogen phosphate, and 15.6 g of potassium sulfate were applied; Treatment PA4: 23.3 g of the controlled-release nitrogen fertilizer prepared in Comparative Example 3, 1.7 g of potassium dihydrogen phosphate, and 15.6 g of potassium sulfate were applied; Treatment PA5: 23.3 g of the controlled-release nitrogen fertilizer prepared in Comparative Example 4, 1.7 g of potassium dihydrogen phosphate, and 15.6 g of potassium sulfate were applied; Treatment of PA6: 23.3 g of the controlled-release nitrogen fertilizer prepared in Comparative Example 5, 1.7 g of potassium dihydrogen phosphate, and 15.6 g of potassium sulfate were applied.

[0049] Each of the above experimental treatments was replicated four times. Rice was transplanted when it reached three leaves and one heart. Before transplanting, the nitrogen, phosphorus, and potassium fertilizers described above were mixed with 30 kg of air-dried soil passed through a 5 mm sieve and then added to each pot. Rice was planted in four holes per pot, with three plants per hole. At maturity, the entire pot of rice was harvested, sun-dried, and the actual yield was calculated based on a moisture content of 13.5%.

[0050] The nitrogen content of rice was determined by continuous flow analyzer after the acidic test solution containing inorganic ammonium salt was obtained by H2SO4-H2O2 digestion method.

[0051] Rice nitrogen absorption = rice dry weight × rice nitrogen content; Nitrogen absorption and utilization rate (kg / kg) = (total nitrogen absorption in the nitrogen application treatment - nitrogen absorption in the non-nitrogen application treatment) / nitrogen application amount × 100%. The obtained experimental data were processed by variance analysis and significance comparison.

[0052] 2. Test results: (1) Rice yield of each treatment Figure 4 shown.

[0053] The results showed that the application of the controlled-release urea containing protocatechuic acid prepared in Example 1 could increase rice yield. Compared with the PK treatment, the rice yield increased by 47.6%; compared with the NPK treatment, the rice yield increased by 14.2%.

[0054] When the controlled-release urea without nitrogen signaling substance prepared in Comparative Example 1 was applied, the rice yield decreased by 9.9% compared with Example 1.

[0055] When the controlled-release urea prepared in Comparative Example 2 and supplemented with only protocatechuic acid was applied, the rice yield decreased by 8.4% compared with Example 1.

[0056] When the controlled-release urea prepared in Comparative Example 3 without adding zinc chloride and tert-butylhydroquinone was applied, the rice yield was reduced by 6.5% compared with Example 1.

[0057] When the controlled-release urea prepared in Comparative Example 4 without adding tert-butylhydroquinone was applied, the rice yield was reduced by 5.8% compared with Example 1.

[0058] When the controlled-release urea prepared in Comparative Example 5 without adding zinc chloride was applied, the rice yield decreased by 5.7% compared with Example 1.

[0059] (2) The nitrogen fertilizer utilization efficiency of rice in each treatment is as follows Figure 5 shown.

[0060] The results showed that the application of the controlled-release urea containing protocatechuic acid prepared in Example 1 could improve the nitrogen fertilizer utilization rate of rice. Compared with the NPK treatment, the nitrogen fertilizer utilization rate of rice increased by 27.0%.

[0061] When the controlled-release urea without nitrogen signaling substance prepared in Comparative Example 1 was applied, the nitrogen fertilizer utilization rate of rice was reduced by 16.8% compared with Example 1.

[0062] When the controlled-release urea prepared in Comparative Example 2 and supplemented with only protocatechuic acid was applied, the nitrogen fertilizer utilization rate of rice decreased by 16.5% compared with Example 1.

[0063] When the controlled-release urea prepared in Comparative Example 3 without adding zinc chloride and tert-butylhydroquinone was applied, the nitrogen fertilizer utilization rate of rice was reduced by 14.8% compared with Example 1.

[0064] When the controlled-release urea prepared in Comparative Example 4 without adding tert-butylhydroquinone was applied, the nitrogen fertilizer utilization rate of rice was reduced by 12.7% compared with Example 1.

[0065] When the controlled-release urea prepared in Comparative Example 5 without adding zinc chloride was applied, the nitrogen fertilizer utilization rate of rice was reduced by 13.1% compared with Example 1.

[0066] Test Example 3 1. Test method: The rice variety "Shengdao 22" was selected for field trials in Shibahu Village, Kenli Street, Kenli District, Dongying City, Shandong Province from May to October 2024. The experimental treatments are as follows: Treatment PK: no nitrogen fertilizer was applied, but 340 g of diammonium phosphate and 270 g of potassium sulfate were applied; Treatment NPK: 1012 g of urea, 340 g of diammonium phosphate, and 270 g of potassium sulfate were applied; Treatment PA1: 1222 g of the controlled-release nitrogen fertilizer prepared in Example 1, 340 g of diammonium phosphate, and 270 g of potassium sulfate were applied; Treatment PA2: 1052 g of the controlled-release nitrogen fertilizer prepared in Comparative Example 1, 340 g of diammonium phosphate, and 270 g of potassium sulfate were applied; Treatment PA3: 1072 g of the controlled-release nitrogen fertilizer prepared in Comparative Example 2, 340 g of diammonium phosphate, and 270 g of potassium sulfate were applied; Treatment PA4: 1221 g of the controlled-release nitrogen fertilizer prepared in Comparative Example 3, 340 g of diammonium phosphate, and 270 g of potassium sulfate were applied; Treatment PA5: 1222 g of the controlled-release nitrogen fertilizer prepared in Comparative Example 4, 340 g of diammonium phosphate, and 270 g of potassium sulfate were applied; Treatment of PA6: 1221 g of the controlled-release nitrogen fertilizer prepared in Comparative Example 5, 340 g of diammonium phosphate, and 270 g of potassium sulfate were applied; Treatment PA7: 1220 g of the controlled-release nitrogen fertilizer prepared in Example 2, 340 g of diammonium phosphate, and 270 g of potassium sulfate were applied; Treatment PA8: 1220 g of the controlled-release nitrogen fertilizer prepared in Example 3, 340 g of diammonium phosphate, and 270 g of potassium sulfate were applied; Treatment PA9: 1220 g of the controlled-release nitrogen fertilizer prepared in Example 4, 340 g of diammonium phosphate, and 270 g of potassium sulfate were applied.

[0067] The above experimental treatments were replicated four times, two rice seedlings were planted in each hole, the rice planting density was 30 cm × 12 cm, and the plot area of each experimental treatment was 15.75 m 3 Controlled-release nitrogen fertilizers, diammonium phosphate, and potassium sulfate were applied during the rice greening period in all treatments; urea in the NPK treatment was applied four times on average, during the rice greening period, jointing period, flowering period, and grain filling period.

[0068] At the seedling stage, tillering stage, jointing stage, heading stage, booting stage, grain filling stage and maturity stage, rice plants within 30 cm in length were randomly selected from each group to measure their biomass and total nitrogen content to calculate the nitrogen absorption of rice at each growth stage. Figure 6 As shown, the controlled-release nitrogen fertilizer prepared in Example 1 releases nitrogen and phenolic acids that are well matched to the nitrogen requirements of rice during its growth and development period. Its controlled-release period is over 100 days, releasing at least 25% of the nitrogen nutrients during the rice tillering stage, at least 40% during the rice booting stage, and at least 15% during the rice heading stage. 80% of the phenolic acids are released before the end of the rice booting stage. This fertilizer provides continuous nutrient supply and stimulation to the rice root system and the soil in which it resides. While supplementing nitrogen to the rice, it also effectively enhances the rice's ability to absorb, transform, and utilize nitrogen, reducing nitrogen waste and losses through volatilization and leaching, significantly improving nitrogen utilization efficiency during the early stages of rice growth and development.

[0069] At the end of tillering, five random sites were selected in each experimental plot, and 10 rice plants were selected at each site to count and calculate the sheath blight disease index. Disease index = ∑ (number of diseased plants at each level × disease level) ( / total number of plants × highest disease level) × 100.

[0070] At maturity, 80 rice plants in the middle three rows of each experimental plot were harvested, dried in the sun, and the actual yield was calculated based on a moisture content of 13.5%.

[0071] 2. Test results: (1) The disease index of rice leaf sheath blight in each treatment is as follows Figure 7 shown.

[0072] The results showed that the application of the controlled-release urea containing protocatechuic acid prepared in Example 1 could reduce the infection of rice sheath blight pathogens. Compared with the NPK treatment, the sheath blight disease index was reduced by 62.9%.

[0073] When the controlled-release urea without nitrogen signal substance prepared in Comparative Example 1 was applied, the sheath blight disease index increased by 112.3% compared with Example 1.

[0074] When the controlled-release urea prepared in Comparative Example 2 and containing only protocatechuic acid was applied, the sheath blight disease index increased by 112.7% compared with Example 1.

[0075] When the controlled-release urea prepared in Comparative Example 3 without adding zinc chloride and tert-butylhydroquinone was applied, the sheath blight disease index increased by 74.9% compared with Example 1.

[0076] When the controlled-release urea prepared in Comparative Example 4 without adding tert-butylhydroquinone was applied, the sheath blight disease index increased by 73.5% compared with Example 1.

[0077] When the controlled-release urea prepared in Comparative Example 5 without adding zinc chloride was applied, the sheath blight disease index increased by 4.1% compared with Example 1.

[0078] The application of the salicylic acid-containing controlled-release urea prepared in Example 2 can reduce the infection of rice sheath blight pathogens. Compared with the NPK treatment, the sheath blight disease index is reduced by 65.7%.

[0079] The application of the controlled-release urea containing p-hydroxybenzoic acid and komaric acid prepared in Example 3 can reduce the infection of rice sheath blight pathogens. Compared with the NPK treatment, the sheath blight disease index is reduced by 68.7%.

[0080] The application of the controlled-release urea containing salicylic acid, protocatechuic acid and vanillin prepared in Example 4 can reduce the infection of rice sheath blight pathogens. Compared with the NPK treatment, the sheath blight disease index was reduced by 70.2%.

[0081] (2) Rice yield of each treatment Figure 8 shown.

[0082] according to Figure 8 It can be seen that the application of the controlled-release urea containing protocatechuic acid prepared in Example 1 can increase rice yield. Compared with the NPK treatment, the rice yield increased by 8.5%.

[0083] When the controlled-release urea without nitrogen signaling substance prepared in Comparative Example 1 was applied, the rice yield was reduced by 7.3% compared with Example 1.

[0084] When the controlled-release urea prepared in Comparative Example 2 and supplemented with only protocatechuic acid was applied, the rice yield decreased by 5.8% compared with Example 1.

[0085] When the controlled-release urea prepared in Comparative Example 3 without adding zinc chloride and tert-butylhydroquinone was applied, the rice yield was reduced by 4.7% compared with Example 1.

[0086] When the controlled-release urea prepared in Comparative Example 4 without adding tert-butylhydroquinone was applied, the rice yield was reduced by 4.4% compared with Example 1.

[0087] When the controlled-release urea prepared in Comparative Example 5 without adding zinc chloride was applied, the rice yield decreased by 4.5% compared with Example 1.

[0088] The application of the salicylic acid-containing controlled-release urea prepared in Example 2 can increase rice yield. Compared with the NPK treatment, the rice yield increased by 7.0%.

[0089] Application of the controlled-release urea containing p-hydroxybenzoic acid and komaric acid prepared in Example 3 can increase rice yield. Compared with the NPK treatment, the rice yield is increased by 9.8%.

[0090] Application of the controlled-release urea containing salicylic acid, protocatechuic acid and vanillin prepared in Example 4 can increase rice yield. Compared with the NPK treatment, the rice yield is increased by 11.4%.

[0091] In summary, the controlled-release nitrogen fertilizer prepared by the present invention adds protocatechuic acid, salicylic acid, p-hydroxybenzoic acid, komaric acid and vanillin as nitrogen signal substances, which can effectively improve the nitrogen fertilizer utilization rate and disease suppression of rice, thereby improving rice yield and quality, and the mixing effect of multiple types of phenolic acid compounds is even better.

[0092] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A controlled-release nitrogen fertilizer for rice containing nitrogen signal substances, characterized in that: The controlled-release nitrogen fertilizer for rice containing nitrogen signal substances comprises nitrogen fertilizer particles, a signal substance layer, and a coating layer from the inside out; The nitrogen fertilizer particles are fast-acting nitrogen fertilizers; the signal substance layer is a phenolic acid-β-cyclodextrin inclusion complex; The phenolic acid-β-cyclodextrin inclusion compound is prepared by the following method: β-cyclodextrin is completely dissolved in distilled water, and an ethanol solution containing phenolic acid, a chelating agent, and an antioxidant is slowly added dropwise under heating and stirring. After the addition is completed, the reaction is continued under heating and stirring. After the reaction is completed, the product is frozen overnight and then placed at room temperature. Finally, the phenolic acid-β-cyclodextrin inclusion complex is obtained by vacuum filtration.

2. The controlled-release nitrogen fertilizer for rice containing nitrogen signal substances according to claim 1, characterized in that: The quick-acting nitrogen fertilizer is urea; the phenolic acid is selected from at least one of protocatechuic acid, salicylic acid, p-hydroxybenzoic acid, komaric acid, and vanillin; the antioxidant is tert-butylhydroquinone; and the chelating agent is zinc chloride.

3. The controlled-release nitrogen fertilizer for rice containing nitrogen signal substances according to claim 1, characterized in that: The added amount of the phenolic acid accounts for 1.0-3.0% of the weight of the fast-acting nitrogen fertilizer; the molar ratio of the phenolic acid to β-cyclodextrin is 1:1; the mass ratio of the phenolic acid to the antioxidant is 1000:1; the mass ratio of the chelating agent to the fast-acting nitrogen fertilizer is 1:1000; and the volume ratio of the distilled water to the ethanol solution is 2:

1.

4. The controlled-release nitrogen fertilizer for rice containing nitrogen signal substances according to claim 1, characterized in that: The heating temperature was 60° C.; the dropping rate was 1 mL / min; the reaction time was 48 h; the freezing temperature was −20° C.; and the storage time at room temperature was at least 10 min.

5. The controlled-release nitrogen fertilizer for rice containing nitrogen signal substances according to claim 1, characterized in that: The coating layer is obtained by spraying a coating material; the coating material is obtained by adding bio-based polyol to isocyanate, introducing nitrogen at room temperature and continuously stirring.

6. The controlled-release nitrogen fertilizer for rice containing nitrogen signal substances according to claim 5, characterized in that: The bio-based polyol is selected from vegetable oil; the vegetable oil is castor oil, soybean oil or palm oil; the isocyanate is selected from pentamethylene diisocyanate, isophorone diisocyanate or hexamethylene diisocyanate; the added amount of the coating material accounts for 4% of the mass of the quick-acting nitrogen fertilizer.

7. The controlled-release nitrogen fertilizer for rice containing nitrogen signal substances according to claim 1, characterized in that: The nitrogen-containing signal substance-specific controlled-release nitrogen fertilizer for rice is prepared by the following method: (1) Add nitrogen fertilizer particles into the coating machine and preheat them, control the hot air flow rate, and evenly spray the phenolic acid-β-cyclodextrin inclusion complex onto the surface of the quick-acting nitrogen fertilizer. After the reaction solidifies, a signal substance layer is formed on the surface of the nitrogen fertilizer particles. (2) Spraying the coating material onto the signal substance layer prepared in step (1) in multiple times, and obtaining a controlled-release nitrogen fertilizer for rice containing nitrogen signal substances after solidification.

8. The controlled-release nitrogen fertilizer for rice containing nitrogen signal substances according to claim 7, characterized in that: In step (1), the preheating temperature is 70°C and the time is 10 min; the spraying speed is 25 g / min; the hot air flow rate is 300m 3 / min.

9. The controlled-release nitrogen fertilizer for rice containing nitrogen signal substances according to claim 7, characterized in that: In step (2), the spraying speed is 25 g / min; the coating material is sprayed 6 to 10 times; and the curing time is 10 minutes.

10. Use of the controlled-release nitrogen fertilizer for rice containing nitrogen signal substances according to any one of claims 1 to 9 in at least one of the following 1) to 3): 1) Improve rice's nitrogen utilization: The controlled-release period is greater than 100 days, with no less than 25% of nitrogen released during the rice tillering stage, no less than 40% of nitrogen released during the rice booting stage, and no less than 15% of nitrogen released during the rice heading stage; 2) Increase the number of rice grains; 3) Reduce the occurrence of common rice diseases.

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