Special potassium-promoting signal substance-containing sustained and controlled release bulk blending fertilizer for flue-cured tobacco and preparation method thereof

Abstract

The invention discloses a special potassium-promoting signal substance-containing slow / controlled-release bulk blending fertilizer for flue-cured tobacco and a preparation method thereof, and belongs to the technical field of controlled-release fertilizer production. The coated controlled-release potash fertilizer is prepared by adding signal substances, and the utilization rate of the fertilizer can be effectively improved. Signal substances including citric acid, lauric acid, rutin, glutamic acid and berberine are synchronously released along with the potash fertilizer, and the citric acid and the lauric acid promote the activity of microorganisms and enhance the mineral dissolving capacity of the microorganisms through soil acidification and chelation, so that the nutrient absorption of plants is improved; rutin and glutamic acid significantly improve the absorption efficiency of potassium ions by adjusting the ion permeability of plant roots and the activity of transporter, and berberine further optimizes the absorption, transport and distribution of potassium ions by adjusting calcium and potassium transport systems in cells. The absorption and utilization of potassium ions by tobacco plants are improved, and the quality of tobacco leaves is improved.

Description

Technical Field

[0001] The invention relates to the technical field of slow-release fertilizer production, and in particular to a slow-release mixed fertilizer containing potassium-promoting signal substances specially used for flue-cured tobacco and a preparation method thereof. Background Art

[0002] Potassium ions are an important factor affecting the quality of flue-cured tobacco leaves. They can improve the color, combustibility and hygroscopicity of tobacco leaves, and promote the synthesis and accumulation of some aromatic substances. Potassium plays a key role in the growth and development of tobacco. It participates in the metabolism and transportation of substances in tobacco and can improve the root vitality of tobacco plants. Potassium ions can also change the expression of genes involved in plant physiological processes, thereby causing changes in the physiology and morphology of tobacco plants. Potassium deficiency will have an adverse effect on the growth of tobacco plants and the quality of tobacco leaves.

[0003] Due to the differences in soil environment and climatic conditions, compared with foreign tobacco leaves, Chinese flue-cured tobacco leaves generally have a low potassium content. According to statistics, the total potassium content in the soil nationwide is 0.05%-2.50%, and the quick-acting potassium content in tobacco fields is mostly 100-150mg / kg. Therefore, under the condition that the soil potassium content is not high, the application of potassium fertilizer is an indispensable measure to improve the quality of tobacco leaves.

[0004] Applying slow / controlled release potassium fertilizer to improve the potassium nutrition of flue-cured tobacco has become a hot topic in the research of potassium nutrition of flue-cured tobacco. At present, there are also some reports on the use of slow / controlled release potassium fertilizer in tobacco production. However, the potassium content in tobacco does not change regularly due to the increase in potassium dosage. The potassium supply characteristics of the soil will affect the potassium content of tobacco leaves. The potassium in tobacco soil in Yunnan, my country often exists in the form of minerals and is not easily absorbed directly by plants. The calcium and magnesium content in the calcareous soil in the north is relatively high, which will hinder the absorption and utilization of potassium by tobacco plants. Although the existing slow / controlled release potassium fertilizer can control the release rate and release cycle of potassium to a certain extent, due to the lack of interaction with tobacco plants and soil, the absorption and utilization efficiency of potassium ions by tobacco plants still needs to be further improved. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the object of the present invention is to provide a slow-release blended fertilizer containing potassium-promoting signal substances specially used for flue-cured tobacco and a preparation method thereof.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] In a first aspect of the present invention, there is provided a coated controlled-release potassium fertilizer containing a potassium-promoting signal substance, which is prepared by the following method:

[0008] The signal substance is added to the sodium alginate-starch adhesive and dispersed evenly to obtain a first coating liquid, and the first coating liquid is sprayed onto the surface of the potash fertilizer particles to form a first coating layer;

[0009] The polyurea SA component and the modified polyurea SB component are mixed to obtain a second coating liquid, and the second coating liquid is continuously sprayed onto the surface of the potash fertilizer particles to form a second coating layer; thus, a coated controlled-release potash fertilizer containing a potassium-promoting signal substance is prepared.

[0010] The signal substance is composed of a signal substance A, a signal substance B and a signal substance C; wherein the signal substance A is selected from one or more of jasmonate, citric acid and lauric acid; the signal substance B is selected from one or more of rutin, naringenin and glutamic acid; the signal substance C is selected from one or more of berberine, cyclic adenosine monophosphate and cyclic guanosine monophosphate.

[0011] Preferably, the signal substance consists of signal substance A, signal substance B and signal substance C in a weight ratio of 1:1:1.

[0012] Among the signal substances of the present invention, signal substance A is used to increase the content of available potassium in soil; signal substance B is used to promote the absorption of potassium by tobacco roots; and signal substance C is used to increase the transport of potassium in tobacco. The three types of signal substances interact with each other and jointly improve the utilization efficiency of potassium by tobacco.

[0013] More preferably, the signal substance A is composed of citric acid and lauric acid in a weight ratio of 2:1; the signal substance B is composed of rutin and glutamic acid in a weight ratio of 1:2; and the signal substance C is berberine.

[0014] After citric acid and lauric acid enter the soil, they promote actinomycetes and Bacillus to produce organic acids, which can react with metal ions in minerals to form metal-organic complexes, thereby destroying the structure of minerals, promoting the release of potassium in minerals, and increasing the available potassium content in the soil;

[0015] Rutin can regulate the activity of antioxidant enzymes, induce ROS accumulation, activate potassium transporter genes of the KUP / HAK / KT family, and promote the absorption of potassium ions by the roots. Glutamate can enhance the activity of the H+ / K+ exchange system and regulate the activity of ATPase, thereby increasing the potassium ion permeability of root cells and improving the absorption efficiency of potassium ions by plant roots, thereby promoting the absorption efficiency of potassium by tobacco roots.

[0016] Berberine increases the intracellular calcium ion concentration by regulating the activity of sodium-calcium exchanger (NCX), further activates calcium-dependent protein kinase, and phosphorylates potassium transporter, thereby optimizing the absorption, transport and distribution of potassium ions in the plant body and improving the efficiency of potassium operation in tobacco.

[0017] The above-mentioned preferred signal substance A, signal substance B and signal substance C are composed of a weight ratio of 1:1:1 as signal substances. When in use, the signal substance and potassium fertilizer are dissolved with water, and the signal substance A (citric acid and lauric acid) dissolves the potassium ions fixed by soil minerals; the signal substance B (rutin and glutamic acid) further promotes the tobacco root system to absorb and utilize the potassium ions dissolved from the potassium fertilizer and soil; the signal substance C (berberine) further transports and distributes the potassium absorbed by the root system, thereby increasing the potassium accumulation in the tobacco leaves, thereby improving the quality of the tobacco leaves.

[0018] Preferably, the sodium alginate-starch adhesive is prepared by the following method:

[0019] Potassium permanganate is added to the starch slurry, stirred evenly, reacted for 1-2 hours, filtered to obtain a clear solution; sodium alginate is added to the clear solution, stirred to prepare a sodium alginate-starch adhesive.

[0020] Potassium permanganate destroys the macromolecular structure of corn starch through oxidation reaction, causing it to form smaller polymers or functional groups, thereby improving the binding ability of starch with other substances and increasing the bonding strength of the adhesive.

[0021] Preferably, the weight ratio of potassium permanganate, starch and sodium alginate added is 0.5:5:3.

[0022] Signal substances are prone to oxidation reactions at high temperatures and in the presence of oxygen, causing them to lose their activity or function. In order to maintain the performance stability of the signal substance, the present invention uses the signal substance together with a sodium alginate-starch adhesive. Sodium alginate has the ability to scavenge free radicals. Sodium alginate can react with free radicals through the carboxyl (-COOH) and alcohol hydroxyl (-OH) in its structure to reduce the content of free radicals, thereby inhibiting the oxidation of the signal substance and protecting the signal substance.

[0023] Preferably, the weight ratio of the signal substance to the sodium alginate-starch adhesive is (0.5-1.5):2; and the spraying amount of the first coating liquid is 1-2% of the weight of the potash fertilizer particles.

[0024] Preferably, the modified polyurea SB component is prepared by the following method:

[0025] The modifier is added to the polyurea SB component and dispersed uniformly by ultrasonication in a water bath at 25° C.; the modifier is one or more of graphene oxide, glass fiber powder, bentonite, aminosilane, and paraffin.

[0026] More preferably, the modifier consists of graphene oxide, glass fiber powder and bentonite in a weight ratio of 1:1:1; or, consists of aminosilane and paraffin in a weight ratio of 1:1.

[0027] Graphene oxide contains a large number of oxidized groups, such as carboxyl (–COOH), hydroxyl (–OH) and epoxy (–C–O–C). These functional groups can react with amino (–NH2) or isocyanate groups (–NCO) in polyurea to form covalent bonds or hydrogen bonds, which helps to improve the mechanical strength, conductivity, thermal stability and other properties of polyurea composites. Glass fiber powder forms active groups amino or hydroxyl groups under the action of surface coupling agents, which can react with amino or isocyanate groups in polyurea to form chemical bonds. This chemical connection enhances the mechanical properties of the composite. Bentonite has a layered structure and a large specific surface area. Its surface can undergo physical adsorption or chemical reaction with polyurea. The hydroxyl groups in bentonite form hydrogen bonds with amino (–NH2) or isocyanate groups in polyurea. The layered structure of bentonite can improve the structural stability of the composite material and improve the crack resistance and anti-aging properties of polyurea. The combination of graphene oxide, glass fiber powder and bentonite with polyurea not only improves the mechanical properties of polyurea, but also enhances its thermal stability, corrosion resistance and durability.

[0028] The aminosiloxane molecule has a siloxane group (Si–O–Si) that can chemically bond with inorganic materials, while its amino group (–NH2) can react with the isocyanate group (–NCO) in polyurea to form a urea group (–NH–CO–NH–). This reaction can enhance the bonding force between polyurea and the aminosiloxane surface, and improve the interfacial adhesion and overall mechanical properties of the composite material. The lubricity of paraffin can reduce the friction coefficient of the polyurea surface, improve the surface smoothness of the composite material, reduce wear and friction, and paraffin itself has strong hydrophobicity, so it can improve the hydrophobicity of polyurea and reduce the interaction between the polyurea surface and water molecules. When aminosiloxane and paraffin work together to combine with polyurea, the interfacial bonding force between polyurea and other materials is enhanced through the coupling effect of aminosiloxane, and the surface properties and durability of polyurea are improved through the lubricity and hydrophobicity of paraffin. The synergistic effect of the two can significantly improve the mechanical properties, thermal stability, water resistance, corrosion resistance and wear resistance of polyurea composite materials.

[0029] More preferably, the weight ratio of the modifier to the polyurea SB component is 1:10.

[0030] Preferably, the polyurea SA component and the modified polyurea SB component are mixed in a weight ratio of 1:1; and the spraying amount of the second coating liquid is 3-7% of the weight of the potash fertilizer particles.

[0031] The second aspect of the present invention provides the use of the above-mentioned coated controlled-release potassium fertilizer containing potassium-promoting signal substances in the following (1) or (2):

[0032] (1) Improve tobacco's absorption and utilization of potassium ions;

[0033] (2) Preparation of slow-release and controlled-release blended fertilizers for flue-cured tobacco.

[0034] The third aspect of the present invention provides a slow-release and controlled-release blended fertilizer for flue-cured tobacco, comprising the following components in parts by weight:

[0035] 38-42 parts of nitrogen, phosphorus and potassium compound fertilizer, 35-50 parts of coated controlled-release potassium fertilizer containing potassium-promoting signal substances, 15-30 parts of coated controlled-release ammonium nitrate, 10-20 parts of coated controlled-release diammonium phosphate, 1-5 parts of boron fertilizer, and 1-3 parts of molybdenum fertilizer.

[0036] Preferably, the coated controlled-release ammonium nitrate is prepared by the following method:

[0037] The second coating liquid is sprayed on the surface of the ammonium nitrate particles, and the spraying amount of the second coating liquid is 3-7% of the weight of the ammonium nitrate particles to prepare coated controlled-release ammonium nitrate.

[0038] Preferably, the coated controlled-release diammonium phosphate is prepared by the following method:

[0039] The second coating liquid is sprayed on the surface of the diammonium phosphate particles, and the spraying amount of the second coating liquid is 3-7% of the weight of the diammonium phosphate particles to prepare coated controlled-release diammonium phosphate.

[0040] Preferably, the nitrogen, phosphorus and potassium compound fertilizer is a tobacco-specific compound fertilizer (N-P2O5-K2O-15-8-25).

[0041] Beneficial effects of the present invention:

[0042] (1) The present invention can effectively improve fertilizer utilization by adding signal substances to prepare coated potassium sulfate containing potassium signal substances. The signal substances citric acid, lauric acid, rutin, glutamic acid, and berberine are released synchronously with potassium fertilizers. Citric acid and lauric acid promote the activity of microorganisms and enhance their mineral solubility through soil acidification and chelation, thereby improving plant nutrient absorption; rutin and glutamic acid significantly improve the absorption efficiency of potassium ions by regulating the ion permeability of plant roots and the activity of transport proteins, and berberine further optimizes the absorption, transport and distribution of potassium ions by regulating the calcium and potassium transport systems in cells. The interaction of these three types of signal substances forms a complex ecological network, which promotes plant nutrient absorption, microbial activities, and soil nutrient cycles, improves tobacco plants' absorption and utilization of potassium ions, and improves tobacco leaf yield and quality.

[0043] (2) Signal substances participate in physiological processes such as cell signal transduction and information transmission in an active state, but are prone to oxidation reactions at high temperatures and in the presence of oxygen, causing them to lose their activity or function. In order to maintain the stability of the signal substances, it is necessary to add suitable protective agents to the easily oxidized environment. The present invention uses the signal substance together with a sodium alginate-starch adhesive. Sodium alginate has the ability to scavenge free radicals. Sodium alginate can react with free radicals through the carboxyl (-COOH) and alcohol (-OH) groups in its structure, thereby inhibiting the oxidation process. The sodium alginate and starch composite coated signal substance can not only protect the signal substance, but also be enzymatically hydrolyzed or hydrolyzed with starch in the soil to produce polysaccharides. The polysaccharides can adsorb organic acids and adhere to the surface of minerals, thereby promoting the decomposition of potassium-containing minerals and improving the utilization efficiency of potassium.

[0044] (3) After the controlled-release fertilizer made of polyurea material as the membrane material is applied to the soil, its volume continues to swell as water infiltrates the soil, causing the pores of the membrane to become larger, thereby accelerating the release of nutrients and reducing the controlled-release period of the controlled-release fertilizer. The present invention modifies the polyurea material by adding a modifier, thereby improving the mechanical strength, hardness, wear resistance and thermal stability of the polyurea, effectively improving the hydrophobicity of the polyurea material, optimizing the problem of enlarged membrane pores caused by the high elasticity of the polyurea material, and extending the controlled-release period.

[0045] (4) Based on the coated controlled-release potassium fertilizer containing potassium-promoting signal substances prepared by the present invention, the present invention also provides a slow-release and controlled-release blended fertilizer specifically for flue-cured tobacco. Compared with the existing compound fertilizers, the nutrient release of the slow-release and controlled-release blended fertilizer specifically for flue-cured tobacco of the present invention is more in line with the fertilizer requirement law of flue-cured tobacco at different growth stages, and meets the physiological characteristics of tobacco at different growth stages. The slow-release and controlled-release potassium fertilizer is released synchronously with the signal substances to jointly promote plant growth, meet the demand of tobacco for potassium fertilizer in the later stage, improve fertilizer utilization rate, and is of great significance to sustainable agricultural development. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 : The results of the static water release of K element of the coated controlled-release potassium fertilizer containing potassium-promoting signal substances prepared in Example 1.

[0047] Figure 2 : Release of signal substances under different temperature conditions (25°C and 50°C) of the coated controlled-release potash fertilizer prepared in Example 1.

[0048] Figure 3 : Release of signal substances of the coated controlled-release potash fertilizer prepared in Comparative Example 5 under different temperature conditions (25°C and 50°C). DETAILED DESCRIPTION

[0049] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0050] As mentioned above, potassium ions are an important factor affecting the quality of flue-cured tobacco leaves. Potassium deficiency will have an adverse effect on the growth of tobacco plants and the quality of tobacco leaves. Although the existing coated controlled-release potassium fertilizers can control the release rate and release cycle of potassium to a certain extent. However, tobacco's absorption of potassium is affected by many factors. The more potassium content, the more tobacco can absorb. The existing coated controlled-release potassium fertilizers lack interaction with tobacco plants and soil, so the absorption and utilization efficiency of potassium ions by tobacco plants still needs to be further improved.

[0051] In view of this, the present invention first provides a coated controlled-release potassium fertilizer containing potassium-promoting signal substances. The present invention adds three types of signal substances to the coated controlled-release potassium fertilizer, thereby improving the effects from three dimensions: increasing the available potassium content in the soil, promoting the absorption of potassium by tobacco roots, and improving the transport of potassium in the tobacco body. This achieves mutual communication among fertilizers, tobacco plants and soil, and ultimately improves the absorption and utilization of potassium ions by tobacco plants.

[0052] In order to improve the stability of the signal substance, the present invention uses the signal substance together with a sodium alginate-starch adhesive. Sodium alginate has the ability to scavenge free radicals. Sodium alginate can react with free radicals through the carboxyl group (-COOH) and alcohol group (-OH) in its structure, thereby inhibiting the oxidation process and protecting the signal substance.

[0053] Based on the coated controlled-release potassium fertilizer containing potassium-promoting signal substances prepared by the present invention, the present invention further compounds it with nitrogen-phosphorus-potassium compound fertilizer, coated controlled-release ammonium nitrate, coated controlled-release diammonium phosphate, boron fertilizer and molybdenum fertilizer to prepare a blended fertilizer, which helps to improve the utilization rate of fertilizers, reduce fertilization costs, and improve crop yield and quality.

[0054] 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 in conjunction with specific embodiments.

[0055] The test materials used in the examples and comparative examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels. The experimental methods without detailed conditions are carried out in accordance with conventional test methods or the operating instructions recommended by the supplier. Among them:

[0056] Polyurea S was purchased from Shunde New Materials (Shanghai) Co., Ltd., trade name: STWD8031; polyurea SA component corresponds to component A therein, and polyurea SB component corresponds to component B therein.

[0057] The manufacturer of tobacco-specific compound fertilizer (N-P2O5-K2O-15-8-25): Honghe Henglin Chemical Co., Ltd., trade name: tobacco-specific fertilizer. The manufacturer of boron fertilizer: Toyota Chemical (Shanxi) Group Co., Ltd., trade name: granular boron fertilizer. The manufacturer of molybdenum fertilizer: Suzhou Bogerui Chemical Technology Co., Ltd., trade name: sodium molybdate.

[0058] Example 1: Preparation of coated controlled-release potassium fertilizer containing potassium-promoting signal substances

[0059] Pass corn starch through a 100-mesh sieve, add 20 ml of water and 5 g of corn starch into a beaker, place the beaker in a water bath, heat to 60°C and stir continuously to completely dissolve the starch to obtain a starch slurry; dissolve 0.5 g of potassium permanganate in 100 ml of water to prepare a potassium permanganate solution; slowly add the prepared potassium permanganate solution to the starch slurry and stir evenly. The reaction continues for 1.5 hours, filter to obtain a clear solution, weigh 3 g of sodium alginate and add it to the clear solution, stir continuously to obtain a sodium alginate-starch adhesive.

[0060] Citric acid and lauric acid are mixed evenly at a weight ratio of 2:1 to serve as signal substance A; the signal substance B is rutin and glutamic acid mixed evenly at a weight ratio of 1:2 to serve as signal substance B; berberine is used as signal substance C. Signal substance A, signal substance B and signal substance C are mixed evenly at a weight ratio of 1:1:1 to serve as signal substances.

[0061] The signal substance and sodium alginate-starch adhesive were mixed at a weight ratio of 4.5:10, and the signal substance was evenly dispersed by ultrasonication for 30 minutes to prepare the first coating liquid. The first coating liquid was sprayed onto the surface of potassium sulfate particles to form the first coating layer. The spraying amount of the first coating liquid accounted for 1.5% of the mass of the potassium sulfate particles. The speed of the coating machine was 20r / min, the temperature was set to 75°C, and the hot air flow rate was 330m 3 / min, spraying speed is 4.5g / min.

[0062] Graphene oxide, glass fiber powder and bentonite were weighed and mixed in a weight ratio of 1:1:1 to obtain a modifier. The modifier was added to the polyurea SB component, and the weight ratio of the modifier to the polyurea SB component was 1:10. The modifier was evenly dispersed by ultrasonication in a 25°C water bath for 30 minutes to prepare a modified polyurea SB component.

[0063] Then, the polyurea SA component and the modified polyurea SB component were mixed at a mass ratio of 1:1 to prepare a second coating solution.

[0064] The second coating liquid is continuously sprayed on the surface of the potassium sulfate particles to form a second coating layer. The spraying amount of the second coating liquid accounts for 5% of the mass of the potassium sulfate particles. The speed of the coating machine is 20r / min, the temperature is set to 75°C, and the hot air flow rate is 330m 3 / min, the spraying speed was 4.5g / min, the coating material reaction and curing time was 15min, and the coated controlled-release potassium fertilizer containing potassium-promoting signal substances was prepared.

[0065] Example 2: Preparation of coated controlled-release potassium fertilizer containing potassium-promoting signal substances

[0066] The difference from Example 1 is that aminosilane and paraffin are mixed in a weight ratio of 1:1 as a modifier.

[0067] Comparative Example 1:

[0068] No signal substance was added, and only sodium alginate-starch adhesive was used as the first coating liquid. The rest was the same as in Example 1.

[0069] Comparative Example 2:

[0070] The signal substance A in Example 1 and the sodium alginate-starch adhesive were mixed in a weight ratio of 4.5:10 as the first coating solution, and the rest was the same as in Example 1.

[0071] Comparative Example 3:

[0072] The signal substance B in Example 1 and the sodium alginate-starch adhesive were mixed at a weight ratio of 4.5:10 as the first coating solution, and the rest was the same as in Example 1.

[0073] Comparative Example 4:

[0074] The signal substance C in Example 1 and the sodium alginate-starch adhesive were mixed in a weight ratio of 4.5:10 as the first coating solution, and the rest was the same as in Example 1.

[0075] Comparative Example 5:

[0076] Only starch slurry is used as adhesive to replace the "sodium alginate-starch adhesive" in Example 1, and the rest is the same as Example 1.

[0077] Application Example 1: Preparation of slow-release and controlled-release blended fertilizer for flue-cured tobacco

[0078] The second coating liquid in Example 1 was sprayed on the surface of the ammonium nitrate particles. The spraying amount of the second coating liquid was 5% of the weight of the ammonium nitrate particles. The speed of the coating machine was 20 r / min, the temperature was set to 75°C, and the hot air flow rate was 330 m 3 / min, the spraying speed was 4.5g / min, the coating material reaction and curing time was 15min, and coated controlled-release ammonium nitrate was prepared.

[0079] The second coating liquid in Example 1 was sprayed on the surface of the diammonium phosphate particles. The spraying amount of the second coating liquid was 5% of the weight of the diammonium phosphate particles. The speed of the coating machine was 20 r / min, the temperature was set to 75°C, and the hot air flow rate was 330 m 3 / min, the spraying speed was 4.5g / min, the coating material reaction curing time was 15min, and the coated controlled-release diammonium phosphate was prepared.

[0080] The tobacco-specific compound fertilizer (N-P2O5-K2O-15-8-25), the coated controlled-release potassium fertilizer containing potassium-promoting signal substances prepared in Example 1, coated controlled-release ammonium nitrate, coated controlled-release diammonium phosphate, boron fertilizer and molybdenum fertilizer were mixed in a weight ratio of 40:40:20:15:3:2 to prepare a slow-release blended fertilizer specifically for flue-cured tobacco.

[0081] Application Example 2: Preparation of slow-release and controlled-release blended fertilizer for flue-cured tobacco

[0082] The preparation of coated controlled-release ammonium nitrate and coated controlled-release diammonium phosphate is the same as that of Application Example 1;

[0083] The tobacco-specific compound fertilizer (N-P2O5-K2O-15-8-25), the coated controlled-release potassium fertilizer prepared in Comparative Example 1, the coated controlled-release ammonium nitrate, the coated controlled-release diammonium phosphate, the boron fertilizer and the molybdenum fertilizer were mixed in a weight ratio of 40:40:20:15:3:2 to prepare a special slow-release blended fertilizer for flue-cured tobacco.

[0084] Application Example 3: Preparation of slow-release and controlled-release blended fertilizer for flue-cured tobacco

[0085] The preparation of coated controlled-release ammonium nitrate and coated controlled-release diammonium phosphate is the same as that of Application Example 1;

[0086] The tobacco-specific compound fertilizer (N-P2O5-K2O-15-8-25), the coated controlled-release potassium fertilizer prepared in Comparative Example 2, the coated controlled-release ammonium nitrate, the coated controlled-release diammonium phosphate, the boron fertilizer and the molybdenum fertilizer were mixed in a weight ratio of 40:40:20:15:3:2 to prepare a special slow-release blended fertilizer for flue-cured tobacco.

[0087] Application Example 4: Preparation of slow-release and controlled-release blended fertilizer for flue-cured tobacco

[0088] The preparation of coated controlled-release ammonium nitrate and coated controlled-release diammonium phosphate is the same as that of Application Example 1;

[0089] The tobacco-specific compound fertilizer (N-P2O5-K2O-15-8-25), the coated controlled-release potassium fertilizer prepared in Comparative Example 3, the coated controlled-release ammonium nitrate, the coated controlled-release diammonium phosphate, the boron fertilizer and the molybdenum fertilizer were mixed in a weight ratio of 40:40:20:15:3:2 to prepare a special slow-release blended fertilizer for flue-cured tobacco.

[0090] Application Example 5: Preparation of slow-release and controlled-release blended fertilizer for flue-cured tobacco

[0091] The preparation of coated controlled-release ammonium nitrate and coated controlled-release diammonium phosphate is the same as that of Application Example 1;

[0092] The tobacco-specific compound fertilizer (N-P2O5-K2O-15-8-25), the coated controlled-release potassium fertilizer prepared in Comparative Example 4, the coated controlled-release ammonium nitrate, the coated controlled-release diammonium phosphate, the boron fertilizer and the molybdenum fertilizer were mixed in a weight ratio of 40:40:20:15:3:2 to prepare a slow-release blended fertilizer specifically for flue-cured tobacco.

[0093] Test Example 1:

[0094] 1. Determination of K element static water release:

[0095] The static water release curve of K of the coated controlled-release potassium fertilizer containing potassium-promoting signal substances prepared in Example 1 at 25°C was measured. Figure 1 shown.

[0096] The results show that the coated controlled-release potassium fertilizer containing potassium-promoting signal substances prepared in Example 1 of the present invention has a potassium release trend of: slow release in the early stage, accelerated release rate in the middle stage, and continuous slow release in the late stage, which is in line with the "slow-fast-slow" nutrient demand law of tobacco.

[0097] 2. Signal substance release assay:

[0098] The release of signal substances from the coated controlled-release potassium fertilizers prepared in Example 1 and Comparative Example 5 was measured at 25°C and 50°C (simulated high temperature). Figure 2-Figure 3 shown.

[0099] The results show that: in the coated controlled-release potash fertilizer prepared in Comparative Example 5, a part of the signal substance loses its activity at 25°C, and the inactivation of the signal substance is more obvious at 50°C; while in the coated controlled-release potash fertilizer prepared in Example 1, due to the addition of sodium alginate protective agent, the signal substance has little difference at 25°C and 50°C. This shows that the use of sodium alginate-starch adhesive together with the signal substance can play a better protective role on the signal substance.

[0100] Test Example 2:

[0101] 1. Test method:

[0102] The experiment was conducted in a tobacco planting field in Qujing City, Yunnan Province, and the flue-cured tobacco variety tested was Yunyan 87.

[0103] The experiment set up 6 treatments, each with 3 replicates, namely:

[0104] Treatment 1: applying the slow-release blended fertilizer specially prepared in Application Example 1 for flue-cured tobacco;

[0105] Treatment 2: applying the slow-release blended fertilizer specially prepared in Application Example 2 for flue-cured tobacco;

[0106] Treatment 3: applying the slow-release blended fertilizer specially prepared in Application Example 3 for flue-cured tobacco;

[0107] Treatment 4: applying the slow-release blended fertilizer specially prepared in Application Example 4 for flue-cured tobacco;

[0108] Treatment 5: Applying the slow-release blended fertilizer specially prepared in Application Example 5 for flue-cured tobacco.

[0109] Control (CK): No potassium fertilizer was applied, only nitrogen fertilizer and phosphorus fertilizer (N-P2O5=15-8) was applied as the blank area.

[0110] The cell size is 30m 2 60 tobacco plants were planted in each plot, and the dosage of slow-release mixed fertilizer for each treatment of flue-cured tobacco was 2.5 kg (1 kg of potassium), and the field management conditions remained consistent.

[0111] On the 90th day after tobacco transplanting, tobacco plants in each treatment were taken, and the root, stem and leaf samples at each period were dried. The potassium content was determined by inductively coupled plasma emission spectrometry, and the apparent potassium utilization rate (%) was calculated according to the following formula.

[0112] Apparent potassium utilization rate (%) = (total potassium absorption of plants in the potassium application area - total potassium absorption of plants in the blank area) / potassium application amount × 100

[0113] 2. Test results:

[0114] The test results are shown in Table 1.

[0115] Table 1: Determination results of potassium content and apparent potassium utilization

[0116]

[0117] The results show that the slow-release blended fertilizer specially prepared for flue-cured tobacco by the present invention can promote the absorption of potassium by tobacco, enrich potassium in the leaves of tobacco, and improve the quality of tobacco leaves. Moreover, in the coated controlled-release potassium fertilizer containing potassium-promoting signal substances of the present invention, by combining the signal substance A that increases the content of available potassium in the soil, the signal substance B that promotes the absorption of potassium by tobacco roots, and the signal substance C that increases the transport of potassium in tobacco, the three types of signal substances interact with each other, and jointly improve the absorption and utilization efficiency of potassium by tobacco.

[0118] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A coated controlled-release potash fertilizer containing a potassium-promoting signal substance, characterized in that: Prepared by the following method: The signal substance is added to the sodium alginate-starch adhesive and dispersed evenly to obtain a first coating liquid, and the first coating liquid is sprayed onto the surface of the potash fertilizer particles to form a first coating layer; The polyurea SA component and the modified polyurea SB component are mixed to obtain a second coating liquid, and the second coating liquid is continuously sprayed onto the surface of the potash fertilizer particles to form a second coating layer; thus, a coated controlled-release potash fertilizer containing a potassium-promoting signal substance is prepared. The signal substance is composed of a signal substance A, a signal substance B and a signal substance C; wherein the signal substance A is selected from one or more of jasmonate, citric acid and lauric acid; the signal substance B is selected from one or more of rutin, naringenin and glutamic acid; the signal substance C is selected from one or more of berberine, cyclic adenosine monophosphate and cyclic guanosine monophosphate.

2. The coated controlled-release potash fertilizer containing a potassium-promoting signal substance according to claim 1, characterized in that: The signal substance consists of a signal substance A, a signal substance B and a signal substance C in a weight ratio of 1:1:

1.

3. The coated controlled-release potash fertilizer containing a potassium-promoting signal substance according to claim 1 or 2, characterized in that: The signal substance A is composed of citric acid and lauric acid in a weight ratio of 2:1; the signal substance B is composed of rutin and glutamic acid in a weight ratio of 1:2; and the signal substance C is berberine.

4. The coated controlled-release potash fertilizer containing a potassium-promoting signal substance according to claim 1, characterized in that: The sodium alginate-starch adhesive is prepared by the following method: Potassium permanganate is added to the starch slurry, stirred evenly, reacted for 1-2 hours, filtered to obtain a clear solution; sodium alginate is added to the clear solution, stirred to prepare a sodium alginate-starch adhesive.

5. The coated controlled-release potash fertilizer containing a potassium-promoting signal substance according to claim 4, characterized in that: The weight ratio of potassium permanganate, starch and sodium alginate added is 0.5:5:

3.

6. The coated controlled-release potash fertilizer containing potassium-promoting signal substances according to claim 1, characterized in that: The weight ratio of the signal substance to the sodium alginate-starch adhesive is (0.5-1.5):2; the spraying amount of the first coating liquid is 1-2% of the weight of the potash fertilizer particles.

7. The coated controlled-release potash fertilizer containing a potassium-promoting signal substance according to claim 1, characterized in that: The modified polyurea SB component is prepared by the following method: Adding a modifier to the polyurea SB component and uniformly dispersing it by ultrasonication in a water bath at 25° C.; the modifier is one or more of graphene oxide, glass fiber powder, bentonite, aminosilane, and paraffin; Preferably, the modifier consists of graphene oxide, glass fiber powder and bentonite in a weight ratio of 1:1:1; or, consists of aminosilane and paraffin in a weight ratio of 1:

1.

8. The coated controlled-release potash fertilizer containing potassium-promoting signal substances according to claim 1, characterized in that: The polyurea SA component and the modified polyurea SB component are mixed in a weight ratio of 1:1; the spraying amount of the second coating liquid is 3-7% of the weight of the potash fertilizer particles.

9. Use of the coated controlled-release potassium fertilizer containing potassium-promoting signal substances according to any one of claims 1 to 8 in the following (1) or (2): (1) Improve tobacco's absorption and utilization of potassium ions; (2) Preparation of slow-release and controlled-release blended fertilizers for flue-cured tobacco.

10. A slow-release and controlled-release blended fertilizer specially used for flue-cured tobacco, characterized in that: The composition comprises the following components in parts by weight: 38-42 parts of nitrogen, phosphorus and potassium compound fertilizer, 35-50 parts of the coated controlled-release potassium fertilizer containing potassium-promoting signal substance according to any one of claims 1-8, 15-30 parts of coated controlled-release ammonium nitrate, 10-20 parts of coated controlled-release diammonium phosphate, 1-5 parts of boron fertilizer, and 1-3 parts of molybdenum fertilizer.

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