Preparation method and application of selenium nano liquid fertilizer

Abstract

The invention discloses a preparation method and application of a selenium nano liquid fertilizer, and belongs to the technical field of selenium-rich yield-increasing foliar fertilizers for crops. The preparation method comprises the following steps: firstly, crushing fresh vegetables, mixing the crushed vegetables with fresh yellow serofluid, homogenizing under specific conditions, filtering to remove residues, and adjusting the pH value of filtrate to 2.0-4.0; then adding Na2SeO3, and carrying out a stirring reaction to generate selenium nanoparticles with the particle size of 20-80 nm; and finally, fixing the volume to a target volume by using fresh yellow serofluid, and continuously stirring to obtain the selenium nano liquid fertilizer. The selenium nanoparticles are efficiently synthesized from natural reducing substances in plants, the reaction time is short, chemical reagents or microorganisms do not need to be added, the prepared liquid fertilizer can be stably stored for 6 months at the room temperature in a dark environment, meanwhile, resource utilization of the yellow serofluid is achieved, and the liquid fertilizer has multiple benefits of selenium enrichment, yield increase, environmental protection and the like and is suitable for large-scale popularization and application. The method is suitable for selenium-enriched yield-increasing planting of various crops such as rice, wheat and corn.

Description

Technical Field

[0001] This invention relates to a method for preparing and applying a liquid fertilizer, specifically a method for preparing and applying a selenium nano-liquid fertilizer; it belongs to the technical field of foliar fertilizers for increasing crop yield with selenium enrichment. Background Technology

[0002] Inorganic selenium has low safety and bioactivity, making it unsuitable for direct ingestion. Organic selenium, on the other hand, has high bioactivity and is non-toxic. If obtained through diet, it can not only supplement the body's selenium requirements but also enhance immunity and resist various diseases. Nano-selenium possesses the unique physicochemical properties of nanomaterials, making it easily absorbed and utilized by crops. It can be converted into organic selenium through photosynthesis, which can be safely absorbed and utilized by the human body, while simultaneously promoting crop growth, increasing photosynthetic rate, and improving yield. Therefore, developing economical and convenient methods for preparing selenium nano-liquid fertilizers plays a crucial role in promoting the development of selenium-enriched agricultural products.

[0003] In the existing technology, there are already a number of patents and technologies related to selenium-enriched nano-fertilizers. For example, the technology with patent application number CN202210701594.3 uses microorganisms to synthesize nano-selenium fertilizer, which contains bioactive nano-elemental selenium. This method is green and environmentally friendly, but traditional microbial strains generally have poor tolerance to selenium, and their rate of reducing inorganic selenium to nano-selenium is very slow. It often requires a long fermentation time to reduce sodium selenite to nano-selenium, resulting in very low production efficiency and hindering the large-scale application of this technology.

[0004] Furthermore, some common selenium-enriched fertilizers on the market, such as those with selenite or selenium-enriched minerals as the main additives, have low bioavailability. Plants absorb only 5%-30% of the selenium, meaning most of it is not absorbed and utilized by crops, resulting in resource waste. On the other hand, improper application can easily lead to environmental pollution. Excess selenium remains in the soil and migrates and transforms with changes in soil physicochemical properties, polluting surface and water bodies, affecting the normal development of fish, birds, and terrestrial animals, and even entering the human body through the food chain, harming human health.

[0005] Given the high cost and unsatisfactory performance of existing selenium nano-fertilizers, it is necessary to conduct in-depth research to provide a new, economical, convenient, and environmentally friendly solution for increasing crop yield through selenium enrichment. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a low-cost, efficient, and green method for preparing selenium nano-liquid fertilizer, which not only opens up a new avenue for the resource utilization and pollution control of yellow slurry water, but also enables crops to achieve selenium enrichment and increased yield.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention first discloses a method for preparing selenium nano-liquid fertilizer, comprising the following steps:

[0009] S1. Raw material processing and homogenization: After thoroughly crushing the fresh vegetables, place them in a homogenizer, add fresh yellow liquid, and stir at 40℃-60℃ and 400~500rpm to homogenize thoroughly. Filter to remove residue, and then adjust the pH of the filtrate to 2.0~4.0.

[0010] S2. Generation of selenium nanoparticles: Add Na2SeO3 to the homogenate obtained in step S1, and continue stirring for 4 to 6 hours at 40℃-60℃ and 400~500rpm to generate selenium nanoparticles and obtain selenium nano solution.

[0011] S3. Preparation of liquid fertilizer: Use fresh yellow slurry to adjust the volume of selenium nano solution to the target volume, and continue stirring to obtain selenium nano liquid fertilizer.

[0012] The yellow liquid used in the above preparation method is produced during the processing of soy products. It is rich in nutrients such as soy isoflavones, carotenoids, proteins, minerals, oligosaccharides, vitamins, and saponins, making it an important raw material for the production of green organic fertilizers. However, most soy product companies in my country directly discharge yellow liquid into the environment, not only failing to fully utilize its nutritional value but also seriously polluting the ecological environment. This preparation method effectively turns yellow liquid from waste into a valuable resource.

[0013] Preferably, in step S3 above, the stirring conditions are: stirring continuously at 400-500 rpm for 30 minutes at 40℃-60℃.

[0014] More preferably, in the aforementioned step S1, the weight ratio of fresh vegetables to the volume ratio of fresh whey is (100-150g): 500mL.

[0015] More preferably, the mass ratio of the aforementioned Na2SeO3 to fresh vegetables is (4-6):1000.

[0016] More preferably, the aforementioned pH value is 3.0 to 4.0.

[0017] More preferably, the generated selenium nanoparticles have a particle size between 20 and 80 nm and good dispersibility, because the macromolecules such as proteins in the yellow slurry can maintain their stability well.

[0018] More preferably, the aforementioned fresh vegetables are selected from one or more of purple cabbage, common cabbage, bitter melon, broccoli, tomato, red pepper and Chinese cabbage, with purple cabbage being the preferred choice as it has a strong ability to generate selenium nanoparticles, low cost, and large biomass.

[0019] This invention also discloses a selenium nano liquid fertilizer, which is prepared by the aforementioned method and can increase the yield of rice by more than 8% per mu.

[0020] The present invention further discloses the application of the aforementioned selenium nano liquid fertilizer in crop cultivation. The specific application method is as follows: the prepared selenium nano liquid fertilizer is diluted with water at a volume ratio of 1:20 and then sprayed during the critical growth period of the crop.

[0021] Preferably, the aforementioned crops are rice, wheat, corn, etc., and the spray is applied once each during the booting stage, heading stage, and grain-filling stage.

[0022] The advantages of this invention are:

[0023] (1) This invention fully utilizes the naturally abundant and released phytochelates, reduced glutathione, non-protein thiol groups, vitamin C, and other reducing substances in vegetables such as purple cabbage, and under specific pH conditions of 2.0–4.0, Se... 4+ Quickly restore to Se 0 It only takes 4 to 6 hours to generate a large number of selenium nanoparticles with a particle size between 20 and 80 nm. They have good dispersibility, no agglomeration, and the reaction time is greatly shortened. This solves the problem of low production efficiency of liquid fertilizer in the existing technology. Moreover, no additional chemical reagents or specific strains are required. The preparation process is simple, the cost is low, and it is suitable for large-scale production.

[0024] (2) This invention uses yellow slurry as a reaction medium and nutrient carrier to transform it into high-performance liquid fertilizer, providing an economical, convenient, and environmentally friendly new solution for increasing crop yield by selenium enrichment. This solution not only solves the problem of environmental pollution caused by soybean product by-products, but also realizes the resource utilization of yellow slurry, and can well maintain the dispersion and stability of selenium nanoparticles, thus having significant advantages in energy saving and environmental protection.

[0025] (3) The selenium nano liquid fertilizer prepared by the present invention has good stability. Through the inhibitory effect of selenium nanoparticles on microorganisms such as lactobacillus, combined with sealed storage conditions, it is ensured that the liquid fertilizer does not turn sour or smelly. After being stored at room temperature for 6 months, the structure of selenium nanoparticles remains stable, which solves the industry pain point that liquid fertilizer is difficult to store and transport for a long time in the prior art.

[0026] (4) The liquid fertilizer prepared by this invention has small nanoparticle size, high activity, and high concentration, which can be efficiently absorbed and utilized by crops directly through the stomata or epidermis of crop leaves. Verification has shown that after spraying this selenium nano-liquid fertilizer, the average selenium content in brown rice increases by 4.69 to 5.53 times, the thousand-grain weight of rice increases by more than 6.33%, and the yield per mu of rice increases by more than 8.37%, achieving simultaneous selenium enrichment and yield increase in rice. This liquid fertilizer, after adjusting the dilution ratio, is also suitable for crops such as wheat and corn, and has excellent application and promotion prospects. Attached Figure Description

[0027] Figure 1 This is a TEM characterization image of the selenium nanoparticles prepared in Example 1 of this invention;

[0028] Figure 2 This is a TEM characterization image of the selenium nanoparticles prepared in Example 4 of this invention;

[0029] Figure 3 This is a TEM characterization image of the selenium nanoparticles prepared in Example 6 of this invention;

[0030] Figure 4 This is an EDS energy dispersive spectroscopy (EDS) spectrum of the selenium nanoparticles prepared in Example 1 of this invention.

[0031] Figure 5 This is a TEM characterization image of the selenium nanoparticles prepared in Comparative Example 1 of this invention.

[0032] Figure 6 This is a TEM characterization image of the selenium nanoparticles prepared in Comparative Example 2 of this invention;

[0033] Figure 7 This is a TEM characterization image of the selenium nanoparticles prepared in Comparative Example 3 of this invention.

[0034] Figure 8 This is a TEM characterization image of the selenium nanoparticles prepared in Comparative Example 4 of this invention.

[0035] Figure 9 This is a TEM characterization image of the selenium nanoparticles prepared in Comparative Example 5 of this invention.

[0036] Figure 10 This is a TEM characterization result of the selenium nano-liquid fertilizer prepared in Example 4 of this invention after being left to stand at room temperature in the dark for 6 months.

[0037] Figure 11 This is a comparison chart showing the changes in the thousand-grain weight of potted rice after spraying commercially available Xizewang foliar fertilizer and the selenium nano liquid fertilizer prepared in Example 4.

[0038] Figure 12This is a comparison graph showing the changes in selenium content in brown rice of potted rice after spraying commercially available Xizewang foliar fertilizer and selenium nano liquid fertilizer prepared in Example 4.

[0039] Figure 13 This is a comparison chart showing the changes in paddy rice yield per mu after spraying commercially available Xizewang foliar fertilizer and selenium nano liquid fertilizer prepared in Example 4.

[0040] Figure 14 This is a comparison graph showing the changes in selenium content in brown rice of field rice after spraying commercially available Xizewang foliar fertilizer and selenium nano liquid fertilizer prepared in Example 4.

[0041] Figure 15 This is a graph from the Huace Company's identification report on the selenium content in brown rice from the Datian demonstration area. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0043] In this invention, firstly, using fresh yellow pulp and suitable homogenization conditions, phytochelates, reduced glutathione, non-protein sulfhydryl groups, vitamin C, and other reducing substances in the crushed fresh vegetable tissue are fully dissolved and released. After filtration to remove residue, the pH of the filtrate is adjusted to 2.0–4.0, which enhances the ability of these reducing substances to release Se from sodium selenite. +4 Convert to Se 0 The activity of the enzyme promotes the generation of selenium nanoparticles, and a selenium nanoparticle solution is prepared. Finally, the selenium nanoparticle solution is diluted to the target volume with fresh yellow liquid to obtain a selenium nanoparticle liquid fertilizer.

[0044] The fresh vegetables available include, but are not limited to, fresh purple cabbage, regular cabbage, bitter melon, broccoli, tomatoes, red peppers, or Chinese cabbage. To select suitable vegetables, the morphology, particle size, and quantity of selenium nanoparticles in the filtrate were detected using transmission electron microscopy. The results clearly show that the quantity (density) of selenium nanoparticles produced by the above vegetables is as follows: bitter melon > purple cabbage > red pepper > tomato > broccoli > regular cabbage > Chinese cabbage. Although the number of selenium nanoparticles produced by the purple cabbage homogenate is slightly lower than that of the bitter melon, the biomass of purple cabbage is significantly greater than that of bitter melon, and it is also cheaper, making it suitable for large-scale production. Therefore, this invention preferentially selects purple cabbage as the raw material for preparing selenium nanoparticle liquid fertilizer.

[0045] Example 1

[0046] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 2.0.

[0047] S2. Add 0.4 g Na2SeO3 to the filtrate and continue stirring at 40℃-60℃ and 400-500 rpm for 4-6 hours to generate a selenium nanoparticle solution. The TEM characterization results of the selenium nanoparticles are as follows: Figure 1 As shown;

[0048] S3. Preparation of liquid fertilizer: Use fresh yellow slurry to make up the volume of selenium nano solution to 1000ml, and continue stirring to generate selenium nano liquid fertilizer.

[0049] Example 2

[0050] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 2.0.

[0051] S2. Add 0.5g Na2SeO3 to the filtrate and continue stirring at 40℃-60℃ and 400-500rpm for 4-6 hours to generate selenium nanoparticle solution;

[0052] S3. Preparation of liquid fertilizer: Use fresh yellow slurry water to make up the volume of selenium nano solution to 1000ml, and continue stirring to generate selenium nano liquid fertilizer.

[0053] Example 3

[0054] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 2.0.

[0055] S2. Add 0.6g Na2SeO3 to the filtrate and continue stirring at 40℃-60℃ and 400-500rpm for 4-6 hours to generate selenium nanoparticle solution;

[0056] S3. Preparation of liquid fertilizer: Use fresh yellow slurry to make up the volume of selenium nano solution to 1000ml, and continue stirring to generate selenium nano liquid fertilizer.

[0057] Example 4

[0058] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 3.0.

[0059] S2. Add 0.5 g Na2SeO3 to the filtrate and continue stirring at 40℃-60℃ and 400-500 rpm for 4-6 hours to generate a selenium nanoparticle solution. The TEM characterization results of the selenium nanoparticles are as follows: Figure 2 As shown;

[0060] S3. Preparation of liquid fertilizer: Use fresh yellow slurry to make up the volume of selenium nano solution to 1000ml, and continue stirring to generate selenium nano liquid fertilizer.

[0061] Example 5

[0062] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 4.0.

[0063] S2. Add 0.4g Na2SeO3 to the filtrate and continue stirring at 40℃-60℃ and 400-500rpm for 4-6 hours to generate a large number of selenium nanoparticles and obtain a selenium nano solution.

[0064] S3. Preparation of liquid fertilizer: Use fresh yellow slurry to make up the volume of selenium nano solution to 1000ml, and continue stirring to generate selenium nano liquid fertilizer.

[0065] Example 6

[0066] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 4.0.

[0067] S2. Add 0.5 g Na2SeO3 to the filtrate and continue stirring at 40℃-60℃ and 400-500 rpm for 4-6 hours to generate a large number of selenium nanoparticles, thus preparing a selenium nanoparticle solution. The TEM characterization results of the selenium nanoparticles are as follows: Figure 3 As shown;

[0068] S3. Preparation of liquid fertilizer: Use fresh yellow slurry to make up the volume of selenium nano solution to 1000ml, and continue stirring to generate selenium nano liquid fertilizer.

[0069] Example 7

[0070] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 4.0.

[0071] S2. Add 0.6g Na2SeO3 to the filtrate and continue stirring at 40℃-60℃ and 400-500rpm for 4-6 hours to generate a large number of selenium nanoparticles and obtain a selenium nano solution.

[0072] S3. Preparation of liquid fertilizer: Use fresh yellow slurry to make up the volume of selenium nano solution to 1000ml, and continue stirring to generate selenium nano liquid fertilizer.

[0073] Comparative Example 1

[0074] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 1.0.

[0075] S2. Add 0.6 g Na2SeO3 and continue stirring at 40℃-60℃ and 400-500 rpm for 4-6 hours to generate a selenium nanoparticle solution. The TEM characterization results of the selenium nanoparticles are as follows: Figure 5 As shown;

[0076] S3. Preparation of liquid fertilizer: Use fresh yellow slurry to make up the volume of selenium nano solution to 1000ml, and continue stirring to generate selenium nano liquid fertilizer.

[0077] Comparative Example 2

[0078] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 2.0.

[0079] S2. Add 0.6 g Na2SeO3 and continue stirring at 30℃ and 400-500 rpm for 4-6 hours to generate a selenium nanoparticle solution. The TEM characterization results of the selenium nanoparticles are as follows: Figure 6 As shown;

[0080] S3. Use fresh yellow liquid to bring the selenium nano solution to a final volume of 1000ml, and continue stirring to produce selenium nano liquid fertilizer.

[0081] Comparative Example 3

[0082] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 2.0.

[0083] S2. Add 0.6 g Na2SeO3 and continue stirring at 80℃ and 400-500 rpm for 4-6 hours to generate a selenium nanoparticle solution. The TEM characterization results of the selenium nanoparticles are as follows: Figure 7 As shown;

[0084] S3. Use fresh yellow liquid to bring the selenium nano solution to a final volume of 1000ml, and continue stirring to produce selenium nano liquid fertilizer.

[0085] Comparative Example 4

[0086] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, homogenize thoroughly at a temperature above 60℃ and 400-500rpm, filter to remove residue, and then adjust the pH value of the homogenate to 4.0.

[0087] S2. Add 0.6 g Na2SeO3 and stir for 4–6 hours at 80 °C and 400–500 rpm to generate selenium nanoparticles and prepare a selenium nanoparticle solution. The TEM characterization results of the selenium nanoparticles are as follows: Figure 8 As shown;

[0088] S3. Preparation of liquid fertilizer: Use fresh yellow slurry to make up the volume of selenium nano solution to 1000ml, and continue stirring to generate selenium nano liquid fertilizer.

[0089] Comparative Example 5

[0090] S1. After thoroughly crushing 100g of fresh purple cabbage, place it into a homogenizer, add 500ml of fresh yellow pulp water, and homogenize thoroughly at 40℃-60℃ and 400-500rpm. Filter to remove residue, and then adjust the pH of the filtrate to 5.0.

[0091] S2. 0.6 g of Na2SeO3 was added, and the mixture was stirred for 4–6 hours at 40℃–60℃ and 400–500 rpm to generate selenium nanoparticles and prepare a selenium nanoparticle solution. The TEM characterization results of the selenium nanoparticles are as follows: Figure 9 As shown;

[0092] S3. Preparation of liquid fertilizer: Use fresh yellow slurry to make up the volume of selenium nano solution to 1000ml, and continue stirring to generate selenium nano liquid fertilizer.

[0093] The selenium nanoparticles generated in each embodiment of the present invention have a particle size between 20-80 nm and good dispersibility, such as... Figures 1 to 3 As shown, Figure 4 Energy dispersive spectroscopy (EDS) characterization results confirmed that the main elemental component of the spherical nanoparticles in the prepared liquid fertilizer was selenium. However, the number of selenium nanoparticles generated under the reaction conditions of Comparative Examples 1–5 was reduced, and the particle size of nanoparticles in some comparative examples even showed an increasing trend, such as… Figures 5 to 9 As shown.

[0094] Specifically, Table 1 better illustrates the performance differences of the liquid fertilizer products in each embodiment and comparative example. It can be seen that in Comparative Example 1, at a pH of 1.0 and a homogenate temperature of 40°C–60°C, the density of selenium nanoparticles was relatively high, but precipitation easily occurred after long-term storage. In Comparative Examples 2 and 3, with the pH maintained at 2.0, when the homogenate temperature was below 40°C or above 60°C, compared to Examples 1–3, the number of selenium nanoparticles decreased, but the dispersion was good. Compared to Examples 5–7, in Comparative Example 4, with the pH maintained at 4.0, when the homogenate temperature was above 60°C, the number of generated selenium nanoparticles decreased, and the particle size tended to decrease with increasing temperature. In Comparative Example 5, under the conditions of pH 5.0 and 40°C–60°C, the density of selenium nanoparticles decreased with increasing pH, and the particle size tended to increase, but the dispersion remained good.

[0095] Therefore, under conditions of pH 2.0–4.0 and 40℃–60℃, the filtrate will contain Se. +4 Restore to Se 0 The activity of this group is the highest, producing a large number of selenium nanoparticles, resulting in a stronger selenium-enriched yield-increasing effect on crops. TEM detection results also show that... Figure 2 The selenium nanoparticles are the most numerous and have the highest density, therefore Example 4 is the optimal example.

[0096] Table 1 Comparison of raw materials, processes, and performance of each embodiment and comparative example.

[0097]

[0098]

[0099] The selenium nanoparticle liquid fertilizer prepared in Example 4 was sealed and stored indoors in the dark for 6 months. Then, TEM was used to detect the changes in the selenium nanoparticles, and the characterization results are as follows: Figure 10 As shown, the changes in the particle size and number of selenium nanoparticles are small, and the dispersibility remains good, indicating that the selenium nanoparticle liquid fertilizer prepared by this invention is relatively stable and can be stored for a long time in an indoor light-proof environment.

[0100] Furthermore, the stability of Example 4 and the commercially available liquid fertilizer (Xizewang foliar fertilizer) under different storage conditions is recorded in detail in Table 2 below:

[0101] Table 2. Changes in the state of the liquid fertilizer prepared in Example 4 and the commercially available liquid fertilizer over time under different storage conditions.

[0102]

[0103] As shown in Table 2, commercially available liquid fertilizers, under sealed conditions, produce a small amount of sediment after 6 months, indicating poor stability. In contrast, the liquid fertilizer prepared in Example 4 of this invention exhibits good stability under sealed storage conditions, remaining neither acidic nor foul-smelling for 6 months, and producing only a small amount of sediment after 12 months. However, under open conditions, influenced by anaerobic microorganisms, it develops an odor after 3 months, and by 12 months, the odorous substances are completely decomposed into odorless products, while a significant amount of sediment is produced, rendering the liquid fertilizer almost completely ineffective. This demonstrates that the liquid fertilizer prepared in this invention has superior stability compared to commercially available products, and that selecting suitable storage conditions is crucial for the transportation of liquid fertilizers.

[0104] Application Example 1

[0105] This application example is an experiment on potted rice using the selenium nano liquid fertilizer prepared in Example 4.

[0106] First, rice seeds (lotus seedlings, Anhui Quanyin Chaoda Seed Industry Co., Ltd.) were disinfected with a 0.1% (m / v) sodium hypochlorite solution. After cleaning, they were sown on moist quartz sand for germination cultivation (28℃, 70% humidity). When the seedlings reached the three-leaf stage, 6 rice seedlings were transplanted into each pot of paddy soil. The control group and the sprayed group each had 3 pots of rice planted and were placed in a glass greenhouse for cultivation under light.

[0107] During the booting, heading, and early grain-filling stages of rice, the rice seedlings in the spraying group were sprayed three times with a diluted solution of the selenium nano-liquid fertilizer prepared in Example 4 (diluted at a ratio of 1:20), with 200 mL of diluted solution applied to each pot of rice each time. The control group rice was sprayed with 200 mL of commercially available Xizewang foliar fertilizer diluted solution per pot each time, following the dilution ratio specified in the instructions. After the rice matured, the thousand-grain weight and the selenium content in the brown rice were measured.

[0108] The test results showed that, compared with the control group, the thousand-grain weight of rice increased by 6.33% after spraying with the selenium nano-liquid fertilizer of this invention. Figure 11 As shown in the figure. The selenium content in rice was determined using liquid chromatography-atomic fluorescence spectrometry. The average selenium content in the control group brown rice was 35 μg / kg, while the average selenium content in the sprayed group brown rice reached 231 μg / kg, an increase of 5.53 times compared to the control group. Figure 12 As shown.

[0109] Application Example 2

[0110] This application example is a field rice application experiment of the selenium nano liquid fertilizer prepared in Example 4.

[0111] Six mu (approximately 0.4 hectares) of Nanjing 9108 paddy field were divided into six smaller plots: Control Area-1, Control Area-2, Control Area-3, Demonstration Area-1, Demonstration Area-2, and Demonstration Area-3. During the booting, heading, and grain-filling stages, Demonstration Area-1, Demonstration Area-2, and Demonstration Area-3 were each sprayed once with a diluted selenium nano-liquid fertilizer solution prepared according to this invention (the selenium nano-liquid fertilizer stock solution was diluted 1:20, with 30 liters of diluted solution applied per mu). Control Area-1, Control Area-2, and Control Area-3 were all sprayed with a commercially available diluted Xizewang foliar fertilizer solution (diluted according to the instructions). After the rice matured, the actual yield was measured, and the dry weight of the rice in each control group and demonstration area was calculated after deducting moisture content.

[0112] Analysis results as follows Figure 13 As shown, the average yield of rice in the control area was 609.7 kg / mu, while the average yield in the demonstration area was 660.7 kg / mu, representing an 8.37% increase in rice yield per mu. The average selenium content in brown rice in the control area was 40.3 μg / kg, while the average selenium content in brown rice in the demonstration area reached 229.7 μg / kg, an increase of 4.69 times. Figure 14 As shown.

[0113] Furthermore, Huace Company was commissioned to test the selenium content of the brown rice in the demonstration area of ​​this application example 2, such as... Figure 15 As shown, the selenium content was 220 μg / kg, thus it can effectively increase the yield of rice crops by enriching them with selenium.

[0114] In summary, this invention, through raw material innovation (purple cabbage + yellow sap) and process innovation (pH and temperature control), produces a selenium nano-liquid fertilizer with high stability and excellent performance. It solves the technical pain points of existing selenium-enriched fertilizers, such as low efficiency, high cost, and poor effect, and has economic, social, and environmental benefits. It is of great significance for promoting green agricultural development and the development of functional agricultural products.

[0115] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A method for preparing a selenium nano-liquid fertilizer, characterized in that, The method comprises the following steps: S1, raw material processing and homogenization: the fresh vegetables are fully broken and placed in a homogenizer, fresh yellow sap water is added, and the mixture is stirred at 40-60℃ and 400-500 rpm to fully homogenize, the residue is removed by filtration, and the pH value of the filtrate is adjusted to 2.0-4.0; S2, generating selenium nanoparticles: Na2SeO3 is added to the filtrate prepared in step S1, and the mixture is continuously stirred at 40-60℃ and 400-500 rpm for 4-6 hours to generate selenium nanoparticles, obtaining a selenium nanoparticle solution; S3, preparing a liquid fertilizer: the selenium nanoparticle solution is diluted to the target volume with fresh yellow sap water, and the mixture is continuously stirred to prepare a selenium nanoparticle liquid fertilizer.

2. The method for preparing selenium nano-liquid fertilizer according to claim 1, characterized in that, In step S3, the stirring conditions are as follows: continuously stirring at 400-500 rpm for 30 min at 40-60℃.

3. The method for preparing a selenium nano-liquid fertilizer according to claim 1, characterized in that, In step S1, the ratio of the weight of fresh vegetables to the volume of fresh yellow sap water is (100-150g):500mL.

4. The method for preparing selenium nano-liquid fertilizer according to claim 1, characterized in that, The mass ratio of Na2SeO3 to fresh vegetables is (4-6):1000.

5. The method for preparing selenium nano-liquid fertilizer according to claim 1, characterized in that, In step S1, the pH value is adjusted to 3.0-4.

0.

6. The method for preparing selenium nano-liquid fertilizer according to claim 1, characterized in that, In step S2, the particle size of the generated selenium nanoparticles is 20-80nm.

7. The method for preparing a selenium nano-liquid fertilizer according to claim 1, characterized in that, The fresh vegetables are selected from one or more of purple cabbage, common cabbage, bitter gourd, broccoli, tomato, red pepper and Chinese cabbage.

8. A selenium nano-liquid fertilizer, characterized in that, The method of any one of claims 1-7 can increase the yield of rice per mu by more than 8%.

9. The use of the selenium nano-liquid fertilizer according to claim 8 in crop planting, characterized in that, The selenium nanoparticle liquid fertilizer is diluted with water at a volume ratio of 1:20 and sprayed during the growth period of crops.

10. Use according to claim 9, characterized in that, The crops are rice, wheat or corn, and the spraying is performed once at the booting stage, the heading stage and the filling stage.

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