Alfalfa seed pellet coating material and preparation method of alfalfa seed pellets

Abstract

The invention relates to the technical field of seed pelleting processing, in particular to an alfalfa seed pelleting material and a preparation method of alfalfa seed pellets. Through scientific compatibility and synergistic effects in a pill coating material system, the water-retaining agent guarantees a moisture basis, the microbial agent constructs a biological barrier and promotes conversion, the inorganic nutrients provide material support, and the bioactive substances stimulate intrinsic potentials and synergistically act on the alfalfa seed germination physiological process, so that the alfalfa seed germination rate is increased, and the alfalfa seed germination rate is increased. Finally, the technical effects of remarkably promoting the germination rate and uniformity of the seeds and improving the nodulation rate are achieved, and a solid foundation is laid for developing high-quality and high-yield alfalfa seeds.

Description

Technical Field

[0001] This invention relates to the field of seed pelleting technology, and in particular to an alfalfa seed pelleting material and a method for preparing alfalfa seed pellets. Background Technology

[0002] Seed pelleting is a new seed treatment method designed to meet the needs of mechanized precision sowing. By coating seeds with a functional outer layer, seed morphology is improved, small seeds are enlarged, and light seeds are made heavier, thus achieving precise, uniform, and efficient mechanized sowing, improving sowing performance, and significantly reducing the sowing amount.

[0003] Currently, the application of seed pelleting has expanded from vegetables, tobacco, flowers, and forage grasses to field crops and cash crops such as corn and cotton. Numerous mature pelleting coating technologies have been developed and put into application. For example, CN1137615C discloses a corn seed pelleting processing technology, CN1049792C discloses a pelleting manufacturing method for small seeds, and CN100556291C discloses a pelleting formula and processing method for flower microparticle seeds. In recent years, pelleting technology has moved towards standardization, simplification, and intelligentization, significantly improving sowing precision, germination rate, and crop production efficiency, becoming an important component of the modern agricultural technology system.

[0004] Alfalfa seeds are small, have a low thousand-seed weight, and are irregularly shaped. Traditional direct sowing methods easily lead to uneven sowing depth, high seed consumption, and inconsistent seedling emergence, affecting the alfalfa seedling population structure, yield, and quality. This severely restricts modern precision sowing, yield improvement, and quality enhancement of alfalfa. Pelletizing alfalfa seeds can significantly improve seed germination rate and seedling uniformity under adverse conditions such as drought and salinity, and provide crucial protection for seedlings, effectively reducing the risk of missing seedlings and ensuring population density and health. This technology is a comprehensive and highly efficient support for overcoming the defects of the original seed, achieving precision sowing and cost reduction, ensuring efficient nitrogen fixation, improving stress resistance and seedling protection, and ultimately achieving the goal of high-quality, high-yield, and stable alfalfa production. It has significant practical implications for improving the efficiency of alfalfa cultivation and the overall industry level.

[0005] Specifically, direct seeding of alfalfa faces multiple challenges, resulting in slow early growth, weak and sparse seedlings, which significantly affect the success rate of establishment and early growth. The main reasons are: (1) Temperature constraints: Low temperatures in spring delay seed germination and emergence, and seedling growth is slow; if early frost occurs in autumn, the growing period is insufficient, making it difficult to safely overwinter. (2) Climate challenges: Drought and low rainfall in spring, with high evaporation, lead to insufficient soil moisture, affecting seed water absorption and germination and seedling root development; late frost damage can easily damage tender seedlings, and windy conditions in spring also exacerbate soil moisture loss. (3) Difficulty in rhizobium colonization: Low temperature, drought, and barren soil environment significantly inhibit rhizobium activity and colonization efficiency, resulting in weak nitrogen fixation capacity and insufficient nutrient supply in seedlings, manifested as stunted plants, yellowing, and stunted growth. These factors combine to severely limit the early establishment speed and robustness of alfalfa seedlings, which is an important limiting factor for high and stable alfalfa yield.

[0006] In the prior art, CN109005751A discloses a formulation and processing method for pelleting salt-tolerant alfalfa seeds, and CN109042656A discloses a formulation and preparation method for pelleting alfalfa seeds. These methods, through the use of binders, inert additives, dyes, ascorbic acid, and glutathione, respectively, improve the salt stress resistance of alfalfa seeds, enhance seed vigor, shorten the average germination time, and exhibit a certain germination-promoting effect. However, how to further improve the germination rate, uniformity, and nodule formation rate of alfalfa seeds remains a technical challenge that needs to be addressed. Summary of the Invention

[0007] To solve the above-mentioned technical problems, the present invention provides an alfalfa seed pelleting material, the raw materials of which include: filler, binder and functional additives; The functional additives include: sodium alginate, mineral-derived organic biostimulants, inorganic nutrients, chitosan oligosaccharides, compound microbial agents, and water-retaining agents; The compound microbial inoculant includes: arbuscular mycorrhizal fungi and rhizobia; The inorganic nutrients include: ammonium polyphosphate, zinc sulfate monohydrate, and ammonium molybdate; The water-retaining agent is a polyacrylate-based water-retaining agent.

[0008] This invention, targeting alfalfa seeds, discovers that inorganic nutrients such as ammonium polyphosphate, zinc sulfate monohydrate, and ammonium molybdate are crucial for improving alfalfa seed germination rate, uniformity, and post-germination nodule formation rate. These nutrients are slowly released during the critical window of seed germination and seedling growth, providing immediate nutritional support for early root development and energy metabolism, laying the foundation for robust seedlings. Furthermore, when combined with sodium alginate and mineral-derived organic biostimulants as pelleting materials, sodium alginate and the mineral-derived organic biostimulants can promote the absorption of these inorganic nutrients by alfalfa seeds, significantly improving germination rate, uniformity, and post-germination nodule formation rate.

[0009] Furthermore, this invention reveals that a compound microbial inoculant composed of arbuscular mycorrhizal fungi and rhizobia can also colonize the seed pellets and rhizosphere. Through synergistic effects with the aforementioned inorganic nutrients, sodium alginate, and mineral-derived organic biostimulants, it further enhances the nodulation rate of alfalfa seeds after germination. Moreover, the compound microbial inoculant also aids in nutrient conversion, antagonizes soil-borne diseases, and improves the adaptability and overall stress resistance of alfalfa seeds and seedlings.

[0010] In addition, in the pelleting material system of the present invention, chitosan oligosaccharide can promote the function of the compound microbial agent, thereby further improving the nodulation rate of alfalfa seeds after germination. At the same time, chitosan oligosaccharide also helps to promote the absorption of the above-mentioned inorganic nutrients by alfalfa seeds and improve nutrient availability.

[0011] Furthermore, in the pelleting material system of this invention, the selection of polyacrylate water-retaining agents can significantly enhance the pelleting's ability to absorb and retain water under adverse conditions such as low temperature and drought, providing a stable and continuous water microenvironment for the early stage of seed germination, promoting further absorption of inorganic nutrients, and thus working synergistically with inorganic nutrients, sodium alginate, and mineral-derived organic biostimulants to improve the germination rate, uniformity, and nodulation rate of alfalfa seeds after germination.

[0012] In some embodiments, the polyacrylate water-retaining agent includes at least one of polyacrylamide, potassium polyacrylate, and cross-linked sodium polyacrylate.

[0013] In some embodiments, the mass ratio of arbuscular mycorrhizal fungi to rhizobia in the compound microbial agent is 1:(20~30).

[0014] Preferably, the mass ratio of arbuscular mycorrhizal fungi to rhizobia is 1:(22~28).

[0015] More preferably, the mass ratio of arbuscular mycorrhizal fungi to rhizobia is 1:(24~26).

[0016] At the above mass ratio, the compound microbial agent has a better effect.

[0017] In some embodiments, the mass ratio of the chitosan oligosaccharide to the compound microbial agent is 1:(1000~1500).

[0018] Preferably, the mass ratio of the chitosan oligosaccharide to the compound microbial agent is 1:(1000~1200).

[0019] More preferably, the mass ratio of the chitosan oligosaccharide to the compound microbial agent is 1:(1000~1100).

[0020] At the above mass ratio, chitosan oligosaccharide has a better promoting effect on compound microbial agents.

[0021] In some embodiments, the inorganic nutrients are in the mass ratio of ammonium polyphosphate, zinc sulfate monohydrate and ammonium molybdate as (45~55):(2~8):1.

[0022] Preferably, the mass ratio of ammonium polyphosphate, zinc sulfate monohydrate, and ammonium molybdate is (48~52):(4~6):1.

[0023] At the above mass ratio, inorganic nutrients are more conducive to promoting alfalfa seed germination.

[0024] In some implementation schemes, ammonium polyphosphate accounts for 1%-5% of the total mass of alfalfa seed pelleting material, zinc sulfate monohydrate accounts for 0.1%-0.3% of the total mass of alfalfa seed pelleting material, and ammonium molybdate accounts for 0.02%-0.06% of the total mass of alfalfa seed pelleting material.

[0025] In some embodiments, the mass ratio of sodium alginate, mineral-derived organic biostimulants, and inorganic nutrients is 1:(45~55):(30~40).

[0026] Preferably, the mass ratio of sodium alginate, mineral-derived organic biostimulants and inorganic nutrients is 1:(48~52):(30~35).

[0027] At the above mass ratio, sodium alginate and mineral-derived organic biostimulants have a stronger promoting effect on the absorption of inorganic nutrients by alfalfa seeds.

[0028] In some implementation schemes, mineral-derived organic biostimulants account for 3%-5% of the total mass of alfalfa seed pelleting material.

[0029] In some embodiments, the filler includes at least one of bentonite, kaolin, attapulgite, diatomaceous earth, vermiculite powder, perlite powder, talc powder, peat, lignin sulfonate, cellulose powder, and starch.

[0030] In some embodiments, the adhesive comprises at least one of the following: sodium carboxymethyl cellulose (CMC-Na), polyvinyl acetate, hydroxyethyl cellulose, methyl cellulose, polyvinylpyrrolidone, pregelatinized starch, dextrin, sodium carboxymethyl starch, guar gum, xanthan gum, gum arabic, sodium alginate, polyvinyl alcohol, sodium polyacrylate, and polyethylene glycol.

[0031] In some embodiments, the mineral-derived organic biostimulant includes at least one of humic acid and potassium fulvate.

[0032] Preferably, the filler includes bentonite, diatomaceous earth, and peat.

[0033] Preferably, the bentonite is sodium-based bentonite with an expansion ratio ≥ 8.

[0034] Preferably, the particle size of the filler is <200 mesh.

[0035] In some embodiments, the adhesive is sodium carboxymethyl cellulose.

[0036] Preferably, the mass ratio of sodium carboxymethyl cellulose to sodium alginate is 4:(1-4).

[0037] Sodium alginate in this invention also functions as a binder. This invention has found that, for the alfalfa seed pelleting material system of this invention, when sodium carboxymethyl cellulose and sodium alginate are combined as a binder, the disintegration rate can be better controlled within a suitable range, which is beneficial to improving the germination rate and uniformity of alfalfa seeds.

[0038] Preferably, the mass ratio of bentonite, diatomite, and peat is (3~8):(1~2):1.

[0039] As a preferred embodiment, the raw materials for alfalfa seed pelleting material include the following components by weight: 40-60 parts bentonite, 15-20 parts diatomaceous earth, 5-15 parts peat, 0.2-0.8 parts sodium carboxymethyl cellulose, 0.05-1 parts sodium alginate, 1-5 parts ammonium polyphosphate, 0.1-0.8 parts zinc sulfate monohydrate, 0.02-0.1 parts ammonium molybdate, 2-8 parts humic acid, 0.001-0.008 parts chitosan oligosaccharide, 0.1-0.5 parts arbuscular mycorrhizal fungi, 2-8 parts rhizobium, 1-5 parts water-retaining agent, and 20-30 parts water.

[0040] More preferably, the raw materials include the following components by weight: 48-52 parts bentonite, 16-20 parts diatomaceous earth, 8-12 parts peat, 0.2-0.6 parts sodium carboxymethyl cellulose, 0.08-0.15 parts sodium alginate, 2-4 parts ammonium polyphosphate, 0.2-0.4 parts zinc sulfate monohydrate, 0.05-0.08 parts ammonium molybdate, 4-6 parts humic acid, 0.002-0.004 parts chitosan oligosaccharide, 0.1-0.15 parts arbuscular mycorrhizal fungi, 2-4 parts rhizobium, and 1-3 parts water-retaining agent.

[0041] Preferably, the raw materials also include 20-30 parts of water.

[0042] Furthermore, the present invention provides a method for preparing alfalfa seed pellets, comprising: coating alfalfa seeds with the aforementioned alfalfa seed pelleting material.

[0043] Preferably, the mass ratio of alfalfa seeds to pelleting material is 1:(0.3-5).

[0044] Preferably, the preparation method includes: The alfalfa seeds are rolled at a uniform speed, and a portion of the binder aqueous solution (preferably 20%-30% of the total amount) and a portion of the filler (preferably 20%-35% of the total amount) are added alternately in sequence, while chitosan oligosaccharide is added to form smaller pelleted seeds; the binder aqueous solution (preferably 40%-70% of the total amount) and a portion of the filler (preferably 55%-65% of the total amount) are added alternately in sequence, while sodium alginate, mineral-derived organic biostimulants, inorganic nutrients, arbuscular mycorrhizal fungi, and water-retaining agents are added (preferably in small amounts and in multiple alternating additions) to form medium-sized pelleted seeds; the remaining portion of the binder aqueous solution and filler are added alternately in sequence, while rhizobia are added to obtain alfalfa seed pellets of the target particle size.

[0045] Preferably, after obtaining alfalfa seed pellets of the target particle size, they are dried at 35℃~40℃ until the moisture content is <10%.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides an alfalfa seed pelleting material. Through the scientific formulation and synergistic effect within the pelleting material system—water-retaining agent to ensure moisture, microbial agent to build a biological barrier and promote transformation, inorganic nutrients to provide material support, and bioactive substances to stimulate intrinsic potential—these factors work synergistically to promote the physiological process of alfalfa seed germination. Ultimately, this achieves the technical effect of significantly promoting seed germination rate and uniformity, and increasing nodulation rate, laying a solid foundation for the development of high-quality and high-yield alfalfa seeds. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. In the embodiments provided in this specification, where specific techniques or conditions are not specified, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased through legitimate channels. Parts in the following embodiments refer to parts by weight. The arbuscular mycorrhizal fungi in the following embodiments are those containing... Intra-rooted lump Arbuscular mycorrhizal fungi preparations, with a propagation count ≥70 cells / g (Jin Yuan Tang, Diege®); Rhizobium is a fungus containing... Bradyrhizobium japonicum Rhizobium preparations with an effective viable count ≥1×10⁻⁶ 9 CFU / g (Leading Biotech, Fustar®). The bentonite in the following examples is sodium bentonite with a swelling ratio of 8. Cross-linked sodium polyacrylate (Evonik, VISIOMER®).

[0048] Example 1 This embodiment provides an alfalfa seed pelleting material, comprising the following components by weight: 50 parts bentonite, 18 parts diatomaceous earth, 10 parts peat, 0.4 parts sodium carboxymethyl cellulose, 0.1 parts sodium alginate, 3 parts ammonium polyphosphate, 0.3 parts zinc sulfate monohydrate, 0.06 parts ammonium molybdate, 5 parts humic acid, 0.003 parts chitosan oligosaccharide, 0.12 parts arbuscular mycorrhizal fungi, 3 parts rhizobium, 2 parts cross-linked sodium polyacrylate, and 25 parts water.

[0049] Furthermore, this embodiment provides alfalfa seed pellets prepared by coating the above-mentioned alfalfa seed pelleting material. The alfalfa seeds are 30 portions, with a purity >98% and a germination rate >85%. The preparation method is as follows: Prepare an adhesive solution by mixing the adhesive with water. Start the seed coating machine and roll the alfalfa seeds at a uniform speed in the trough. Simultaneously, add 20% of the total volume of the adhesive solution to the atomizing disc in the trough. After the seed surface is moistened, add 30% of the total mass of the filler, along with chitosan oligosaccharide. Add all components in small amounts and alternately to form small pellets. Continue adding 60% of the total volume of the adhesive solution and 60% of the total mass of the filler to the atomizing disc in the trough. Add sodium alginate, humic acid, ammonium polyphosphate, zinc sulfate monohydrate, ammonium molybdate, arbuscular mycorrhizal fungi, and cross-linked sodium polyacrylate. Add all components in small amounts and alternately to form medium-sized pellets. Continue adding the remaining 20% ​​of the adhesive solution and 10% of the filler to the atomizing disc in the trough, along with rhizobia, to obtain alfalfa seed pellets of the target particle size. Stop the machine, sieve the seeds, and dry them at 35℃~40℃ until the moisture content is <10%. Store them in bags for later use.

[0050] Example 2 This embodiment provides an alfalfa seed pelleting material, comprising the following components by weight: 50 parts bentonite, 18 parts diatomaceous earth, 10 parts peat, 0.4 parts sodium carboxymethyl cellulose, 0.1 parts sodium alginate, 3 parts ammonium polyphosphate, 0.3 parts zinc sulfate monohydrate, 0.06 parts ammonium molybdate, 5 parts humic acid, 0.003 parts chitosan oligosaccharide, 0.22 parts arbuscular mycorrhizal fungi, 2.9 parts rhizobium, 2 parts cross-linked sodium polyacrylate, and 25 parts water.

[0051] Furthermore, this embodiment provides alfalfa seed pellets prepared by coating the above-mentioned alfalfa seed pelleting material, prepared according to the method of Example 1.

[0052] Example 3 This embodiment provides an alfalfa seed pelleting material, comprising the following components by weight: 50 parts bentonite, 18 parts diatomaceous earth, 10 parts peat, 0.4 parts sodium carboxymethyl cellulose, 0.1 parts sodium alginate, 3 parts ammonium polyphosphate, 0.3 parts zinc sulfate monohydrate, 0.06 parts ammonium molybdate, 5 parts humic acid, 0.002 parts chitosan oligosaccharide, 0.121 parts arbuscular mycorrhizal fungi, 3 parts rhizobium, 2 parts cross-linked sodium polyacrylate, and 25 parts water.

[0053] Furthermore, this embodiment provides alfalfa seed pellets prepared by coating the above-mentioned alfalfa seed pelleting material, prepared according to the method of Example 1.

[0054] Example 4 This embodiment provides an alfalfa seed pelleting material, comprising the following components by weight: 50 parts bentonite, 18 parts diatomaceous earth, 10 parts peat, 0.4 parts sodium carboxymethyl cellulose, 0.1 parts sodium alginate, 2.8 parts ammonium polyphosphate, 0.52 parts zinc sulfate monohydrate, 0.04 parts ammonium molybdate, 5 parts humic acid, 0.002 parts chitosan oligosaccharide, 0.121 parts arbuscular mycorrhizal fungi, 3 parts rhizobium, 2 parts cross-linked sodium polyacrylate, and 25 parts water.

[0055] Furthermore, this embodiment provides alfalfa seed pellets prepared by coating the above-mentioned alfalfa seed pelleting material, prepared according to the method of Example 1.

[0056] Example 5 This embodiment provides an alfalfa seed pelleting material, comprising the following components by weight: 50 parts bentonite, 18 parts diatomaceous earth, 10 parts peat, 0.4 parts sodium carboxymethyl cellulose, 0.6 parts sodium alginate, 3 parts ammonium polyphosphate, 0.3 parts zinc sulfate monohydrate, 0.06 parts ammonium molybdate, 4.5 parts humic acid, 0.003 parts chitosan oligosaccharide, 0.12 parts arbuscular mycorrhizal fungi, 3 parts rhizobium, 2 parts cross-linked sodium polyacrylate, and 25 parts water.

[0057] Furthermore, this embodiment provides alfalfa seed pellets prepared by coating the above-mentioned alfalfa seed pelleting material, prepared according to the method of Example 1.

[0058] Comparative Example 1 This comparative example provides an alfalfa seed pelleting material, which differs from Example 1 only in that: Replace the arbuscular mycorrhizal fungi with an equal amount of Bacillus subtilis.

[0059] Furthermore, this comparative example provides alfalfa seed pellets prepared by coating the above-mentioned alfalfa seed pelleting material, prepared according to the method of Example 1.

[0060] Comparative Example 2 This comparative example provides an alfalfa seed pelleting material, which differs from Example 1 only in that: Replace the rhizobium with an equal amount of Bacillus subtilis.

[0061] Furthermore, this comparative example provides alfalfa seed pellets prepared by coating the above-mentioned alfalfa seed pelleting material, prepared according to the method of Example 1.

[0062] Comparative Example 3 This comparative example provides an alfalfa seed pelleting material, which differs from Example 1 only in that: Ammonium polyphosphate was replaced with an equal amount of a mixture of urea and monoammonium phosphate, with a mass ratio of urea to monoammonium phosphate of 1:1.

[0063] Furthermore, this comparative example provides alfalfa seed pellets prepared by coating the above-mentioned alfalfa seed pelleting material, prepared according to the method of Example 1.

[0064] Comparative Example 4 This comparative example provides an alfalfa seed pelleting material, which differs from Example 1 only in that: Replace the cross-linked sodium polyacrylate with an equal amount of carboxymethyl starch.

[0065] Furthermore, this comparative example provides alfalfa seed pellets prepared by coating the above-mentioned alfalfa seed pelleting material, prepared according to the method of Example 1.

[0066] Experimental Example 1 This experimental example measures the seed vigor index of alfalfa seed pellets prepared in the above examples and comparative examples. The steps are as follows: A paper germination test was conducted according to the germination standard of alfalfa seed pellets in the "Test Procedures for Forage Seeds" (GB / T 2930.10-2001). One hundred alfalfa seed pellets were selected for each group and placed in a 11.5×11.5cm paper containing three layers of filter paper. 2 Four replicates were performed in covered petri dishes, with naked alfalfa seeds serving as the control group (CK). The petri dishes were placed in a light incubator and cultured at a constant temperature of 20℃ under 8 hours of light and 16 hours of darkness. Initial seed counts were recorded on day 4, and final counts on day 10. The number of normal seedlings, abnormal seedlings, fresh ungerminated seeds, hardened seeds, and dead seeds were counted. After germination on day 10, 10 normal seedlings were randomly selected from the petri dishes to measure their length and weigh them, and germination potential and germination rate were calculated. Seed germination was monitored every 24 hours during the culture period, and the average germination time was calculated based on the radicle breaking through the seed coat by 2 mm.

[0067] Germination potential (%) = Number of normal seedlings in the initial germination count / Number of seeds tested; Germination rate (%) = Number of all normal seedlings at the end of germination / Number of seeds tested; Average germination time = ∑nt / Σn, where n is the number of newly germinated seeds at time t, and t is the germination time.

[0068] The test results are shown in Table 1.

[0069] Table 1

[0070] Experimental Example 2 This experiment measured the nodulation rate of alfalfa seed pellets prepared in the above examples and comparative examples after germination. The steps are as follows: The investigation was conducted 21 days (21 days) after the alfalfa seeds emerged from the seed pellets and 63 days (63 days) after the seedlings emerged. Five sites were selected in both the inoculated and control areas, and 10 plants were dug up from each site for investigation. Plants with even one visible root nodule were considered to have nodulated nodules. The ratio of nodulated nodules to the investigated plants is the nodulation rate.

[0071] The test results are shown in Table 2.

[0072] Table 2

[0073] In summary, the alfalfa seed pelleting material of the present invention is a composite alfalfa seed pelleting material system that integrates multiple functions such as moisture retention, biological growth promotion, nutritional support, and physiological activation, and achieves the technical effects of promoting seed germination rate and uniformity, and improving nodule formation rate.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An alfalfa seed pelleting material, the raw materials of which include: Fillers, binders, and functional additives; characterized in that the functional additives include: sodium alginate, mineral-derived organic biostimulants, inorganic nutrients, chitosan oligosaccharides, compound microbial agents, and water-retaining agents; The compound microbial inoculant includes: arbuscular mycorrhizal fungi and rhizobia; The inorganic nutrients include: ammonium polyphosphate, zinc sulfate monohydrate, and ammonium molybdate; The water-retaining agent is a polyacrylate-based water-retaining agent.

2. The alfalfa seed pelleting material according to claim 1, characterized in that, The polyacrylate water-retaining agent includes at least one of polyacrylamide, potassium polyacrylate, and cross-linked sodium polyacrylate.

3. The alfalfa seed pelleting material according to claim 1 or 2, characterized in that, In the compound microbial agent, the mass ratio of arbuscular mycorrhizal fungi to rhizobium is 1:(20~30).

4. The alfalfa seed pelleting material according to claim 3, characterized in that, The mass ratio of chitosan oligosaccharide to the compound microbial agent is 1:(1000~1500).

5. The alfalfa seed pelleting material according to claim 1 or 2, characterized in that, In the inorganic nutrients, the mass ratio of ammonium polyphosphate, zinc sulfate monohydrate, and ammonium molybdate is (45~55):(2~8):

1.

6. The alfalfa seed pelleting material according to claim 5, characterized in that, The mass ratio of sodium alginate, mineral-derived organic biostimulants and inorganic nutrients is 1:(45~55):(30~40).

7. The alfalfa seed pelleting material according to claim 1 or 2, characterized in that, The filler includes at least one of the following: bentonite, kaolin, attapulgite, diatomaceous earth, vermiculite powder, perlite powder, talc powder, peat, lignin sulfonate, cellulose powder, and starch; And / or, the adhesive comprises at least one of the following: sodium carboxymethyl cellulose, polyvinyl acetate, hydroxyethyl cellulose, methylcellulose, polyvinylpyrrolidone, pregelatinized starch, dextrin, sodium carboxymethyl starch, guar gum, xanthan gum, gum arabic, sodium alginate, polyvinyl alcohol, sodium polyacrylate, and polyethylene glycol; And / or, the mineral-derived organic biostimulant includes at least one of humic acid and potassium fulvate.

8. The alfalfa seed pelleting material according to claim 7, characterized in that, Its raw materials include the following components by weight: 40-60 parts bentonite, 15-20 parts diatomaceous earth, 5-15 parts peat, 0.2-0.8 parts sodium carboxymethyl cellulose, 0.05-1 parts sodium alginate, 1-5 parts ammonium polyphosphate, 0.1-0.8 parts zinc sulfate monohydrate, 0.02-0.1 parts ammonium molybdate, 2-8 parts humic acid, 0.001-0.008 parts chitosan oligosaccharide, 0.1-0.5 parts arbuscular mycorrhizal fungi, 2-8 parts rhizobium, and 1-5 parts water-retaining agent.

9. A method for preparing alfalfa seed pellets, characterized in that, include: Alfalfa seeds are coated with the alfalfa seed pelleting material according to any one of claims 1 to 8.

10. The preparation method according to claim 9, characterized in that, The mass ratio of alfalfa seeds to pelleting material is 1:(0.3-5).

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