A compound fertilizer for rice and its use in preventing rice damping-off caused by fusarium

Abstract

The application discloses a kind of compound fertilizer special for rice and its purposes in preventing and treating rice damping-off caused by fusarium, belong to fertilizer technical field.The fertilizer includes the following components according to mass fraction: ammonium chloride 20-25 parts, potassium chloride 20-25 parts, calcium superphosphate 15-20 parts, ammonium sulfate 5-10 parts, ammonium molybdate 3-5 parts, earthworm manure organic fertilizer 50-60 parts, humic acid 15-20 parts, attapulgite clay powder 10-15 parts, chitosan oligosaccharide 5-8 parts, dandelion extract 3-5 parts, and compound microbial inoculant 3-5 parts.The components in the compound fertilizer cooperate with each other, not only can make the acid effect of the compound fertilizer last long, resist washing, suppress underground salt alkali, adjust soil structure, inhibit fusarium reproduction, and create a suitable growth environment for root growth, but also can improve the disease resistance of rice seedlings and effectively reduce the incidence of rice damping-off.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fertilizers, in particular to a special compound fertilizer for rice and its use in preventing rice damping-off caused by Fusarium. BACKGROUND

[0002] Rice damping-off belongs to soil-borne disease. It is caused by multiple pathogenic fungi, mainly including Fusarium oxysporum, F. graminearum, F. equiseti, F. solani, F. moniliforme of Fusarium genus of Ascomycota Sordariomycetidae, and Rhizoctonia solani of Rhizoctonia genus of Agonomycota, and Pythium of Pythium genus of Oomycota. Fusarium generally overwinters in the form of mycelium and chlamydospores in the disease residues of multiple hosts and soil, and produces conidia to spread by air current when the environmental conditions are suitable, and then invades and damages. Rhizoctonia overwinters in the form of mycelium and sclerotia in the disease residues of hosts and soil, and spreads among seedlings by mycelium to invade and damage. Therefore, rice damping-off caused by Fusarium is more likely to occur, spread more widely, and be more serious.

[0003] At present, fungicides are mainly used to prevent rice damping-off in production, but fungicides have many problems such as short duration of drug effect, easy resistance, and environmental pollution. Therefore, it is necessary to develop a new product for preventing rice damping-off caused by Fusarium, which is green, safe, and has good prevention effect. SUMMARY

[0004] The present application aims to provide a special compound fertilizer for rice and its use in preventing rice damping-off caused by Fusarium, so as to solve the problems of the prior art.

[0005] To achieve the above-mentioned purpose, the present application provides the following solutions.

[0006] One of the technical solutions of the present application is a special compound fertilizer for rice, which comprises the following components in parts by mass: 20-25 parts of ammonium chloride, 20-25 parts of potassium chloride, 15-20 parts of calcium superphosphate, 5-10 parts of ammonium sulfate, 3-5 parts of ammonium molybdate, 50-60 parts of earthworm manure organic fertilizer, 15-20 parts of humic acid, 10-15 parts of attapulgite clay powder, 5-8 parts of chitosan oligosaccharide, 3-5 parts of dandelion extract, and 3-5 parts of compound microbial agent.

[0007] Further, the preparation method of the dandelion extract is as follows: after the dandelion is crushed, it is ultrasonically extracted with an ethanol aqueous solution, centrifuged to obtain supernatant, the supernatant is concentrated by rotary evaporation, and freeze-dried to obtain the dandelion extract.

[0008] Further, the concentration of the ethanol aqueous solution is 50-60wt%; the ratio of the dandelion to the ethanol aqueous solution is 1:55-65; the time of the ultrasonic extraction is 45-55min, and the ultrasonic power is 700-800W.

[0009] Further, the pH value of the ultrasonic extraction is 8.5-9, the rotation speed of the centrifugation is 4000prm, and the time is 15min; the temperature of the freeze drying is-80℃.

[0010] Further, the complex microbial agent comprises Trichoderma harzianum, T. atroviride, Bacillus subtilis and Penicillium.

[0011] Further, in the complex microbial agent, the mass ratio of Trichoderma harzianum: T. atroviride: Bacillus subtilis: Penicillium is 1-2: 1-2: 3-4: 2-3.

[0012] Further, the bacterial content of Trichoderma harzianum is (1.0-3.0)×10 9 cfu / g, the bacterial content of T. atroviride is (1.0-3.0)×10 9 cfu / g, the bacterial content of Bacillus subtilis is (1.0-3.0)×10 8 cfu / g, and the bacterial content of Penicillium is (1.0-3.0)×10 8 cfu / g.

[0013] Bacillus subtilis, Trichoderma and Penicillium can produce various active substances and have inhibitory effect on various pathogenic bacteria. Bacillus subtilis can produce bacteriocins, enzymes, active proteins and polypeptides and other substances, and the main prevention and control object is plant diseases caused by filamentous fungi. The active secondary metabolites of Penicillium mainly include penicillin antibiotics, alkaloids, anthraquinones and bacteriocins, all of which have inhibitory effect on pathogenic bacteria. Trichoderma can produce a large amount of antibacterial substances with different chemical properties, including pentanone, octanone, mushroom-like, polypeptides and amino acid derivatives, among which there are more than 70 kinds of antifungal metabolites. Bacillus subtilis, Trichoderma and Penicillium not only inhibit plant pathogenic bacteria, but also release compounds that induce local and systemic defense responses of plants, and induce plants to enhance disease resistance. Bacillus subtilis, Trichoderma and Penicillium can also produce organic acids, enzymes or capsular polysaccharides to dissolve the insoluble nutrients in the soil, and increase the content of soil organic matter, available phosphorus, available potassium and alkaline nitrogen. The combination of Bacillus subtilis, Trichoderma and Penicillium can not only effectively inhibit the reproduction of Fusarium, but also effectively promote the release of soil nutrients, so that the rice seedlings grow healthily, and the disease resistance of the seedlings to the sheath blight is enhanced.

[0014] In addition, there are many species of Trichoderma, and different species of Trichoderma have different antibiotic abilities, and the application of multiple Trichoderma can improve the control effect. The chitinase activity of Trichoderma harzianum is high, and Trichoderma atroviride has better nutritional competition ability and antibiotic effect. Therefore, Trichoderma harzianum, Trichoderma atroviride, Bacillus subtilis and Penicillium are compounded, and the strains are synergistic, which can achieve the best control effect on rice seedling blight.

[0015] Further, the preparation method of the earthworm manure organic fertilizer comprises the following steps:

[0016] (1) mixing fresh cow dung and corn straw, stirring uniformly, adjusting the moisture content of the material to 60-75wt%, and adopting natural pre-fermentation treatment for 20-30 days to obtain a natural pre-fermentation mixture;

[0017] (2) preparing the natural pre-fermentation mixture as bait to make an earthworm bed, and adding earthworm species to the earthworm bed, shading the earthworm bed, adjusting the humidity to 60-75%, and the temperature to 20-30℃, collecting earthworm manure every 2-5 weeks and continuously adding the natural pre-fermentation mixture to the earthworm bed;

[0018] (3) air-drying the earthworm manure collected in step (2) in a cool place to obtain the earthworm manure organic fertilizer.

[0019] Further, in step (1), the mass ratio of the fresh cow dung and the corn straw is 1:1-2.

[0020] Further, the moisture content of the fresh cow dung is 80-90wt%.

[0021] Further, in step (2), the height of the earthworm bed is 1.5-2.0m, the width is 2.5-3.0m, and the length is 5.0-6.0m, and the inoculation density of the earthworm species is 2-2.5kg / m 2 , and the dry weight ratio of the earthworm manure collection amount to the continuously added natural pre-fermentation mixture is 1:1-5.

[0022] Further, the natural pre-fermentation treatment in step (1) is performed, and the substrate is turned over once every 3 days in the first 6 days, and once a week in the later period, and super-pure water is poured every 2 days to keep the substrate humidity at 60-75wt%.

[0023] Further, in step (2), the earthworm is Eisenia foetida.

[0024] The technical scheme two of the present application is a preparation method of the above-mentioned special compound fertilizer for rice, comprising the following steps:

[0025] (1) crushing ammonium chloride, potassium chloride, superphosphate, ammonium sulfate, ammonium molybdate, earthworm manure organic fertilizer, humic acid, chitosan oligosaccharide and dandelion extract, and passing through a 100-200 mesh sieve;

[0026] (2) After crushing and sieving ammonium chloride, potassium chloride, superphosphate, ammonium sulfate, ammonium molybdate, earthworm castings organic fertilizer, humic acid, chitosan oligosaccharide, dandelion extract and compound microbial agent are mixed evenly, the mixture is granulated to obtain the rice-specific compound fertilizer.

[0027] The third technical solution of the present invention: the application of the above-mentioned rice-specific compound fertilizer in the prevention and control of rice damping-off caused by Fusarium, wherein the rice-specific compound fertilizer is used in the dry rice seedling raising process.

[0028] Furthermore, the rice-specific compound fertilizer is applied to the seedbed 2-3 days before sowing and then raked into the soil to a depth of 3-5 cm.

[0029] Furthermore, the application rate of the rice-specific compound fertilizer is 30-50 kg / mu.

[0030] The present invention discloses the following technical effects:

[0031] (1) The raw materials for the rice-specific compound fertilizer of the present invention include ammonium chloride, potassium chloride, superphosphate, ammonium sulfate, ammonium molybdate, earthworm castings organic fertilizer, humic acid, attapulgite clay powder, chitosan oligosaccharide, dandelion extract, and compound microbial inoculant. Among them, ammonium chloride and potassium chloride are chlorine-containing inorganic fertilizers, and the Cl in chlorine-containing inorganic fertilizers... - It can inhibit crops' absorption of NO3 - This reduces the absorption of NO3 in crops. - The concentration of Cl; in addition, Cl -The ammonium nitrogen can be inhibited from nitrification, and the crop can release a large amount of hydrogen ions while absorbing the ammonium nitrogen, so as to improve the soil acidity and inhibit the breeding of pathogenic microorganisms. The calcium superphosphate, ammonium sulfate and ammonium chloride belong to the acid inorganic fertilizer, which can improve the soil acidity and inhibit the breeding of pathogenic microorganisms. The molybdenum element in the ammonium molybdate can inhibit the growth of the fusarium mycelium, destroy the mycelium cell membrane structure, increase the cell membrane permeability, promote the exosmosis of the intracellular electrolyte, lead to the outflow of the soluble sugar, soluble protein and pyruvic acid in the mycelium cell, and then inhibit the normal growth of the mycelium. The humic acid can activate the soil, improve the soil acidity, improve the fertilizer utilization rate, stimulate the root growth, make the seedling root system develop, and improve the disease resistance of the seedling. The attapulgite clay powder contains silicon element, which can significantly improve the stress resistance of the rice, and can also improve the soil. The chitosan is an immunomodulator, which can induce the disease resistance of the rice to the fusarium. The dandelion extract contains various flavonoid compounds, which have a good inhibitory effect on the fusarium. The compound microbial agent can inhibit the breeding of harmful pathogenic bacteria and improve the paddy field soil environment. The earthworm manure organic fertilizer is beneficial to the breeding of beneficial microorganisms and the growth and development of the rice seedling. The synergistic cooperation of the components can not only make the compound fertilizer have a long-lasting acid effect, resist washing, suppress the underground salt alkali, adjust the soil structure, inhibit the breeding of the fusarium, and create a suitable growth environment for the root stem growth, but also improve the disease resistance of the rice seedling and effectively reduce the incidence rate of the rice seedling blight.

[0032] (2) The compound microbial agent of the present application comprises the Trichoderma harzianum, the Trichoderma spicifum, the Bacillus subtilis and the Penicillium, and various microorganisms with bacteriostatic effect, and the synergistic cooperation of the microorganisms makes the overall bacteriostatic effect more excellent.

[0033] (3) The present application utilizes the earthworm composting process to produce organic fertilizer from fresh cow dung and corn straw as raw materials. When the earthworms are composting, the loss of protein and other nutrient elements caused by high-temperature fermentation in various fermentation technology processes is greatly reduced. At the same time, the activity of the earthworms also improves the physical properties and functional structure of the compost raw materials, increases the air permeability, promotes water and gas circulation, enriches the nutrient content in the soil, and provides a good environment for the growth and reproduction of microorganisms. Under the synergistic action of earthworms and microorganisms, the decomposition and transformation of livestock and poultry manure are accelerated. The earthworm manure produced by earthworm composting is in the form of granular structure, has good chemical and physical properties, and is rich in nutrients, and at the same time contains a variety of beneficial microorganisms and enzyme active substances for plant growth, which is beneficial to the growth of plants and soil improvement. At the same time, the earthworm manure has high humus with biological activity, low biological water content and other soluble minerals, combined with large specific gravity and surface area, which makes it have good biological adsorption, is beneficial to the reproduction of microorganisms and the growth and development of rice seedlings. A large number of beneficial microorganisms in the earthworm manure are applied to the soil, which can quickly inhibit the growth of harmful pathogenic bacteria, and the beneficial microorganisms can quickly reproduce, reduce the occurrence of soil-borne diseases, and make the crops less likely to be sick. At the same time, the production and metabolism of a large number of microorganisms can improve the physical and chemical properties of the soil, make the soil composition diversified, produce soil fertility, promote the energy conversion between organic matter and inorganic matter, protect the soil ecological environment, and provide good environmental conditions for the growth and development of rice seedlings. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present application will now be described in detail with reference to the drawings. The detailed description is not to be considered to limit the present application, but to explain certain aspects, features and embodiments of the present application.

[0035] It should be understood that the terms used in the present application merely describe particular embodiments and are not intended to limit the present application. In addition, for numerical ranges in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is specifically disclosed. Each smaller range within any stated range or within any stated intermediate value and any other stated range or intermediate value is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, preferred methods and materials are described. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In the case of conflict between the content of this specification and that of any document incorporated by reference, the content of this specification prevails.

[0037] Many modifications and variations of the specific embodiments of the application can be made without departing from the scope or spirit of the application, which will be apparent to those skilled in the art. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application. The specification and examples are illustrative only.

[0038] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having" or the like are open-ended terms that are intended to mean including, but not limited to.

[0039] The experimental methods described in the following examples and effect verification are all conventional methods unless otherwise specified. The reagents and raw materials (including various microbial agents) described are all commercially available unless otherwise specified. The parts are all mass parts.

[0040] The preparation method of the dandelion extract used in the following examples is as follows: after the dandelion is crushed, 50wt% ethanol aqueous solution is added at a solid-liquid ratio of 1:60 for ultrasonic extraction, the power of ultrasonic extraction is 800W, the time is 50min, the pH value is 9, after ultrasonic extraction, the supernatant is obtained by centrifugation at 4000prm for 15min, the supernatant is concentrated by rotary evaporation, and freeze-drying is carried out at-80℃ to obtain the dandelion extract.

[0041] The composite microbial agent used in the following examples is mixed by Trichoderma harzianum, T. atroviride, Bacillus subtilis and Penicillium, and the mass ratio of T. harzianum, T. atroviride, B. subtilis and Penicillium is 2:2:3:3. Among them, the bacterial content of T. harzianum is 2.0×10 9 cfu / g, the bacterial content of T. atroviride is 2.0×10 9 cfu / g, the bacterial content of B. subtilis is 3.0×10 8 cfu / g, and the bacterial content of Penicillium is 3.0×10 8 cfu / g.

[0042] The preparation method of the earthworm manure organic fertilizer used in the following examples is as follows: fresh cow dung (water content 85wt%) and corn stalks are mixed at a mass ratio of 1:1.5, stirred uniformly, and then the water content of the material is adjusted to 70wt% with distilled water, and the natural pre-fermentation treatment is carried out for 30 days (turning over once every 3 days in the first 6 days, turning over once a week in the later period, and pouring super-pure water every 2 days to keep the substrate humidity at about 70wt%). The natural pre-fermentation mixture is used as bait to make an earthworm bed (specifications: 550cm (length) x 300cm (width) x 200cm (height)), and earthworm species (adult red love victory earthworms, with a density of 2kg / m 2), earthworm bed sunshade, humidity adjustment to 65%, temperature to 25℃, every 4 weeks to collect earthworm manure and continue to add natural pre-fermentation mixture to the earthworm bed; the dry weight ratio of the amount of earthworm manure collected each time to the natural pre-fermentation mixture continuously added is 1:1.5; the collected earthworm manure is air-dried in a cool place to obtain earthworm manure organic fertilizer.

[0043] Example 1

[0044] The raw material composition of the special compound fertilizer for rice is as follows: 20 parts of ammonium chloride, 20 parts of potassium chloride, 15 parts of calcium superphosphate, 5 parts of ammonium sulfate, 3 parts of ammonium molybdate, 50 parts of earthworm manure organic fertilizer, 15 parts of humic acid, 10 parts of attapulgite clay powder, 5 parts of chitosan oligosaccharide, 3 parts of dandelion extract, and 3 parts of compound microbial agent.

[0045] The preparation steps are as follows:

[0046] (1) The ammonium chloride, potassium chloride, calcium superphosphate, ammonium sulfate, ammonium molybdate, earthworm manure organic fertilizer, humic acid, attapulgite clay powder, chitosan oligosaccharide, and dandelion extract are respectively crushed and passed through a 200-mesh sieve;

[0047] (2) The crushed and sieved ammonium chloride, potassium chloride, calcium superphosphate, ammonium sulfate, ammonium molybdate, earthworm manure organic fertilizer, humic acid, attapulgite clay powder, chitosan oligosaccharide, dandelion extract, and compound microbial agent are uniformly mixed, water is sprayed for granulation, and drying is performed until the water content is about 5wt%, to obtain the special compound fertilizer for rice.

[0048] Example 2

[0049] The raw material composition of the special compound fertilizer for rice is as follows: 23 parts of ammonium chloride, 23 parts of potassium chloride, 18 parts of calcium superphosphate, 8 parts of ammonium sulfate, 4 parts of ammonium molybdate, 55 parts of earthworm manure organic fertilizer, 18 parts of humic acid, 13 parts of attapulgite clay powder, 6 parts of chitosan oligosaccharide, 4 parts of dandelion extract, and 4 parts of compound microbial agent.

[0050] The preparation steps are as follows:

[0051] (1) The ammonium chloride, potassium chloride, calcium superphosphate, ammonium sulfate, ammonium molybdate, earthworm manure organic fertilizer, humic acid, attapulgite clay powder, chitosan oligosaccharide, and dandelion extract are respectively crushed and passed through a 200-mesh sieve;

[0052] (2) The crushed and sieved ammonium chloride, potassium chloride, calcium superphosphate, ammonium sulfate, ammonium molybdate, earthworm manure organic fertilizer, humic acid, attapulgite clay powder, chitosan oligosaccharide, dandelion extract, and compound microbial agent are uniformly mixed, water is sprayed for granulation, and drying is performed until the water content is about 5wt%, to obtain the special compound fertilizer for rice.

[0053] Example 3

[0054] The raw material composition of the special compound fertilizer for rice is as follows: 25 parts of ammonium chloride, 25 parts of potassium chloride, 20 parts of calcium superphosphate, 10 parts of ammonium sulfate, 5 parts of ammonium molybdate, 60 parts of earthworm manure organic fertilizer, 20 parts of humic acid, 15 parts of attapulgite clay powder, 8 parts of chitosan oligosaccharide, 5 parts of dandelion extract, and 5 parts of compound microbial inoculant.

[0055] The preparation steps are as follows:

[0056] (1) The ammonium chloride, potassium chloride, calcium superphosphate, ammonium sulfate, ammonium molybdate, earthworm manure organic fertilizer, humic acid, attapulgite clay powder, chitosan oligosaccharide, and dandelion extract are respectively crushed and passed through a 200-mesh screen;

[0057] (2) The crushed and sieved ammonium chloride, potassium chloride, calcium superphosphate, ammonium sulfate, ammonium molybdate, earthworm manure organic fertilizer, humic acid, attapulgite clay powder, chitosan oligosaccharide, dandelion extract, and compound microbial inoculant are uniformly mixed, water is sprayed for granulation, and drying is performed until the water content is about 5wt%, to obtain the special compound fertilizer for rice.

[0058] Comparative Example 1

[0059] The same as Example 1, except that the use of ammonium molybdate is omitted.

[0060] Comparative Example 2

[0061] The same as Example 1, except that the use of chitosan oligosaccharide is omitted.

[0062] Comparative Example 3

[0063] The same as Example 1, except that the use of dandelion extract is omitted.

[0064] Comparative Example 4

[0065] The same as Example 1, except that the earthworm manure organic fertilizer is replaced by an equal amount of matured cow manure.

[0066] Comparative Example 5

[0067] The same as Example 1, except that the compound microbial inoculant is composed of Trichoderma harzianum, Bacillus subtilis, and Penicillium in a mass ratio of 2:3:3.

[0068] Effect verification

[0069] Fertilizer application test

[0070] Test rice variety: The test rice variety is Liangyou 6326 (single-crop rice).

[0071] Test site: The test seedbed is located in the main rice-producing area of Nanchang City, Jiangxi Province, and is found to be a seedbed prone to rhizoctonia blight.

[0072] Test design: 27 experimental plots were randomly divided in the rice seedbed with uniform soil properties and medium fertility, each experimental plot with an area of 30 m 2 , and rice seedlings were grown in dry soil. The experimental groups were applied with the rice special compound fertilizer prepared by examples 1-3 and the compound fertilizer prepared by comparative examples 1-5, and the experimental plot applied with the ordinary commercial compound fertilizer (N-P2O5-K2O 15-15-15) was used as the control group. Three parallel experiments were set in each group, and the final result was the average of the three groups. Three days before rice seeding, the compound fertilizer was spread on the seedbed and plowed into the soil 3-5 cm, the fertilizer application amount was 40 kg / acre, and the soil was irrigated after fertilization. No other fertilizer was applied during the whole seedling period, and no other fungicide was sprayed, and normal field management was carried out.

[0073] Disease investigation: the 2-leaf stage of rice is the peak period of the occurrence of the disease. At the 3-leaf stage of rice, the incidence rate of the disease in each experimental group and the control group was investigated by using the diagonal 5-point sampling method, and 100 plants were investigated at each point.

[0074] Incidence rate = number of diseased plants / total number of investigated plants × 100%;

[0075] Control effect (%) = 100 × (incidence rate of the control group - incidence rate of the experimental group) / incidence rate of the control group.

[0076] The control effect of different treatments on the rice sheath blight is shown in Table 1.

[0077] Table 1

[0078] Group Incidence / % Control effect / % Example 1 0.8 96.5 Example 2 0.7 96.9 Example 3 0.6 97.4 Comparative Example 1 1.3 94.3 Comparative Example 2 3.5 84.6 Comparative Example 3 2.8 87.7 Comparative Example 4 6.2 72.8 Comparative Example 5 2.1 90.8 Control group 22.8 -

[0079] As can be seen from the results in Table 1, the incidence rate of the rice sheath blight treated by the rice special compound fertilizer prepared by examples 1-3 of the present application is significantly reduced, the control effect on the rice sheath blight is remarkable, and it is obviously better than other comparative examples and the control group. This is mainly because the components of the compound fertilizer of the present application have synergistic effect, which can effectively inhibit the reproduction of the fusarium and improve the disease resistance of rice.

[0080] The above examples only describe the preferred mode of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A rice-specific compound fertilizer for preventing and controlling rice damping-off, characterized in that, The raw materials include the following components in terms of mass fraction: ammonium chloride 20-25 parts, potassium chloride 20-25 parts, calcium superphosphate 15-20 parts, ammonium sulfate 5-10 parts, ammonium molybdate 3-5 parts, earthworm manure organic fertilizer 50-60 parts, humic acid 15-20 parts, attapulgite clay powder 10-15 parts, chitosan oligosaccharide 5-8 parts, dandelion extract 3-5 parts, and compound microbial agent 3-5 parts; The preparation method of the dandelion extract is as follows: after the dandelion is crushed, it is ultrasonically extracted with an ethanol aqueous solution, centrifuged to obtain supernatant, the supernatant is concentrated by rotary evaporation, and freeze-dried to obtain the dandelion extract; The concentration of the ethanol aqueous solution is 50-60wt%; the solid-liquid ratio of the dandelion to the ethanol aqueous solution is 1:55-65; the ultrasonic extraction time is 45-55min, and the ultrasonic power is 700-800W; The compound microbial agent includes Trichoderma harzianum, T. atroviride, Bacillus subtilis, and Penicillium; In the compound microbial agent, the mass ratio of Trichoderma harzianum: T. atroviride: Bacillus subtilis: Penicillium is 1-2: 1-2: 3-4: 2-3; The preparation method of the earthworm manure organic fertilizer includes the following steps: (1) mixing fresh cow dung and corn stalks, stirring uniformly, adjusting the water content of the materials to 60-75wt% with water, and naturally pre-fermenting for 7-30 days to obtain a naturally pre-fermented mixture; (2) making the naturally pre-fermented mixture into an earthworm bed, adding earthworm species to the earthworm bed, shading the earthworm bed, adjusting the humidity to 60-75%, and adjusting the temperature to 20-30℃, and collecting earthworm manure every 2-5 weeks and continuously adding the naturally pre-fermented mixture to the earthworm bed; (3) air-drying the earthworm manure collected in step (2) in a cool place to obtain the earthworm manure organic fertilizer.

2. The compound fertilizer for rice according to claim 1, wherein the compound fertilizer for rice is used for controlling rice seedling blight. In step (1), the mass ratio of the fresh cow dung to the corn stalks is 1:1-2.

3. The compound fertilizer for rice according to claim 1, wherein the compound fertilizer for rice is used for controlling rice seedling blight. In step (2), the height of the worm bed is 1.5-2.0 m, the width is 2.5-3.0 m, and the length is 5.0-6.0 m, and the inoculation density of the earthworm species is 2-2.5 kg / m 2 The ratio of the dry weight of the earthworm manure collected each time to the natural pre-fermented mixture continuously added is 1:1-5.

4. A method for preparing the compound fertilizer for rice according to any one of claims 1 to 3, characterized in that, The method includes the following steps: (1) crushing ammonium chloride, potassium chloride, calcium superphosphate, ammonium sulfate, ammonium molybdate, earthworm manure organic fertilizer, humic acid, attapulgite clay powder, chitosan oligosaccharide, and dandelion extract, and passing them through a 100-200 mesh sieve; (2) mixing the crushed and sieved ammonium chloride, potassium chloride, calcium superphosphate, ammonium sulfate, ammonium molybdate, earthworm manure organic fertilizer, humic acid, attapulgite clay powder, chitosan oligosaccharide, dandelion extract, and compound microbial agent uniformly, and granulating to obtain the compound fertilizer special for rice for preventing and treating rice seedling blight.

5. The use of the compound fertilizer for rice according to any one of claims 1 to 3 for the control of rice seedling blight caused by Fusarium species, characterized in that, The compound fertilizer special for rice for preventing and treating rice seedling blight is used in the process of rice dry seedling.