Pelletizing method for alfalfa seeds used in coastal saline-alkali area

Abstract

The invention relates to the technical field of seed treatment, and provides a pelleting method for alfalfa seeds used in a coastal saline-alkali district, and the alfalfa seeds sequentially comprise seeds, a hormone layer, a first oxygenation breathable layer, a nutrition layer, a second oxygenation breathable layer and an outer protection layer from inside to outside; the raw material of the hormone layer comprises gibberellin; the raw materials of the first oxygen-increasing breathable layer comprise an adhesive and a functional material; the raw material of the second oxygenation breathable layer comprises a functional material; the functional material comprises gypsum and / or calcium peroxide; the raw material of the outer protection layer comprises organic acid. By means of the technical scheme, the problem that the emergence rate of alfalfa seeds is low due to the fact that saline-alkali soil in a saline-alkali area is large in viscosity and poor in air permeability in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of seed treatment, and specifically, to a pelleting method for alfalfa seeds used in coastal saline-alkali areas. Background Art

[0002] Soil salinization has become one of the global problems. China is one of the countries with a large area of salinized land in the world. The Bohai Rim region is a concentrated distribution area of coastal saline-alkali land in China. Alfalfa ( Medicagospp. ) is a high-quality leguminous forage with rich protein content, high and stable yield, and high feeding value; alfalfa also has the advantages of being cold and drought tolerant, saline-alkali tolerant, and barren tolerant due to its developed root system, and plays an important role in the efficient utilization and improvement of saline-alkali land in China. However, alfalfa seeds are small and light, and do not meet the requirements of mechanized precision seeding. After pelleting, the quality and volume of alfalfa seeds can be significantly increased; the growth regulators, nutrients, insecticides, and fungicides contained in the seed coating can also improve the resistance of seeds to adverse environments.

[0003] Currently, the pelleting method for promoting seed germination under adverse conditions has become the research focus in the domestic seed processing field. For example, the patent with the publication number CN109042656B discloses a pelleting formula for alfalfa seeds and its preparation method to improve the germination ability of alfalfa seeds under saline-alkali stress. However, the germination of pelleted seeds in China is unstable and the emergence is not ideal, which limits the popularization and application of pelleted alfalfa products in coastal saline-alkali areas. In this area, saline-alkali stress is the most concerned issue among scholars. Among them, the large soil bulk density, low porosity, and poor water permeability and air permeability are important regional environmental factors restricting the germination of alfalfa seeds. The existing pelleting formulas and technologies mostly use water retention agents such as superabsorbent resins to promote seed germination under drought conditions. However, in this area, the drought in spring and autumn usually lasts for a long time, and the pelleted seeds will show the phenomenon of flash seedlings; after rainfall, the soil is sticky and the air permeability is even worse. The pelleted seeds added with water retention agents are wrapped in a "water ball", making the seeds lack oxygen and unable to germinate or emerge above the soil. Therefore, developing a pelleting production process that can overcome problems such as large viscosity and poor air permeability of saline-alkali soil can not only realize the mechanized precision seeding of alfalfa, but also effectively ensure the emergence rate and strong seedlings, which has important practical significance for the comprehensive and efficient utilization of saline-alkali land. Summary of the Invention

[0004] The present invention provides a pelleting method for alfalfa seeds used in coastal saline-alkali areas, which solves the problem of low emergence rate of alfalfa seeds due to the large viscosity and poor air permeability of saline-alkali soil in related technologies.

[0005] The technical solution of the present invention is as follows: The present invention provides an alfalfa seed for coastal saline-alkali areas, which sequentially includes a seed, a hormone layer, a first oxygen-increasing and air-permeable layer, a nutrient layer, a second oxygen-increasing and air-permeable layer, and an outer protective layer from the inside out; The raw materials of the hormone layer include gibberellin; The raw materials of the first oxygen-increasing and air-permeable layer include an adhesive and a functional material; The raw materials of the second oxygen-increasing and air-permeable layer include a functional material; The functional material includes gypsum and / or calcium peroxide; The raw materials of the outer protective layer include organic acid.

[0006] In the present invention, a dyeing layer can be further provided outside the outer protective layer of the pelleted alfalfa seeds according to actual needs.

[0007] As a further technical solution, the gibberellin is introduced by a gibberellin solution, and the mass-volume ratio of gibberellin to the solvent in the gibberellin solution is 100-150 mg:1 L.

[0008] As a further technical solution, in the first oxygen-increasing and air-permeable layer, the mass ratio of the adhesive to the functional material is 1:8-10.

[0009] As a further technical solution, the raw materials of the nutrient layer include one or more of molybdenum fertilizer, zinc fertilizer, potassium dihydrogen phosphate, and attapulgite, Preferably, the raw materials of the nutrient layer include molybdenum fertilizer, zinc fertilizer, potassium dihydrogen phosphate, and attapulgite in a mass ratio of 1:1:1:50-70.

[0010] In the present invention, the molybdenum fertilizer in the nutrient layer can smoothly convert nitrate nitrogen, providing sufficient nitrogen source for the growth of alfalfa seeds. The molybdenum fertilizer can be ammonium molybdate, sodium molybdate, etc., and preferably ammonium molybdate.

[0011] In the present invention, the zinc fertilizer in the nutrient layer is a component or activator of many enzymes, promoting the absorption and utilization of various nutrient elements by alfalfa seeds and providing power for seed growth. The zinc fertilizer can be zinc sulfate monohydrate, zinc sulfate heptahydrate, zinc chloride, etc., and preferably zinc sulfate heptahydrate.

[0012] In the present invention, the potassium dihydrogen phosphate in the nutrient layer contains phosphorus and potassium elements essential for plant growth, and the pore structure of attapulgite can adsorb and store a large amount of water and nutrients, promoting the germination and growth of seeds.

[0013] As a further technical solution, the organic acid includes one or more of citric acid, malic acid, and tartaric acid, Preferably, the organic acid is citric acid.

[0014] As a further technical solution, the raw materials of the hormone layer and the outer protective layer each independently further include a filler; In the hormone layer, the mass of gibberellin is 0.02% - 0.03% of the mass of the filler; In the outer protective layer, the mass of the organic acid is 10% - 20% of the mass of the filler.

[0015] As a further technical solution, the filler includes one or more of attapulgite, bentonite, corn cob biochar, and peanut shell powder, Preferably, the filler in the hormone layer is attapulgite, bentonite, and peanut shell powder with a mass ratio of 60 - 80:20:10, and the filler in the outer protective layer is calcium-based bentonite.

[0016] As a further technical solution, when the functional material includes gypsum and calcium peroxide, the mass ratio of gypsum to calcium peroxide is 1:1 - 3.

[0017] In the present invention, the addition of the filler in the hormone layer and the outer protective layer can not only adjust the size and shape of the seed pellets, but also enhance the pellet strength, regulate the release of seed nutrients, control the nutrient release rate, increase the air permeability of the pelleted alfalfa seeds, and maintain the nutrient balance to ensure that the seeds can obtain a comprehensive and balanced nutrient supply during the germination and seedling stages.

[0018] As a further technical solution, the particle size of the calcium peroxide is 60 - 90 mesh; The particle size of the gypsum is 20 - 40 mesh; The mass fraction of the binder is 0.5% - 1%, and the binder includes one or more of hydroxy methyl cellulose, sodium hydroxy methyl cellulose, methyl cellulose, ethyl cellulose, and polyvinyl alcohol. Preferably, the binder is sodium hydroxy methyl cellulose.

[0019] In the present invention, calcium peroxide is used as an oxygen increasing agent and releases some heat at the same time, providing heat for spring seed germination, and cooperating with the functional components of other layers to jointly promote the germination and emergence of alfalfa seeds in saline-alkali areas.

[0020] The present invention also provides a method for pelleting alfalfa seeds for use in coastal saline-alkali areas, comprising the following steps: S1. Take alfalfa seeds and mix them with the raw materials of the hormone layer to obtain a pelleted core; S2. Mix the pelleted core with the raw materials of the first oxygen increasing and air permeable layer to obtain pelleted seeds I; S3. Coating the surface of the pelleted seeds I with the nutrient layer to obtain pelleted seeds II; S4. Mix the granulated seeds II and the raw materials of the second oxygen-increasing and breathable layer to obtain granulated seeds III; S5. Mix the granulated seeds III and the raw materials of the outer protective layer to obtain granulated alfalfa seeds.

[0021] As a further technical solution, the particle size of the granulated kernel is 0.1 - 0.3 times that of the alfalfa seeds; The particle size of the granulated seeds I is 0.5 - 1.5 times that of the alfalfa seeds; The particle size of the granulated seeds II is 1.8 - 2.0 times that of the alfalfa seeds; The particle size of the granulated seeds III is 2.5 - 3.0 times that of the alfalfa seeds; The particle size of the granulated alfalfa seeds is 3.5 - 4.0 times that of the alfalfa seeds.

[0022] The working principle and beneficial effects of the present invention are as follows: In the present invention, a layered granulation method is adopted. Through the coordination of components such as gibberellin, functional materials, and organic acids located in different layers, and the construction of a porous granulated shell skeleton, the porosity of the soil around the seeds is increased; the acidic substances in the outermost protective layer are used to neutralize carbonate and bicarbonate ions in the soil to reduce the soil salinity around the seeds. The functional components between the layers interact with each other, enabling the alfalfa seeds to better adapt to the special environment of high viscosity and poor air permeability of saline-alkali soil, and significantly promoting the germination and emergence of alfalfa seeds in saline-alkali areas. Brief Description of the Drawings

[0023] The following further describes the present invention in detail with reference to the drawings and specific embodiments.

[0024] Figure 1 It is a structural sectional view of the granulated alfalfa seeds prepared in Example 1 of the present invention; Figure 2 It is an external view of the granulated alfalfa seeds prepared in Example 1 of the present invention after being soaked in water. Specific Embodiments

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of the present invention.

[0026] Example 1 The pelleted alfalfa seeds for coastal saline-alkali areas successively include seeds, a hormone layer, an oxygen-increasing and air-permeable layer, a nutrient layer, an oxygen-increasing and air-permeable layer, an outer protective layer, and a dyeing layer from the inside to the outside; A method for pelleting alfalfa seeds for coastal saline-alkali areas, comprising the following steps: S1. Preparation of the hormone layer: First, dissolve 105 mg of gibberellin (effective content 95 wt%) in 1 L of pure water to obtain a gibberellin solution; After winnowing and manual selection, obtain yellow alfalfa seeds (Zhongmu No. 1) with a germination rate > 95%. Add 50 g of the selected alfalfa seeds to a drum pelletizer (equipment model RH-325), adjust the rotation speed to 150 r / min. After reaching this speed, start adding the gibberellin solution. Observe until the seed surface is fully wetted, and then add 500 g of a filler (a mixture of attapulgite, bentonite, and peanut shell powder with a mass ratio of 80:20:10) for mixing to obtain the pelleted core (the particle size of the pelleted core is 0.3 times the particle size of the alfalfa seeds); S2. Preparation of the oxygen-increasing and air-permeable layer: Pour 2 g of sodium carboxymethylcellulose into 400 g of distilled water and continuously stir until dissolved to prepare an adhesive solution with a mass fraction of 0.5%; Add the adhesive solution, gypsum (particle size 30 mesh) and calcium peroxide (particle size 80 mesh) with a mass ratio of 1:3 to the pelletizer and mix with the pelleted core. Take out a small amount of pelleted seeds and measure the particle size to obtain pelleted seeds I, and the particle size of pelleted seeds I is 1.5 times the particle size of the alfalfa seeds; S3. Preparation of the nutrient layer: Mix 1 g of ammonium molybdate, 1 g of zinc sulfate heptahydrate, 1 g of potassium dihydrogen phosphate, and 50 g of attapulgite to obtain the raw material of the nutrient layer, and continue to coat the nutrient layer on the surface of pelleted seeds I to obtain pelleted seeds II, and the particle size of pelleted seeds II is 2.0 times the particle size of the alfalfa seeds; S4. Preparation of the oxygen-increasing and air-permeable layer: Mix pelleted seeds II and calcium peroxide (particle size 80 mesh) to obtain pelleted seeds III, and the particle size of pelleted seeds III is 3.0 times the particle size of the alfalfa seeds; S5. Preparation of the outer protective layer: After mixing citric acid and calcium-based bentonite (the mass of citric acid is 10% of the mass of calcium-based bentonite), add them into the pelletizer and mix with pelletized seeds III, run idly for 5 minutes, polish, screen and grade, select pelletized seeds with a particle size of about 5.5 cm, transfer them to the water chestnut-type coating machine (equipment model BY-400), run at a speed of 60r / min and a hot air setting of 50°C, spray the dye on the rolling pelletized seeds until the dyeing is uniform, transfer the dyed seeds to the dryer, dry them at 40°C for 20 minutes, and obtain pelletized alfalfa seeds (the particle size of the pelletized alfalfa seeds is 4.0 times the particle size of the alfalfa seeds). The structural profile of the pelletized alfalfa seeds is shown in the figure below. Figure 1 The appearance of pelletized alfalfa seeds after soaking in water is shown in Figure 2 shown.

[0027] Example 2 The difference between this embodiment and embodiment 1 is that the alfalfa seeds (Zhongmu No. 1) are replaced with alfalfa seeds (Zhongmu No. 3).

[0028] Example 3 The pelletized alfalfa seeds used in coastal saline-alkali areas include seeds, hormone layer, oxygen-enhancing breathable layer, nutrient layer, oxygen-enhancing breathable layer, and outer protective layer from the inside out. The pelleting method of alfalfa seeds for coastal saline-alkali areas comprises the following steps: S1. Preparation of hormone layer: First, dissolve 100 mg of gibberellin (effective content 95 wt%) in 1 L of pure water to obtain a gibberellin solution; After winnowing and manual selection, yellow alfalfa seeds (Zhongmu No. 1) with a germination rate of >95% were obtained. 50 g of the selected alfalfa seeds were added to a drum pelletizer (equipment model RH-325), and the speed was adjusted to 150 r / min. After reaching the speed, the gibberellin solution was added, and the seed epidermis was observed to be fully moistened. 500 g of filler (a mixture of attapulgite, bentonite and peanut shell powder in a mass ratio of 70:20:10) was added and mixed to obtain a pelletized kernel (the particle size of the pelletized kernel was 0.1 times the particle size of the alfalfa seed); S2. Preparation of oxygen-enhancing breathable layer: Pour 4g of sodium carboxymethyl cellulose into 400g of distilled water and stir until dissolved to prepare a 1% binder solution; Adding a binder solution, gypsum (with a particle size of 20 mesh) and calcium peroxide (with a particle size of 70 mesh) in a mass ratio of 1:2 into a pelletizer and mixing with the pelletized kernels, taking out a small amount of pelletized seeds, measuring the particle size, and obtaining pelletized seeds I, wherein the particle size of the pelletized seeds I is 0.5 times that of alfalfa seeds; S3. Preparation of nutrient layer: 1 g of ammonium molybdate, 1 g of zinc sulfate heptahydrate, 1 g of potassium dihydrogen phosphate and 30 g of attapulgite were mixed to obtain a raw material for a nutrient layer, and the nutrient layer was further coated on the surface of pelletized seeds I to obtain pelletized seeds II, wherein the particle size of pelletized seeds II was 1.8 times that of alfalfa seeds; S4. Preparation of oxygen-enhancing breathable layer: The pelletized seeds II and calcium peroxide (with a particle size of 70 meshes) are mixed to obtain pelletized seeds III, wherein the particle size of the pelletized seeds III is 2.5 times that of the alfalfa seeds; S5. Preparation of outer protective layer: After mixing citric acid and calcium-based bentonite (the mass of citric acid is 20% of the mass of calcium-based bentonite), add the mixture into a pelletizer, mix with pelletized seeds III, run idle for 5 minutes, polish, sieve and grade, select pelletized seeds with a particle size of about 5.5 cm, transfer them to a water chestnut-type coating machine (equipment model BY-400), operate at a speed of 60 r / min and a hot air setting of 50°C, spray a dye on the rolling pelletized seeds until the dyeing is uniform, transfer the dyed seeds into a dryer, dry them at 40°C for 20 minutes, and obtain pelletized alfalfa seeds (the particle size of the pelletized alfalfa seeds is 3.5 times that of the alfalfa seeds).

[0029] Example 4 The pelletized alfalfa seeds used in coastal saline-alkali areas include seeds, hormone layer, oxygen-enhancing breathable layer, nutrient layer, oxygen-enhancing breathable layer, and outer protective layer from the inside out. The pelleting method of alfalfa seeds for coastal saline-alkali areas comprises the following steps: S1. Preparation of hormone layer: First, dissolve 150 mg of gibberellin (effective content 95 wt%) in 1 L of pure water to obtain a gibberellin solution; After winnowing and manual selection, yellow alfalfa seeds (Zhongmu No. 1) with a germination rate of >95% were obtained. 50 g of the screened alfalfa seeds were added to a drum pelletizer (equipment model RH-325), and the speed was adjusted to 150 r / min. After reaching the speed, the gibberellin solution was added, and the seed epidermis was observed to be fully moistened. 500 g of filler (a mixture of attapulgite, bentonite and peanut shell powder in a mass ratio of 60:20:10) was added and mixed to obtain a pelletized kernel (the particle size of the pelletized kernel was 0.2 times the particle size of the alfalfa seed); S2. Preparation of oxygen-enhancing breathable layer: Pour 2g of sodium carboxymethyl cellulose into 400g of distilled water and stir until dissolved to prepare a binder solution with a mass fraction of 0.5%; Adding a binder solution, gypsum (with a particle size of 40 mesh) and calcium peroxide (with a particle size of 90 mesh) in a mass ratio of 1:1 into a pelletizer and mixing with the pelletized kernels, taking out a small amount of pelletized seeds, measuring the particle size, and obtaining pelletized seeds I, wherein the particle size of the pelletized seeds I is 1 times that of alfalfa seeds; S3. Preparation of nutrient layer: 1 g of ammonium molybdate, 1 g of zinc sulfate heptahydrate, 1 g of potassium dihydrogen phosphate and 70 g of attapulgite were mixed to obtain a raw material for a nutrient layer, and the nutrient layer was further coated on the surface of pelletized seeds I to obtain pelletized seeds II, the particle size of pelletized seeds II being 1.9 times that of alfalfa seeds; S4. Preparation of oxygen-enhancing breathable layer: The pelletized seeds II and calcium peroxide (with a particle size of 90 meshes) are mixed to obtain pelletized seeds III, wherein the particle size of the pelletized seeds III is 2.8 times that of the alfalfa seeds; S5. Preparation of outer protective layer: After mixing citric acid and calcium-based bentonite (the mass of citric acid is 15% of the mass of calcium-based bentonite), add the mixture into a pelletizer, mix with pelletized seeds III, run idle for 5 minutes, polish, sieve and grade, select pelletized seeds with a particle size of about 5.5 cm, transfer them to a water chestnut-type coating machine (equipment model BY-400), operate at a speed of 60 r / min and a hot air setting of 50°C, spray a dye on the rolling pelletized seeds until the dyeing is uniform, transfer the dyed seeds into a dryer, dry them at 40°C for 20 minutes, and obtain pelletized alfalfa seeds (the particle size of the pelletized alfalfa seeds is 3.8 times that of the alfalfa seeds).

[0030] Example 5 The difference between this embodiment and embodiment 1 is that citric acid is replaced by humic acid.

[0031] Example 6 The only difference between this embodiment and embodiment 1 is that in the preparation of the first oxygen-enhancing air-permeable layer in step S2, gypsum is replaced by an equal amount of calcium peroxide.

[0032] Example 7 The difference between this embodiment and embodiment 1 is that in the preparation of the first oxygen-enhancing air-permeable layer in step S2, calcium peroxide is replaced by an equal amount of gypsum.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that no gibberellin solution is added during the preparation of the hormone layer in step S1.

[0034] Comparative Example 2 The difference between this comparative example and Example 1 is only that when preparing the first oxygen-increasing and breathable layer in step S2, calcium peroxide is replaced with an equal amount of gypsum, and the second oxygen-increasing and breathable layer is not prepared.

[0035] Comparative Example 3 The difference between this comparative example and Example 1 is only that when preparing the outer protective layer in step S5, citric acid is not added.

[0036] Experimental Example 1 Taking naked seeds as the control, three groups of 100 seeds of each kind of pelleted alfalfa seeds were randomly selected, and the weight and particle size of each group of seeds were measured; secondly, the compressive resistance and water absorption performance of the pelleted seeds were measured.

[0037] Compressive resistance: The maximum pressure value was measured one by one with a particle strength tester, and the arithmetic mean was taken as the measured value.

[0038] Water absorption performance: A single layer of filter paper was placed in a drying petri dish, 20 ml of distilled water was added to the filter paper and fully wetted, the total weight G1 was weighed, the total weight G2 of 50 pelleted seeds was weighed, the 50 pelleted seeds were evenly distributed on the filter paper, and after the pelleted seeds had fully absorbed water, they were taken out and the pelleted materials scattered on the filter paper were carefully cleaned, and then the weight G3 of the petri dish and the filter paper was weighed again. Then the water absorption performance of the pelleted seeds was calculated according to the formula.

[0039] Water absorption performance = (G1 - G3) / G2 × 100% The results are shown in Table 1 below.

[0040] Table 1 Physical properties of pelleted alfalfa seeds (mean ± standard deviation)

[0041] As can be seen from Table 1, compared with naked seeds, the 1000-grain weight and particle size of the pelleted alfalfa seeds prepared in Examples 1 to 4 were significantly increased, and at the same time, the pelleted alfalfa seeds had excellent compressive resistance and could achieve mechanized precision seeding.

[0042] Experimental Example 2 The following germination characteristic tests were respectively carried out on the pelleted alfalfa seeds prepared in Examples 1 to 7 and Comparative Examples 1 to 4: Take 4 groups each of pelleted alfalfa seeds and unpelleted alfalfa seeds (CK), with 20 seeds in each group. Plant the seeds in flower pots at a sowing depth of 1.5 cm. The tested soil is coastal saline-alkali soil with a soil salt content of 3.5%. Set the soil water contents to 20% and 40% respectively to simulate two soil moisture conditions of drought and excessive moisture. Place the flower pots in an artificial climate chamber with the temperature set at 25 / 20 °C, 14 h of darkness / 10 h of light. During the experiment, replenish water regularly by the weighing method. After sowing, record the seed emergence rate every day. The experiment lasts for 7 days. At the end, measure the seedling height, fresh weight, and dry weight of the seedlings. The results are shown in Table 2.

[0043] Table 2 Germination characteristics of pelleted alfalfa seeds (mean ± standard deviation)

[0044] As can be seen from Table 2, compared with the unpelleted alfalfa seeds, the emergence rate of the pelleted alfalfa seeds in Examples 1 - 4 increased by 10.2% - 19.6%. Under the condition of sufficient soil moisture, the emergence rate of the pelleted alfalfa seeds exceeded 90%, and the seedling height and seedling weight were higher than those of the unpelleted alfalfa seeds. Compared with Comparative Examples 1 - 4, the emergence rate of the pelleted alfalfa seeds in Examples 1 - 4 is higher, indicating that for the layered pelleted alfalfa seeds of the present invention, the functional components between layers interact with each other, significantly promoting the germination and emergence of alfalfa seeds in coastal saline-alkali soil.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An alfalfa seed for coastal saline-alkali areas, characterized in that, It includes a seed, a hormone layer, a first oxygen-increasing and breathable layer, a nutrient layer, a second oxygen-increasing and breathable layer, and an outer protective layer from the inside to the outside in sequence; The raw materials of the hormone layer include gibberellin; The raw materials of the first oxygen-increasing and breathable layer include an adhesive and a functional material; The raw materials of the second oxygen-increasing and breathable layer include a functional material; The functional material includes gypsum and / or calcium peroxide; The raw materials of the outer protective layer include organic acids.

2. The alfalfa seeds for coastal saline-alkali areas according to claim 1, characterized in that The gibberellin is introduced by a gibberellin solution, and the mass-volume ratio of gibberellin to the solvent in the gibberellin solution is 100-150 mg:1 L.

3. The alfalfa seeds for coastal saline-alkali areas according to claim 1, characterized in that, In the first oxygen-increasing and breathable layer, the mass ratio of the adhesive to the functional material is 1:8-10.

4. The alfalfa seeds for coastal saline-alkali areas according to claim 1, characterized in that, The raw materials of the nutrient layer include one or more of molybdenum fertilizer, zinc fertilizer, potassium dihydrogen phosphate, and attapulgite; Preferably, the raw materials of the nutrient layer include molybdenum fertilizer, zinc fertilizer, potassium dihydrogen phosphate, and attapulgite in a mass ratio of 1:1:1:50-70.

5. A alfalfa seed for coastal saline-alkali areas according to claim 1, characterized in that, The organic acids include one or more of citric acid, malic acid, and tartaric acid.

6. The alfalfa seeds for the coastal saline-alkali area according to claim 1, characterized in that, The raw materials of the hormone layer and the outer protective layer also independently include a filler; In the hormone layer, the mass of the gibberellin is 0.02%-0.03% of the mass of the filler; In the outer protective layer, the mass of the organic acid is 10%-20% of the mass of the filler.

7. The alfalfa seeds for coastal saline-alkali areas according to claim 6, characterized in that, The filler includes one or more of attapulgite, bentonite, corn cob biochar, and peanut shell powder; Preferably, the filler in the hormone layer is attapulgite, bentonite, and peanut shell powder in a mass ratio of 60-80:20:10, and the filler in the outer protective layer is calcium-based bentonite.

8. A kind of alfalfa seed used in coastal saline-alkali areas according to claim 1, characterized in that, When the functional material includes gypsum and calcium peroxide, the mass ratio of the gypsum to the calcium peroxide is 1:1-3.

9. A pelleting method for alfalfa seeds used in coastal saline-alkali areas according to any one of claims 1 to 8, characterized in that, It includes the following steps: S1. Take alfalfa seeds and mix them with the raw materials of the hormone layer to obtain a granulated core; S2. Mix the granulated core with the raw materials of the first oxygen-increasing and breathable layer to obtain granulated seeds I; S3. Coating the surface of the granulated seeds I with the nutrient layer to obtain granulated seeds II; S4. Mix the granulated seeds II with the raw materials of the second oxygen-increasing and breathable layer to obtain granulated seeds III; S5. Mix the granulated seeds III with the raw materials of the outer protective layer to obtain granulated alfalfa seeds.

10. A pelleting method for alfalfa seeds used in coastal saline-alkali areas according to claim 9, characterized in that, The particle size of the granulated core is 0.1-0.3 times the particle size of the alfalfa seeds; The particle size of the granulated seeds I is 0.5-1.5 times the particle size of the alfalfa seeds; The particle size of the granulated seeds II is 1.8-2.0 times the particle size of the alfalfa seeds; The particle size of the granulated seeds III is 2.5-3.0 times the particle size of the alfalfa seeds; The particle size of the granulated alfalfa seeds is 3.5-4.0 times the particle size of the alfalfa seeds.

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