Auxiliary fertilizer for improving salt stress resistance of rice and application

Abstract

The invention discloses an auxiliary fertilizer capable of improving salt stress resistance of rice and application of the auxiliary fertilizer. The salt stress resistance of the rice can be improved by applying pomegranate peel leavening and grape skin leavening to soil, and compared with pure use of the pomegranate peel leavening or grape skin leavening, the salt stress resistance of the rice can be improved; the pomegranate peel leavening and the grape peel leavening are compounded for use, so that the salt stress resistance of the rice is synergistically improved. Na < + > can be adsorbed through pores of the activated carbon, so that the soil conductivity is reduced, the slow release of a fermentation product is realized, the action time is prolonged, and the salt stress resistance of the rice is further improved.

Description

Technical Field

[0001] This invention relates to the field of rice cultivation technology, and in particular to an auxiliary fertilizer for improving rice's resistance to salt stress and its application. Background Technology

[0002] Rice is one of the world's most important food crops, with more than half of the global population relying on it as their primary food source. Rich in carbohydrates, protein, B vitamins, and minerals, it is a vital energy source for the human body. Soil salinization is one of the most serious abiotic stresses affecting rice production, and a major environmental factor inhibiting normal growth and development. Current research on plant salt stress resistance typically employs conventional breeding or genetic modification methods, screening or controlling genes involved in the production of various metabolites, proteins, and enzymes related to stress responses. However, these methods are particularly time-consuming and make it difficult to simultaneously manipulate multiple genes or pathways to meet variable abiotic or biotic stress conditions. Various supplemental chemical substances have been shown to improve plant processing, thereby enhancing their survival rate and resilience under various environmental stresses. A common method of supplementing these chemical substances is through fertilization during rice cultivation. Therefore, developing fertilizers that can improve rice's salt stress resistance is of great significance. Summary of the Invention

[0003] Therefore, based on the above background, the present invention provides an auxiliary fertilizer for improving rice's resistance to salt stress and its application.

[0004] The technical solution provided by this invention is as follows:

[0005] An auxiliary fertilizer for improving rice's resistance to salt stress, by weight, is made from the following raw materials:

[0006] 15-55 wt% plant-based baking powder, 45-85 wt% activated carbon;

[0007] The plant-based yeast powder consists of 30-60 wt% pomegranate peel yeast powder and 40-70 wt% grape peel yeast powder.

[0008] Furthermore, the preparation of pomegranate peel baking powder includes the following steps:

[0009] ① After sieving the pomegranate peel powder, sterilize it;

[0010] ② After adding pomegranate peel powder to water, inoculate with compound bacterial solution and carry out anaerobic fermentation;

[0011] ③ After anaerobic fermentation, aerobic fermentation is carried out. After fermentation, the mixture is sterilized, filtered to obtain fermentation liquid, concentrated, and freeze-dried to obtain pomegranate peel fermentation powder.

[0012] Furthermore, the compound bacterial solution is prepared by mixing Lactobacillus plantarum bacterial solution and yeast bacterial solution in a volume ratio of 1:(1-4), and the viable cell concentration of the Lactobacillus plantarum bacterial solution and yeast bacterial solution is 10. 7 ~10 9 CFU / ml.

[0013] Furthermore, the preparation of the grape skin fermentation powder includes the following steps:

[0014] i. Sift the grape skin powder and then sterilize it;

[0015] ii. After adding pomegranate peel powder to water, inoculate with Lactobacillus plantarum solution and carry out aerobic fermentation;

[0016] iii. After fermentation, sterilize and filter the fermentation liquid to obtain grape skin fermentation powder.

[0017] Furthermore, the preparation of the activated carbon includes the following steps:

[0018] 1) Crude activated carbon is prepared by mixing straw with phosphoric acid solution, followed by hydrothermal reaction and then anaerobic carbonization.

[0019] 2) After ultrasonic cleaning, the crude activated carbon is dried;

[0020] 3) After immersing the crude activated carbon in nitric acid solution for reaction, wash it and dry it.

[0021] Furthermore, the plant-based baking powder is composed of 60 wt% pomegranate peel baking powder and 40 wt% grape peel baking powder.

[0022] Furthermore, its preparation includes the following steps:

[0023] (1) Take pomegranate peel fermentation powder and grape peel fermentation powder, add them to an aqueous solution containing PVP and ascorbic acid, and disperse them by ultrasonication;

[0024] (2) After adding activated carbon to the dispersion and mixing, the mixture is kept at a constant temperature of less than 60°C and shaken.

[0025] (3) After vacuum drying the liquid in step (2), it is ready.

[0026] Furthermore, it also includes step (4): adding the dried material from step (3) into a sodium alginate solution, ultrasonically dispersing it evenly, and then slowly adding it dropwise into a CaCl2 solution. After solidification and cross-linking, it is washed multiple times with deionized water and then dried.

[0027] Based on the same inventive concept, the present invention also provides the application of the aforementioned auxiliary fertilizer for improving rice salt stress resistance in the process of improving rice salt stress resistance.

[0028] Based on the same inventive concept, a method for improving rice's resistance to salt stress involves applying an auxiliary fertilizer for improving rice's resistance to salt stress along with the base fertilizer, at least before rice seedling transplanting.

[0029] Choose to apply the aforementioned supplementary fertilizer to enhance rice's resistance to salt stress during the tillering and booting stages.

[0030] The beneficial effects achieved by this invention are as follows:

[0031] During the research on fertilizers to improve rice's resistance to salt stress, the inventors accidentally discovered that applying pomegranate peel ferment and grape peel ferment to the soil could improve rice's resistance to salt stress. Compared to using pomegranate peel ferment or grape peel ferment alone, the combined use of pomegranate peel ferment and grape peel ferment had a synergistic effect on improving rice's resistance to salt stress.

[0032] Furthermore, this invention uses modified activated carbon prepared from straw as raw material to load fermentation products, which not only adsorbs Na through the pores of the activated carbon, but also... + This reduces soil electrical conductivity and enables the slow release of fermentation products, extending the reaction time; furthermore, this invention utilizes sodium alginate-Ca... 2+ The cross-linked system encapsulates activated carbon particles carrying fermentation products, forming a hydrogel protective layer. This not only physically protects the loaded fermentation products but also regulates and prolongs the slow-release effect. Furthermore, it exhibits pH-responsive release, with carboxyl groups ionizing (-COO-) in alkaline soils (pH>7). - The molecular chains extend and expand the pores, accelerating the release of active ingredients.

[0033] Furthermore, the activated carbon used in this invention is prepared from straw, and the fermentation product is prepared from pomegranate peel and grape peel, which can realize waste utilization. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The technical solution of this invention:

[0036] An auxiliary fertilizer for improving rice's resistance to salt stress, by weight, is made from the following raw materials:

[0037] 15-55 wt% plant-based baking powder, 45-85 wt% activated carbon;

[0038] The plant-based yeast powder consists of 30-60 wt% pomegranate peel yeast powder and 40-70 wt% grape peel yeast powder.

[0039] The preparation of the pomegranate peel fermentation powder of the present invention includes the following steps:

[0040] ① After sieving the pomegranate peel powder, sterilize it;

[0041] Pomegranate peel powder is passed through an 80-mesh sieve and then microwaved for sterilization.

[0042] The preparation of the pomegranate peel powder is as follows:

[0043] After washing the pomegranate peel and removing impurities, cut it into small strips with scissors, dry it at a low temperature of 40-50℃ until the moisture content is <3%, and then grind it into powder.

[0044] ② Add pomegranate peel powder to water at a ratio of 1g:20ml, adjust the pH to 6.5 with saturated sodium carbonate, inoculate with compound bacterial solution, seal and carry out anaerobic fermentation for 48 hours at a fermentation temperature of 30℃. Stir once at 12h and 24h during fermentation.

[0045] The compound bacterial solution is prepared by mixing Lactobacillus plantarum bacterial solution and yeast bacterial solution in a volume ratio of 1:(1-4), and the viable cell concentration of the Lactobacillus plantarum bacterial solution and yeast bacterial solution is 10. 7 ~10 9 CFU / ml. The inoculation volume of the compound bacterial solution was 1 ml per 5 g of pomegranate peel powder. The *Lactobacillus plantarum* was purchased from the China Industrial Microbial Culture Collection Center with the accession number CICC21794.

[0046] The preparation of the Lactobacillus plantarum bacterial solution is as follows:

[0047] Lactobacillus plantarum was inoculated into MRS liquid medium for expansion culture to obtain a stock solution; then the stock solution was inoculated into fresh MRS liquid medium and cultured until the bacterial count reached 10⁻⁶. 7 ~10 9 CFU / mL is sufficient.

[0048] The yeast strain is *Saccharomyces cerevisiae*, with accession number CGMCC No. 16508, purchased from the China General Microbiological Culture Collection Center.

[0049] The yeast culture solution is prepared as follows:

[0050] Saccharomyces cerevisiae was inoculated into YPD liquid medium for expansion culture to obtain a stock solution; then the stock solution was inoculated into fresh YPD liquid medium and cultured until the bacterial count reached 10⁻⁶. 7 ~10 9 CFU / mL is sufficient.

[0051] ③ After anaerobic fermentation, aerobic fermentation is carried out at 35℃ for 75 hours with a slight air circulation (0.2 vvm). After fermentation, the mixture is sterilized by microwave and filtered to obtain fermentation liquid. The liquid is then concentrated to a solid content of ≥35% and freeze-dried to obtain pomegranate peel fermentation powder.

[0052] The preparation of the grape skin fermentation powder of the present invention includes the following steps:

[0053] i. After passing the grape skin powder through an 80-mesh sieve, microwave sterilize it.

[0054] The preparation of the grape skin powder is as follows:

[0055] After washing the grape skin powder and removing impurities, dry it at a low temperature of 40-50℃ until the moisture content is <3%, and then grind it into powder.

[0056] ii. Add pomegranate peel powder to water at a solid-liquid ratio of 1g:10ml, inoculate with *Lactobacillus plantarum* culture, and then allow slight aeration (0.2 vvm) for aerobic fermentation at 35℃ for 48 hours. The *Lactobacillus plantarum* was selected from *Lactobacillus plantarum* KFY02, preservation number CGMCC No.15638, purchased from the China General Microbiological Culture Collection Center. The preparation of the culture was the same as above. The inoculation amount of the *Lactobacillus plantarum* culture was 2ml per 5g of grape peel powder.

[0057] iii. After fermentation, the fermentation liquid is sterilized by microwave and filtered to obtain a concentrated solid content of ≥35%. After freeze-drying, grape skin fermentation powder can be obtained.

[0058] This invention uses dried pomegranate peel powder or grape peel powder to ferment and prepare fermented powder. Compared with using fresh pomegranate peel or grape peel, dried pomegranate peel is easier to transport and preserve.

[0059] The preparation of the activated carbon of the present invention includes the following steps:

[0060] 1) The dried straw was crushed and passed through a 60-mesh sieve. It was then mixed with a 60% phosphoric acid aqueous solution at a solid-liquid ratio of 1g:5ml and subjected to hydrothermal reaction at 180℃ for 1.5h. The hydrothermal product was then carbonized in an anaerobic environment at 450℃ for 45min to obtain crude activated carbon.

[0061] 2) The crude activated carbon was ultrasonically cleaned with deionized water (50kHz, 20min) until pH=6-7, and then dried at 105℃;

[0062] 3) The crude activated carbon was immersed in a 3 mol / L nitric acid solution at a solid-liquid ratio of 1 g: 5 ml and refluxed at 80 °C for 2 h. After washing with deionized water until neutral, it was dried at 105 °C.

[0063] The preparation of the auxiliary fertilizer of the present invention includes the following steps:

[0064] (1) Take pomegranate peel fermentation powder and grape peel fermentation powder, add them to an aqueous solution containing 0.1% PVP (PVPK15) and 0.1% ascorbic acid at a solid-liquid ratio of 1g:10mL, and ultrasonically disperse until there is no particle agglomeration to obtain a dispersion.

[0065] (2) After adding activated carbon to the dispersion and mixing, shake at 40°C (120 rpm) for 12 hours.

[0066] (3) After vacuum drying the liquid in step (2), it is ready.

[0067] In specific applications, it also includes step (4): adding the dried material from step (3) into a sodium alginate solution, ultrasonically dispersing it evenly, and then slowly adding it dropwise into a CaCl2 solution. After solidification and cross-linking, it is washed multiple times with deionized water and then dried. Specifically, the dried activated carbon loaded with fermentation material is immersed in a 5% sodium alginate aqueous solution, stirred and dispersed evenly, and then slowly added dropwise into a 2% CaCl2 solution. After the addition is complete, stirring and mixing is continued for 10 minutes. The generated microspheres are then washed three times with deionized water and vacuum dried for 24 hours.

[0068] Unless otherwise specified, the materials mentioned in the following embodiments are prepared using the steps detailed in the technical solution of the present invention.

[0069] Example 1: An auxiliary fertilizer for improving rice's resistance to salt stress, which, by weight, is made from the following raw materials:

[0070] 35wt% plant-based baking powder, 65wt% activated carbon;

[0071] The plant-based yeast powder consists of 60 wt% pomegranate peel yeast powder and 40 wt% grape peel yeast powder.

[0072] The preparation of the auxiliary fertilizer of the present invention includes the following steps:

[0073] (1) Take pomegranate peel fermentation powder and grape peel fermentation powder, add them to an aqueous solution containing 0.1% PVP (PVPK15) and 0.1% ascorbic acid at a solid-liquid ratio of 1g:10mL, and ultrasonically disperse until there is no particle agglomeration to obtain a dispersion.

[0074] (2) After adding activated carbon to the dispersion and mixing, shake at 40°C (120 rpm) for 12 hours.

[0075] (3) After vacuum drying the liquid in step (2), it is ready.

[0076] In specific applications, it also includes step (4): adding the dried material from step (3) into a sodium alginate solution, ultrasonically dispersing it evenly, and then slowly adding it dropwise into a CaCl2 solution. After solidification and cross-linking, it is washed multiple times with deionized water and then dried. Specifically, the dried activated carbon loaded with fermentation material is immersed in a 5% sodium alginate aqueous solution, stirred and dispersed evenly, and then slowly added dropwise into a 2% CaCl2 solution. After the addition is complete, stirring and mixing is continued for 10 minutes. The generated microspheres are then washed three times with deionized water and vacuum dried for 24 hours.

[0077] Comparative Example 1: An auxiliary fertilizer for improving rice's resistance to salt stress, which, by weight, is made from the following raw materials:

[0078] 35wt% pomegranate peel baking powder, 65wt% activated carbon;

[0079] The preparation of the auxiliary fertilizer in this comparative example includes the following steps:

[0080] (1) Take pomegranate peel fermentation powder and add it to an aqueous solution containing 0.1% PVP (PVPK15) and 0.1% ascorbic acid at a solid-liquid ratio of 1g:10mL. Disperse the mixture by ultrasonication until there is no particle agglomeration to obtain a dispersion.

[0081] (2) After adding activated carbon to the dispersion and mixing, shake at 40°C (120 rpm) for 12 hours.

[0082] (3) After vacuum drying the liquid in step (2), it is ready.

[0083] Comparative Example 2: An auxiliary fertilizer for improving rice's resistance to salt stress, which, by weight, is made from the following raw materials:

[0084] 35wt% pomegranate peel baking powder, 65wt% activated carbon;

[0085] The preparation of the auxiliary fertilizer in this comparative example includes the following steps:

[0086] (1) Take pomegranate peel fermentation powder and add it to an aqueous solution containing 0.1% PVP (PVPK15) and 0.1% ascorbic acid at a solid-liquid ratio of 1g:10mL. Disperse the powder by ultrasonication until there is no particle agglomeration to obtain a dispersion.

[0087] (2) After adding activated carbon to the dispersion and mixing, shake at 40°C (120 rpm) for 12 hours.

[0088] (3) After vacuum drying the liquid in step (2), it is ready.

[0089] Comparative Example 3: An auxiliary fertilizer for improving rice's resistance to salt stress, which, by weight, is made from the following raw materials:

[0090] By weight, it is made from the following raw materials:

[0091] 21wt% pomegranate peel powder, 14wt% grape peel powder, 65wt% activated carbon;

[0092] The preparation of the auxiliary fertilizer in this comparative example includes the following steps:

[0093] (1) Take pomegranate peel powder and grape peel powder that have passed through a 2000-mesh sieve respectively, add them to an aqueous solution containing 0.1% PVP (PVPK15) and 0.1% ascorbic acid at a solid-liquid ratio of 1g:10mL, and ultrasonically disperse them until there is no particle agglomeration to obtain a dispersion.

[0094] (2) After adding activated carbon to the dispersion and mixing, shake at 40°C (120 rpm) for 12 hours.

[0095] (3) After vacuum drying the liquid in step (2), it is ready.

[0096] Comparative Example 4: An adjuvant fertilizer for improving rice's resistance to salt stress, which, by weight, is made from the following raw materials:

[0097] By weight, it is made from the following raw materials:

[0098] 21wt% pomegranate peel powder, 14wt% grape skin fermentation powder, 65wt% activated carbon;

[0099] The preparation of the auxiliary fertilizer in this comparative example includes the following steps:

[0100] (1) Take pomegranate peel powder and grape skin fermentation powder that have passed through a 2000-mesh sieve, add them to an aqueous solution containing 0.1% PVP (PVPK15) and 0.1% ascorbic acid at a solid-liquid ratio of 1g:10mL, and ultrasonically disperse them until there is no particle agglomeration to obtain a dispersion.

[0101] (2) After adding activated carbon to the dispersion and mixing, shake at 40°C (120 rpm) for 12 hours.

[0102] (3) After vacuum drying the liquid in step (2), it is ready.

[0103] The experiment was conducted using Huajing No. 5 rice.

[0104] The experiment was conducted using a potted plant experiment, which used a custom-made pot that was 2m long, 2m wide, and 10cm deep.

[0105] The planting soil was taken from a nearby laboratory sample (salt content 0.1%, pH 6.5). Saline-alkali soil was then prepared by adding a salt solution to the soil and stirring until a moderately saline soil with a salt content of 0.5% (5g salt / kg dry soil) was achieved. The salt solution was prepared by adding deionized water to NaCl, Na₂SO₄, and NaHCO₃ in a molar ratio of 5:3:2. NaOH solution was then added to adjust the soil pH to 8.0-8.5. The soil was then placed in trays and divided into groups: a control group, an example group, and comparative examples 1 through 4, with 5 replicates per group.

[0106] Rice seeds were hydroponically cultured. When the seedlings reached a height of approximately 15cm and had 3-4 true leaves, seedlings with a height difference not exceeding 10% were selected and transplanted into pre-prepared saline-alkali soil. During transplanting, the row spacing was controlled at 33-35cm, and the plant spacing at 14-35cm. Five days before transplanting, 12 kg of organic fertilizer (purchased from Xiamen Huaxiangu Agricultural Co., Ltd.) was applied to the soil in each pot of each group, and the soil was turned over.

[0107] In the control group, 4 kg of activated carbon (prepared as above) was applied to each pot of soil along with organic fertilizer.

[0108] When applying organic fertilizer, each pot of the Example Group was accompanied by 4 kg of supplementary fertilizer from Example 1.

[0109] When organic fertilizer was applied to the soil in each pot of Comparative Example 1, 4 kg of supplementary fertilizer from Comparative Example 1 was also applied.

[0110] When organic fertilizer was applied to the soil in each pot of Comparative Example 2, 4 kg of supplementary fertilizer from Comparative Example 2 was also applied.

[0111] When applying organic fertilizer, 4 kg of supplementary fertilizer from Comparative Example 3 was also applied to the soil in each pot of Comparative Example 3.

[0112] When applying organic fertilizer, 4 kg of supplementary fertilizer from Comparative Example 4 was also applied to the soil in each pot of Comparative Example 4.

[0113] Seven days after transplanting, apply 0.5 kg of nitrogen fertilizer (urea) to the soil in each pot.

[0114] Fifteen days after transplanting, the survival rate of seedlings in each pot was counted, and the average survival rate of each group of pots was taken. The results are shown in Table 1.

[0115] After transplanting, water each pot to maintain a water layer of 0.5-1cm.

[0116] Table 1: Survival Rate (Average)

[0117] Grouping control group Example group Comparative Example 1 Comparative Example 2 Comparative Example 3 Groups Comparative Example 4 Groups Survival rate % 84.37 98.21 93.55 90.86 87.39 91.21

[0118] During the harvest period, the yield of each rice plant in each pot was counted, and the average yield of each pot in each group was taken. The results are shown in Table 2.

[0119] Table 2: Average Yield per Plant

[0120]

[0121] The technology of using organic waste such as pomegranate peel or grape skin as fertilizer is existing. However, during the research on improving the salt stress resistance of rice, the inventor accidentally discovered that pomegranate peel fermentation powder or grape skin fermentation powder is beneficial to improving the stress resistance of rice. Further research showed that, as shown in Tables 1 and 2, before transplanting seedlings, for the prepared saline-alkali soil, applying the auxiliary fertilizer of Example 1 on the basis of applying organic base fertilizer significantly improved the survival rate and yield per plant after transplanting. Moreover, compared with the auxiliary fertilizer made from pomegranate peel fermentation powder or grape skin fermentation powder alone, the auxiliary fertilizer prepared from pomegranate peel fermentation powder and grape skin fermentation powder together had the best effect on improving the survival rate and yield per plant after transplanting.

[0122] The present invention and its embodiments have been described above. This description is not restrictive, and the embodiments shown are only one of the embodiments of the present invention. The actual structure is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. An auxiliary fertilizer for improving rice's resistance to salt stress, characterized in that, By weight, it is made from the following raw materials: 15-55 wt% plant-based baking powder, 45-85 wt% activated carbon; The plant-based yeast powder consists of 30-60 wt% pomegranate peel yeast powder and 40-70 wt% grape peel yeast powder.

2. The auxiliary fertilizer for improving rice's resistance to salt stress according to claim 1, characterized in that, The preparation of pomegranate peel baking powder includes the following steps: ① After sieving the pomegranate peel powder, sterilize it; ② After adding pomegranate peel powder to water, inoculate with compound bacterial solution and carry out anaerobic fermentation; ③ After anaerobic fermentation, aerobic fermentation is carried out. After fermentation, the mixture is sterilized, filtered to obtain fermentation liquid, concentrated, and freeze-dried to obtain pomegranate peel fermentation powder.

3. The auxiliary fertilizer for improving rice's salt stress resistance according to claim 2, characterized in that, The compound bacterial solution is prepared by mixing Lactobacillus plantarum bacterial solution and yeast bacterial solution in a volume ratio of 1:(1-4), and the viable cell concentration of the Lactobacillus plantarum bacterial solution and yeast bacterial solution is 10. 7 ~10 9 CFU / ml.

4. The auxiliary fertilizer for improving rice's resistance to salt stress according to claim 1, characterized in that, The preparation of the grape skin fermentation powder includes the following steps: i. Sift the grape skin powder and then sterilize it; ii. After adding pomegranate peel powder to water, inoculate with Lactobacillus plantarum solution and carry out aerobic fermentation; iii. After fermentation, sterilize and filter the fermentation liquid to obtain grape skin fermentation powder.

5. The auxiliary fertilizer for improving rice's resistance to salt stress according to claim 1, characterized in that, The preparation of the activated carbon includes the following steps: 1) Crude activated carbon is prepared by mixing straw with phosphoric acid solution, followed by hydrothermal reaction and then anaerobic carbonization. 2) After ultrasonic cleaning, the crude activated carbon is dried; 3) After immersing the crude activated carbon in nitric acid solution for reaction, wash it and dry it.

6. The auxiliary fertilizer for improving rice's salt stress resistance according to claim 1, characterized in that, The plant-based yeast powder consists of 60 wt% pomegranate peel yeast powder and 40 wt% grape peel yeast powder.

7. An auxiliary fertilizer for improving rice's resistance to salt stress according to any one of claims 1 to 6, characterized in that, Its preparation includes the following steps: (1) Take pomegranate peel fermentation powder and grape peel fermentation powder, add them to an aqueous solution containing PVP and ascorbic acid, and disperse them by ultrasonication to obtain a dispersion. (2) Add activated carbon to the dispersion and mix, then oscillate at a constant temperature below 60°C; (3) After vacuum drying the liquid in step (2), it is ready.

8. The auxiliary fertilizer for improving rice's resistance to salt stress according to claim 7, characterized in that, It also includes step (4): the material dried in step (3) is added to sodium alginate solution, ultrasonically dispersed evenly, and then slowly added to CaCl2 solution. After solidification and cross-linking, it is washed multiple times with deionized water and then dried.

9. The application of the auxiliary fertilizer for improving rice salt stress resistance as described in any one of claims 1 to 8 in improving rice salt stress resistance.

10. A method for improving the salt stress resistance of rice, characterized in that, At least before rice seedling transplanting, apply an auxiliary fertilizer as described in any one of claims 1 to 8 to improve rice's resistance to salt stress; The auxiliary fertilizer according to any one of claims 1 to 8, which enhances the salt stress resistance of rice, can be applied as a top dressing during the tillering or booting stage.

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