Nano-organic selenium fertilizer, preparation method and application thereof

Abstract

The present application relates to the technical field of selenium-rich fertilizer preparation, in particular to a kind of nano organic selenium fertilizer and its preparation method and application.The nano organic selenium fertilizer provided by the present application is obtained by thermal catalytic synthesis from sodium selenite, glucose and urea.Compared with the selenium element added by sodium selenite used in traditional selenium fertilizer, the organic nano selenium particle size is more uniform, the stability is stronger, is conducive to the absorption and utilization of crops, can effectively increase the yield of tomato and melon, and improve the quality of tomato and melon.

Description

Technical Field

[0001] This invention relates to the field of selenium-enriched fertilizer preparation technology, and in particular to a nano-organic selenium fertilizer, its preparation method, and its application. Background Technology

[0002] Selenium is an essential trace element for the human body, and its main source is through selenium-enriched foods, with consuming selenium-enriched agricultural products being the primary method. There are two main ways to produce selenium-enriched agricultural products: one is by planting crops on selenium-rich land, and the other is by applying selenium fertilizers to increase the selenium content of the produce. Currently, the selenium fertilizers used are mainly inorganic selenium, such as sodium selenate and sodium selenite. However, sodium selenate and sodium selenite are highly toxic and have low absorption efficiency, posing certain risks. Furthermore, because most crops have a low absorption and conversion rate for sodium selenite, and the process is lengthy, the input-output ratio is low, resulting in significant waste, high selenium enrichment costs, and some environmental pollution.

[0003] Nano-selenium possesses biological characteristics such as low toxicity, high bioactivity, and high absorption and utilization efficiency, making it a promising candidate for application in the fertilizer field. Nano-selenium can be synthesized through techniques such as chemical reactions, crystallization, and reverse micelle synthesis. However, these techniques are limited by conditions such as high temperature, high pressure, and catalysts. Furthermore, the chemical reagents used in the production process pose potential environmental risks, and chemically synthesized nano-selenium exhibits poor stability, thus affecting its application.

[0004] Previous methods for preparing nano-selenium were all complex, cumbersome, and difficult to control, consuming a lot of energy and thus having high production costs. Moreover, the nano-selenium produced was neither water-soluble nor biocompatible. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a nano-organic selenium fertilizer, its preparation method, and its applications. The preparation method provided by this invention has the advantages of simplicity, ease of implementation, high efficiency, and energy saving. The prepared nano-organic selenium fertilizer possesses both water solubility and biocompatibility.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing nano-organic selenium fertilizer, wherein the raw materials are reacted at a temperature of 43-45℃ for more than 12 hours to obtain the nano-organic selenium fertilizer; the raw materials include the following components in parts by weight: 0.5-1 parts sodium selenite, 3-5 parts glucose and 5-7 parts urea.

[0008] Preferably, the process before the reaction includes: mixing and pulverizing the components in the raw materials in proportion until the particle size is less than 200 mesh.

[0009] Preferably, the raw materials for preparation also include plant growth regulators and fertilizers that supplement phosphorus and potassium elements.

[0010] Preferably, the fertilizer supplementing phosphorus and potassium elements includes potassium dihydrogen phosphate; the plant growth regulator includes sodium naphthaleneacetate and potassium indolebutyrate.

[0011] Preferably, the weight ratio of potassium dihydrogen phosphate to sodium selenite is 2-3:0.5-1, the weight ratio of sodium naphthaleneacetate to potassium indolebutyrate is 0.1-0.2:0.15-0.3, and the weight ratio of sodium naphthaleneacetate to sodium selenite is 0.1-0.2:0.5-1.

[0012] This invention provides a nano-organic selenium fertilizer prepared by the preparation method described above, wherein the average particle size of the nano-organic selenium fertilizer is 65.6 nm, and the weight content of the nano-organic selenium fertilizer with a particle size of 30-100 nm is >93%.

[0013] This invention provides a method for improving crop yield and quality, comprising: diluting nano-organic selenium fertilizer and spraying it onto the leaves of crops; wherein the nano-organic selenium fertilizer is the nano-organic selenium fertilizer prepared by the method described in the above technical solution.

[0014] Preferably, the dilution factor is 800 to 1000 times.

[0015] Preferably, the spraying is performed during the flowering and fruit-setting period, and the spraying is performed 2 to 3 times, with an interval of 10 to 15 days between each application.

[0016] Preferably, the crop includes tomatoes or melons.

[0017] Beneficial effects:

[0018] This invention provides a method for preparing nano-organic selenium fertilizer. The raw materials are reacted at 43-45°C for at least 12 hours to obtain the nano-organic selenium fertilizer. The raw materials include the following components by weight: 0.5-1 parts sodium selenite, 3-5 parts glucose, and 5-7 parts urea. The preparation method provided by this invention combines suitable sodium selenite, glucose, and urea, and synthesizes nano-organic selenium fertilizer through thermocatalysis. It eliminates the need for complex preparation processes and catalysts, resulting in a simple and energy-efficient process. Under 43-45°C conditions, urea slowly absorbs moisture from the air, allowing sodium selenite and glucose to react slowly under high-concentration solid conditions. This reduces sodium selenite to small-particle elemental selenium, which then combines with glucose to form organic nano-selenium. The resulting nano-selenium particles are uniform and, after combining with glucose, exhibit good water solubility and stability. Furthermore, compared to liquid nano-selenium fertilizers, they have a longer shelf life and good biocompatibility, making them easily absorbed by plants.

[0019] Furthermore, the present invention combines plant growth regulators and fertilizers that supplement phosphorus and potassium elements in the nano-organic selenium fertilizer described in the above technical solution, so that the nano-organic selenium fertilizer can promote growth, while also increasing yield and improving crop quality. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0021] Figure 1 The images show the physical samples of the raw materials prepared before and after thermocatalysis in Example 1.

[0022] Figure 2 and Figure 3 The results are from the nanoparticle size analysis of the NS-90Plus. Figure 3 The coordinate unit is nm;

[0023] Figure 4 A photo of the diluted nano-organic selenium fertilizer after standing for 48 hours.

[0024] Figure 5 Results of single-fruit weights for each treatment;

[0025] Figure 6 The results show the number of individual plants for each treatment.

[0026] Figure 7 The yield results for each treatment are shown below.

[0027] Figure 8 Results for each processing length;

[0028] Figure 9 Results for each treatment of melon width;

[0029] Figure 10 For the results of each treatment single fruit weight;

[0030] Figure 11 Results of the yield of commercial melons for each treatment. Detailed Implementation

[0031] A method for preparing a nano-organic selenium fertilizer involves reacting the raw materials at a temperature of 43-45℃ for more than 12 hours to obtain the nano-organic selenium fertilizer; the raw materials include the following components in parts by weight: 0.5-1 parts sodium selenite, 3-5 parts glucose and 5-7 parts urea.

[0032] Unless otherwise specified, the present invention does not have special requirements for the source of raw materials for the preparation of the nano-organic selenium fertilizer, and commercially available products well known to those skilled in the art can be used.

[0033] The raw materials for preparing the nano-organic selenium fertilizer of the present invention, by weight, include 0.5 to 1 part sodium selenite, preferably 0.6 to 0.9 parts, and more preferably 0.6 parts.

[0034] Based on the weight parts of the sodium selenite, the raw materials for preparing the nano-organic selenium fertilizer of the present invention include 3 to 5 parts of glucose, preferably 4 parts.

[0035] This invention utilizes a suitable combination of sodium selenite and glucose to enable a slow reaction between sodium selenite and glucose under high concentration conditions, reducing sodium selenite to generate small-particle elemental selenium. The elemental selenium then combines with the -OH or -COOH groups of glucose to form stable organic nano-selenium.

[0036] Based on the weight parts of sodium selenite, the raw materials for preparing the nano-organic selenium fertilizer of the present invention include 5 to 7 parts of urea, preferably 6 parts. The urea of ​​the present invention can slowly absorb moisture from the air at 43 to 45°C, providing solid conditions for the reaction between sodium selenite and glucose, which is beneficial for promoting the reaction.

[0037] Based on the weight parts of the sodium selenite, the raw materials for preparing the nano-organic selenium fertilizer of the present invention preferably include 0.1 to 0.2 parts of a fertilizer supplementing phosphorus and potassium elements, more preferably 0.15 to 0.2 parts, and even more preferably 0.2 parts. In the present invention, the fertilizer preferably includes potassium dihydrogen phosphate.

[0038] Based on the weight parts of sodium selenite, the raw materials for preparing the nano-organic selenium fertilizer of the present invention preferably include 0.25-0.5 parts of plant growth regulator, more preferably 0.3-0.2 parts, and even more preferably 0.35 parts. In the present invention, the plant growth regulator preferably includes sodium naphthaleneacetate and potassium indolebutyrate, and the weight ratio of sodium naphthaleneacetate to potassium indolebutyrate is preferably 0.1-0.2:0.15-0.3, more preferably 0.15-0.2:0.15-0.2, and even more preferably 0.2:0.15. The present invention, by compounding suitable plant growth regulators, enables the nano-organic selenium fertilizer to promote growth, while also increasing yield and improving crop quality.

[0039] In this invention, the raw materials are mixed in a certain proportion and then pulverized to a particle size of less than 200 mesh to obtain primary fertilizer.

[0040] After obtaining the primary fertilizer, this invention reacts the primary fertilizer at a temperature of 43-45℃ for at least 12 hours to obtain the nano-organic selenium fertilizer. In this invention, the reaction temperature is preferably 44-45℃, more preferably 45℃; the reaction time is preferably 12-24 hours, further preferably 12-16 hours, and more preferably 15 hours. This invention uses a suitable reaction temperature for a thermocatalytic reaction, reducing sodium selenite to small-particle elemental selenium. The elemental selenium then combines with glucose to form organic nano-selenium. This process is not limited by high temperature, high pressure, or catalysts, and has the advantages of simplicity, ease of implementation, high efficiency, and energy saving, enabling the mass production of highly safe nano-organic selenium fertilizer.

[0041] This invention utilizes the 2,3-diaminonaphthalene (DAN) fluorescence method (DAN fluorescence method) to determine that the main product after the reaction is elemental selenium. This provides a theoretical basis.

[0042] This invention provides a nano-organic selenium fertilizer prepared by the preparation method described above, wherein the average particle size of the nano-organic selenium fertilizer is 65.6 nm, and the weight content of the nano-organic selenium fertilizer with a particle size of 30-100 nm is >93%.

[0043] This invention provides a method for improving crop yield and quality, comprising: diluting nano-organic selenium fertilizer and spraying it onto the leaves of crops; wherein the nano-organic selenium fertilizer is the nano-organic selenium fertilizer prepared by the method described in the above technical solution.

[0044] In this invention, the dilution ratio is preferably 800 to 1000 times, more preferably 800 times; the spraying period is preferably during the flowering and fruit setting period, the number of sprayings is preferably 2 to 3 times, more preferably 2 times, and the interval between each spraying is preferably 10 to 15 days, more preferably 10 days; the crop is preferably tomato or melon.

[0045] The method provided by this invention can promote crop growth, increase crop yield, and improve crop quality.

[0046] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, describes a nano-organic selenium fertilizer, its preparation method, and its application, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0047] Example 1

[0048] A nano-organic selenium fertilizer is prepared according to the following parts by weight: 1 part sodium selenite, 5 parts glucose, 7 parts urea, 2 parts potassium dihydrogen phosphate, 0.2 parts sodium naphthaleneacetate, and 0.15 parts potassium indolebutyrate. The preparation method is as follows:

[0049] After the components are mixed evenly in proportion, they are pulverized by a pulverizer to a particle size of less than 100 mesh and then bagged.

[0050] The bagged raw materials were placed at 45°C for 12 hours, during which time the raw materials changed from white to reddish-brown (see...). Figure 1 The white substance in the bag on the right is the raw material for preparation before thermal catalysis, and the reddish-brown substance on the left is the raw material for preparation after thermal catalysis (i.e., nano-organic selenium fertilizer), thus obtaining the nano-organic selenium fertilizer.

[0051] Example 2

[0052] A nano-organic selenium fertilizer is prepared according to the following parts by weight: 0.5 parts sodium selenite, 3 parts glucose, 5 parts urea, 3 parts potassium dihydrogen phosphate, 0.1 parts sodium naphthaleneacetate, and 0.2 parts potassium indolebutyrate. The preparation method is as follows:

[0053] After the components are mixed evenly in proportion, they are pulverized by a pulverizer to a particle size of less than 100 mesh and then bagged.

[0054] The bagged raw materials were placed in an environment of 43°C for 16 hours, and the raw materials changed from white to reddish-brown, thus obtaining the nano-organic selenium fertilizer.

[0055] Example 3

[0056] A nano-organic selenium fertilizer is prepared according to the following parts by weight: 0.8 parts sodium selenite, 3 parts glucose, 7 parts urea, 3 parts potassium dihydrogen phosphate, 0.15 parts sodium naphthaleneacetate, and 0.2 parts potassium indolebutyrate. The preparation method is as follows:

[0057] After the components are mixed evenly in proportion, they are pulverized by a pulverizer to a particle size of less than 200 mesh and then packaged.

[0058] The bagged raw materials were placed in an environment of 45°C for 12 hours, and the raw materials changed from white to reddish-brown, thus obtaining the nano-organic selenium fertilizer.

[0059] Example 4

[0060] A nano-organic selenium fertilizer is prepared according to the following parts by weight: 0.75 parts sodium selenite, 4 parts glucose, 6 parts urea, 2 parts potassium dihydrogen phosphate, 0.2 parts sodium naphthaleneacetate, and 0.3 parts potassium indolebutyrate. The preparation method is as follows:

[0061] After the components are mixed evenly in proportion, they are pulverized by a pulverizer to a particle size of less than 200 mesh and then packaged.

[0062] The bagged raw materials were placed in an environment of 44°C for 16 hours, and the raw materials changed from white to reddish-brown, thus obtaining the nano-organic selenium fertilizer.

[0063] Example 5

[0064] A nano-organic selenium fertilizer is prepared according to the following parts by weight: 0.6 parts sodium selenite, 4 parts glucose, 6 parts urea, 3 parts potassium dihydrogen phosphate, 0.2 parts sodium naphthaleneacetate, and 0.15 parts potassium indolebutyrate. The preparation method is as follows:

[0065] After the components are mixed evenly in proportion, they are pulverized by a pulverizer to a particle size of less than 200 mesh and then packaged.

[0066] The bagged raw materials were placed at 45℃ for 15 hours, during which time the raw materials changed from white to reddish-brown. Figure 1 Thus, the nano-organic selenium fertilizer is obtained.

[0067] Example 6

[0068] A nano-organic selenium fertilizer is prepared according to the following parts by weight: 0.9 parts sodium selenite, 5 parts glucose, 5 parts urea, 3 parts potassium dihydrogen phosphate, 0.2 parts sodium naphthaleneacetate, and 0.2 parts potassium indolebutyrate. The preparation method is as follows:

[0069] After the components are mixed evenly in proportion, they are pulverized by a pulverizer to a particle size of less than 200 mesh and then packaged.

[0070] The bagged raw materials were placed in an environment of 45°C for 16 hours, and the raw materials changed from white to reddish-brown, thus obtaining the nano-organic selenium fertilizer.

[0071] Comparative Example 1

[0072] An inorganic selenium foliar fertilizer is prepared according to the following weight proportions: 0.6 parts sodium selenite, 4 parts glucose, 6 parts urea, 3 parts potassium dihydrogen phosphate, 0.2 parts sodium naphthaleneacetate, and 0.15 parts potassium indolebutyrate. The preparation method is as follows:

[0073] After the components are mixed evenly in proportion, they are pulverized by a pulverizer to a particle size of less than 200 mesh and then bagged.

[0074] Comparative Example 2

[0075] A nano-organic selenium fertilizer is prepared according to the following parts by weight: 0.6 parts sodium selenite, 4 parts glucose, 6 parts urea, 3 parts potassium dihydrogen phosphate, 0.2 parts sodium naphthaleneacetate, and 0.15 parts potassium indolebutyrate. The preparation method is as follows:

[0076] After the components are mixed evenly in proportion, they are pulverized by a pulverizer to obtain a particle size of less than 200 mesh, thus obtaining a mixture.

[0077] The mixture is combined with water and then packaged; the weight ratio of the mixture to water is 1:4.

[0078] The bagged raw materials were placed in an environment of 45°C for 15 hours, and the raw materials changed from white to reddish-brown liquid fertilizer, thus obtaining the nano-organic selenium fertilizer.

[0079] Test Example 1

[0080] The particle size of the nano-organic selenium fertilizer prepared in Example 5 was determined using a laser particle size analyzer (NS-90Plus nanoparticle size analyzer). The results are as follows: the average particle size was 65.6 nm, of which >93% were distributed in the range of 30–100 nm (see...). Figure 2 and Figure 3 ).

[0081] Test Example 2

[0082] The nano-organic selenium fertilizers prepared in Example 5 and Comparative Example 2 were diluted 500 times with water, dissolved, and left to stand for 48 hours. The results are shown in the figure. Figure 4 , Figure 4 The bag on the left shows the nano-organic selenium fertilizer prepared in Example 5, and the bag on the right shows the nano-organic selenium fertilizer prepared in Comparative Example 2. The measuring cylinder on the left shows the result of diluting the nano-organic selenium fertilizer prepared in Example 5 by 500 times and letting it stand for 48 hours, and the measuring cylinder on the right shows the result of diluting the nano-organic selenium fertilizer prepared in Comparative Example 2 by 500 times and letting it stand for 48 hours.

[0083] Depend on Figure 4 It can be seen that the nano-organic selenium fertilizer prepared in Example 5 of the present invention has a small amount of precipitation after dilution, and most of the fertilizer is still in a dissolved state; the nano-organic selenium fertilizer prepared in Comparative Example 2 has a large amount of precipitation after dilution, and only a small part is in a dissolved state.

[0084] The above results demonstrate that the present invention utilizes urea to slowly absorb water, and the resulting nano-selenium particles are small, with a large proportion of organic selenium formed by combining with glucose, and most of it is in a dissolved state.

[0085] Test Example 3

[0086] The nano-organic selenium fertilizer prepared in Example 5 was dissolved at 800 times the concentration and left to stand for 36 hours. Only a small amount of precipitate was observed, indicating that the solid thermocatalyzed fertilizer has stronger liquid stability than the foliar fertilizer reacted at high temperature and is less likely to combine into large particles and precipitate.

[0087] Test Example 2

[0088] Test crop: Tomato (Jingzun 108).

[0089] Experimental fertilizers: 30g per mu of nano-organic selenium fertilizer (organic nano-selenium fertilizer) prepared in Example 5; 30g per mu of inorganic selenium foliar fertilizer prepared in Comparative Example 1.

[0090] Selection of test site:

[0091] In the greenhouse base in Grape Township, Turpan City, the owner is Guo Moumou. The soil fertility is moderately high. 8 cubic meters of organic fertilizer were applied per mu in autumn. The farmer's usual fertilization methods included the following base fertilizer application per mu: 75 kg superphosphate, 25 kg potassium fertilizer, 2 kg boron fertilizer, 2 kg zinc fertilizer, and 3 kg magnesium sulfate.

[0092] Seedlings were started in nutrient bags on January 15, 2020. Transplanting took place on February 24, 2020. Row spacing was 60cm, row width 70cm, and plant spacing 35cm. 3000 seedlings were transplanted per acre. The first watering was on March 16. The second watering was on April 5, followed by watering every 12 days until watering ceased on May 23. A total of 6 waterings were conducted. 20 kg / acre of a solanaceous fertilizer was applied with each watering. Weeding was done once, pruning was done 3 times, and pest and disease control was carried out 5 times. The first harvest began on May 6, 2020, and harvesting was completed before June 15, 2020.

[0093] The experiment consisted of three treatments: foliar spraying of the experimental fertilizer and an equal volume of water (control group). Each treatment plot was 40 m² in size. 2 Arrangement and fertilization method: The experimental fertilizer was diluted 800 times and sprayed twice during the flowering and fruit setting period, with an interval of 10 days between each application; Experiment period: March 15, 2020 to May 25, 2020.

[0094] Statistics and Surveys

[0095] Plant height, stem diameter, single fruit weight, number of fruits per plant, yield per plant, commercial yield and quality analysis (VC, soluble sugar, titratable acid, soluble solids, lycopene).

[0096] Determination methods: Single fruit weight was determined by weighing method; total sugar was determined by Fehling's method; titratable acid was determined by acid-base titration method; vitamin C was determined by sodium dichloroindophenol titration method; soluble solids content was determined by handheld glycoside analyzer; and lycopene was determined by Sudan Red colorimetric method.

[0097] The selenium content in tomatoes was determined according to the national standard GB 5009.93-2017 "Determination of Selenium in Food - Method I: Hydride Atomic Fluorescence Spectrometry".

[0098] Statistics were performed using Excel and DPS software.

[0099] Results and Analysis

[0100] Table 1. Effects of different treatments on crop biological traits

[0101]

[0102] Table 1 shows that both organic nano-selenium foliar fertilizer and inorganic selenium foliar fertilizer increased the plant height of tomato plants, but there was no significant difference between the treatments (P>0.05). Leaf color was darker in the organic nano-selenium foliar fertilizer and treatments, and the fruits were more uniform. In contrast, the control group had yellowish leaves, and the fruits were less uniform in size and shape. Therefore, considering the entire growth period, the application of organic nano-selenium foliar fertilizer, in addition to farmers' usual fertilization practices, has a certain promoting effect on various growth indicators of tomatoes.

[0103] The effects of organic nano-selenium foliar fertilizer on the single fruit weight of tomato are shown in the results. Figure 5 ,from Figure 5 It can be seen that the single fruit weight of each treatment was 166.99g, 187.62g, and 174.64g, respectively. The organic nano-selenium foliar fertilizer and inorganic selenium foliar fertilizer treatments increased by 20.63g and 7.65g / fruit, respectively, compared with the control, with increases of 10.99% and 4.38%, respectively. The organic nano-selenium foliar fertilizer treatment showed a significant difference compared with the control (P<0.05), while there was no significant difference between the control and inorganic selenium foliar fertilizer (P>0.05).

[0104] The effect of organic nano-selenium foliar fertilizer on the number of tomatoes is shown in the results. Figure 6 ,from Figure 6 It can be seen that the number of fruits in each treatment was 12.40, 14.07, and 13.20, respectively. The number of fruits in the organic nano-selenium foliar fertilizer and inorganic selenium foliar fertilizer increased by 1.67 and 0.80, respectively, compared with the control, with increases of 11.85% and 6.06%, respectively. The organic nano-selenium foliar fertilizer treatment showed a significant difference compared with the inorganic selenium foliar fertilizer treatment (P<0.05), while there was no significant difference between the control and the inorganic selenium foliar fertilizer treatment (P>0.05).

[0105] The results of the effect of organic nano-selenium foliar fertilizer on the yield of single tomato plants are shown in the figure. Figure 7 ,from Figure 7 It can be seen that the yield per plant in each treatment was 2.071, 2.577, and 2.305 kg / plant, respectively. The organic nano-selenium foliar fertilizer and inorganic selenium foliar fertilizer increased the yield per plant by 0.506 and 0.234 kg / plant, respectively, compared with the control, with increases of 19.64% and 10.18%, respectively. The organic nano-selenium foliar fertilizer treatment showed a highly significant difference compared with the control (P<0.01), while the control showed a significant difference compared with the inorganic selenium foliar fertilizer (P<0.05). The organic nano-selenium foliar fertilizer significantly increased the yield per plant compared with the inorganic selenium foliar fertilizer (P<0.05), but did not reach the highly significant level (P>0.01).

[0106] The effects of organic nano-selenium foliar fertilizer on tomato quality are shown in Table 2.

[0107] Table 2. Quality Analysis Results of Tomatoes

[0108]

[0109] Note: Different lowercase letters in the table indicate significant differences (P<0.05); uppercase letters indicate extremely significant differences (P<0.05). The same applies to the following table.

[0110] The indicators characterizing tomato quality were total sugar, vitamin C, soluble sugar, soluble solids, titratable acid, solid-acid ratio, and lycopene. Table 2 shows that nano-selenium fertilizer had a certain effect on increasing soluble sugar (see Table 2). Compared with the control, the treatments increased by 0.12 and 0.06%, with increases of 3.82 and 2.03%, respectively, but the differences were not statistically significant (P>0.05). The vitamin C content of each treatment was 6.97, 16.07, and 10.76 mg / 100g, respectively, an increase of 9.10 and 3.749 mg / 100g compared with the control, representing increases of 13%. The organic nano-selenium foliar fertilizer and the control showed highly significant differences in soluble solids content (P<0.01), with the organic nano-selenium foliar fertilizer and inorganic selenium foliar fertilizer treatments showing no difference compared to the control (P>0.05). Among all treatments, the control had the highest titratable acid content, while the organic nano-selenium foliar fertilizer had the lowest, but there was no significant difference between the treatments (P>0.05). The organic nano-selenium foliar fertilizer showed a slightly higher solid-acid ratio than the control, but there was no significant difference (P>0.05).

[0111] The application of organic nano-selenium foliar fertilizer significantly increased the vitamin C and lycopene content of tomatoes, while having no significant effect on the solid-acid ratio, soluble sugar content, soluble solids, and titratable acidity. Lycopene and vitamins are important indicators for measuring tomato nutrition, and both indicators showed highly significant differences compared to the control, demonstrating that organic nano-selenium foliar fertilizer treatment has a positive effect on improving tomato quality.

[0112] The effects of organic nano-selenium foliar fertilizer on the selenium content in tomatoes are shown in Table 3.

[0113] Table 3 Selenium content in tomatoes

[0114] deal with Comparison Organic nano selenium fertilizer Inorganic selenium foliar fertilizer Selenium content (μg / kg) 4.3±1.2cC 59.5±5.3aA 23.6±4.9bB

[0115] As shown in Table 3, the selenium content of each treatment was 4.3, 69.5, and 23.6 μg / kg. The organic nano-selenium foliar fertilizer and inorganic selenium foliar fertilizer both met the standard for selenium-enriched vegetables (>10 μg / kg) compared with the control, with increases of 55.2 and 19.3 μg / kg, respectively. The organic nano-selenium foliar fertilizer treatment showed a highly significant difference compared with the control (P<0.01), and the selenium content per plant of organic nano-selenium foliar fertilizer was significantly different from that of inorganic selenium foliar fertilizer (P<0.01), indicating that tomato plants have a relatively strong ability to absorb organic nano-selenium.

[0116] In conclusion, organic nano-selenium foliar fertilizer treatment can significantly increase single fruit weight and fruit setting rate, thereby significantly improving tomato yield. It also increases the content of vitamin C, lycopene, and selenium in tomatoes, resulting in a significant overall improvement in tomato quality.

[0117] Test Example 3

[0118] Test crop: Melon (Xizhoumi 25).

[0119] Experimental fertilizers: 30g per mu of nano-organic selenium fertilizer (organic nano-selenium fertilizer) prepared in Example 5; 30g per mu of inorganic selenium foliar fertilizer prepared in Comparative Example 1.

[0120] Experimental Site Selection: The test site had high soil fertility, with 20 cubic meters of organic fertilizer per mu (approximately 0.16 acres). The site was located in a 10,000-mu (approximately 667-acre) greenhouse base in Turpan City, owned by Mr. Li. Transplanting took place on August 15th, and the seedlings had been cultivated for 22 days at the Turpan Regional Science and Technology Park Seedling Center.

[0121] The experiment consisted of three treatments: foliar spraying of the experimental fertilizer and an equal volume of water (control group). The three treatments were arranged in plots of 0.3 acres each. The fertilization method was basal application (fertilizer applied on raised beds). The experimental fertilizer was diluted 800 times and applied twice during the flowering and fruit setting period, with an interval of 10 days between each application. The experiment was conducted from August 15, 2020 to November 15, 2020.

[0122] Statistics and Surveys

[0123] Analysis of melon length, width, single fruit weight, marketable melon yield, and quality (VC, soluble sugar, titratable acid, soluble solids).

[0124] Determination methods: Single fruit weight was determined by weighing method; total sugar was determined by Fehling's method; titratable acid was determined by acid-base titration method; vitamin C was determined by sodium dichloroindophenol titration method; and soluble solids content was determined by handheld saccharimeter.

[0125] The selenium content in tomatoes was determined using the national standard GB5009.93-2017 "Determination of Selenium in Food - Method I: Hydride Atomic Fluorescence Spectrometry".

[0126] Statistics were performed using Excel and DPS software.

[0127] Results and Analysis

[0128] The results of the effect of organic nano-selenium foliar fertilizer on melon growth are shown in Figure 8 ,from Figure 8It can be seen that the melon lengths of the treatments were 18.52, 17.69, and 17.20 cm, respectively, which were 1.32 and 0.49 cm longer than the control (CK), with increases of 7.67% and 2.85%, respectively. However, there were no significant differences between treatments A and B and the control (CK) (P<0.05).

[0129] The results of the effect of organic nano-selenium foliar fertilizer on melon width are shown in Figure 9 ,from Figure 9 It can be seen that the melon lengths of the treatments were 17.31, 16.89, and 16.94 cm, respectively. Treatment B increased by 0.37 cm compared to the control, but the difference was not statistically significant (P<0.05). Treatment A showed little difference compared to the control.

[0130] The effects of organic nano-selenium foliar fertilizer on the single fruit weight of melon are shown in the results. Figure 10 ,from Figure 10 It can be seen that the single fruit weights of CK, A, and B treatments were 2.025, 2.196, and 2.286 kg, respectively. Compared with CK, treatments A and B increased by 0.171 and 0.261 kg / fruit, respectively, with increases of 7.48% and 12.9%. The difference between treatment B and CK was statistically significant (P<0.05).

[0131] The effects of organic nano-selenium foliar fertilizer on the quality of melons are shown in Table 4.

[0132] Table 4 Quality Analysis of Melon

[0133] detection indicators Soluble solids (%) Vitamin C (mg / 100g) Total sugar (%) Titratable acid (%) B 17.8±0.44b 16.6±1.08b 12.90±0.36a 0.178±0.064a A 17.5±0.36b 14.7±1.31a 13.13±0.23a 0.180±0.048a CK 16.3±0.40a 14.5±0.86a 12.68±0.75a 0.184±0.38a

[0134] Generally, the indicators for characterizing melon quality are total sugar, vitamin C, and total sugar and soluble solids. The results in Table 4 show that organic nano-selenium foliar fertilizer has a certain effect on increasing total sugar (see Table 4). Compared with the control (CK), treatment A increased by 0.45% and 0.22%, and treatment B by 3.55% and 1.73%, respectively, but the difference was not statistically significant (P<0.05). Treatment B increased vitamin C by 2.1 mg / 100g compared to CK, an increase of 14.48%, which was statistically significant (P<0.05). Soluble solids in both treatments A and B increased compared to the control, and treatment B showed a statistically significant difference compared to CK (P<0.05). Treatments CK, A, and B had little effect on titratable acid content (P<0.05).

[0135] Overall, the use of organic nano-selenium foliar fertilizer can increase soluble solids and vitamin C content, thereby improving the quality of melons.

[0136] The effects of organic nano-selenium foliar fertilizer on the selenium content in melons are shown in Table 5.

[0137] Table 5 Selenium content in tomatoes

[0138] deal with Comparison A Inorganic Selenium Foliar Fertilizer B Organic Nano Selenium Fertilizer Selenium content (μg / kg) 2.6±0.4cC 13.9±1.6bB 31.5±2.7aA

[0139] As shown in Table 5, the selenium content of each treatment was 2.6, 69.5, and 23.6 μg / kg. The organic nano-selenium foliar fertilizer and the commercially available inorganic selenium foliar fertilizer both met the standard for selenium-enriched vegetables (>10 μg / kg) compared with the control, with increases of 65.2 and 19.3 μg / kg, respectively. The organic nano-selenium foliar fertilizer treatment showed a highly significant difference compared with the control (P<0.01), and the selenium content per plant of the organic nano-selenium foliar fertilizer was also highly significant compared with the commercially available inorganic selenium foliar fertilizer (P<0.01), indicating that tomato plants have a relatively strong ability to absorb organic nano-selenium.

[0140] The results of the effect of organic nano-selenium foliar fertilizer on the yield of commercial melons are shown in the figure. Figure 11 The commercial yield of melons refers to the melons meeting commercial requirements (20 yuan / kg) in terms of appearance (uniform netting, consistent color, no cracks) and quality (sugar content). Figure 11 It can be seen that the marketable melon yields of treatments CK, A, and B were 810.4, 1043.6, and 994.8 kg / mu, respectively. Treatments A and B yielded 233.2 and 184.4 kg / mu more than CK, respectively, with yield increases of 28.76% and 22.75%. Treatments A and B showed significant differences compared to CK (P<0.05).

[0141] In conclusion, the application of organic nano-selenium foliar fertilizer significantly increased the yield of marketable melons and improved their quality to a certain extent, while also ensuring that the selenium content of the melons met the selenium enrichment standard.

[0142] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a nano-organic selenium fertilizer, characterized in that, The components of the raw materials are mixed and pulverized to a particle size of less than 200 mesh, and then reacted at a temperature of 43-45℃ for 12-16 hours to obtain the nano-organic selenium fertilizer. The raw materials consist of the following components in parts by weight: 0.5-1 parts sodium selenite, 3-5 parts glucose, 5-7 parts urea, 2-3 parts potassium dihydrogen phosphate, 0.1-0.2 parts sodium naphthaleneacetate, and 0.15-0.3 parts potassium indolebutyrate. The average particle size of the nano-organic selenium fertilizer is 65.6 nm, and the weight content of nano-organic selenium fertilizer with a particle size of 30-100 nm is >93%.

2. A method for improving crop yield and quality, characterized in that, include: The nano-organic selenium fertilizer is diluted and sprayed onto the leaves of crops; the nano-organic selenium fertilizer is the nano-organic selenium fertilizer prepared by the method described in claim 1.

3. The method according to claim 2, characterized in that, The dilution factor is 800 to 1000 times.

4. The method according to claim 2, characterized in that, The spraying period is during the flowering and fruit setting stage, and the number of sprayings is 2 to 3 times, with an interval of 10 to 15 days between each spraying.

5. The method according to claim 2 or 4, characterized in that, The crops mentioned include tomatoes or melons.

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